Extreme Somatosensory Evoked Potential (ESEP): An EEG Sign Forecasting the Possible Occurrence of Seizures in Children

Abstract

In a population of 15,000 children, it was found that tactile stimulation, mainly tapping o n the soles or heels of the feet, could elicit high-voltage evoked potentials in the EEGs of 1% of them. A longitudinal study of 16 of these patients showed a stereotyped electroclinical evolution. At first, only extreme somatosensory evoked potential (ESEPs) were observed in nonepileptic children with normal EEG records first period). Then, after a variable delay, spontaneous EEG abnormalities appeared, first only during sleep, and then also during wakefulness, usually as spikes involving the same parietal and midline regions where the ESEPs were evident (second and third periods). Seizures then began Vi,urth period) within 5 months to 2 years after the appearance of the interictal focal abnormalities. Such seizures were rare, but in some cases they were grouped in bouts that amounted to status epilepticus. The seizures were usually of the partial motor type, with adversion of the head, but infrequently they assumed the tonic-clonic type; they occurred mainly during the daytime. The fits were short-lived, however, and after a year had mostly disappeared, while the ESEPs and spontaneous interictal focal abnormalities sometimes persisted for several years before disappearing, too. The subjects were otherwise neurologically and psychologically normal throughout the observation and follow-up period.High-voltage potentials evoked by a single somatosensory stimulus are widely known to occur in the EEG of patients with focal seizures (Dawson, 1947; Forster et al., 1949; Gastaut and Alajouanine, 1955; Tassinari, 1968; Green, 1971). These are usually related to a lesion involving somatosensory areas. De Marco (1971), however, reported the occurrence of large evoked potentials in five nonepileptic patients without neurological evidence of cerebral organic lesions. The potentials, which were evoked by heel tapping monoor bilaterally, appeared on the surface EEG recording as focal spikes involving the parietal and parasagittal regions, each spike being evoked by a single stimulation, usually of the contralateral foot (De Marco and Negrin, 1973).' This paper describes our attempt to determine the clinical relevance

Tactile‐evoked Rolandic Discharges: A Benign Finding?

“…We also wished to determine if tactileenhanced discharges are an EEG sign forecasting the possible occurrence of seizures in children, as hypothesised by De Marco and Tassinari (4). In this study, no patients were found to have developed epilepsy characterized by the stereotypic electroclinical pattern, as described by …”

“…In 1981, De Marco and Tassinari (4) found that in 1% of children without overt neurologic pathology, they could elicit high-voltage evoked potentials in the parietal and parasagittal region with tapping on the soles or heels of the feet. A longitudinal study of these patients showed a stereotypical electroclinical evolution occurring over 4 time periods.…”

Potencial evocado somato-sensitivo em crianças com pontas evocadas por estímulo somato-sensitivo no eletrencefalograma

“…As porções distais dos membros inferiores (calcanhar ou artelhos) ou membros superiores (dedos ou região dorsal da mão) parecem ser os locais mais apropriados para a estimulação e obtenção de PE.A cada estímulo corresponde uma ponta bifásica ou polifásica, por vezes seguida de onda lenta. PE foram registradas em 1 a 3% das crianças examinadas em serviços de eletrencefalografia [2][3][4] . As PE decorrem de hiperexcitabilidade cortical, que também seria responsável pelo aparecimento de pontas espontâneas no EEG e poderia originar crises epilépticas.…”

“…Nestas epilepsias a evolução é favorável e não há lesão cerebral. Podem ocorrer PE, também, em epilepsias generalizadas idiopáticas ou criptogênicas e parciais sintomáticas [3][4][5][6][7][8] . O potencial evocado somato-sensitivo (PES) tem sido estudado desde 1950 em pacientes adultos com patologias neurológicas mas só nos últimos anos passou a ser valorizado como rotina diagnostica em neurologia infantil [9][10][11][12] .…”

Pontas parietais evocadas ao eletrencefalograma e convulsões febris

“…Podemos observar que na faixa etária de 2 a 7 anos as PE apareceram em 7,26% das crianças com CF. A localização das PE foi parietal (P , P ou P ) em 12 dos 13 casos, Marco 3,5,7,8,9,21^ pesquisando sistematicamente pela percussão e estímulos táteis principalmente dos pés, obteve PE em cerca de 1% dos casos. Grande parte das crianças com PE buscaram atendimento por distúrbios de comportamento e/ou escolaridade e parte por CF e crises não febris repetidas, mas sem natureza reflexa.…”