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Open Access Open Badges Case report

Cerebral hypoxia, missing cortical somatosensory evoked potentials and recovery of consciousness

Gustav Pfeiffer1*, Rüdiger Pfeifer2 and Stefan Isenmann3

Author Affiliations

1 Abteilung weiterführende Neurorehabilitation, Fachklinik Bad Liebenstein, Kurpromenade 2, 36448 Bad Liebenstein, Germany

2 Clinic of Internal Medicine I, University Hospital Jena, Erlanger Allee, Germany

3 Department of Neurology and Clinical Neurophysiology, Helios Hospital Wuppertal, Centre for Clinical Medicine, and University Witten/Herdecke, Wupperrtal, Germany

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BMC Neurology 2014, 14:82  doi:10.1186/1471-2377-14-82

Published: 11 April 2014



Bilaterally absent N20 components of the sensory evoked potentials (SEP) from the median nerve are regarded as accurately predicting poor outcome after cardiac arrest.

Case presentation

We are reporting on a patient, who regained consciousness despite this ominous finding. Early after cardiac arrest, MRI showed signal alterations in diffusion weighted imaging (DWI) bilaterally in the primary visual and sensorimotor cortex and in the basal ganglia. SEP were repeatedly absent. The patient survived shut out form sensory and visual experience and locked in for voluntary movements, but kept her verbal competence in several languages.


SEP inform about integrity only of a narrow cortical strip. It is unguarded, but common practice, to conclude from absent SEP, that a patient has suffered diffuse cortical damage after cardiac arrest. Cerebral MRI with DWI helps to avoid this prognostic error and furthers understanding of the sometimes very peculiar state of mind after cardiac arrest.

Consciousness; Coma; Cardiac arrest; Evoked potentials; Diffusion weighted imaging; Rehabilitation; Minimally conscious state