Brain stem and motor evoked responses in "locked-in" syndrome

A patient suffering for an ischemic "locked-in" syndrome following a subarachnoid hemorrhage, was evaluated with brain stem acoustic evoked potentials (BAEPs), short latency somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs). Neuroradiological findings failed to reveal any lesion in the brain stem, while a transcranial Doppler showed increased flow velocity upon the basilar artery, suggesting vascular spasm. BAEPs were normal and SEPs showed to be slightly impaired while MEPs upon magnetic cortical stimulation were heavily deranged. Neurophysiological investigations appeared remarkable for the early diagnosis of the disease, when neuro-radiological findings were still negative.