DVDs, Books, and other Materials about Child Development and Children with Disabilities |
 Home Page  Curriculum Vitae   Products by Topics  FAQs  Free Downloads  Resource Links  Order Info  Contact Us |
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
differences?
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
academic performance?
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
interventions?
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.
You are welcome to copy and paste this page for your own clinical or educational use.
* Glossary of Hand Preference Terms
* The Erhardt Hand Preference Assessment
(EHPA)
* Documentation of Hand
Preference Chart (free pdf download)
* Hand Function * Prehension Videos
