Several occupational therapists contributed to the ideas that were compiled into this document related to hand dominance. The book Hand Function in the Child by Henderson and Pehoski has a good chapter by Elizabeth Murray about hand dominance. Kristin Levine also has a good chapter on hand dominance in the book Fine Motor Dysfunction.
Mary Benbow, an occupational therapist, has stated that all but the very cognitively high and low children eventually establish a dominance, and can actually establish dominance quite a bit older than 3-4 years old (even as late as 8 or 9 years old). Not all dominances emerge in Kindergarten.
Dominance should not be forced. It is also important to note that not all body dominances (hand, leg and eye) are same sided. Leg dominance depends on if the leg is stabilizing or moving. Many postural factors affect which leg a child will use to stabilize or weight bear on when doing leg activities, especially in contrived situations. There could be mixed hand dominance; e.g., a dominance for reaching out, a different dominance for tool manipulation, or even different dominances for different tools (scissors, pencils, etc.). Cutting and writing with different hands is often observed in children who prefer the opposite hand for sports activities. This is not considered abnormal, but rather one side has developed greater strength (and that hand is used for coloring, ball throwing, etc.) and the other hand has developed greater fine motor control/dexterity (used for writing/cutting).
The literature also indicates that crossed dominance is common and is not necessarily indicative of a problem. If students with cross dominance are functional, it is not necessary to try to change this use, although the underlying problem may be addressed if it is causing a true functional deficit in another performance area. Handedness is comprised of hardware (musculoskeletal, strength) and software (neurological), interacting to produce an efficient response system. If a child switches hands, it prevents the establishment of an efficient synergy for response. Jan Olsen (Handwriting Without Tears) suggests that a child should learn to print with one hand. Otherwise, switching cuts the practice benefit. In cases where a child switches hands, Jan suggests evaluating the child's skills with both hands to decide which hand is more skilled for handwriting (watch how child picks up, holds, and moves the pencil, uses the helping hand, etc., and seeing which hand is better at writing). Pick the more skilled hand and try to encourage use of that hand.
You can begin with data collection about hand use and get the teacher or other adult to record (briefly) to try to establish a pattern, even a slight preference. It is important to rely on the classroom teacher's observations in addition to yours as it is not uncommon for the child to do one thing in the class and something different when the therapist is sitting next to him/her. We may inadvertently sit on the same side or present materials in a certain way to encourage use of one hand over the other for that particular task. If the data indicates that no hand preference at all has been established, look at production and try to determine which hand is more skilled for schoolwork (writing and drawing). Ask the student which hands feel easier to use.
Observe carefully what you see: when does the switching occur - partway through the activity (weak proximal stability [shoulder girdle] so switching occurs as hand tires), mixed throughout (confused), one hand starts and then the other usually completes each item (maybe trunk or global). What's the underlying quality of each hand (e.g., card turning by each hand. which is of better quality — body positioning/symmetry, eye use during the task, gross reaching out, skilled hand use, and so on). Several other important issues should be considered in looking at hand dominance:
Use a chalkboard and work with figure a 8 vertically and horizontally. Have the child use right hand to make a horizontal line from beginning to end of board surface as s/he walks the length. Then do the same with the left hand.
Watch how the eyes react to tracking an object (pencil eraser is fine) vertically and horizontally. If there is consistent blinking or aversion of the eyes, it may indicate a problem with crossing midline. You can do an imitation of postures which involves touching right hand to left shoulder, left hand to right knee and other similar things. If the child doesn't do well with this, check back with the teacher after a few weeks and rescreen the child.
Supply lots of proximal strengthening and bilateral activities if indicated.
You can incorporate Brain Gym movements (Educational Kinesiology) that involve laterality.
Try presenting things at midline and encouraging child to finish the activity with whichever hand s/he started with. Let the child choose which hand s/he wishes to use -- a rule can be established that the hand that the child starts with is the one s/he has to finish with. The child can then child can choose a different hand only when the current task is completed.
If you notice avoidance of midline, focus on crossing midline with both upper extremities. Once a child crosses the midline freely, hand dominance usually becomes more clear. It is never recommended to encourage a child to use one hand over the other, unless it is evident that the child consistently initiates an activity with the same hand. If this is the case, switching may occur due to fatigue. Focus on strengthening to see if the child will be able to sustain grasp to complete a task.
Any activity that encourages the different movements of each hand will help to encourage differentiation of function. The activity has to be repeated over time with feedback. One hand does the activity and the other hand assists.
