Linguistic processing and reaction time differences in stutterers and nonstutterers.

Linguistic processing by the left and right cerebral hemispheres was investigated in 10 adult male stutters and 10 matched nonstutterers. Subjects performed a lexical decision task in which nonword and real-word stimuli were presented tachistoscopically to the right and left visual hemifields. Vocal and manual reaction times to real words were measured to assess hemispheric participation in processing linguistic information and to determine differences between response modes. The stuttering group exhibited a left visual field efficiency or right hemisphere preference for this task and were slower in both vocal and manual reaction times. Ramifications for hemispheric processing theories and laryngeal dysfunction hypotheses are discussed.