PROGRESSIVE NONFLUENT APHASIA - LANGUAGE, COGNITIVE, AND PET MEASURESCONTRASTED WITH PROBABLE ALZHEIMERS-DISEASE

The purpose of this study was to compare the language and cognitive pr ofiles of four progressive nonfluent aphasia (PNFA) patients with 25 p robable Alzheimer's disease (pAD) patients, and to identify the distin ct cortical defects associated with cognitive deficits in PNFA using p ositron emission tomography (PET). Longitudinal observations of PNFA p atients revealed progressively telegraphic speech and writing and a gr adual deterioration of sentence comprehension, but memory and visual f unctioning were relatively preserved. Direct. contrast with pAD patien ts revealed that PNFA patients are significantly impaired on grammatic al phrase structure aspects of sentence comprehension and expression, phonemic judgments, repetition, and digit span, but not on other cogni tive measures. PET studies of PNFA revealed reduced cortical activity throughout the left hemisphere. In addition, there was a prominent def ect in left superior and middle temporal and inferior frontal regions of PNFA patients that differed significantly from the distribution of regional cerebral dysfunction in pAD. We conclude that PNFA is associa ted with a distinct profile of language and cognitive difficulty, and that this pattern of impairment is related to cortical dysfunction in a specific distribution of the left hemisphere.