Study of Evoked Potentials in Aphasics

Abstract

Recent advances in electroencephalography permit one to record summated potentials over the surface of the scalp evoked by electrical stimuli applied to the median nerve or by light flashes or clicks. There are two phases of evoked potentials following median nerve stimulation: an early one and a late one. The early component exhibits relatively fast spikes which various authors (2-8) describe under different names. These will be discussed below. The late component exhibits one or two slower waves. It has been shown that the late phase

The Determination of Sensory Deficits in Children With Hemiplegic Cerebral Palsy

“…Several authors have studied the reJationship between SEP abnormalities as weil as functionaJ outcome. Liberson (1966) studied SEP waveforms in 15 males with aphasia (ail right hemlpJeglcs). The SEP was fiat or had a markedly lowered amplitude in 10/15 aphasics.…”

“…Studles revlewed m the literature have evaluated the relationslllp between SEP and cllnical sensory function (Karnaze et al, 1987;Laget et al, 1976;Larson et al, 1966;Liberson, 1966;Maugiere et al, 1983;Williamson et al, 1970;Wong et al, 1982;Zeman and Yiannikas, 1989) and concluded that SEP have a good relationship to neurologlcal impairment (muscle weakness and sensory loss), as weil as, functional outcome. These studies have not described the specifie methods by which the clinical sensory loss was measured and the degree of sensory deficits detected.…”

“…Sorne of these studies have not specified which sensory modalities were assessed (Williamson et al, 1970;Wong et al, 1982). Studies by Laget et al (1976), Liberson (1966), Maugiere et al (1983) and Williamson et al (1970), gauged sensory loss on the integrity of only 1 sensory modality. Even though one sensory modality may correlate to SEP fmdmgs other sensory modalities rnay or may not be aftected.…”

Evoked Response Studies of the Thalamic Pain Syndrome*

“…It is difficult to determine if significance can be attached to the minor alteration in wave form seen in some of the SERs recorded ipsilateral to stimulation of the affected side. Studies of patients with major parietal infarcts (Larson et al 1966, Liberson 1966, Williamson et al 1970 or with postcentral gyrus extirpations (Stohr & Goldring 1969) have shown that both contralateral and ipsilateral SERs depend upon lemniscal conduction to a functioning cortical sensory area contralateral to the stimulus. In some patients with infarcts, however, marked amplitude differences (Larson et al 1966) or slightly different latencies ( Williamson et al 1970) between contralateral and ipsilateral responses to median nerve stimulation have suggested that conduction along extralemniscal pathways is responsible for genesis of some portion of the SER.…”

Frühe somatosensorisch evozierte Potentiale bei zerebrovaskulär ischämischen Erkrankungen - Teil III: Korrelationen zu Alter, Geschlecht, klinischen Daten, EEG, Emissions- und Transmissions-Computertomographie

“…Veränderungen somatosensonsch evozierter Potentiale bei zerebrovaskulär ischämischen Erkrankungen wurden in Einzeluntersuchungen auf Korrelationen zur klinischen Symptomatik (3, 6, 13,17,30,46), Reversibilität (38), Hirndurchblutung und morphologischen Veränderungen (6, 32) untersucht. Abnorme Befunde sind bei Läsionen im Hirnstamrn (3,32,33,49), Thalamus (1 5,19,27,32,5 1, 53,58), in der Capsula intema (46) und in der Postzentralregion (17,34,45), bei sensiblen und motorischen Defiziten (2, 29,45), bei Anosognosie (l6), Aphasien (25) 19) und dementiellen Erkrankungen (MW 2,7). Erstgenannte zeigten auch signifikante Abweichungen für die Amplitudenratio links/rechts (MW 2.43) gegenüber allen anderen Gruppen.…”