Neurophysiological assessment of patients with type 2 spinocerebellar ataxia
Introduction. Type 2 spinocerebellar ataxia (SCA2) is the condition most often described (to date) in patients with hereditary ataxia, its prevalence being 52 per 100,000 persons. Objective. In patients with SCA2 neurogenic patterns are identified by means of electrophysiological techniques. Patients and methods. A transverse study was made of 70 persons with SCA2 of different periods of duration and from different regions of the country. The control group was made up of 108 volunteers. Electrophysiological recordings made were: conventional and quantitative electromyography, late F wave and H reflex responses. Multivariate methods with a confidence interval of 95% (α= 0.05) were used for statistical analysis. Results. Conventional electromyography showed a pattern of isolated contractions, predominantly in patients who had had the disorder ≤5 years, classified as Grade I by the authors; in those with a history of >5 years there was a pattern of very isolated contractions with motor potentials of amplitudes >10 µV, without denervation, classified as Grade II. The patients with worse clinical condition were concentrated in this latter group. Significant differences were observed between Groups I, II and control and also regarding the late responses of the F wave and H reflex. Conclusions. For the first time two types of neurogenic patterns of SCA2 have been established to describe alterations which denote participation of the first and second motor neurones
Objetivo Identificar con técnicas electrofisiológicas la existencia de patrones neurógenos en enfermos de AEC2.
Pacientes y métodos Se realizó un estudio transversal a 70 sujetos enfermos de AEC2 con tiempo de evolución variable y procedentes de diferentes regiones del país. El grupo control contó con 108 sujetos voluntarios. Registros electrofisiológicos realizados: electromiografía convencional y cuantitativa, y respuestas tardías onda F y reflejo H. En el análisis estadístico se aplicaron métodos multivariados con una confiabilidad del 95% (a= 0,05).
Resultados El electromiograma convencional mostró un patrón de contracción aislado, predominante en enfermos con tiempo de evolución £5 años, denominado por los autores grado I, y en los de tiempo >5 años se encontró un patrón muy aislado con potenciales de unidades motoras de amplitudes >10 mV, sin desnervación, denominado grado II. En este último patrón neurógeno se concentraron los enfermos con manifestaciones clínicas más graves. Existieron diferencias significativas al comparar los patrones grado I y II con el grupo control, así como en las respuestas tardías onda F y reflejo H.
Conclusiones Se definieron por primera vez dos tipos de patrón neurógeno en la AEC2 para describir alteraciones que denotan participación de la primera y segunda motoneurona
