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FREQUENTLY ASKED QUESTIONS (FAQs) ABOUT HAND PREFERENCE
Q. What is the difference in meaning
between these groups of words?
* Hand dominance, handedness, and hand preference
A. Hand dominance means that one hand has the most influence or control. Handedness means that one hand is more reliable for use across a range of skillful acts. Hand preference means that one hand is preferred or chosen.
* Cerebral dominance, cerebral lateralization, and cerebral asymmetry
A. Cerebral dominance implies that the hemisphere controlling language is the most important one. Cerebral lateralization or asymmetry emphasizes that the hemispheres are different, and the relationship between them is complementary.
* Ambidexterity and mixed dominance
A. Ambidexterity is defined as the ability to use both hands equally well, an unusual skill in the normal population. The term mixed dominance has been used to describe a confusion or delay in the development of hand dominance in persons with disabilities.
Q. When does hand
dominance emerge in normal development?
A. According to Dr. Arnold Gesell, the developmental progression in the first year begins with use of one hand, then the other, then alternating hands, and then using both hands together, first symmetrically (about 4 months), then one assisting the other (about 1 year). Tasks requiring each hand to perform different skilled movements develop during the preschool years and beyond. A majority of children show a preference by age 3 and most by school age, but Dr. Gesell wrote that hand dominance doesn't become well integrated in some normal children until eight or nine years of age (Gesell & Ames, 1947). It is also true that some adults demonstrate skillful ambidexterity, especially in sports.
Q. What affects
hand dominance more: genetic or environmental factors? Does this differ
in children with disabilities?
A. It is generally agreed that genetic factors play the most important part in determining handedness. However, situational or environmental factors such as the task (precision or power), the materials (size, shape, weight), and positioning (child and object) affect choices for reaching/grasping, lifting/carrying, and unilateral/bilateral hand use. Children with disabilities usually have one arm/hand that is less affected than the other. Thus, despite genetic predisposition, they choose the limb that is most efficient. However, even they demonstrate choices based on situational factors, such as using one hand for distal tasks such as finger feeding, and the other hand for tasks requiring skills in more proximal movements such as shoulder/elbow/wrist control during utensil use. In fact, studies have shown that handedness is simply not a unidimensional trait, since specialization for the control of distal and proximal musculature may be located in different hemispheres. Thus behaviors that rely upon axial musculature and involve strength more than dexterity show less laterality bias than fine motor behaviors such as writing (Healey, Liederman & Geschwind, 1986; Peters & Pang, 1992).
Q. How do left-handers compare with right-handers in
functional performance, and why should we be knowledgeable about the
A. A large number of research studies have found that the number of left-handers is greater in persons with learning disabilities. Even studies of individuals without disabilities show that right-handers do better than left-handers academically, but those differences are not apparent until adolescence. However, in young children, handedness is seldom found to be related to learning or problem-solving abilities (Coren, 1992). Elementary age right-handers and left-handers performed equally well on the Southern California Motor Accuracy Test (Smith, 1983). We should understand the problems experienced by normal left-handers in a primarily right-handed society (writing from left to right, using scissors, operating zippers, etc.), since so many children with disabilities have less involvement on the left side (due to greater incidence of left hemisphere damage). In other words, some of their functional problems may be due to the use of the left hand, rather than the disability.
Q. Is it important for
eye, hand, ear, and foot dominances to be congruent?
A. According to the literature, 75% of the normal population has eye-hand congruency, 63% have congruent ear and hand, and 85% have congruent foot and hand. Crossed eye-hand dominance may be more efficient for certain activities such as batting a baseball.
Q. If a child keeps
alternating hands when writing, how do we determine which hand should be
used? What are the implications of unclear or mixed dominance for
A. "Mixed dominance" may be a symptom of dysfunction rather than a cause. A study of children with mild neurological impairment from early brain insult showed that the right-handers and those with mixed handedness did equally well in school (Saigal, et al, 1992). So, we must first determine if the actual products (handwriting and content) are functionally inadequate. If so, we need to analyze the child's posture and movements, the nature of the task, and the characteristics of the environment. Those clinical observations and specific evaluations can be recorded on forms such as the Documentation of Hand Preference and Quality of Performance Chart, the Erhardt Developmental Prehension Assessment (EDPA)(Erhardt, 1994), and the Erhardt Hand Preference Assessment (Erhardt, 2012a, 2012b). From that information we can plan intervention consisting of activities that 1) remediate missing developmental components, and 2) adapt the environment to enhance function.
Q. What are some examples of
missing developmental components and environmental adaptations relating
to incomplete acquisition of hand dominance, and the appropriate
A. Essential developmental components include postural control, eye-hand coordination, unilateral/bilateral/bimanual function, and perceptual concepts (body image, laterality, and internal/external directionality). However, opportunities should also be provided for non-directed exploration of objects/materials, a natural way for children to follow the normal developmental progression toward handedness (Knickerbocker, 1980). The purpose of intervention is to remediate motor development so that the brain can continue with its maturational goals of 1) establishing at least one hand for skilled work, and 2) the ability of both hands to interact for a variety of tasks. If those developmental components are very delayed or permanently impaired, environmental adaptations include postural supports in floor, sitting, and standing positions and adapted clothing/toys/tools for feeding, writing, etc. These adaptations should be constantly modified, as the child's needs change.
Coren, S. (1992). The Left-Hander Syndrome. New York: The Free Press.
Crinella, F.M, Beck, F.W., & Robinson, J.W. (1971). Unilateral dominance is not related to neurophysiological integrity. Child Development, 42, 2033-2054.
Erhardt, R.P. (1994). The Erhardt Developmental Prehension Assessment (EDPA ). Maplewood, MN: Erhardt Developmental Products.
Erhardt, R.P. (2012a). Hand Preference: Theory, Assessment, and implications for Function. Maplewood, MN: Erhardt Developmental Products.
Erhardt, R.P. (2012b). The Erhardt Hand Preference Assessment. Maplewood, MN: Erhardt Developmental Products.
Gesell, A. & Ames, L.B. (1947). The development of handedness. The Journal of Genetic Psychology, 70, 155-175.
Healey, J.M., Liederman, J., & Heschweind, N. (1986). Handedness is not a unidimensional trait. Cortex, 22, 33-53.
Knickerbocker, B.M. (1980). A Holistic Approach to the Treatment of Learning Disorders. Thorofare, NJ: Charles B. Slack.
Peters, M. & Pang, J. (1992). Do " right-armed" lefthanders have different lateralization of motor control for the proximal and distal musculature? Cortex, 28, 391-399.
Porac, C., & Coren, S. (1981). Lateral preferences and human behavior. New York: Springer-Verlag.
Saigal, S., Rosenbaum, P., Szatmari, P. & Hoult, L. (1992). Non-right handedness among ELBW and term children at eight years in relation to cognitive function and school performance. Developmental Medicine and Child Neurology, 34, 425-433.
Smith, S.M. (1983). Performance difference between hands in children on the motor accuracy test. American Journal of Occupational Therapy, 37(2), 96-101.
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