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E E Medina

Publications and source records attributed to E E Medina.

6 recordsLinked to original sources
PubMed1998

[Neurophysiological evaluation of patients with spinocerebellar ataxia type 2].

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% (alpha = 0.05) were used for statistical analysis. RESULTS: Conventional electromyography showed a pattern of isolated contractions, predominantly in patients who had had the disorder < or = 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 microV, 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.

Adolescent↗
PubMed1998

[Electrophysiological characteristics of asymptomatic relatives of patients with type 2 spinocerebellar ataxia].

INTRODUCTION: Electrophysiological studies have been shown to be useful in hereditary ataxia, but only a small number of patients have been studied, and the duration of the illness, serial studies and molecular definition have not been taken into account. OBJECTIVE: We proposed, by means of electrophysiological techniques, to characterize the functional evolutionary state of the afferent and efferent systems in asymptomatic relations of patients with type 2 spinocerebellar ataxia (SCA2). Patients and methods. A 10 year longitudinal, prospective study was made of 59 children of patients with SCA2. The sequence included four studies: 1986, 1991, 1994 and 1996, all with informed consent for the investigation. The control group consisted of 108 volunteers. The electrophysiological studies recorded were: conduction studies in peripheral nerves and multimodal evoked potentials. For statistical analysis multivariate methods were used with a confidence interval of 95% (alpha = 0.05). RESULTS: Electrophysiological alterations were observed even in the absence of clinical signs, such as reduced amplitude of sensory potentials, morphological changes and prolonged latency of the central components of somatosensory evoked potentials, and of brain stem auditory evoked potentials, whilst the visual evoked potentials remained normal. Of 79 relations studied during the 10 year investigation, 17 had clinical signs and were considered to be patients with SCA2. CONCLUSIONS: Four stages of the illness were defined: 'healthy', presymptomatic, and patients with and without nerve conduction block. These characterized the degenerative mechanisms of the afferent and efferent systems of the relations of patients with SCA2 who became ill themselves.

Adolescent↗