Somatosensory evoked potentials quantify clinical improvement of cerebral vasospasm after intravenous administration of nimodipine.

The calcium antagonist nimodipine (Nimotop; Bayer AG Leverkusen) has been shown to prevent cerebral vasospasm after aneurysm surgery. Ten patients with clinical and angiographic evidence of vasospasm showed accompanying delays in central conduction time, quantified by somatosensory evoked potential measurements, but nimodipine infusion markedly improved neurological status and level of consciousness in all cases within 10-60 minutes. Conduction time was simultaneously reduced on the affected side. No focal deficits developed during therapy (mean 7.1 days) with nimodipine, which also appears to be effective in relieving existing vasospasm. Evoked potentials provided a noninvasive quantitative parameter that correlated well with vasospastically induced clinical signs.