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Fluorodeoxyglucose positron emission tomography in semantic dementia after 6 months of memantine: an open‐label pilot study
Author(s) -
Chow Tiffany W.,
Fam David,
GraffGuerrero Ariel,
Verhoeff Nicolaas P. G.,
TangWai David F.,
Masellis Mario,
Black Sandra E.,
Wilson Alan A.,
Houle Sylvain,
Pollock Bruce G.
Publication year - 2013
Publication title -
international journal of geriatric psychiatry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 129
eISSN - 1099-1166
pISSN - 0885-6230
DOI - 10.1002/gps.3832
Subject(s) - memantine , positron emission tomography , frontotemporal dementia , dementia , semantic dementia , anterior cingulate cortex , psychology , audiology , fluorodeoxyglucose , insula , nuclear medicine , placebo , medicine , orbitofrontal cortex , neuroscience , cognition , prefrontal cortex , pathology , alternative medicine , disease
Objectives To follow up on the increases we reported in normalized metabolic activity in salience network hubs from a 2‐month open‐label study of memantine in frontotemporal dementia (FTD). Methods We repeated fluorodeoxyglucose positron emission tomography (FDG‐PET) after 6 months of drug use and subjected the data to Statistical Parametrical Mapping (SPM) analysis to reveal clusters of significant change from baseline. We also sought correlations between changes in behavioral disturbances on the Frontal Behavioral Inventory (FBI) and the PET signal. Results Recruitment of one progressive nonfluent aphasia and one behavioral variant FTD precluded statistical analysis for any FTD subtype other than semantic dementia (SD). The baseline‐to‐6‐month interval showed increased normalized metabolic activity in the left orbitofrontal cortex ( p < 0.002) for five participants with SD. The 2–6‐month interval revealed a late increase in normalized metabolic activity in the left insula ( p < 0.013), right insula ( p < 0.009), and left anterior cingulate ( p < 0.005). The right anterior cingulate showed both an initial increase and a delayed further increase (2–6 months, p < 0.016). FBI scores worsened by 43.3%. One participant with SD opted not to continue memantine beyond 2 months yet showed similar FDG‐PET increases. Conclusions Increases in normalized cortical metabolic activity in salience network hubs were sustained in SD over a 6‐month period. Because one participant without medication also showed these changes, further investigation is recommended through a double‐blind, placebo‐controlled study with FDG‐PET as an outcome measure. Copyright © 2012 John Wiley & Sons, Ltd.