SOME CONSIDERATIONS ABOUT GIANT EVOKED POTENTIALS

Abstract
Giant evoked potentials include some cortical evoked responses of great amplitud related to different neurological disorders. The majority of these have mioclonias as a common clinical feature: progressive mioclonic epilepsies, generalized idiopathic epilepsies, toxic and infectious mioclonias. Other disorders like focal hemispheric lesions, cerebrovascular diseases, corticobasal degeneration, and progressive supranuclear palsy have shown cortical evoked responses of great amplitude. The aim of the present paper is to present other pathological process like hypoxia, cerebellar dysfunction, corpus callosum agenesia, and the classic progressive mioclonic epilepsy of Lafora body. A particular evoked response of great amplitude in the auditory brainstem response is considered too. Some ideas about the possible mechanisms related to these giant responses are proposed. They include neuronal hiperexcitability in response to the loss of inhibitory efferent influences, increase of long term synaptic excitability with reduction of polisynaptic inhibitory mechanisms, and abnormal recurrent collateralization in response to neuronal loss, among others.

Key words
Epilepsia, hipoxia, parálisis supranuclear progresiva, potenciales evocados gigantes, potencial evocado auditivo de tronco cerebral, potencial evocado somatosensorial

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