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INTRODUCTION: Despite the advances made to explain the aetiopathogenesis of Guillain-Barre syndrome (GBS), there are a number of conflicting opinions as regards its behaviour. AIM. To analyse the controversial issues regarding the clinical-epidemiological behaviour of GBS. DEVELOPMENT: We highlight the variety of opinions concerning the characterisation of GBS. We also analyse the possible causes of the regularities and irregularities in its behaviour. We believe the irregularities may be determined by environmental and genetic factors. Among the environmental factors, we consider the most important to be the variability of the previous phenomenon. There are genetically determined factors that can make some individuals more susceptible and others more vulnerable to developing GBS. We discuss the reasons that, in our view, hinder epidemiological processing using traditional statistical methods. CONCLUSIONS: GBS is a condition that behaves in a very particular manner. It displays very interesting regularities and irregularities that may be determined by the influence of environmental and genetic factors. The low incidence of the condition is a hindrance when it comes to processing epidemiological data with traditional statistical methods, which are ineffective for characterising the behaviour of the syndrome. Tools therefore need to be developed that make it possible to better study the dynamics of the syndrome and help to explain the mechanisms involved in its causality.

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Steinert's myotonic dystrophy (SMD) is a systemic-type dominant autosomal disease, with variable clinical expression. Recent magnetic resonance studies conducted in patients with this disease have described the presence of lesions in the white matter of the brain and there have also been reports of a correlation between these and the presence of cognitive disorders. Nevertheless, very little work has been published about the electroencephalographic (EEG) findings in this disease. In this study both conventional and quantitative EEG were performed on 10 patients with SMD aged between 17 and 50 years. 90 percent of the patients showed a posterior alpha rhythm that was disorganised but which reacted on opening and closing the eyes, as well as the presence of continuous theta activity over the base activity that was bilaterally more pronounced towards the frontal-central regions. In the quantitative analysis we observed an increase in the absolute energies for the slow bands and a decrease for the fast bands on the frequency spectrum. In most patients (80 percent) spectral peaks were found within the theta range of frequencies as a correlate of the slow activity observed in the conventional analysis...(AU)

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INTRODUCTION: Steinert's myotonic dystrophy (SMD) is a systemic-type dominant autosomal disease, with variable clinical expression. Recent magnetic resonance studies conducted in patients with this disease have described the presence of lesions in the white matter of the brain and there have also been reports of a correlation between these and the presence of cognitive disorders. Nevertheless, very little work has been published about the electroencephalographic (EEG) findings in this disease. PATIENTS AND METHODS: In this study both conventional and quantitative EEG were performed on 10 patients with SMD aged between 17 and 50 years. RESULTS: 90% of the patients showed a posterior alpha rhythm that was disorganised but which reacted on opening and closing the eyes, as well as the presence of continuous theta activity over the base activity that was bilaterally more pronounced towards the frontal-central regions. In the quantitative analysis we observed an increase in the absolute energies for the slow bands and a decrease for the fast bands on the frequency spectrum. In most patients (80%) spectral peaks were found within the theta range of frequencies as a correlate of the slow activity observed in the conventional analysis. CONCLUSIONS: It can be concluded that a quantitative EEG could be useful in the study of what, for many years, has been considered to be a 'neuromuscular' disease and that the use of other more precise methods, such as cerebral coherence and brain electrical tomography, could shed new light on the functional management of these patients.

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INTRODUCTION: Multifocal motor neuropathy is a severe chronic demyelinating, disimmune, crippling and potentially treatable disease. The clinical features are characterized by a syndrome of progressive motor deficiency with muscle atrophies, fasciculations, areflexia, myokimias and cramps, that sometimes we misdiagnosed as motor neuron disease. Electrophysiologically it is characterized by the occurrence of multifocal conduction blocks of motor fibres. CLINICAL CASES: Three patients with asymmetric multifocal motor neuropathy are reported in whom diagnosis was made by nerve conduction studies. All the patients had developed an asymmetric chronic progressive motor deficit that involved mostly upper limbs. One patient exhibited mild tactile sensory disturbances and a sural nerve biopsy showed moderated involvement of myelinated fibers. All the patients showed electrophysiologically, multifocal conduction blocks of motor fibers with spared conduction through sensory fibers at the same segments where motor conduction was blocked. The response to high doses intravenous cyclophosphamide therapy followed by 100 mg orally for six months, was satisfactory in all three patients. There was no response to previous trials with prednisone, azathioprine, and intravenous immunoglobulin. One patient was also submitted to several sessions of plasma exchange without benefit. The patient had been previously diagnosed as having motor neuron disease. CONCLUSION: The importance of early diagnosis of this disorder and the possibility of successful treatment with high doses of intravenous cyclophosphamide is stressed.

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