Archivos de neurobiologia最新文献

Visual evoked responses were recorded in response to a series of consonants and non-linguistic signs randomly presented. We compared, with a sample of 16 young volunteers, P300 and N400 latency and amplitude in order to detect possible asymmetries. Results in amplitude showed a significant asymmetry within right hemisphere, both in P300 and N400 components. Latency results failed to present any significant difference during the discrimination of consonants, while non-linguistic signs discrimination reflect an asymmetrical tendency in P300 component.

Dystonia is a movement disorder characterized by sustained twisting movements and muscle contractions and abnormal postures. Dystonia is a symptom present in many diseases of the central nervous system. Anatomical data reveal that dystonia appears in diseases involving the basal ganglia, diencephalon, brain stem and cerebellum. Physiological studies revealed an abnormal facilitation of polysynaptic reflexes at the brain stem level. A common pathogenic mechanism for dystonia must be found in order to delineate in effective treatment. From clinical and biochemical data we suggest that dystonia is produced by abnormal shift to the norepinephrine/dopamine neurotransmission in favor of norepinephrine in different brain areas.

Except in Wilson's disease, few secondary dystonias are susceptible to benefit from an aetiological treatment. The somatic distribution of dystonia often determines the therapeutic strategy. Thus, stereotactic surgery may be the treatment of choice for hemidystonia while anticholinergic medication may alleviate generalized dystonia, particularly in childhood. Finally, local infiltrations of botulinum toxin are particularly useful for various forms of local and segmental dystonia. Certain subsyndromes as myoclonic dystonia, levodopa sensitive dystonia and paroxysmal choreoathetosis may benefit from relatively specific treatment strategies.

One case of oculopharyngeal muscular dystrophy is reported, in a 75 year old white male with manifest family history of palpebral ptosis. He displayed bilateral ptosis and dysphagia. Diagnosis was carried out after clinical, electrical and bioptic procedures. Data obtained have been discussed with previous reports in the literature. It was necessary to perform a cricopharyngeal myotomy to overcome the malnutrition secondary to his swallowing problem.

Blepharospasm is a cranial dystonia characterized by forceful spasms of the orbicularis oculi muscle which may lead to functional blindness in approximately two-thirds of patients. Botulinum toxin injection is a simple procedure, very effective and with little morbidity. It is considered as the treatment of choice for patients with disabling blepharospasm.

We present the clinical manifestations and morphological characteristics in a case from a patient with familial history of leprosy that presented peripheral neuropathy without cutaneous lesions. The nerves affected showed a loss of myelinated and unmyelinated fibers as well as chronic inflammatory infiltrate. The presence of Hansen's bacillus was demonstrated in macrophages, Schwann cells, endothelial cells, and fibroblasts at light and ultrastructural levels. In this case, the demonstration of the bacillus in the biopsy of peripheral nerve confirmed the diagnosis.

We studied the etiology of seizures in 46 patients who developed seizures after age 65 years. The most frequent cause was cerebrovascular disease, accounting for 41.3% of all cases. Clinical diagnosis of Alzheimer's disease was made in 5 patients (10.8%). Other etiologies were; metabolic encephalopathies in 6.5%, craniocerebral trauma in 4.3% and glioma in 2.1%. The etiology of seizures remained unknown in 34.7%. They had generalized tonic-clonic seizures in 48%. They were partial or partial secondarily generalized in 44.1%. The role of Alzheimer's disease in late onset seizures has not been important enough in previous studies. We believe that a well-designed prospective study will let us know the real frequency of the causes of seizures in the elderly.