We examined 57 patients with mild Alzheimer’s disease by using three kinds of verbal semantic memory tests (category fluency, confrontation naming and generation of verbal definition) and correlated each score with regional cerebral glucose metabolism determined by ¹⁸F-fluorodeoxyglucose and positron emission tomography. The scores of all three verbal semantic memory tests correlated significantly with regional cerebral glucose metabolism in the left inferior temporal gyrus, even after controlling for the effects of age, sex and educational attainment. In contrast, the scores of the word recall test did not correlate significantly with regional cerebral glucose metaboliosm in the left inferior temporal gyrus, neither before nor after controlling for these confounders. Our results suggested that the left inferior temporal lobe contributes to verbal semantic memory.

Motor, perceptual, and cognitive skill learning abilities of mild Alzheimer''s disease (AD) patients were compared to sex-, age-, and education-matched controls. We excluded patients who were unable to perform each skill learning task with a predetermined criterion. In those who completed the task, skill learning was as good as in normal controls. On the cognitive and perceptual skill learnings, some of the AD patients, whose cognitive but not declarative memory functions were more severely impaired than in those who completed the whole session, failed to complete the task, while all patients could complete the motor task. These results support the view that patients with mild AD can acquire motor, perceptual, and cognitive skills and that the neural system subserving procedural skill is not related to the neural systems for declarative memory.

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We describe three sibling patients with autosomal dominantly inherited sensory neuropathy, sensorineural hearing loss and dementia. The features of cognitive-behavioral deficits in the patients, including executive dysfunction, apathy, indifference and inattention, were consistent with a frontal lobe dysfunction. Magnetic resonance imaging showed a diffuse brain atrophy. A fluorodeoxyglucose positron emission tomography in one patient and a single photon emission computed tomography in another demonstrated a glucose hypometabolism or a hypoperfusion in the medial frontal and thalamic regions. Primary frontal involvement or frontal dysfunction secondary to thalamic lesions may contribute to the nature of dementia in these patients.

To elucidate the nature of language disturbance in Alzheimer’s disease (AD) and the cerebral area involved in it, we studied 65 AD patients with the Western Aphasia Battery (WAB) and with ¹⁸F-fluorodeoxyglucose and positron emission tomography. Partial correlations were evaluated between the Aphasia Quotient of WAB and regional cerebral glucose metabolism normalized by the mean metabolic rate in the bilateral primary sensorimotor areas after controlling age, sex, education and severity of illness. Language disturbance in AD is accounted for by deficits in the semantic processing of language and is related to glucose hypometabolism in the inferior temporal gyrus and inferior parietal lobule, especially in the dominant side. These results offer further evidence suggesting that the lexico-semantic processing system is mediated in these regions.