Working memory deficits and levels of N-acetylaspartate in patients with schizophreniform disorder.
OBJECTIVE
The authors used proton magnetic resonance spectroscopic imaging ((1)H-MRSI) to assess potential reductions of N-acetylaspartate (a marker of neuronal integrity) in the hippocampal area and dorsolateral prefrontal cortex of patients with schizophreniform disorder. In addition, they assessed the relationship between N-acetylaspartate levels and working memory deficits.


METHODS
Twenty-four patients with DSM-IV schizophreniform disorder and 24 healthy subjects were studied. Subjects underwent (1)H-MRSI and were given the N-back working memory test.


RESULTS
The schizophreniform disorder patients had selective reductions of N-acetylaspartate ratios in the hippocampal area and the dorsolateral prefrontal cortex, and a positive correlation was seen between N-acetylaspartate ratios in the dorsolateral prefrontal cortex and performance during the 2-back working memory condition.


CONCLUSIONS
Similar to findings reported in schizophrenia studies, N-acetylaspartate reductions in the hippocampal area and the dorsolateral prefrontal cortex were seen in patients with schizophreniform disorder. Moreover, the results support other evidence that neuronal pathology in the dorsolateral prefrontal cortex accounts for a proportion of working memory deficits already present at illness outset.
Bertolino
Alessandro
A
Department of Psychiatry and Neurological Sciences, University of Bari, Italy. bertolia@psichiat.uniba.it
Sciota
Domenico
D
Brudaglio
Flora
F
Altamura
Mario
M
Blasi
Giuseppe
G
Bellomo
Antonello
A
Antonucci
Nicola
N
Callicott
Joseph H
JH
Goldberg
Terry E
TE
Scarabino
Tommaso
T
Weinberger
Daniel R
DR
Nardini
Marcello
M
D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis* / Q000378:metabolism; D003401:Creatine / Q000032:analysis / Q000378:metabolism; D005260:Female; D006624:Hippocampus / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000378:metabolism; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000737:chemistry* / Q000378:metabolism; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000378:metabolism
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine