Use of multimodal electrophysiological monitoring to predict outcome after subarachnoid hemorrhage? A prospective series.

AIM: Electrophysiological monitoring (EM) is still controversial in the prediction of outcome after subarachnoid hemorrhage (SAH). The absence of evoked potentials (EP) is a good predictor for unfavorable, whereas the prediction of favorable outcome may be less useful. Aim of this study was to evaluate, if multimodal EM provides significant information about the patients' outcome or if this method might be dispensable.

METHODS: Multimodal EP data were recorded sequentially in 51 SAH-patients. The following data were recorded: World Federation of Neurological Surgeons (WFNS-) grade, Fisher grading score, endovascular versus neurosurgical treatment, aneurysm location and clinical outcome according to the Glasgow Outcome Scale (GOS). Multimodal electrophysiological monitoring included median nerve somatosensory evoked potential (M-SSEP), tibial nerve somatosensory evoked potential (T-SSEP), flash-visual evoked potential (f-VEP), brainstem auditory evoked potential (BAEP) and central conduction time (CCT) of M-SSEP. EP data were recorded sequentially; the first and last studies were evaluated.

RESULTS: No correlation was found between initial and last M-SSEP, T-SSEP, BAEP and initial f-VEP and the patients' outcome. An 'unfavorable' outcome was in conjunction with an initial delayed CCT (>6 ms, P=0.03) and the final f-VEP correlated well with the patients' outcome (P=0.03).

CONCLUSION: In conclusion, neither T-SSEP, f-VEP, BAEP nor CCT can be used as valid predictor for outcome after SAH. The patient's initial clinical grading still provides the only satisfying predictor, independent of the patient's clinical course.