Correlations between assessed manual laterality and predicted speech laterality in a normal population

The correlation of handedness and lateral speech representation was investigated in an adult normal population of left- and right-handers. Handedness was assessed by multivariate analysis of manual test scores. Assessment of speech laterality was based on scores derived from the Dichotic Listening Test.

Results showed that: (1) self-reports of “left-handedness” were unreliable estimates of manual performance; (2) self-classified left-handers, in contrast to right-handers, varied along levels of both manual and speech laterality; (3) the association between speech and manual laterality was greater when handedness was based on multiple performance scores; (4) familial sinistrality was twice as frequent in those test-classified left- and right-handers who showed speech representation on the same side as the dominant hand.