Somatosensory evoked potentials in a patient with a cervical glioma and syrinx

Short-latency somatosensory evoked potentials (SSEPs) were obtained in a 61-year-old patient with a cervical spinal cord glioma extending from C3 to C7. SSEPs in response to tibial nerve stimulation were normal; however, all components of the median nerve responses were markedly abnormal bilaterally (except for normal brachial plexus responses). This selective abnormality of median nerve SSEPs has not been reported previously in a patient with cervical cord tumor associated with a syrinx and illustrates the use of the SSEP in the anatomical localization of the lesion.