Early cortical gray matter loss and cognitive correlates in non-demented Parkinson's patients.
BACKGROUND
Whereas the motor dysfunction in Parkinson's disease (PD) has been related to deficits in basal ganglia (BG) structures, neural correlates of cognitive changes remain to be fully defined. This study tested the hypothesis that cognitive changes in non-demented PD may be related to cortical gray matter (GM) loss.


METHODS
High-resolution T1-weighted magnetic resonance images of the brain and comprehensive cognitive function tests were acquired in 40 right-handed, non-demented PD subjects and 40 matched controls. GM changes were assessed using voxel-based morphometry (VBM) in FSL. VBM and cognitive results were compared between PD and controls, and correlation analyses were performed between those brain areas and cognitive domains that showed significant group differences.


RESULTS
PD patients demonstrated significant GM reduction localized predominantly in frontal and parieto-occipital regions. Patients also showed reduced performance in fine motor speed and set-shifting compared to controls. Fine motor speed and set-shifting were associated with GM volume in the frontal cortex in controls, whereas these domains were associated primarily with occipital GM regions in PD patients.


CONCLUSIONS
Non-demented PD subjects demonstrate cortical structural changes in frontal and parieto-occipital regions compared to controls. The association between typically recognized "frontal lobe" function and occipital lobe volume suggested a compensatory role of occipital lobe to primary fronto-striatal pathology in PD. Further longitudinal study of these changing structure-function relationships is needed to understand the neural bases of symptom progression in PD.
Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, USA.
Eun-Young
EY
Lee
Suman
S
Sen
Paul J
PJ
Eslinger
Daymond
D
Wagner
Michele L
ML
Shaffer
Lan
L
Kong
Mechelle M
MM
Lewis
Guangwei
G
Du
Xuemei
X
Huang
D002540:Cerebral Cortex / Q000473:pathology*; D003071:Cognition; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000473:pathology*
Cognition; Gray matter volume; MRI; Parkinson's disease; Voxel-based morphometry