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The Somatosensory Evoked Potential in Patients with Cerebrovascular Diseases
Author(s) -
MIYOSHI Seido,
LÜDERS Hans,
KATO Motohiro,
KUROIWA Yoshigoro
Publication year - 1971
Publication title -
psychiatry and clinical neurosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.609
H-Index - 74
eISSN - 1440-1819
pISSN - 1323-1316
DOI - 10.1111/j.1440-1819.1971.tb01484.x
Subject(s) - somatosensory evoked potential , medicine , somatosensory system , median nerve , audiology , cardiology , psychology , anesthesia , surgery , psychiatry
Summary The somatosensory evoked potential in hand area for contralateral median nerve stimuli was studied by summation method using a digital computer. Thirty‐four recordings were obtained from 27 patients with cerebrovascular diseases. Analysis time were 62.5 msec and 500 msec. Nine components, N1, P1, N2, P2, N3, N1P1, P1N2, N2P2, P2N3 appeared in 62.5 msec and the later component appeared in 500 msec analysis time. Each component was compared with those of 40 normal subjects. It was considered abnormal when it came out of the median ± 2SD of normal control. When all of ten were normal it was classified normal; when seven to nine were normal, as slightly abnormal; when four to six, as moderately abnormal, and when less than three, as severely abnormal. Of 34 recordings, 5 normal, 11 slightly abnormal, 4 moderately abnormal and 14 were severely abnormal. The SEP evoluted well during the course of illness with association to the clinical improvement, and the alteration of SEP correlated well with the severity of neurological state, though there were some exceptional cases. There were nine recordings of which SEPs were abnormal not only in the affected side but also in the unaffected hemisphere. Three attenuated, three enhanced responses and other three showed symmetric small P1N2 pattern. The former six cases appeared in the severely abnormal group. The symmetric small P1N2 pattern seen in three cases was considered to be one of abnormal types. As to correlation of each component of SEP and neurological state, position, vibration and two‐point discrimination sensations were closely related to the absence of every all the ten components. Pain and temperature were not related to N1 and N1P1, but related to the absence of the remainder components. Touch and electrical sensation were questionably related to the absence of Nl and N1P1 and related significantly to the remainder components. As to delay of the latency and attenuation of the amplitude, there was no relationship between the components and each neurological state except for delayed P2 which was questionably related to impaired vibration sense (P = 0.2). Muscle power was significantly related to the defect of N2P2 and questionably to defect of N1P1, P1N2, P2N3 and the later component and attenuation of N1P1 and N2P2. Spasticity and hyperreflexia were not related to any of SEP components. In comparison of EEG and SEP, the percentage of abnormality in SEP was higher than that of routine EEG.