552 Electroencephalography and clinical Neurophysiology, 1989, 73:552-556 Elsevier Scientific Publishers Ireland, Ltd. EEG 02404 Short communication Sensorimotor and auditory central time in locked-in syndrome E. Facco, P. Caputo, D. Fiore * and G.P. Giron Lab. of Neurophysiology, Department of Anesthesiology and Intensive Care, University of Padua, Padua (Italy), and * Department of Neuroradiology, Hospital of Padua, Padua (Italy) (Accepted for publication: 20 July 1989) Summary Motor evoked potentials (MEPs) following magnetic cortical stimulation, somatosensory evoked potentials from median nerve (SEP) and auditory brain-stem responses (ABR) were recorded in a patient with locked-in syndrome during the acute and chronic phases of the clinical course. During the acute phase both ABR and SEP were normal. The MEP from the right upper limb showed a delayed and low voltage potential, while that from the left upper limb was absent. The CT scan showed a ponto-mesencephalic hypodensity. In the chronic phase the MEP from the left upper limb had reappeared and showed a normal latency, while the one from the right upper limb worsened; at that time a new small left fronto-parietal hypodensity had appeared on CT scan, The combined use of MEP, SEP and ABR was able to confirm that the brain-stem damage involved the pyramidal but spared the lemniscal pathways, while MEP changes during the clinical course appeared to reflect both clinical and radiological findings. Key words: Evoked potentials; Auditory evoked potential; Somatosensory evoked potential; Motor evoked potential; Locked-in syndrome; Brain-stem Short latency evoked potentials (SLEPs) can provide help- ful information on pontine and midbrain function in patients with brain-stem lesions (Noel and Desmedt 1975; Starr and Hamilton 1976; Gilroy et al. 1977; Brown et al. 1981; Oh et al. 1981; Seales et al. 1981; Ragazzoni et al. 1982; Stern et al. 1982; Hammond et al. 1985; Kaji et al. 1985; Morocutti et al. 1985; Towle et al. 1985; Ferbert et al, 1988) and during posterior fossa surgery for clipping of basilar aneurysms (Lam et at. 1985). So far, SLEPs have been recorded only in a few cases of locked-in syndrome, showing abnormalities of both auditory brain-stem responses (ABRs) and somatosensory evoked potentials (SEPs) in most patients (Noel and Desmedt 1975; Starr and Hamilton 1976; Gilroy et al. 1977; Brown et al. 1981; Oh et ak 1981; Seales et al. 1981; Stern et al. 1982; Kaji et al. 1985; Towle et ak 1985; Ferbert et al. 1988), while no data are available in the literature on motor evoked poten- tials (MEPs). In this paper we report a case of locked-in syndrome whose MEP, ABR and SEP from median nerve were recorded during the acute and chronic phases of the clinical course. Correspondence to: E. Facco, M.D., Ist. Anestesiologia e Rianimazione, Universit~t di Padova, Via C. Battisti 267, 35121 Padua (Italy). Patient and methods The patient was a 56-year-old man who suddenly presented dysarthria and weakness of the left limbs followed by aniso- coria. In a few hours he showed bilateral myosis, loss of horizontal eye movements, hypertonus, quadriplegia and res- piratory failure as well, but remained able to open his eyes on command. He was intubated and submitted to mechanical ventilation. The CT scan disclosed a ponto-mesencephalic hy- podensity (Fig. 1A, B). During the clinical course the patient underwent severe extracranial complications (bronchopneumoma. pneumo- thorax, sepsis and reversible cardiac arrest) from which he recovered. After 2 months from the attack the neurological condition began to improve slightly: the patient showed weak movements of the upper limbs and left leg, partial recovery of ocular and facial movements. Afterwards the respiratory function progres- sively improved, allowing the removal of mechanical ventila- tion. The CT scan performed in the chronic phase, after the patient recovered from the extracranial complications, showed a new small hypodensity in the left fronto-parietal region (Fig. 1C. D). The patient was discharged from the intensive care unit 6 months after the attack. lhe SLEPs were recorded on the 10tb hospital day (before the occurrence of cardiac arrest) and after 5 months. 0013-4649/89/$3.50 © 1989 Elsevier Scientific Publishers Ireland, Ltd.