Hand-eye dominance in a population with mental handicaps: prevalence and a comparison of methods.

Background: The primary purpose of this study was to investigate hand-eye dominance in a population with mental handicaps and how the distribution compared with the general population. In addition, this study investigated the correlation between two methods of hand-eye dominance testing.

Methods: Two methods were used to determine eye dominance: the hole-in-the-hand method and the eye dominance wand. Hand dominance was determined by the subject's choice of accepting hand. The sample was comprised of a population of 421 athletes participating in the 1997 Special Olympic Games in Toronto. All subjects unable to give a dominant hand or unable to perform either of the ocular dominance tests were eliminated from analysis. Athletes who demonstrated strabismus or a difference in visual acuity between the two eyes of greater than 1 line were separated in the analysis, reducing the sample population to 191.

Results: The hole-in-the-hand method of eye dominance showed that 40.3% of this population exhibited crossed dominance. The eye dominance wand found crossed dominance in 36.6% of this population. The eye dominance wand demonstrated moderate agreement with the hole-in-the-hand method; however, there was some crossover of eye dominance between tests, when the tests were compared on a case-by-case basis.

Conclusions: The prevalence rate of this population of persons with mental handicaps agrees with the prevalence rates found by Robison et al., in which 41% of a general nonhandicapped population demonstrated crossed dominance. The results suggest that persons with mental handicaps have prevalence rates of crossed dominance similar to those found in the general population.