Summary
Brain-stem auditory-evoked potentials (BAEPs) were recorded in 35 post-comatose patients after severe closed head trauma. Compared to the normal BAEPs obtained from 30 normal controls, significant individual abnormality could be detected in only 2 patients. This abnormality consisted of lateral asymmetry, but not prolonged interpeak latencies or abnormal amplitude ratios. Further, no differences were found between groups as regards interpeak latencies. A significant reduction of BAEP amplitudes was seen in the patient group, being most pronounced in the 13 patients with hearing loss. It is concluded that the BAEP does not sufficiently reveal brainstem lesions expected to persist after severe closed head trauma, presumably because the structures generating waves IV and V are not permanently affected. The amplitude reductions observed may be explained by the diffuse cochlear damage known to occur concurrently with head trauma.
Zusammenfassung
Akustisch evozierte Hirnstammpotentiale (AEHP) wurden bei 35 post-komatösen Patienten nach schwerem Schädelhirntrauma (SHT) abgeleitet. Bezogen auf die an 30 Kontrollpersonen ermittelten Normewerte konnten nur in 2 Einzelfällen signifikante Veränderungen des AEHP bestimmt werden. Dies war jedoch nur wegen eines abnormalen Seitenunterschieds, nicht aber aufgrund verlängerter Interpeak-Latenzen oder erniedrigtem Amplitudenverhältnis V/I möglich. Die Patientengruppe zeigte bei normalen Interpeak-Latenzen eine generelle Amplitudenreduktion, am ausgeprägtesten bei den Patienten mit Hörminderung. Das AEHP erscheint somit nicht hinreichend geeignet, strukturelle, nach dem SHT fortbestehende Hirnstammläsionen im Einzelfall nachzuweisen. Vermutlich ist dabei das neurale Substrat, das die Wellen IV und V des AEHP generiert, nicht auf Dauer geschädigt. Die beobachtete Amplitudenreduktion ist eher auf diffuse cochleäre Schädigungen, die im Zusammenhang mit dem SHT bekannt sind, zurückzuführen.
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Scherg, M., von Cramon, D. & Elton, M. Brain-stem auditory-evoked potentials in post-comatose patients after severe closed head trauma. J Neurol 231, 1–5 (1984). https://doi.org/10.1007/BF00313643
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DOI: https://doi.org/10.1007/BF00313643