Somatosensory and Auditory Brain Stem Conduction after Head Injury: A Comparison with Clinical Features in Prediction of Outcome

Abstract

Evoked potential conduction times in brain stem auditory (BCT) and central somatosensory pathways (CCT) were recorded from 23 normal subjects and 101 patients with severe head injury. Abnormalities in the CCT and the BCT findings correlated with the clinical indices of brain damage (coma score, motor response, pupil response, and spontaneous and reflex eye movements) in the head-injured patients and each correlated with outcome at 6 months from the injury. The CCT in the “best” hemisphere produced the strongest correlation with outcome (P<0.001). The correlation of the CCT with outcome was stronger in the 47 patients examined 2 to 3 days after the injury (P<0.001) compared to the 34 patients examined within 24 hours after the injury (P<0.02). No such difference was noted for the BCT. Serial studies within the first 2 weeks of injury did not show a consistent pattern and repetition of the investigation over this period did not provide any additional information. We used an INDEP-SELECT discriminant analysis program to determine whether information from the evoked potential data could improve prediction of outcome based on clinical data alone. With the addition of the CCT, the predictive accuracy (expressed as the correct classification probability) increased only slightly from 77 to 80%, and the difference was not significant. We conclude that central somatosensory and auditory brain stem conduction times provide useful prognostic information in paralyzed or sedated patients, but when neurological examination is feasible the benefits of evoked potential analysis do not justify the effort involved in data collection.

Predictive value of somatosensory evoked potentials for awakening from coma*

“…Of these 12, seven articles reported on traumatic coma in 456 children and adults, but the results could not be separated by age group (5)(6)(7)(8)(9)(10)(11). Data were compiled for this mixed group separately (see Results), but not included in the figures.…”

A preliminary investigation of motor evoked potential abnormalities following sport-related concussion

“…Electrophysiological evidence for the acute and long-term effects of concussion has been demonstrated using EEG [7][8][9][10][11][12] and various evoked potential techniques: somatosensory evoked potentials (SSEP) [13][14][15][16][17][18][19], brainstem auditory evoked potentials (BSAEP) [18][19][20], visual evoked potentials (VEP) [10,11,19] and motor evoked potentials (MEP) [17,21]. MEPs provide a direct physiological assessment of the integrity of the motor cortex and descending motor pathways [22,23].…”

Guidelines for Quality Management of Apallic Syndrome / Vegetative State

“…Median nerve SSEPs correlate with outcome in hypoxic AS cases (Binder H and Saltuari L, unpublished data). Laureys et al in a PET study on patients in full stage AS, recorded a cascade of functional disconnection of auditory evoked potentials along the auditory cortical pathway, from the primary auditory area to parietal associative and limbic areas, when the primary auditory cortex was activated by appropriate stimulation and a brain stem response was recorded [83,[140][141][142]169].…”