Faculty Bibliography

A 54-year-old man abruptly became mute with mild right hemiparesis. Written expression, comprehension of speech and print, calculating ability, and verbal short-term recall, although slow, were largely preserved. Extensive studies demonstrated complete loss of inner speech. He was unable to speak to himself and unable to appreciate the phonological structure of words. Instead, his preserved language skills were based on a highly developed visual imagery. This case greatly extends the range of language skills previously thought possible in individuals who suffer the loss of inner speech

A 51-year-old man developed severe quadriparesis without sensory loss after a fall on the occiput. When he was treated with corticosteroids, the weakness worsened slightly for 2 days, but he then progressively improved and ultimately walked unassisted. Two months later, postmortem examination disclosed metastatic tumors in the superior portion of each precentral gyrus. The subjacent white matter was edematous. No spinal cord abnormalities were found. The clinical, radiologic, and neuropathologic findings suggest that the quadriplegia resulted from these bilateral cerebral lesions and not from spinal cord dysfunction. The rapid development of cerebral edema, perhaps precipitated by trauma, seemed to account for the acute onset of symptoms in this case

A 6-year-old boy developed hemorrhage in the left temporal lobe and subsequently underwent left temporal lobectomy. Afterwards, he was completely unable to learn to read or write. Psychological tests showed impairment in verbal learning and memory, with right ear and right visual field superiority in verbal perception. A Wada test showed no aphasia after right carotid injection. We conclude that damage to the speech-dominant temporal lobe resulted in the inability to learn to read or write. Despite the lesion, speech remained strongly lateralized to the left hemisphere, accounting for the right-sided advantage in verbal perception. Some patients with developmental dyslexia may have dysfunction of a strongly dominant left hemisphere rather than a delay or incompleteness of language lateralization

Severe Broca aphasia and left hemiplegia without right limb apraxia occurred suddenly in a right-handed man with no personal or family history of left-handedness. Postmortem examination showed infarction of the right hemisphere, limited almost entirely to the precentral gyrus. In this patient, cerebral dominance for speech lay in the right hemisphere, but dominance for limb praxis lay in the left. This case provides evidence that cerebral dominance for speech and handedness in dextrals may be dissociated. It also suggests that lesions of the precentral gyrus are of major importance in producing Broca aphasia

Visual discrimination was studied in each visual field of a patient with surgical section of the posterior corpus callosum. Light-detection thresholds were increased nearly equally in right and left visual fields, suggesting that normal thresholds require the cooperative activity of both posterior cerebral hemispheres, mediated by the corpus callosum. In contrast, there was superiority in the right visual field in naming, coping, and matching letter, number, and colors, but not unfamiliar shapes. The results are attributed to a differential effect of experience on perception in each visual field. The right-visual-field superiority in learning to perceive arrays on letters, numbers, and colors may result directly from the superiority of the left hemisphere in speech