SINGING WITH AND WITHOUT WORDS - HEMISPHERIC ASYMMETRIES IN MOTOR CONTROL

Singing is relatively preserved and can even improve the language prod uction of aphasic patients who have lesions of the left hemisphere but an intact right hemisphere. In contrast, singing is impaired followin g lesions or anesthesia of the right hemisphere, suggesting a right he misphere role in singing. To assess the influence of singing upon hemi spheric control of articulatory output in normal subjects, we measured lip opening asymmetry by single-frame photographic analysis. Spontane ous speech, reciting the words of a song, and singing with words all s howed right-side lip opening superiority, revealing a major left hemis phere role in control of verbal articulation. Singing without words, o n the other hand, did not show asymmetric facial motor activation, sug gesting that the right hemisphere also participates in singing. In add ition, we assessed auditorily perceivable differences in articulation when lip movement on one side of the mouth was artificially restricted (hemibuccal speech). Articulation quality was higher when speaking fr om the right side of the mouth.