Correlation of global N-acetyl aspartate with cognitive impairment in multiple sclerosis.
BACKGROUND
Whole-brain N-acetyl aspartate (NAA), a measure of neuronal function, can be assessed by multislice echo-planar spectroscopic imaging.


OBJECTIVE
To test the hypothesis that the global brain NAA/creatine (Cr) ratio is a better predictor of cognitive dysfunction in multiple sclerosis than conventional magnetic resonance imaging measures.


METHODS
Survey.


METHODS
Research-oriented hospitals.


METHODS
Twenty patients, 16 women and 4 men (mean age, 36 years), with early relapsing-remitting multiple sclerosis (mean Expanded Disability Status Scale score, 2.5).


METHODS
Correlation between the global NAA/Cr ratio and a cognitive dysfunction factor comprising 16 measures from an extensive neuropsychological test battery that best distinguished patients with multiple sclerosis from healthy control subjects.


RESULTS
A significant partial correlation between the global NAA/Cr ratio and the cognitive dysfunction factor was found (partial r = 0.62, P = .01), and 9 cognitively impaired patients had significantly lower global NAA/Cr ratios than 11 unimpaired patients (P = .04). No significant correlations were found between the cognitive dysfunction factor and conventional magnetic resonance imaging measures (ie, brain parenchymal fraction and lesion volume).


CONCLUSIONS
Multislice echo-planar spectroscopic imaging provides global metabolic measures that distinguish between cognitively impaired and unimpaired patients with multiple sclerosis and correlate with a global cognitive measure. Standardization of the technique is needed, and larger-scale studies that include healthy controls are suggested.
Mathiesen
Henrik Kahr
HK
Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Kettegaard Alle 30, DK-2650 Hvidovre, Denmark. henrikm@drcmr.dk
Jonsson
Agnete
A
Tscherning
Thomas
T
Hanson
Lars G
LG
Andresen
Jente
J
Blinkenberg
Morten
M
Paulson
Olaf B
OB
Sorensen
Per Soelberg
PS
D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism*; D004185:Disability Evaluation; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000150:complications* / Q000523:psychology*; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests
D001224:Aspartic Acid; C000179:N-acetylaspartate