The Midnight Disease by Alice Weaver Flaherty

Author:Alice Weaver Flaherty
Language: eng
Format: epub
Publisher: Houghton Mifflin Harcourt

If language function is so strongly lateralized in the brain that Broca’s and Wernicke’s areas are found only in the left hemisphere, what are the equivalent areas in the right hemisphere doing? They are not irrelevant to speech processing, but their role appears to center around interpreting and producing vocal inflections and the emotional tone of speech. For instance, a lesion in the right hemisphere counterpart of Wernicke’s area produces an insensitivity to tone that can block the ability to appreciate humor, irony, passion. A lesion in the right hemisphere counterpart of Broca’s area produces speech with unusual inflections and tone that neurologists have called, for lack of a more confusing Latin name, robotic speech or sudden foreign accent syndrome. Neurologists, whose dreams are different from those of other folks, dream of finding a patient with this syndrome. When I was a resident, we thought we had found one, but it turned out that he was just from Montreal.

The neurologist Oliver Sacks tells of a ward of aphasic patients listening to President Reagan give a speech on television. Although unable to fully understand his words, the patients compensated by being particularly sensitive to his tone and inflections, which they found farcical. A patient with a right hemisphere lesion who could not judge tone was also present. She concentrated on Reagan’s exact words—which she too found ridiculous. Sacks concluded from this that it takes a fully working brain to be deluded by politicians. Nancy Etcoff and her colleagues confirmed Sacks’s anecdote experimentally by showing that in a controlled setting aphasics had better lie-detecting ability than undergraduates at the Massachusetts Institute of Technology. Lest anyone object that MIT students do not count as completely normal controls, she also had a smaller group of more typical control subjects.

Right hemisphere counterparts of Wernicke’s and Broca’s area are also important for the interpretation and generation of melody. This fact fits with the hypothesis that the first music was song and that it arose directly from highly inflected, emotional speech. Electrical stimulation of the right hemisphere equivalent of Wernicke’s area can cause musical hallucinations. In fact, the composer Dmitry Shostakovich, who reportedly had a metallic shell fragment resting against his temporal lobe, said, “Since the fragment has been there, each time [I lean] my head to one side, I can hear music—different each time!” Reportedly he would use this method while composing, producing melodic ideas for his symphonies.

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