Neurophysiological evaluation in patients with clinically defined multiple sclerosis with special reference to the study of the P300 wave
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.
Objetivo Evaluar el estudio de la onda P300 en un grupo de pacientes con EM.
Pacientes y métodos Se estudió la onda P300 en 26 pacientes, 22 mujeres y 4 varones, con EM clínica definida (criterios de Poser et al), y con estudios de velocidad de conducción motora y sensitiva normales. A todos se les realizó una batería de potenciales evocados multimodales (PEM), imágenes de resonancia magnética nuclear y estudio inmunológico de líquido cefalorraquídeo. Diecisiete pacientes tenían la forma clínica exacerbaciónremisión (ER) y 9 la forma progresiva primaria (PP).
Resultados Los PEM más alterados fueron los potenciales evocados visuales y los potenciales evocados somatosensoriales (PESS) de los pacientes con EM. Al comparar las formas clínicas evolutivas, los PESS fueron estadísticamente significativos en la forma clínica PP, lo que podría explicarse por el mayor compromiso de la médula espinal de estos enfermos. Realizamos análisis comparativos de la onda P300 con 26 sujetos sanos de edades y sexos similares a los enfermos, y encontramos diferencias significativas para la latencia y la amplitud de P300 entre el grupo de EM y los controles. Los pacientes con mayor tiempo de evolución de la enfermedad mostraron anomalías en la P300 significativamente superiores.
Conclusión El estudio evolutivo de la P300, de fácil ejecución y bajo coste, podría tener valor para la evaluación evolutiva de las alteraciones cognitivas en los pacientes con EM
