[Neurophysiological assessment in patients with clinically defined multiple sclerosis with special reference to P300 wave study].

INTRODUCTION

In the cognitive sphere, alterations have been found in up to 65% of patients with multiple sclerosis (MS). Study of the P300 wave is a positive component of long latency related to cognitive function: amplitude with attention, and latency with the ability to process information.

OBJECTIVE

To assess a study of the P300 wave in a group of patients with MS.

PATIENTS AND METHODS

The P300 wave was studied in 26 patients, 22 women and 4 men, with definite clinical MS (on criteria of Poser et al), with normal motor and sensory conduction velocity studies. All patients had a battery of multi-modal evoked potentials (MEP), nuclear magnetic resonance imaging and immunological study of the cerebrospinal fluid. Seventeen patients had the exacerbation-remission (ER) and nine the primary progressive (PP) clinical forms of the disorder.

RESULTS

The most markedly altered MEP were the visual and somatosensory evoked potentials (SSEP) of the patients with MS. When the types of clinical course were compared, the SSEP were statistically significant in the PP form, which may be explained by the greater spinal involvement of these patients. Comparative analysis of the P300 wave was done for 26 healthy patients of similar age and sex to that of the patients, and significant differences were found in P300 latency and amplitude between the MS and control groups. The patients who had had the disease for longer had significantly greater anomalies in the P300 waves.

CONCLUSION

Study of the evolution of the P300 wave, which is cheap and easy to do, may be valuable in the evolutional assessment of cognitive changes in patients with MS.