Gordon and Bogen (1974)
GORDON, H.W. and J.E. Bogen. “Hemispheric Lateralization of Singing after Intracarotic Sodium Amylobarbitone.” Journal of Neurology, Neurosurgery, and Psychiatry 37 (1974): 727-38.
The experimenters examined subjected utilizing a presurgical screening procedure, which transiently depresses one hemisphere of the brain for 5-15 minutes, using a sodium amylobarbitone solution to one or the other carotid arteries. The procedure is used in part to identify hemispheric dominance and lateralization of function. All patients were severe epileptics being considered for cerebral commissurotomy, which cuts the fibers of the corpus callosum connecting the two hemispheres of the brain. During depression of each hemisphere, patients were requested or encouraged to speak and sing, by means of verbal requests and demonstrations, in order to compare functions attributable to each hemisphere singly. This has been described as a transient reversible hemispherectomy as it can permit the comparison of functioning under the control of one hemisphere to baseline functioning of both, before and after the procedure. The findings were that singing was more impaired than speech after depression of the right hemisphere, whereas the opposite was true during depression of the left hemisphere. However, notable was the fact that singing did not appear in either case until at least one spoken word had been elicited. While the authors claim speech intonation was normal during right hemisphere depression, despite loss of pitch control during singing, and suggest that control of pitch for speech may be lateralized opposite the same for song, their means of assessing speech intonation is not described. They mention phonetic pitch and stress as normal, but fail to distinguish the different types of prosody (i.e. linguistic vs. affective). Since a finding of normal affective intonation during right hemisphere depression would be remarkable considering the preponderance of evidence from later studies (cf. Zurif 1974, Ross & Mesulam 1979, and Ross 1981) suggesting otherwise, it is likely that the experimenters in this study failed to notice loss of affective expression, while sentence stress for example appeared normal.
