Subcortical aphasia: a longitudinal PET study.
OBJECTIVE
Very few neuroimaging studies have focused on follow-up of subcortical aphasia. Here, overt language production tasks were used to correlate regional cerebral blood flow (rCBF) changes and language performance in patients with vascular subcortical lesions.


METHODS
Seven aphasic patients were scanned twice with positron emission tomography (PET) at 1-year interval during a word-generation task. Using SPM2, Language-Rest contrast at PET1 was correlated to language performance and to time-lag from stroke. The same contrast was performed at PET2 and session effect (PET2-PET1) was correlated with performance improvement.


RESULTS
At PET1, correlation between rCBF and delay from stroke involved mainly ventral regions of the left temporal cortex and mesial frontal cortex. Correlations between rCBF and performance showed predominantly left dorsal regions in the frontal, temporal, and parietal lobes, but also the left ventral temporal cortex. One year apart, language performance improved and rCBF increased in perisylvian regions bilaterally. Best performers at PET2 showed an increase of activity in left ventral temporal cortex as well as in right middle temporal gyrus.


CONCLUSIONS
On follow-up, expected language improvement and increase of activation in the classical language areas and their counterparts were observed. Moreover, all correlational analyses both at PET1 and on follow-up implicated the anterior part of the left inferior temporal gyrus, suggesting a disconnection between the superior and inferior parts of the left temporal cortex and a specific role for this region in lexical semantic processing.
de Boissezon
Xavier
X
INSERM U455, University Hospital Purpan, Toulouse, France.
Démonet
Jean-François
JF
Puel
Michèle
M
Marie
Nathalie
N
Raboyeau
Gaëlle
G
Albucher
Jean-François
JF
Chollet
François
F
Cardebat
Dominique
D
D000328:Adult; D000368:Aged; D001039:Aphasia, Broca / Q000473:pathology* / Q000628:therapy*; D001041:Aphasia, Wernicke / Q000473:pathology* / Q000628:therapy*; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D005625:Frontal Lobe / Q000473:pathology; D006801:Humans; D007802:Language; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D020521:Stroke / Q000473:pathology* / Q000628:therapy*; D013702:Temporal Lobe / Q000473:pathology; D016896:Treatment Outcome