Event-related-potential low-resolution brain electromagnetic tomography (ERP-LORETA) suggests decreased energetic resources for cognitive processing in narcolepsy.
OBJECTIVE
Event-related potentials (ERPs) are sensitive measures of both perceptual and cognitive processes. The aim of the present study was to identify brain regions involved in the processes of cognitive dysfunction in narcolepsy by means of ERP tomography.


METHODS
In 17 drug-free patients with narcolepsy and 17 controls, ERPs were recorded (auditory odd-ball paradigm). Latencies, amplitudes and LORETA sources were determined for standard (N1 and P2) and target (N2 and P300) ERP components. Psychometry included measures of mental performance, affect and critical flicker fusion frequency (CFF).


RESULTS
In the ERPs patients demonstrated delayed cognitive N2 and P300 components and reduced amplitudes in midline regions, while N1 and P2 components did not differ from controls. LORETA suggested reduced P300 sources bilaterally in the precuneus, the anterior and posterior cingulate gyri, the ventrolateral prefrontal cortex and the parahippocampal gyrus. In psychometry, patients demonstrated deteriorated mood, increased trait anxiety, decreased CFF and a trend toward reduced general verbal memory and psychomotor activity.


CONCLUSIONS
Narcoleptic patients showed prolonged information processing, as indexed by N2 and P300 latencies and decreased energetic resources for cognitive processing.


CONCLUSIONS
Electrophysiological aberrations in brain areas related to the 'executive attention network' and the 'limbic system' may contribute to a deterioration in mental performance and mood at the behavioral level.
Department of Neurology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. Electronic address: michael.saletu@chello.at.
Michael
M
Saletu
Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria.
Peter
P
Anderer
Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria.
Gerda Maria
GM
Saletu-Zyhlarz
Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria.
Magdalena
M
Mandl
Department of Neurology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
Josef
J
Zeitlhofer
Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria.
Bernd
B
Saletu
D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000473:pathology* / Q000503:physiopathology; D009483:Neuropsychological Tests; D010147:Pain Measurement; D011594:Psychometrics; D014057:Tomography, X-Ray Computed / Q000379:methods