Data reported in the literature show that evoked potentials (EP) may have a diagnostic and physiopathological significance in epilepsies and epileptic syndromes. Their correlation to clinical and laboratory findings is higher when multimodal EP, bilateral median and tibial somatosensory evoked potentials (SEP) and recordings with additional derivations are performed. Two types of abnormalities can be described. First, the SEP and/or visual evoked potentials (VEP) 'degradation' (increased latency, decreased amplitude and irregular morphology) is related to a localized lesion. This is typical of symptomatic partial epilepsies, with a variable degree according to lesion size. Second, the finding of normal early components and increased amplitude late components is related to an excessive neuronal excitability. This aspect is peculiar to idiopathic partial epilepsies, where it is diffuse and particularly evident in the epileptic area. In reflex epilepsies, the cortical hyperexcitability is prevalent in photosensitive idiopathic epilepsies and may coexist with lesional findings in startle epilepsy. These data are not substantially changed by therapeutic doses of antiepileptic drugs; they are only slightly modified by sodium valproate or benzodiazepines in reflex epilepsies.
|Translated title of the contribution||Evoked potentials and epilepsies|
|Number of pages||7|
|Journal||Bollettino - Lega Italiana contro l'Epilessia|
|Publication status||Published - 1996|
ASJC Scopus subject areas
- Clinical Neurology