Reduced prefrontal N-acetylaspartate in stroke patients with apathy.
BACKGROUND
Although substantial numbers of stroke patients suffer from apathy, its causes are still poorly understood. Previous studies suggest that dysfunction of the frontal lobes is implicated in the pathophysiology of motivation. Our aim was to investigate the association between proton magnetic resonance spectroscopy (H1-MRS) measurements in unaffected frontal lobes and apathy in a group of first-time stroke patients.


METHODS
31 patients with a first-time ischemic stroke located outside the frontal lobes and 20 healthy subjects were included in the study. The authors performed single voxel H1-MRS in order to measure the N-acetylaspartate/creatine (NAA)/Cr, glutamate+glutamine (Glx)/Cr, choline (Cho)/Cr and myo-inositol (mI)/Cr ratios in the frontal lobes. Patients were assessed between days 7 and 12 post stroke. Diagnosis of apathy was made on the basis of clinical observation, interview and Apathy Scale.


RESULTS
13 out of 31 patients (42%) demonstrated apathy. Patients with apathy had lower NAA/Cr ratios in the right frontal lobe than non-apathetic subjects. The patient group was divided into two subgroups: Those with left hemisphere strokes, and those with right hemisphere strokes. Of these subjects, significantly lowered NAA/Cr ratios were found in the right hemispheres of apathetic patients in the subgroup with left-sided brain lesions.


CONCLUSIONS
These findings point to the association between apathy and frontal lobe integrity, suggest different reactions of the hemispheres and indicate that changes in the NAA/Cr ratio are related to the apathy.
Glodzik-Sobanska
Lidia
L
Center for Brain Health, NYU School of Medicine, 550 First Avenue, HN-400, NY 10016-6481, USA. lidia.sobanska@med.nyu.edu
Slowik
Agnieszka
A
Kieltyka
Agnieszka
A
Kozub
Justyna
J
Sobiecka
Barbara
B
Urbanik
Andrzej
A
Szczudlik
Andrzej
A
D000368:Aged; D000369:Aged, 80 and over; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D003863:Depression / Q000523:psychology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009042:Motivation; D017397:Prefrontal Cortex / Q000378:metabolism* / Q000473:pathology; D011569:Psychiatric Status Rating Scales; D020521:Stroke / Q000378:metabolism* / Q000473:pathology / Q000523:psychology*
D001224:Aspartic Acid; C000179:N-acetylaspartate