Primary progressive aphasia: PPA and the language network

Authors

  • Sreepadma P. Sonty BA,

    1. Cognitive Neurology and Alzheimer's Disease Center
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  • M.-Marsel Mesulam MD,

    1. Cognitive Neurology and Alzheimer's Disease Center
    2. Department of Neurology, Northwestern University, Chicago, IL
    3. Department of Psychiatry, Northwestern University, Chicago, IL
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  • Cynthia K. Thompson PhD,

    1. Cognitive Neurology and Alzheimer's Disease Center
    2. Department of Neurology, Northwestern University, Chicago, IL
    3. Department of Communication Sciences and Disorders, Northwestern University, Chicago, IL
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  • Nancy A. Johnson PhD,

    1. Cognitive Neurology and Alzheimer's Disease Center
    2. Department of Psychiatry, Northwestern University, Chicago, IL
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  • Sandra Weintraub PhD,

    1. Cognitive Neurology and Alzheimer's Disease Center
    2. Department of Psychiatry, Northwestern University, Chicago, IL
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  • Todd B. Parrish PhD,

    1. Cognitive Neurology and Alzheimer's Disease Center
    2. Department of Radiology, Northwestern University, Chicago, IL
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  • Darren R. Gitelman MD

    Corresponding author
    1. Cognitive Neurology and Alzheimer's Disease Center
    2. Department of Neurology, Northwestern University, Chicago, IL
    3. Department of Radiology, Northwestern University, Chicago, IL
    4. VA Chicago Lakeside Division, Chicago, IL
    • 320 E. Superior Street, Searle 11-470, Chicago, IL 60611
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  • This article is a US Government work and, as such, is in the public domain in the United States of America.

Abstract

Primary Progressive Aphasia (PPA) is a behaviorally focal dementia syndrome with deterioration of language functions but relative preservation of other cognitive domains for at least the first two years of disease. In this study, PPA patients with impaired word finding but intact comprehension of conversational speech and their matched control subjects were examined using voxel-based morphometry (VBM) and functional magnetic resonance imaging (fMRI). fMRI compared signal changes during phonological and semantic language tasks with those during a control task (matching letters). PPA patients showed longer reaction times and reduced accuracy versus controls on the language tasks, but no performance differences on the control task. VBM demonstrated reduced gray matter in left superior temporal and inferior parietal regions in the PPA group. However, these patients showed a normal pattern of activation within the classical language regions. In addition, PPA patients showed activations, not seen in normals, in fusiform gyrus, precentral gyrus, and intra-parietal sulcus. These activations were found to correlate negatively with measures of naming and task performance. The additional activations in PPA may therefore represent a compensatory spread of language-related neural activity or a failure to suppress activity in areas normally inhibited during language tasks. Ann Neurol 2003;53:000–000

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