Prognostic value of evoked potentials and clinical grading in primary subarachnoid haemorrhage

In a retrospective study of 64 patients suffering from primary subarachnoid haemorrhage (SAH), the clinical grading according to Hunt and Hess as well as the initial findings of brainstem auditory evoked potentials (BAEP) and median-nerve somatosensory potentials (SEP) were correlated with each other and with disease outcome to determine the prognostic value of evoked potential testing in comparison to the initial clinical grading according to Hunt and Hess. All patients were treated in a neurological intensive care unit. Normal evoked potentials usually indicate a favourable course. Alterations of SEP and BAEP increase in parallel with the severity of clinical findings. Unilateral or bilateral loss of SEP or BAEP indicates a poor prognosis. Clinical and electrophysiological findings show a close correlation, but only BAEP provide prognostic information beyond Hunt/Hess grading. In SAH patients, clinical grading was well as evoked potentials correlate significantly with outcome. Use of both clinical and EP rating improves prognostic accuracy.