Relative processing demands influence cerebral laterality for verbal-motor integration in persons with Down syndrome.
The study of cerebral specialization in the Down syndrome (DS) population has revealed an anomalous pattern of organization. In particular, dichotic-listening studies have suggested a left-ear/right hemisphere dominance for speech perception, whereas motor control research has revealed a left hemisphere dominance for executive-motor control. In the present investigation, we employed a recent adaptation of the dichotic listening procedure to examine interhemispheric integration during the performance of a lateralized verbal-motor task. Specifically, using the selective dichotic-listening procedure, participants were required to complete a rapid left or right hand pointing movement to one of two pictorial icons corresponding to the word presented to their precued ear. We observed that persons with DS (N = 17) and age-matched controls (N = 35) exhibited a right-ear advantage (REA) for our dichotic-aiming task. While these results appear to contradict previous dichotic listening studies, we propose that the manifestation of a lateral ear advantage in the DS population may have more to do with the response requirements of the task than with the characteristics or complexity of the stimulus material.
Heath
Matthew
M
Dept of Kinesiology and Program in Neural Science, Indiana University, Bloomington, 47408, USA. heathm@indiana.edu
Welsh
Timothy N
TN
Simon
Dominic A
DA
Tremblay
Luc
L
Elliott
Digby
D
Roy
Eric A
EA
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D003071:Cognition / Q000502:physiology*; D004007:Dichotic Listening Tests; D004314:Down Syndrome / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D016555:Matched-Pair Analysis; D008606:Mental Processes; D000091402:Prohibitins; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology