A B C D E F G H I J K L M N O P Q R S T U V W XYZ

MA

See mental age.

MABI

See Mother's Assessment of the Behavior of her Infant.

MacArthur Communicative Development Inventory: Infants

This language assessment tool includes a vocabulary checklist and a parental checklist that assesses first signs of understanding, comprehension of early phrases, and starting to talk. Play, pretending, early gestures, and imitating are also probed.

MacArthur Communicative Development Inventory: Toddlers

A parental checklist to assess vocabulary, sentences, and grammar, and different ways of expressing two-word meanings.

Macewen sign

A cracked-pot sound elicited on percussion (tapping) of the skull; present with increased intracranial pressure.

macrocephaly

Abnormally large head; macrocephaly refers to a head circumference (occipitofrontal circumference) more than 2 standard deviations above the mean for age. It can be familial, associated with a number of dysmorphic (atypical appearance) syndromes, such as Sotos syndrome, fragile X syndrome, and several storage diseases, and is an important marker for hydrocephalus (excess fluid in the brain). In the same way that microcephaly (abnormally small head) is not automatically associated with mental retardation, macrocephaly is not associated with intellectual giftedness. More significant degrees of macrocephaly are likely to indicate the presence of neurodevelopmental disorders.

macrocornea

Enlarged cornea, which can occur in glaucoma (increased pressure in the eye, often hereditary) and mucopolysaccharidoses.

macroorchidism

Large testicles; this finding can occur in a number of generic syndromes (e.g., fragile X svndrome) after puberty.

magnetic resonance imaging (MRI)

A scan that uses nuclear magnetic resonances (NMR) to visualize parts of thc body such as the brain. MR scans do not use radiation, but provide good information about the structural formation of the brain. They are useful for identifying minor brain malformations as well as major ones. MR scans are used to evaluate anomalies of cortical architecture (the rind [outer crust] of the brain) (e.g.. lissencephaly [smooth, rather than convoluted, brain surface]) and to evaluate people with refractory seizure disorders for an identifiable focus (location where the seizure activity begins). MRI scans provide information about white and gray matter differences. A not-infrequent finding in children with developmental delay is an immature myelination pattern (a picture of delayed myelination such as is typical for a younger child). The significance of this pattern is currently under investigation.

MAI

See Movement Assessment of Infants.

mainstreaming

An educational term indicating the placement of children with disabilities in general classrooms. Advocates believe that mainstreaming removes stigma, enhances the social status of exceptional children, facilitates modeling of appropriate behavior, provides a more stimulating and competitive environment, and offers more flexible, cost-efficient service. However, simply placing a child in a general education class does not ensure academic achievement or social acceptance. Appropriate modification of classroom expectations based upon an analysis of the student's strengths and weaknesses is essential for mainstreaming to be effective and to provide successful experiences for the student. See also integration.

maladaptive behavior

Recurrent, often habitual, behaviors and behavior patterns that prevent an individual, family, or organization from attaining a desired goal or meeting the demands of the environment. Examples of such behaviors include temper tantrums, swearing, and theft. It is not necessarily the behaviors themselves, but the intensity and frequency of the behaviors that render them "maladaptive." Children are placed in classrooms for students with emotional and behavior disorders when school performance problems result in or are exacerbated by persistent or unusual maladaptive behavior. There are four types of maladaptive behavior: verbal and physical aggression, causing interpersonal relationship difficulty; anxious and withdrawn behaviors that hamper interaction and achievement; immaturity or failure to consistently demonstrate age-appropriate behaviors; and socialized aggressive behavior, typically manifested as vandalism or group intimidation and violence. Maladaptive behavior is typically a symptom rather than the problem per se; the origin and etiology (cause) of the feelings and thought processes that result in the behavior should be investigated. Maladaptive behavior can be assessed through behavioral checklists, interviews with teachers and caregivers, and via direct observation of the child's behavior in different settings. Interventions to decrease maladaptive behavior and alleviate its cause include behavior modification, psychotherapy, and medication.

malaise

Discomfort; a nonspecific uneasiness; feeling sick or out-of-sorts; malaise is a frequent accompaniment of, and prodrome for, many illnesses.

male-limited

Pattern of inheritance that seems to be transmitted only from fathers to their male offspring.

malformation

A morphological defect (abnormality of structure or shape) of an organ, part of an organ, or larger body region, resulting from an intrinsically abnormal developmental process. Intrinsic implies that the anlage (primordium) was abnormal from the beginning; if the anlage was normal, the morphological defect is referred to as a disruption. If the structural abnormality is at the tissue level rather than the organ level, it is referred to as a dysplasia. A cumulative number of mild superficial morphological defects (minor atypical features) may be of developmental significance.

malignancy

Cancer.

malingering

“enjoying ill health." Malingering has two forms: 1) refusal to engage in pre-illness activities on the basis of "still feeling sick" long after a normal recuperative period and with no obvious signs of continued illness, and 2) faking illness. Whether conscious or unconscious, malingering serves to avoid some undesired obligation or difficult situation through the perceived "legitimate" route of illness when no other "legitimate" route seems feasible. Children with developmental disabilities often malinger when school demands become too stressful.

malleolus

The bony prominence on both sides of the ankle.

mandible

Jaw; jawbone.

mandibulofacial dysostosis

See Treacher Collins syndrome.

mania

A state of impulsive, excessive, excited, and uncontrolled behavior coupled with accelerated thought and verbal activity, a lessened physiological need for sleep or food, and an excessive, unrealistic feeling of elation. This state is seen in several mental disorders, but is most frequently noted as one phase in bipolar affective disorder. Three additional subcategones of mania are noted: kleptomania (shoplifting), pyromania (firesetting), and nymphomania (sexual intercourse). In these subcategories, the excesses of behavior and activity are limited to a single-area of behavioral expression.

manic-depressive illness

See bipolar illness.

manometry

Pressure measurement; a technique that quantifies the force of contraction of the muscular wall of the gut by the use of pressure transducers. Manometry is used in the evaluation of swallowing disorders.

manual English

Sign English; a sign system that employs a rapid succession of specific symbols and manual movements, including fingerspelling. Unlike American Sign Language (ASL), manual English employs English syntax (grammar) as its foundation.

MAP

See Miller Assessment for Preschoolers; See also Muma Assessment Program.

maple syrup urine disease (MSUD)

An inborn error of metabolism. A familial cerebral degenerative disease in which the breakdown of branched chain ammo acids causes the urine to smell sweet, like maple syrup. Babies appear normal at birth, hut rapid cerebral deterioration is common. Untreated, this leads to opisthotonos (an arching of the back), spasticity (increased muscle tone), intermittent hypertonia (increased muscle tone), brain damage, and mental retardation. With optimal dietary treatment beginning in the first 2 weeks of life and strict adherence to the diet, IQs are potentially normal. There is an intermediate form with some residual enzyme activity in skin cells. It presents between 6 and 9 months of age with seizures and intermittent ataxia (unsteady gait) and drowsiness. This form nearly always results in mild to moderate mental retardation. Inheritance is autosomal recessive.

marasmus

Severe protein-calorie deprivation; infantile atrophy (wasting), athrepsia; malnutrition with a marked weight for height deficit. Marasmus is marked by failure to thrive, progressing to an infant's falling below 75% of expected weight for age; below 65% of expected weight is considered life-threatening. Loss of subcutaneous (inner) fat gives the facies a lined and aged appearance. Skin folds hang loose, the "sucking pads" protrude in the cheeks, and irritability and anxiety may be replaced by apathy. Hypoproteinemia (loss of protein) may lead to peripheral (noncentral) swelling ("starvation edema"). The developmental impact of this malnutrition state tends to be reversible. Also referred to as protein energy malnutrition (PEM).

March of Dimes Foundation

An organization founded by President Franklin D. Roosevelt in 1938 as the National Foundation for Infantile Paralysis to combat the nation's polio epidemic. When, in 1938, entertainer Eddie Cantor suggested people send dimes directly to the White House, the organization became known as the March of Dimes Birth Defects Foundation. This name was officially adopted in 1979. With Dr. Jonas Salk's development of a polio vaccine, the foundation refocused its efforts toward the prevention of birth defects and the overall improvement of pregnancy outcomes. The foundation provides research funding, professional education, and volunteer services.

Marcus Gunn jaw winking phenomenon

A congenital condition in which unilateral eyelid ptosis (drooping) accompanies ipsilateral (on the same side) jaw movement; when the jaw moves to the opposite side, the involved lid elevates.

Marfan habitus (Marfanoid)

A term to describe someone with the physical appearance of Marfan syndrome but who does not necessarily have that syndrome. The habitus (appearance) includes tall stature, long arms and legs, arachnodactyly or spiderlike digits (long, thin fingers and toes), and decreased subcutaneous (inner) fat. This may represent a familial body pattern or another syndrome, such as homocystinuria.

Marfan syndrome

A genetic syndrome that affects connective tissue to produce a Marfan habitus, hyperextensible joints, subluxation (dislocation) of the lens of the eyes, and serious cardiovascular abnormalities. The tall stature results from extremities (arms or legs) that are disproportionately long compared to the trunk; the head is dolichocephalic (long) with prominent supraorbital ridges (brows) and a long, thin face. Intelligence is normal, but learning disabilities and attention-deficit/hyperactivity disorder have been reported in more than a third of patients. Incidence is 3 in 200,000. Inheritance is autosomal dominant, with a recurrence risk of 50%. Named after the French pediatrician Bernard Marfan (1858-1942).

Marfanoid

See Marfan habitus.

Marinesco-Sjögren syndrome

A genetic syndrome with cataracts, mental retardation, cerebellar ataxia (unsteady gait), and short stature. Inheritance is autosomal recessive.

Maroteaux-Lamy syndrome

Mucopolysaccharidosis (MPS) VI; a genetic syndrome of growth deficiency, coarse facies, stiff joints, cloudy corneas, hepatosplenomegaly (enlargement of the liver and spleen), and normal intelligence.

Marshall syndrome

A genetic syndrome with cataracts, sensorineural (involving the inner ear or the auditory nerve) deafness, and a fades with a short depressed nose; mental retardation is an occasional finding. Inheritance is autosomal dominant.

Marshall-Smith syndrome

A syndrome with accelerated height, failure to thrive in weight, mild to moderate mental retardation, shallow orbits and prominent eyes, and broad fingers that taper at the ends.

Martin-Bell syndrome

See fragile X syndrome.

mass reflex

The stimulus of a tap on the suprapubic region (the bony prominence just above the bladder) that produces the response of total body startle or flexion.

Master of Public Health (MPH)

A graduate degree in epidemiology of disease and the various factors that influence its prevention, spread, and treatment at a population level.

Master of Social Work (M.S.W.)

A degree granted to the student who completes a 2-year graduate program in social work; the M.S.W. curriculum contains both academic and clinical training.

mastoid

Postauricular (behind the ear) part of the temporal bone that can become infected concomitant with an otitis media (middle-ear infection). Modern antibiotic therapy of otitis media and mastoiditis has markedly reduced the need for surgical intervention (mastoidectomy).

MAT

See Matrix Analogies Test.

MAT-SF

See Matrix Analogies Test-Short Form.

Matching Familiar Figures Test (MFF, MFFT)

A measure of impulsivity and reflectivity for children 3-6 years of age. Each item consists of an index picture and four to eight similar pictures, only one of which exactly matches the target figure. Time to respond and number of errors are used to place the child in one of four subgroups: impulsives, reflectives, fast accurates, and slow inaccurates. Visual discrimination problems may interfere with this interpretive scheme.

maternal deprivation

Inadequate or absent parenting or nurturance with immediate and potentially long-term consequences on a child's growth and development. Short-term effects can include failure to thrive and developmental and language disorders; sociopathy may be a long-term outcome. This term is actually so poorly defined that, along with its pejorative connotation, it is probably better replaced by a more accurate delineation of underlying mechanisms, such as abuse, neglect, feeding disorder, or disorder of parenting.

maternal smoking during pregnancy

A risk factor that contributes to fetal distress, low birth weight, and prematurity; it does not have any direct developmental impact.

mathematics disorder

A disorder in which mathematical ability, as measured by individually administered standardized tests, is substantially below that expected, given the person's chronological age, measured intelligence, and age-appropriate education. The disorder significantly interferes with academic achievement and with activities of daily living that require mathematical ability.

Matrix Analogies Test-Short Form (MAT-SF) and Expanded Form (MAT-EF)

An assessment of nonverbal reasoning for students ages 5-17 years that requires the student to correctly select from six options a missing element in an analogical matrix. The MAT-EF is for individual administration; the MAT-SF can be used to screen groups of children. The test items are similar to those used in the Raven Progressive Matrices. Administration time is approximately one half hour.

Matson Evaluation of Social Skills with Youngsters (MESSY)

A rating scale to measure social skills in children 4-8 years of age; it can be used with children who have mental retardation, visual impairments, or hearing impairments.

maturation

Biological change as a linear function of increasing age. In Gesell's maturational theory, advances in the level of development and behavior are primarily neuroanatomically preprogrammed. Such a theory is not compatible with a large amount of individual variation in the achievement of specific milestones.

maturational theory of development

A theory of human development that attributes achievement of different developmental milestones primarily to the genetically preprogrammed maturation of the central nervous system through myelination of the nerve pathways (insulation through the laying down of a fatty protective layer). Environmental factors play a lesser role, providing these factors remain within certain broadly defined limits (relating to, for example, feeding, clothing, physical contact, and interpersonal interaction). The theory is mostly concerned with development in infancy and early childhood and allows for an increasingly greater impact of environmental and emotional factors in older children.

maxillonasal dysplasia

Binder syndrome; a distinctive facies with flattened nose, hypotelorism (widely spaced eyes), mid-face hypoplasia (flattening), relative prognathism (a prominent jaw) with reverse overbite, and normal intelligence without other associated anomalies (malformation, deformation, disruption, or dysplasia). Plastic surgery is indicated.

mazes

A supplementary Wechsler scale subtest performance test consisting of one sample problem and nine maze problems. The child is required to draw a line from the center of the maze to the outside without reaching a dead end or crossing any of the lines representing walls. Each maze is presented separately, and all mazes are timed. The subtest measures visual-motor skills, planning, anticipation, and directionality; visual memory, attention, and focusing skills are also involved. Success on the subtest requires visual-motor coordination executed quickly and accurately. Mazes is an optional subtest that is not used in the computation of the IQ when the standard performance subtests are administered. Although not routinely required, mazes can provide much information with children who have language impairments or who are from culturally different backgrounds. Mazes is usually a difficult test for children with visual-spatial problems. The test is discontinued after two consecutive failures.

MBD

See minimal brain damage/dysfunction; see also attention-deficit/hyperactivity disorder (ADHD).

MBP

See myelin basic protein.

MBTI

See Myers-Briggs Type Indicator.

McCarthy reflex

An infant reflex in which the stimulus of a tap on the supra-orbital (just above the eve or brow) area produces an ipsilateral (on the same side) blinking response.

McCarthy Scales of Children's Abilities

A test of abilities for children ages 2-6 to 8-6. Abilities are assessed in six areas: verbal, quantitative, perceptual performance, general cognitive, memory, and motor development.

McCarthy Screening Test (MST)

An assessment of abilities critical to early school success for children 4 to 6-6 years of age; the test items are derived from six scales of the McCarthy Scales of Children's Abilities. The MST classifies children as "at risk" or "not at risk" for later need of special education services. Administration time is 20 minutes.

McDaniel-Piers Young Children's Self-Concept Scale

A 40-item measure for 6-to 9-year-old children that is a downward extension of the Piers-Harris Children's Self-Concept Scale. Items deemed appropriate for younger children were selected from the original instrument, and their wording was simplified. The tester reads the item and the child responds yes or no on an answer sheet. The scale provides a total score and three subscores: feeling self, school self, and behaving self.

mean

The arithmetic average of all the scores in a set of scores. To obtain the mean, the sum of all the scores in the set is divided by the total number of scores in the set. Example: 8+2-6+4 = 20/4 = 5. In the set of scores, 20 (the sum of the scores) divided by 4 (the number of scores) results in a mean of 5. This most commonly used measure is responsive to the exact position of each score in a distribution, but is sensitive to a few relatively extreme scores. See also measures of central tendency.

mean length of utterance (MLU)

The average number of morphemes in a sentence; a simple measure of early language development.

meaningful

Of consequence. In reference to memory, contextual, connected terms are easier to retain than less-meaningful, disjointed, or nonsense terms. Meaningfulness is not synonymous with a word's definition or meaning.

means test

Financial criteria that determine eligibility for certain government-funded health or social services. An applicant's current income, assets, debts, dependents, and earning status are weighed against preexisting criteria for eligibility. Failure to meet the criteria implies that the applicant already has sufficient "means" to meet his or her obligations and does not need government subsidy. Programs that apply means tests include Supplemental Security Income (SSI), Medicaid, Food Stamps, Special Health Care Needs, and Aid to Families with Dependent Children (AFDC).

measles

See rubeola.

measures of central tendency

Descriptive statistics that measure the central value in a distribution of scores. The three most commonly used measures are 1) mean (appropriate for interval and ratio scale data); 2) median (appropriate for ordinal, interval, or ratio scale data); and 3) mode (the only measure of central tendency appropriate for nominal scale data).

Mebaral

See methylphenobarbital.

Mecham Verbal Language Developmental Scale (VLDS)

A test of general communication ability for children from birth to 15 years of age; an extension of the communication subscale of the Vineland Social Maturity Scale, the VLDS uses an interview method to yield a language age equivalent.

mechanical ventilation

The use of a respirator (breathing machine) to assist an individual with respiratory distress.

meconium

The newborn baby's first stool.

medial

Toward the mid-line, anatomically.

median

The median is the midpoint, or the point that divides a range of scores in half. When the number of scores is odd, the middle score is the median (example: 10, 8, 6, 4, 1; median = 6). When the number of scores is even, the median is the average of the middle pair of scores (example: 10, 9, 7, 4, 2, 1; median = 7 + 4/2 = 5.5). Because the median divides a set of scores into equal groups, 50% of the scores are below the median; thus, the median is always the 50th percentile. See also measures of central tendency.

median cleft palate face syndrome

Frontonasal dysplasia; a nongenetic, congenital defect in mid-facial development producing marked hypertelorism (widely spaced eyes), cleft lip/nose/palate, and a widow's peak anterior (front) hairline. One fifth of cases exhibit mental retardation.

mediastinum

A region of the chest that includes all the contents of the thorax except the lungs.

Medicaid

A federally supplemented state-administered health insurance program for people with financial needs. Medicaid employs a financial means test to determine eligibility. Administration of the program is usually handled through local income-maintenance (welfare) offices.

Medicaid spenddown

Eligibility for Medicaid as a needy individual on the basis of having expended sufficient assets/income on medical expenses.

medical home

Primary medical care that is comprehensive, continuous, and accessible.

Medicare

A federally funded comprehensive health insurance program enacted as a supplemental entitlement under the Social Security Act of 1935. Medicare has two parts: Hospital Insurance (HI) and Supplemental Medical Insurance (SMI). Eligible populations include 1) all persons ages 65 and over who are eligible for the cash benefits of Old Age and Survivors Insurance, commonly called Social Security; 2) all beneficiaries with disabilities, including workers, widows, and widowers 50 years of age and older, and insured workers' adult children 18 years of age and older whose disability originated before the age of 22; and 3) insured workers' family members who need dialysis or a kidney transplant.

megavitamin therapy

The use of extremely high doses of vitamins to treat schizophrenia, autism, and a range of developmental disorders. The expansion of the therapeutic regimen to include minerals and trace elements (orthomolecular therapy) does not alter its essential lack of efficacy. Vitamin deficiency can cause developmental symptoms, and some children's metabolism does require higher vitamin intake; however, outside the fairly narrow range of vitamin deficiency syndromes, (mega)vitamin treatment of developmental disorders is an unacceptable alternative intervention.

Mellaril

See thioridazine.

Melnick-Fraser syndrome

Branchio-oto-renal (BOR) syndrome; a genetic syndrome with hearing loss, kidney abnormalities, and branchial arch anomalies (malformation, deformation, disruption, or dysplasia) (e.g., preauricular pits, neck fistulas). Prevalence is 1 in 40,000. Inheritance is autosomal dominant with variable expression.

memory

The store of things learned and retained from an organism's activity or experience. Most theoretical models of memory include a sensory register, short-term memory, working memory, and long-term memory. Long-term memory has been conceptually divided into semantic (meaning systems) memory (memory for words), procedural memory (memory for the steps comprising an activity), and episodic memory (memory for one's past history). Other conceptualizations of memory include auditory memory, visual memory, motor memory, and recognition memory. See also declarative knowledge, procedural knowledge.

menarche

Onset of menstruation in adolescent girls; the average age is 13 years, approximately 3 years after the adolescent growth spurt. It tends to occur earlier in physically larger girls and later in physically smaller girls. There is a strong genetic influence with familial patterns of early or late menarche. Very early (before 8 years of age) menarche may suggest precocious puberty and the need for an endocrinological evaluation. Late menarche is not uncommon in the presence of severe mental retardation, especially when accompanied by short stature; it is also sometimes associated with sex chromosome anomalies (malformation, deformation, disruption, or dysplasia).

meninges

The layers of tissue covering the brain and spinal cord. There are three layers labeled from outside to inside: the dura mater, the arachnoid, and the pia mater. The arachnoid is thin and transparent with a space between it and the pia mater, where cerebrospinal fluid (CSF) is found. The pia mater is the closest to the brain and spinal cord. Inflammation or infection of these layers is called meningitis.

meningitis

An infection of the meninges (covering of the brain and spinal cord). The infection is commonly bacterial hut may be viral and termed aseptic meningitis. Other causes (e.g., fungal, protozoan) are less common in normal hosts. Bacterial meningitis can be treated with antibiotics; however, damage to the brain may occur from the inflammatory response to the infection. Complications include brain abscess, infarction (stroke), hydrocephalus (excess fluid in the brain), subdural effusions (fluid under one of the meningeal layers), and seizures. Diagnosis is made by examining the cerebrospinal fluid (CSF) obtained by lumbar puncture for white blood cells, bacteria, and chemical abnormalities. Antibiotic treatment is aimed at the causative organism. Long-term sequelae include mental retardation, learning disabilities, attention-deficit/hyperactivity disorder (ADHD), cerebral palsy, seizure disorders, and sensorineural (involving the inner ear or the auditory nerve) hearing loss. Outcome depends on the organism, age of the child (younger children have poorer prognoses), and duration of symptoms prior to treatment.

meningomyelocele

See myelomeningocele.

Menkes' kinky hair syndrome

A genetic syndrome with seizures and a severe neurodegencrative course ending in death; growth deficiency and mental deficiency; and sparse, lightly colored hair that demonstrates structural abnormalities under the microscope. Abnormal copper metabolism has been documented. Inheritance is X-linked recessive.

mental age (MA)

Age-equivalent score; a measure of mental development as determined by intelligence and achievement tests, expressed as the age for which that level of performance is the average. Intelligence test tasks are arranged in a progressive order of difficulty so that age levels can be assigned to items. Mental age is determined by the highest age level of the tasks successfully passed. For example, a child with a mental age score of 8 is considered to have the general mental ability of an average 8-year-old, regardless of chronological age. Mental age serves as the numerator in the calculation of a ratio IQ. Although mental age provides a general description of an individual's level of performance, MA units vary throughout the developmental period, and by the early teens the concept of mental age has little meaning. Furthermore, two children with the same mental age may display different skills, strengths, and rates of progress in school, suggesting that additional information is necessary to best describe a child's cognitive abilities.

mental retardation (MR)

Substantial limitations in present cognitive functioning. Mental retardation is characterized by significantly subaverage intellectual functioning, existing concurrently with related limitations in two or more of the following applicable adaptive skill areas: communication, self-care, home living, social skills, community use, self-direction, health and safety, functional academics, leisure, and work. Mental retardation manifests before age 18. In the past, mental retardation was qualified by severity of cognitive impairment as mild (IQ between 69 and 50-55), moderate (IQ between 50-55 and 35-40), severe (IQ between 35-40 and 20-25), and profound (IQ below 20-25). In 1992, this categorization was replaced by a more qualitative description of the level of supports necessary for a given person to function. Although mental retardation denotes a level of behavioral performance without reference to etiology (cause), in light of current genetic, biochemical, and neuroanatomical knowledge, a functional description of mental retardation mandates a meticulous evaluation for such an etiology.

mental retardation attendant (MRA)

Outdated terminology for a one-to-one caregiver for an individual with mental retardation or developmental disabilities. Behavioral coach is the current preferred terminology for such a person.

Mental Retardation Facilities and Community Mental Health Centers Construction Act of 1963 (PL 88-164)

The federal legislation that created university affiliated facilities (UAFs), now known as university affiliated programs (UAPs), as centers for clinical training and research in mental retardation.

mental status

Examination of cognition, memory, and orientation (awareness of one's environment with regard to place, time, and people). Disruption may be relatively permanent (as in mental retardation) or transient (as in diabetic ketoacidosis).

mentum

Central point of the chin.

Merrill Language Screening Test (MLST)

A brief screening test of receptive and expressive language and articulation for kindergarten and first-grade students. Using a storytelling technique, five areas are assessed: production of complete sentences, utterance length, verb tense agreement, elaboration, and communication competence.

Merrill-Palmer Scale of Mental Tests

A battery of infant tests for children 18-71 months of age; the items are predominantly nonverbal and heavily based on perceptual-motor skills. The instrument is rarely used, but isolated subtests are employed in more individualized assessments. The newer Extended Merrill-Palmer Scale exhibits improved standardization but is a more verbal test.

mesomelic

Referring to the central segment of a limb (forearm or leg).

mesomorph

Athletic body type.

MESSY

See Matson Evaluation of Social Skills with Youngsters.

meta-analysis

Quantitative research synthesis; statistical methods for integrating data across studies. It is an inductive method that proceeds from particular observations (studies) to general inclusive statements and yields a statistic that represents the magnitude of experimental effects reported in these studies.

metabolite

A chemical by-product or waste produced in the body. The presence of a metabolite of abnormal quantity or quality in the blood or urine suggests the presence of a metabolic disorder. Untreated metabolic disorders often have significant developmental consequences. Metabolic screening describes a panel of laboratory tests to search for the presence of atypical metabolites and is a frequent item in the assessment of a child with serious mental retardation of unknown etiology (cause).

metachromatic leukodystrophy (MLD)

A progressive and ultimately fatal disorder of the central nervous system due to an enzyme (arylsulfatase A) deficiency. Hyporeflexia and profound mental retardation are characteristic in MLD. Incidence is 1 in 40,000. Inheritance is autosomal recessive, with a recurrence risk of 25%.

metacognition

Knowledge about one's thought processes and how to regulate strategies for thought or learning. Knowledge about cognition develops during adolescence. Regulation of learning is generally acquired early (in preschool) and includes planning, monitoring one's activities, and checking outcomes. Some students with learning disabilities and many students with attention-deficit/hyperactivity disorder (ADHD) have difficulty with one or more aspects of metacognition.

metatarsus adductus

An orthopedic deformity of infants in which the feet appear to turn inward at mid-foot.

methyl mercury

A chemical fungicide that can affect the developing central nervous system; prenatal exposure has been linked to cerebral palsy, mental retardation, and blindness.

methylmalonic aciduria

A metabolic disorder that, if untreated, leads to episodic vomiting, lethargy, and coma as well as mental retardation. Treatment includes a protein-restricted diet and vitamin B₁₂. Incidence is 1 in 100,000. Inheritance is autosomal recessive, with a recurrence risk of 25%.

methylphenidate (MPH)

Trade name Ritalin; the most commonly used stimulant medication for treatment of attention-deficit/hyperactivity disorder (ADHD) and hyperactivity in children and adults. It is manufactured in multiples of 5 milligrams. The duration of action is 4 hours, although a long-acting (SR, sustained release) formulation is available. Because of its addictive potential, the distribution of Ritalin is regulated as a controlled substance; however, addiction is not a problem in subjects with attentional problems. Side effects include headache, stomachache, anorexia (loss of appetite), poor growth, and sleep problems; these can usually be managed by titrating the dosage.

methylphenobarbital

Trade name Mebaral; a derivative of phenobarbital used in the past instead of phenobarbital because it was thought to have fewer side effects. It has no advantage over phenobarbital in controlling seizures.

metoclopramide

Trade name Reglan; a dopamine antagonist used in the treatment of gastroesophagcal reflux.

Metropolitan Readiness Tests-Fifth Edition (MRT)

A skill-based assessment of skills in reading, mathematics, and language development that contribute to early learning success for children in prekindergarten through first grade.

MFF

See Matching Familiar Figures Test.

MFFT

See Matching Familiar Figures Test.

MFP

See Multidisciplinary Feeding Profile.

microcephaly

Abnormally small head; significantly small head sizes are variously considered to be 2.0, 2.5, or 3.0 standard deviations below the mean for age. Small head size automatically implies small brain size, but this in turn does not necessarily indicate mental retardation. Nevertheless, decreasing head size does correlate with an increasing incidence of mental retardation, whereas milder decreases in head size (on the order of 1.5 standard deviations below the mean) have been associated with learning disabilities and language disorders. Proportional microcephaly—a small head size with short stature—is less strongly correlated with mental retardation. Microcephaly can result from intrauterine infection and radiation, as well as numerous genetic syndromes. Familial microcephaly can be a marker for familial mental retardation.

micrognathia

A small jaw; can be a normal variant, a familial trait, a minor malformation, or part of an identifiable syndrome (e.g., Pierre Robin syndrome).

micronutrient

A dietary element necessary only in small quantities.

micropolygyria

A migrational anomaly in cerebral architecture where the gyri (hills) are too small and too numerous. There are also abnormalities in the number of cortical layers and their orientation (columnar rather than laminar, as in the normal brain). Clinically, these people have severe mental retardation and hypotonia (decreased muscle tone) or spasticity (increased muscle tone) depending upon the areas of brain affected. This can be present in syndromes such as Zeilweger syndrome (cerebrohepatorenal syndrome, an autosomal recessive disorder); however, most eases are sporadic. Magnetic resonance imaging (MRI) can visualize this pattern of gyral architecture.

microswitch

An adaptive technology category of electronic devices and mechanisms that simplifies the operation of electrical equipment from toys to computers. These devices reduce the more elaborate operation of many common items to the manipulation of a single control, increasing the accessibility and utility of the items for individuals with severe physical disabilities.

micturition

Urination.

mid-line

Sagittal plane; an imaginary vertical line dividing the body into the left and right sides. The motor acts of skipping and of drawing a line from the right to the left side of the page variously involve crossing the mid-line. Difficulty crossing the mid-line or coordinating both sides of the body can be an indication of a perceptual or neurological problem.

mid-parental height

The arithmetic mean of the heights of both biological parents; used to project a child's adult height and expected height growth percentile.

mid-temporal epilepsy

See benign rolandic epilepsy.

Mietens syndrome

A genetic syndrome with mild mental retardation, short stature, corneal clouding (with visual defect), narrow nose, flexion contractures of the elbows, and short forearms. Inheritance is probably autosomal recessive.

Milani-Comparetti Motor Development Screening Test

A motoscopic (visual pattern analysis) evaluation procedure for children in the first 2 years of life that relates postural control and active movement to primitive reflexes, tilting, righting, and parachute reactions. The protocol sheet provides a graphic record of the child's progress.

mild mental retardation

Mental retardation in which the IQ level is between 50 and 70. Adults with mild mental retardation typically achieve functional literacy and are able to live independently (or with minimal assistance) in the community. Sometimes referred to as educable mental retardation (EMR).

MILI

See Multilevel Informal Language Inventory.

milieu teaching

A naturalistic language intervention strategy using everyday instances of social-communicative exchange to teach elaborated language. It incorporates many features of incidental teaching but is broader in focus. This model requires teachers to 1) arrange the environment to facilitate a child's use of language, 2) assess the functioning levels of a child, and 3) discover ways for a child to interact with the environment.

milieu therapy

A form of residential treatment that attempts to create and maintain a wholly positive living environment within a residential community by enlisting the efforts of all staff members as providers of therapeutic contact. See also residential treatment.

milkmaid grip

A grasp that waxes and wanes abruptly; seen in choreoathetosis.

Miller Assessment for Preschoolers (MAP)

A comprehensive developmental screening test for identifying children (ages 2-9 to 5-8) who exhibit moderate preacademic problems. Administration time is approximately 20-30 minutes.

Miller-Dieker syndrome

Lissencephaly syndrome; a specific pattern malformation including lissencephaly (smooth, rather than convoluted, brain surface), with other central nervous system malformations: small brain stem, heterotopia (tissue displacement), absence of the corpus callosum, and areas of pachygyria (broad, flat cerebral convolutions). Also associated with facial anomalies, microcephaly (abnormally small head), a high forehead with vertical and central furrowing, small nose with anteverted nostrils, and low-set, posteriorly rotated ears. Severe mental retardation with hypotonia (decreased muscle tone), opisthotonos (arching of the hack), failure to thrive, and seizures are the rule. Death usually occurs in the first 2 years of life. Etiology (cause) is a visible deletion on chromosome 17 p 13.

Miller-Yoder Language Comprehension Test (MY)

A picture-format test of language comprehension for children between the ages of 4 and 8 years. Comprehension of short sentences with a variety of grammatical structures is assessed.

Milwaukee brace

A thoracolumbosacral brace that goes from the chin to the hips and is used to treat scoliosis (spinal curvature).

Milwaukee Project

A controlled, intensive early intervention program for 20 disadvantaged children (and their mothers, who have mental retardation) from early in their first year of life to 6 years of age. The dramatically positive results of this study remain controversial.

minimal brain damage/dysfunction (MBD)

A loosely organized constellation of symptoms that includes short attention span, distractibility, impulsivity, hyperactivity, emotional lability (changeability), motor incoordination, visual-perceptual motor disturbance, and language disorder. MBD encompasses the current attention-deficit disorder (with and without hyperactivity), learning disability, developmental language disorder, and clumsy child syndrome. The utility of the MBD concept is that it stresses comorbidity—the marked overlap among these diagnostic categories.

Minneapolis Preschool Screening Instrument (MPSI)

A brief screening test for 4-year-olds, for the purpose of identifying children who may need special education services.

Minnesota Percepto-Diagnostic Test (MPD)

A test of visual-perceptual motor skills with separate age norms for children 5-14 years of age as well as for adults. The test requires the subject to copy six designs, with the score based on rotations, separations, and distortions. The results assist in the classification of learning disabilities and emotional disorders. The six stimulus cards are rotations of two Bender Gestalt figures.

minor dysmorphic features

Mild superficial malformations; singly these dysmorphic characteristics are best considered normal variants or familial traits; the presence of several of these features may contribute to an overall appearance that is part of a specific syndrome. When no syndrome is identified, the presence of more than four minor dysmorphic features on a scale such as the Waldrop scale (developed by Mary Waldrop) is interpreted as suggesting a disturbance occurring during the first trimester of pregnancy and affecting the ectodermal layer of the embryo and contributing to mild abnormalities of ectodermal derivatives — hair, skin, and brain. Increased dysmorphology scores are associated with attention problems, hyperactivity, cognitive impairments, and the entire spectrum of neurodevelopmental disabilities. In the presence of a developmental diagnosis, a high minor malformation score provides support for a prenatal etiology (origin). Common minor dysmorphic features include abnormal hair whorl patterns, microcephaly (abnormally small head), macrocephaly (enlarged head circumference), epicanthal folds, pinna (external ear) anomalies (malformation, deformation, disruption, or dysplasia), high-arched or steepled palate, geographic tongue, clinodactyly (deflection of fingers), palmar crease abnormalities (e.g., simian crease, Sydney line), sandal gap deformity, and syndactyly (webbing of the fingers or toes).

minor motor seizure

Lennox-Gastaur syndrome; consists of at least four seizure types: atonic (akinetic), myoclonic, brief tonic, and atypical absence/petit mal. The etiology (cause) of these seizures ranges from infections of the brain (encephalitis and meningitis) to perinatal problems and genetic disorders. Minor motor seizures are generally present throughout the individual's life span and can be seen with focal and generalized tonic-dome seizures. Mental development in children with these types of seizures is slow, with 65% having an IQ below 75, reflecting the frequency of seizures as well as the underlying brain disease. Many anticonvulsants are used, but the success rate is poor. Those used include valproic acid (Depakene), clonazepam (Klonopin, formerly Clonopin), ethosuximide (Zarontin), adrenocorticotropic hormone (ACTH), lorazepam (Ativan), primidone (Myso-line), and diazepam (Valium). The ketogenic diet is also prescribed under some circumstances.

minor neurological dysfunction

See soft neurological sign.

minor tranquilizer

Sedatives and antianxiety drugs.

mirror movements

Associated or overflow movements on the contralateral (opposite) side of the body, such as those that can be observed when testing fine-finger movements. A soft neurological sign or sign of minor neurological dysfunction.

missing parts test

A type of test in which the subject must identify the part missing from a picture.

mitochondrial myopathy

A class of disorders affecting peripheral (noncentral) muscles and the central nervous system, often resulting in progressive weakness, seizures, and cognitive deterioration. One such example is MERRF syndrome, in which the muscle tissue has a characteristic pattern described as red ragged fibers. These disorders are inherited through the mitochondria, which are found in the cytoplasm. Because the only cytoplasm in the embryo comes from the egg, these disorders are always inherited from the mother.

mixed cerebral palsy

Describes a case of cerebral palsy that has significant features of more than one subtype, usually a combination of a spastic subtype with an extrapyramidal subtype. There are no fixed guidelines for how many individual characteristics of each subtype need to be present to qualify for the descriptor "mixed." This is especially confusing, because the more closely one examines a given case of cerebral palsy, the more likely one is to find signs of more than one subtype: all cases are mixed to some extent. A good rule of thumb is to label the case as mixed only when the presence of each subtype must be recognized because of the risks for associated deficits specific to those subtypes.

MLD

See metachromatic leukodystrophy.

MLST

See Merrill Language Screening Test.

MLU

See mean length of utterance.

MMR

Combined live attenuated vaccines against measles, mumps, and rubella; one of the primary routine immunizations (vaccinations) of childhood.

mnemonic

Relating to memory, and especially to artificial techniques to improve the memory.

mobility

The ability to move with appropriate ease, flexibility, and range. A person with physical or motor disabilities may be impaired in one or more of these respects, requiring assistive devices and environmental modifications to facilitate mobility. Thus, an amputee may require a prosthesis; a person with orthopedic disabilities may require special shoes, braces, canes, or crutches; and a person with cerebral palsy or a stroke may require a wheelchair. In addition, ramps, elevators, widened doors, and car and bus lifts may be necessary environmental modifications to ensure complete mobility. For many people, personal mobility may be compromised by a lack of accessible public transportation to allow linkage with needed health and welfare services. The Americans with Disabilities Act of 1990 (PL 101-336) mandates the removal of architectural barriers from all public buildings and the alteration of facilities and their amenities to ensure physical accessibility to individuals with disabilities as one aspect of widening the experiences of, and opportunities for, Americans with disabilities.

Möbius syndrome

Congenital and usually bilateral facial (sixth and seventh cranial nerves) paralysis with an expressionless, masklike facies. This is a fairly nonspecific syndrome with a variety of associated features (e.g., micrognathia [small jaw] and clubfoot) and diverse etiologies (causes), including rare autosomal dominant inheritance. Other cranial nerve involvement (III, IV, V, IX, X, and XII) can lead to ptosis (drooping eyelids) and feeding and articulation problems. The Möbius syndrome may be part of a broader malformation pattern including syndactyly (webbing of the fingers or toes), clubfoot, and limb reduction defects. Only 15% of people with this syndrome have mental retardation, but early appearance of the expressionless face, poor speech, feeding disorder, and other impairments may misleadingly contribute to a misdiagnosis of mental retardation. In older children, the dull, apathetic. Möbius facies can resemble the adenoidal facies. Named after the German neurologist Paul Möbius (1853-1907).

mode

The most frequent score in a set of scores (e.g., 3 is the mode for the data 1, 1, 2, 3, 3, 3, 4, 9, 9, 18). When two scores occur more frequently than others with the same frequency, the distribution is bi-modal (e.g., 2 and 7 are the modes for the data 1, 2, 2, 2, 3, 6, 7, 7. 7, 10, 12). When the same is true of more than two scores, the distribution is multimodal (e.g., 4, 5, and 10 are the modes for the data 2, 4, 4, 4. 6, 5, 5, 5, 7, 9, 10, 10. 10, 11).

modeling

Behavior modification technique that uses imitation. See also behavior modeling.

moderate mental retardation

Mental retardation in which the IQ level is between 35 and 55. Adults with moderate mental retardation typically have learned to read survival words, have been trained to perform semiskilled labor, and can live in supervised group homes in the community. Sometimes referred to as trainable mental retardation (TMR).

Mohr syndrome

Mohr-Rimoin syndrome; oral-facial-digital syndrome, type II (OFD-II). A genetic syndrome with cleft tongue, a peculiar facies, an abnormality of the big toe, and conductive deafness. Mental retardation is an occasional associated feature. Inheritance is autosomal recessive.

Mongolian spot

Bluish discoloration of the skin over the back and buttocks, present at birth, more common in African American babies, and tending to fade with time; not to be confused with bruising secondary to battered child syndrome.

Mongoloid/mongolism/mongolian idiocy

An antiquated and unacceptable term to describe people with Down syndrome. Derived originally from John Langdon H. Down's (1828-1896) hypothesis in 1866 of an ethnic atavism (racial throwback) etiology (cause) for this subgroup of individuals with mental retardation, and later fostered by both popular misconceptions and pseudoscientific theories masquerading as physical anthropology. (The term Mongoloid still has an accurate, if restricted, usage in anthropology.)

Mongoloid slant

An apparently upward (going from the nose laterally) slant to the palpebral fissure (eye slit). A component of the facies in Down syndrome, many other genetic syndromes, a racial and familial characteristic, and a potentially sporadic isolated finding of no clinical significance. The Mongoloid slant may be more common in conditions with microcephaly (abnormally small head) or with malar (cheekbone) hypoplasia (atypical tissue development).

monitoring ability

The capacity to exercise quality control over one's performance. Difficulty with monitoring can result in careless mistakes with no perceptual awareness of their having occurred. Children with attention problems often demonstrate poor self-monitoring skills.

monoplegia

Literally, "one palsy"; a topographical subtype of spastic cerebral palsy. By the usual mechanisms of brain injury, it is very difficult to localize the resulting impairment to a single extremity (arm or leg); thus, a pure monoplegic cerebral palsy is exceedingly rare. What is thought to be a monoplegia usually turns out, on closer inspection, to be a hemiplegia (paralysis of half the body) with almost undetectable lower extremity involvement, the common Erb palsy, or the rare Klumpke palsy. Because of the mildness of the condition, the associated findings are minimal.

monosomy

A condition in which one of a pair of chromosomes is missing, resulting in only 45 chromosomes (as found in Turner syndrome—the absence of one X chromosome). No other complete monosomies are compatible with life. Individuals with a partial monosomy are missing part of one chromosome in a pair. Children with partial monosomies of chromosomes other than the sex chromosomes tend to have major anatomical abnormalities (e.g., heart disease), dysmorphic (atypical) features, and mental retardation.

monotherapy

The practice of using a single anticonvulsant in seizure treatment. The selection of the appropriate anticonvulsant is based on the type of seizures and the potential toxicity. Although monotherapy is the ideal treatment, it is not always successful, and in complicated cases polytherapy (more than one medication) may be needed.

monozygotic twins

Identical twins; two individuals with the same genetic makeup (same genotype) who came from the same egg and sperm.

Monroe Diagnostic Reading Test

A reading readiness test for kindergarten and primary grade children. It profiles reading skills and yields an arithmetic, spelling, and mental age for comparison.

Montessori method

Educational approach developed by Italian physician Maria Montessori (1870-1952) that is based on the heavily sensorimotor activity programs developed by two French physicians (Jean Marc Gaspard Itard [l774-1838] and Edouard Seguin [1812-1880]) for their work with people with mental retardation. There are two major divisions in the current application of the Montessori method: the International Montessori, which adheres fairly strictly to the original program; and the American Montessori, which has developed a more eclectic approach.

mood

A pervasive and sustained emotion that, if extreme, has a marked impact upon a person's perception of the world. Examples of mood include depression, anxiety, anger, and elation. See also emotion.

mood disorder

A class of psychiatric disorders in which mood is abnormally depressed or elevated beyond a specific time period and is accompanied by behavior and cognitive changes uncharacteristic of the person's normal level of functioning. Examples of such mood disorders include major depressive disorder, panic states, and manic-depressive illness (bipolar and unipolar types). In children, particularly those with developmental disabilities mood deviance is more commonly present as anhedonia (inability to feel happy) or irritability, rather than active depression or elation. These variations are viewed both in children and adults as diagnostic equivalents to more classic mood deviances. When such modes of expression are presented, other behavior, cognitive, and physiological symptoms may not be so apparent.

Moos Family Environment Scale

A 90-item self-report instrument to measure the social and environmental characteristics of all types of families and to generate 10 conceptually based subscales and three factors. Originally normed on 285 families, the reported psychometric properties have recently been challenged by more recent data that have failed to replicate and support the original results. Nonetheless, the scale remains a frequently used instrument.

Moral Judgement Inventory (forms A and B)

A structured interview for elementary school-age children to adults, designed to assess stages of moral development as defined by Lawrence Kohlberg. There are two forms of the interview, each consisting of three stories and accompanying questions addressing various aspects of the moral issue presented. To facilitate scoring, examples are provided to exemplify answers characteristic of Kohlberg's five developmental stages.

morbidity

Illness or disease.

morbidity rate

A count of the number of diseases per unit of population per unit of time.

Morgan Neonatal Neurobehavioral Examination

An assessment of tone and motor patterns, primitive reflexes, and behavioral responses in newborns born at term.

Moro reflex

A primitive reflex in which sudden extension of the head at the neck (stimulus) produces extension followed by flexion of all four extremities (arms or legs) (an embrace response). It is present in all newborns and fades in the first several months. Absence, exaggeration, and asymmetry are significant.

moron

Obsolete and unacceptable term for an individual with mental retardation and an IQ between 50 and 70. Derived from the Greek word for "stupid," its usage to describe the highest class of feebleminded was suggested by Henry Herbert Goddard (1866-1957) and adopted by the American Association for the Study of the Feeble-minded in 1910.

morpheme

The smallest meaning-bearing unit in a language. For example, the word dog is a morpheme; in the plural form dogs, the s is an added morpheme. In the sentence, clean the table, all three words are morphemes because even the two-syllable word table cannot be divided without destroying its meaning. The acquisition of grammatical morphemes generally occurs in the same sequence and is probably controlled by a combination of syntactic (language structure) and semantic (meaning systems) complexity.

morphology

The study of meaning units in any particular language; the study of morphemes. See morpheme.

Morquio syndrome

Brailsford syndrome; mucopolysaccharidosis (MPS) IV. A genetic syndrome of growth deficiency, mildly coarse facies with severe kyphosis (curvature of the spine) and knock-knees, cloudy corneas, and hepatomegaly (liver enlargement); intelligence is usually normal. Named after the Uruguayan pediatrician Luis Morquio (1867-1935).

mortality

Death.

mortality rate

The number of deaths per unit of population per unit of time.

mosaicism

A condition in which different cells in an individual have a different genetic makeup. For example, some children with Down syndrome have trisomy 21 in skin cells but not in blood cells. In general, individuals with mosaicism have less severe manifestations of chromosomal abnormalities; however, they do manifest many of the characteristics of disorders.

motherese

Baby talk; short, simple, repetitive sentences that adults use with a high-pitched voice when talking with infants and young children.

Mother's Assessment of the Behavior of her Infant (MABI)

A modification of the Braxelon Neonatal Behavior Assessment Scale (BNBAS) that can be administered by mothers.

motivation

A hypothetical construct devised to make behavior more understandable and predictable. Although some theorists have described motivation as an unconscious trait resulting primarily from early learning experiences, others conceptualize it in terms of conscious beliefs and values and stress the effects of recent success and failure experiences. Individuals are motivated to achieve particular goals. When individuals attend to one thing and not .mother, they are motivated with regard to the former and not the latter. The motivational orientations of teachers and students may be incompatible. Students who do not work hard on school tasks may not be unmotivated; instead, they may have different goals. The term unmotivated is often used pejoratively, as though the student's lack of success is his or her own fault. This is a simplification of motivational theory. Any motivational change must begin with the question "Why?" and encompass both past and present experiences. Motivation may be classified as external and internal; most efforts to improve students' motivation use an external frame of reference. This is sometimes, but not always, appropriate.

motor disorders

A disorder of movement that involves a delay in the achievement of or a limitation in the performance of gross-motor (posture and locomotion) or fine-motor (eye-hand) skills.

Motor-Free Visual Perception Test (MVPT)

An individual test for visual perception in children in which the tasks avoid motor involvement. The 36 test items tap spatial relationships, visual discrimination, figure-ground, visual closure, and visual motor; each item is multiple choice and requires only a pointing response. The raw score yields a perceptual age and a perceptual quotient for children whose visual-perceptual abilities are between the levels of a 4-year-old and a 9-year-old.

motor function

Functioning of the voluntary muscles of the body and the nerves supplying them. Important features are muscle mass, tone, and strength. Motor dysfunction is found in many forms of cerebral palsy. For example, in a right hemiplegia (paralysis of half the body), muscle mass and strength are decreased on the right side compared to the left, but muscle tone is increased. The pattern of dysfunction is used to determine not only into which diagnostic category a person fits hut also the location of the lesion in the nervous system. A knowledge of the level of a lesion in a case of myelomeningocele (protuberance of both the spinal cord and its lining) may allow some prediction of later functional levels in motor skills.

motor impersistence

An impaired ability to maintain a motor position for an age-appropriate time period. A number of tests have standardized norms for standing on one foot, but the behavior may be observed spontaneously during the physical examination.

motor memory

The ability to recall distinct motor patterns; the capacity to remember letter formations and play piano chords are examples. Children with motor memory limitations may have particular trouble with handwriting. See also memory.

motor neuron disease

An impairment of voluntary movement by the destruction of nerve cells involved in the motor pathway. In upper motor neuron disease, the motor nerve cells that are destroyed are in the brain; in lower motor neuron disease, they are in the spinal cord.

motor overflow

Involuntary movements that are associated with voluntary movements; see also associated movements.

motor planning

Praxis; the ability to plan new or nonhabitual movements.

mouth breathing

A behavior commonly secondary to nasal obstruction (adenoidal facies). When not associated with allergy and nasal obstruction, it is sometimes present in mental retardation.

mouth-opening finger-spreading phenomenon

A test of associated movements in which the child's relaxed arms are draped over the examiner's extended forearm and the child is asked to close the eyes, open the mouth, and stick out the tongue. The degrees of extension and spreading of the fingers and spooning (hyperextension) are noted. Excessive response for age suggests nervous system immaturity.

Movement ABC

See Movement Assessment Battery for Children.

Movement Assessment Battery for Children (Movement ABC)

A physical skills assessment and program-planning instrument for children ages 4-12 years; it yields both normative and qualitative measures of manual dexterity, hall skills, and static and dynamic balance, and offers guidelines for management and remediation.

Movement Assessment of Infants (MAI)

A test used to evaluate and describe motor skills in infants from birth to 12 months of age; 65 items comprise four subtests of tone, primitive reflexes, automatic reactions, and voluntary movement.

movement disorder

A condition characterized by involuntary movements–including chorea, athetosis (involuntary twisting of the upper extremities), tremor, dystonia (impaired muscle tone), and tics–or a decrease or absence of normal movement. Movement disorders may be associated with neurological or developmental problems in the cases of cerebral palsy and Rett syndrome. These can be acute (generally precipitated by an identifiable event such as an infection or head injury) or chronic. Chronic disorders may be isolated, associated with progressive neurological deterioration, or found with a systemic (body) disease. Movement disorders caused by medication generally resolve after the medication is discontinued. Those caused by diffuse brain damage after head injury or lack of oxygen to the brain tend to be resistant to many medications such as haloperidol or anticonvulsants, which are generally used to treat movement disorders. There are many genetic causes of movement disorders: Tourette syndrome, Wilson syndrome, juvenile Huntington disease, and Lesch-Nyhan syndrome. Some movement disorders, such as transient tics, resolve; others, such as the fine tremor of thyrotoxicosis (toxic hyperactivity of the thyroid gland), respond to treatment of the underlying condition; while still others do not respond to medication and may worsen with age.

MPD

See multiple personality disorder; See also Minnesota Percepto-Diagnostic Test.

MPH

See methylphenidate; also denotes an advanced degree, Master of Public Health.

MPS

See mucopolysaccharidosis.

MPSI

See Minneapolis Preschool Screening Instrument.

MR

See mental retardation.

MR scans

See magnetic resonance imaging.

MRA

See mental retardation attendant.

MRI

See magnetic resonance imaging.

MRT

See Metropolitan Readiness Tests.

MS

See multiple sclerosis.

MSBP

See Munchausen syndrome by proxy.

MSEL

See Mullen Scales of Early Learning.

MST

See McCarthy Screening Test.

MSUD

See maple syrup urine disease.

M.S.W.

See Master of Social Work; see also social work.

Muckle-Wells syndrome

A genetic syndrome with urticaria (hives), progressive sensorineural (involving the inner ear or the auditory nerve) deafness, and nephritis (kidney disease) due to a pathological process known as amyloidosis; onset is in adolescence. Inheritance is autosomal dominant with variable expressivity.

mucolipidoses

A group of diseases characterized by physical findings similar to the mucopolysaccharidoses (MPS); there is a storage of mucopolysaccharides (complex carbohydrates) and other chemicals in body tissues with normal levels of metabolites in the urine. There are four types —mucopolylipidoses I-V; mucopolylipidosis II is also called I-cell (for inclusion cell) disease. In all of these disorders, an enzyme that enables the breakdown of mucopolysaccharides is not working; therefore, the levels of mucopolysaccharides build up in the cells and cause damage. The resulting physical features include coarsening of the face, poor growth, enlarged liver and spleen, restricted joint mobility, and progressive mental deterioration. These disorders are generally inherited in an autosomal recessive manner and can be diagnosed by testing for enzyme activity or visualizing deposits of mucopolysacchandes and their products under the microscope. The course of the disorder is dependent upon the type of enzyme deficiency and can range from blindness and mental retardation to death in childhood.

mucopolysaccharidosis (MPS)

A group of heterogeneous genetic syndromes in which excess mucopolysaccharide (complex carbohydrate) is stored in various body tissues and organs; depending on the specific enzyme deficit, the severity, the time course, and the organ system involved, a variety of clinical pictures can result. Coarse, thickened facial features, stiff joints leading to a crouched jockey stance, growth deficiency, hepatosplenomegaly (enlargement of the liver and spleen), microcephaly (abnormally small head), corneal clouding, and mental retardation are present in diverse combinations and with varying degrees of severity depending on the specific type and subtype of enzyme deficiency, as follows: IH, Hurler; IS, Scheie; IH/S, Hurler-Scheie compound; II, Hunter; III, Sanfilippo; IV, Morquio; V, former designation for Scheie; VI, Maroteaux-Lamy; and VII, Sly. Hunter syndrome is X-linked; all of the other MPS syndromes are autosomal recessive with a 25% recurrence risk.

Mullen Scales of Early Learning (MSEL)

A developmental assessment tool with an information processing orientation; it consists of five subscales that may be employed independently: visual receptive, visual expressive, language receptive, language expressive, and in infants, gross motor. The MSEL is for children 15-69 months of age; the Infant MSEL is for children from birth to 36 months of age. The scales are both screening and diagnostic tests.

multiaxial classification system

An approach to diagnosis that utilizes several different dimensions in composing, the final formulation, rather than reducing data to a single label or category. A case is characterized in terms of a number of clinically important factors, rather than being assigned to a single diagnostic category. The Diagnostic and Statistical Manual of Mental Disorders (4th edition) has five axes: Axis I, the primary classification or diagnosis of a psychiatric syndrome; Axis II, existence and evaluation of an individual's developmental and personality disorders of childhood or adolescence that persist into adulthood; Axis III, determination of possible physical or medical disorders; Axis IV, the severity of psychosocial stressors in the recent past that may have contributed to the current clinical problem or may influence the course of treatment; and Axis V, a global assessment of adaptive functioning, with ratings made for both current functioning and the highest level of functioning during the past year. Although a multiaxial approach to developmental disabilities is desirable, the Diagnostic and Statistical Manual of Mental Disorders (4th edition) is not sufficiently refined in the major developmental categories.

multicultural education

Teaching toward a pluralistic society. This concept includes both the impact of various cultures and ethnicities on society at large, as well as an awareness of cultural diversities of learning and behavior within the educational system.

multidisciplinary

Describing a team approach to the diagnosis and treatment of developmental disabilities; in such a team, the interactions among the professionals representing two or more disciplines are limited to each professional's independent case formulation, focusing on that professional's traditional boundaries; integration of the findings is cumulative, with disagreements being arbitrated by nonprofessional parameters such as discipline hierarchy or bureaucratic policy.

Multidisciplinary Feeding Profile (MFP)

A numerical rating scale to describe a variety of feeding-related behaviors in dependent individuals with severe disabilities; the scale takes 30-45 minutes to administer.

multifactorial

Descriptive of a disorder caused by the interaction of multiple factors (e.g., genetic, environmental, psychological), with each factor contributing a small, but additive or multiplicative, effect. Contrast with polygenic.

multifocal

In many places.

Multilevel Informal Language Inventory (MILI)

An informal language assessment for children from kindergarten through grade six that uses survey scenes, survey stories, and other probes to assess critical semantic (meaning systems) relations and syntactic (language structure) constructions.

multiple disabilities

The coexistence of more than one disability in a single individual. The more severe a single disability, the more likelihood that a second disability may be present. The overall impact of multiple disabilities is greater than the impact of the sum of the individual disabilities.

multiple lentigines syndrome

LEOPARD syndrome; a genetic syndrome with Lentigines (dark freckles), Electrocardiographic (EEG) abnormalities, Ocular hypertelorism (widely spaced eyes), Pulmonic stenosis (a heart valve problem), genital Abnormalities, growth Retardation, and sensorineural (involving the inner ear or the auditory nerve) Deafness. Inheritance is autosomal dominant with variable expressivity.

multiple personality disorder (MPD)

A psychiatric disorder characterized by two or more distinct personalities, each with its own identity, characteristics, and memories. The etiology (cause) for such extreme psychological fragmentation is severe physical, sexual, or emotional trauma occurring under conditions that allow for no physical escape, so that the individual can only escape psychologically. The personalities often coexist with no awareness of each other. Thus, multiple personality disorder is a creative psychological solution to a horrifying, inescapable situation. Unfortunately, such an escape route becomes a difficulty in and of itself. Untreated people with multiple personality disorder have severe emotional disabilities.

multiple sclerosis (MS)

A progressive disease of the central nervous system with adult onset; not to be confused with childhood onset muscular dystrophy.

Muma Assessment Program (MAP)

A nonstandardized criterion-referenced "testing for teaching" assessment of cognitive-linguistic-communication systems for children from preschool through early elementary ages that taps: different learning styles; sensory motor skills; rule- and nonrule-governed learning; and concepts of conservation, quantity, and likeness.

Münchausen syndrome by proxy (MSBP)

A condition in which a child is presented for medical care with symptoms that are fabricated or produced by the caregiver. Significant maternal psychopathology is usually the cause. Fictitious developmental disability symptoms have been reported. The syndrome is at one end of the spectrum of child abuse. Münchausen syndrome (typically manufactured by the adult who concocts symptoms to obtain repeated and unnecessary surgical and medical procedures) is named after the 18th-century German raconteur Baron Karl Friedrich Hieronymous Münchausen, whose exploits were exaggerated in Rudolph Eric Raspe's (1737-94) satirical and ludicrous Adventures of Baron Münchausen.

murmur

A soft sound; usually refers to an unusual heart sound that may be innocent (not indicative of heart disease) or pathological (indicative of heart disease). The presence of a heart murmur does not reflect the severity of any heart disease that may be present. Some childhood heart murmurs resolve spontaneously (are outgrown).

muscular dystrophy

A group of genetic disorders leading to progressive muscular atrophy (wasting) and weakness; the different types exhibit varying distribution, severity, and temporal evolution. When the muscles that carry out respiration are involved, the disorder can become fatal.

music therapy

A treatment approach that utilizes music and movement in a variety of forms to modify nonmusical behavior and to promote mental health, social development, emotional adjustment, and motor coordination. Used as a therapeutic tool in rehabilitation to meet recreational or educational goals, music therapy includes playing instruments, moving to music, creating music, singing, and listening to music. Music therapy is utilized in a variety of applications in hospitals, schools, institutions, and private settings through both individual and group approaches, often in conjunction with other types of therapy and/or rehabilitation. Both music education and music therapy contribute to special education by promoting learning and self-growth through enjoyable activities.

mutation

A change in the gene such that the protein coded for by that gene is manufactured in a nonfunctional form. Commonly, disorders inherited in an autosomal dominant manner (by a single gene) can be caused by a mutation to a single gene.

mutism

Inability or refusal to speak. Deaf-mute refers to a person who docs not speak and has severe hearing impairment; deaf and dumb is not acceptable usage.

MVPT

See Motor-Free Visual Perception Test.

MY

See Miller-Yoder Language Comprehension Test.

myasthenia gravis

An immunological syndrome of muscle weakness and exhaustion that occurs in episodic and reversible attacks.

myelin basic protein (MBP)

A biochemical marker of brain injury; increased levels of MBP in the cerebrospinal fluid (CSF) correlate with brain (white matter) damage and degenerative (demyelinating) disorders.

myelination

Myelinization; the process of covering the axon (part of the nerve cell) with a sheet of myelin (a fatty insulation material). The rate of development can be slowed by delays or abnormalities in myelination.

myelomeningocele

Meningomyelocele, spina bifida; a congenital detect of the spinal column resulting in the protrusion of the spinal cord and its coverings (meninges) from the baby's back. There are varying levels of functional impairment (motor paralysis and sensory loss) depending on the size and level of the sack. The condition is also associated with hydrocephalus (excess fluid in the brain) and a variable degree of cognitive impairment. Long-term considerations include ambulation and bowel/bladder control.

Myers-Briggs Type Indicator (MBTI)

A self-administered measure of personality dispositions and preferences; this 20- to-30-minute test has a seventh-grade reading level and places the individual on four Jungian continua: extraversion/introversion, sensing/intuition, thinking/feeling, and judging/perceiving. The Murphy-Meisgeier Type Indicator for children extends the MBTI down to grades two to eight to allow a better delineation of individual learning styles.

myoclonic-astatic

See Lennox-Gastaut syndrome.

myoclonus

Rapid and sudden unpredictable jerks that are involuntary, rhcse are present in some kinds of seizures. They may occur normally when falling asleep or with hiccups (i.e., myoclonus of the diaphragm).

myoclonus, epileptic

Synchronous, small, recurring twitches generally occurring in the fingers and hands and associated with chronic seizure disorders such as Lennox-Gastaut syndrome. Myoclonic movements are preceded by abnormalities of the electroencephalogram (EEC). These movements are associated with viral encephalitis (brain inflammation), metabolic disturbances such as uremia (found in kidney disease), and progressive cerebral degenerative diseases.

myoclonus, nonepileptic

Myoclonus not associated with seizures, as found in many situations (e.g., in typical people who are going to sleep). A familial form of myoclonus (probably autosomal dominant) called paramyoclonus multiplex, or essential myoclonus, combines frequent but nonprogressive myoclonus with low-average intelligence. This condition is also associated with an exaggerated startle, hypertonia (increased muscle tone) in infancy, nocturnal leg jerking, and an unsteady gait. It often responds to clonezepam (Klonopin). Myoclonus may originate in the brain stem or the spinal cord and produce myoclonic jerks unresponsive to sensory stimuli that persist in sleep. Response to anticonvulsant medication in this situation is generally poor. Cortically mediated myoclonus is generally precipitated or aggravated by sensory stimuli such as light or noise; these contractions are irregular and disappear in sleep.

myopathy

Disease of muscle, such as muscular dystrophy.

myopia

Nearsightedness; common in the third and fourth decades of life; corrected by minus diopter (concave) lenses. A child with myopia typically squints and cannot see the blackboard.

myotactic reflex

See stretch reflex.

myotonic dystrophy

See Steinert syndrome.

myringotomy

The surgical incision of the tympanic membrane (ear drum) to relieve pressure and allow fluid drainage from the middle ear; it is usually accompanied by the insertion of a polyethylene (PE) tube designed to be pressure equalizing (PE) so as to maintain drainage for several months.

myxedema

A condition including edema, puffiness, fatigue, weight gain, apathy, and sluggish deep-tendon reflexes resulting from hypothyroidism; the acquired or adult form of congenital cretinism.

myxovirus

A ribonucleic (RNA) group of viruses that can produce respiratory disorders but also includes the viruses for measles and mumps.