Somatosensory evoked potentials and transcranial color Doppler monitoring in subarachnoid hemorrhage

Abstract

The outcome of patients with subarachnoid hemorrhage (SAH) is broadly influenced by the complications that may result from the hemorrhage. We describe a series of subjects, in which neurophysiological monitoring executed by simultaneous recording of somatosensory evoked potentials (SEPs) and transcranial color Doppler (TCD) was performed to reveal possible, early complications following acute SAH. We described the absolute and interhemispheric values of SEPs from the upper limb and TCD examinations of the cerebral arteries in 13 subjects with acute SAH. In cases with middle cerebral artery (MCA) vasospasm, N20 SEP amplitude absolute values for the hemisphere involved in the vasospasm were much lower than the contralateral ones. The N20 amplitude ratio reduction correlated with reciprocal of MCA mean flow velocity values detected within each patient. In the subjects with early ischemic damage following SAH, the affected hemisphere showed N20 amplitude drop; in addition, the relationship between SEPs and TCD findings was missing. Our findings emphasize the utility of simultaneous evaluation of SEPs and TCD in SAH follow-up, since the two methods reflect different pathomechanisms of possible secondary brain damage in aneurysmal SAH.