Fluorodeoxyglucose F18 positron emission tomography in progressive apraxia of speech and primary progressive aphasia variants.
OBJECTIVE
To determine patterns of hypometabolism on fluorodeoxyglucose F18 positron emission tomography (FDG-PET) in patients with progressive apraxia of speech (PAS) and primary progressive aphasia (PPA) variants and to use these patterns to further refine current classification.


METHODS
We identified all patients who had FDG-PET and PAS or PPA who were evaluated by an expert speech-language pathologist. Patterns of hypometabolism were independently classified by 2 raters blinded to clinical data. Three speech-language pathologists reclassified all patients into 1 of 7 operationally defined categories of PAS and PPA blinded to FDG-PET data.


METHODS
Tertiary care medical center.


METHODS
Twenty-four patients with PAS or PPA and FDG-PET.


METHODS
Fluorodeoxyglucose F18 PET hypometabolic pattern.


RESULTS
Of the 24 patients in the study, 9 had nonfluent speech output; 14, fluent speech; and 1 was unclassifiable. Twenty-one patients showed FDG hypometabolism; the remaining 3 did not. Among the patients showing hypometabolism, 8 had a prerolandic pattern of which 7 had nonfluent speech including progressive nonfluent aphasia (n = 3), PAS (n = 1), and mixed nonfluent aphasia/apraxia of speech (n = 3); the other patient had PPA unclassifiable. The remaining 13 had a postrolandic pattern, all with fluent speech (P < .001), including logopenic progressive aphasia (n = 6), progressive fluent aphasia (n = 6), and semantic dementia (n = 1). Patterns of hypometabolism differed between the nonfluent variants and between the fluent variants, including progressive fluent aphasia.


CONCLUSIONS
Patterns of FDG-PET hypometabolism support the clinical categorizations of fluency, the distinction of apraxia of speech from progressive nonfluent aphasia, and the designation of a progressive fluent aphasia category.
Josephs
Keith A
KA
Department of Neurology, Division of Behavioral Neurology, Mayo Clinic, Rochester, Minnesota 55905, USA. josephs.keith@mayo.edu
Duffy
Joseph R
JR
Fossett
Tepanta R
TR
Strand
Edythe A
EA
Claassen
Daniel O
DO
Whitwell
Jennifer L
JL
Peller
Patrick J
PJ
D000368:Aged; D000369:Aged, 80 and over; D018888:Aphasia, Primary Progressive / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology*; D001072:Apraxias / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology*; D001931:Brain Mapping; D015331:Cohort Studies; D003937:Diagnosis, Differential; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests
D019788:Fluorodeoxyglucose F18