The development of hand preference and dichotic language lateralization in males and females with congenital adrenal hyperplasia.
People with congenital adrenal hyperplasia (CAH) are exposed to elevated levels of androgens in utero due to overproduction by the adrenal cortex. In order to test whether high levels of prenatal androgens influence the development of handedness preferences and left-hemisphere language representation, we studied 39 patients with CAH (28 females, 11 males) and 25 unaffected sibling controls (17 females, 8 males). Hand preference for 15 unimanual activities was evaluated via questionnaire and pantomime, and a consonant-vowel dichotic listening test was administered. Contemporary theories disagree as to whether high testosterone is said to increase or decrease the probability of developing a typical right-hand preference. Results showed no significant differences on the handedness inventory. Relative to controls, however, patients with CAH showed a significantly larger right-ear advantage on the dichotic syllables task, indicating stronger left-hemisphere lateralization of language. These results support an emerging body of evidence suggesting that high testosterone may bias lateralized development toward the population norm, but run counter to the Geschwind-Behan-Galaburda model which associates high prenatal testosterone with a greater prevalence of left-handedness.
a Department of Psychology , University of Western Ontario , London , ON , Canada.
Elizabeth
E
Hampson
Handedness; androgen; language lateralization; prenatal; testosterone