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Int J Geriatr Psychiatry. 2016 Sep;31(9):1064-74. doi: 10.1002/gps.4423. Epub 2016 Jan 25.

Amyloid deposition in semantic dementia: a positron emission tomography study.

Author information

1
Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
2
Centre for Addiction and Mental Health, Campbell Family Mental Health Research Institute, Toronto, Ontario, Canada.
3
University Health Network, Toronto, Ontario, Canada.
4
Baycrest Health Sciences, Toronto, Ontario, Canada.
5
Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada.
6
Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
7
Department of Medicine, Division of Neurology, Mt. Sinai Hospital, Toronto, Ontario, Canada.
8
Departments of Psychiatry and Neurology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.

Abstract

BACKGROUND:

Pittsburgh compound B ([11C]-PIB) identifies amyloid-β (Aβ) deposition in vivo. Asymptomatic Aβ deposition has been reported consistently in some healthy older subjects. Of patients with frontotemporal dementia, those who have later onset have a higher potential for Aβ deposition.

OBJECTIVE:

Comparison of Aβ deposition in Alzheimer's disease (AD), healthy older controls, and patients with early- and late-onset semantic dementia (SD), a subtype of frontotemporal dementia.

METHODS:

Subjects were recruited from tertiary academic care centers specializing in assessment and management of patients with neurodegenerative disease. We used the radiotracer [11C]-PIB in a high-resolution positron emission tomography scanner to evaluate 11 participants with SD (six with onset before age 65 and five with later onset), 9 with probable AD, and 10 controls over age 60. The main outcome measures were frontal, temporal, parietal, and total [11C]-PIB standardized uptake value ratios to establish PIB-positive (PIB+) cutoff.

RESULTS:

The five patients with late-onset SD were PIB-negative. Two of six with early-onset SD, seven of nine with AD, and 1 of 10 controls were PIB+. The SD participants who were PIB+ did not have memory or visuospatial deficits that are typical in AD.

CONCLUSIONS:

Aβ deposition does not seem to be associated with late-onset SD. Future larger studies might confirm whether a significant minority of early-onset SD patients exhibit Aβ deposition. Copyright © 2016 John Wiley & Sons, Ltd.

KEYWORDS:

Alzheimer disease; Pittsburgh compound B; amyloid; frontotemporal dementia; positron emission tomography; semantic dementia

PMID:
26807731
DOI:
10.1002/gps.4423
[Indexed for MEDLINE]

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