[Cervical spondylotic myelopathy: motor and somatosensory evoked potentials, clinical and radiological correlation]. / Myélopathie cervicarthrosique: intérêt des explorations électrophysiologiques et corrélations avec les données radiologiques.

Somatosensory and motor evoked potentials (EPs) have been recorded in 38 patients with cervical spondylosis, documented by MRI. All were symptomatic, 23 presented with myelopathy. Somatosensory evoked potentials were abnormal in 66p.cent as well as motor evoked potentials. The N13 potential, generated by the posterior dorsal horn of the cervical spinal cord, was abnormal in 63p.cent of patients and was the only disorder detected in 12p.cent. Together, somatosensory and motor evoked potentials were abnormal in 82p.cent of patients. There was no correlation between EPs findings and radiological data. Similary, MRI and clinical data were agreeing in only 50p.cent of patients. When a spondylotic myelopathy is suspected, SEPs proved more sensitive to detect somatosensory dysfunctionning than clinical testing and radiological data were discordant with clinical status in 50p.cent of cases. In order to obtain a high sensitivity, both somatosensory and motor evoked potentials should be recorded on all limbs with a special attention to segmental cervical and cervico-medullary responses. EPs data help to identify patients with cervical cord dysfunction and thus contribute to the therapeutic decision for surgery.

[Auditory perception disorders due to bilateral cortical lesions. An electrophysiology study]. / Troubles perceptifs auditifs par lésion corticale bilatérale. Etude électrophysiologique.

A 78-year-old right handed man with a past history of atrial fibrillation developed in November 1994, a slight right hemiparesis with aphasia which cleared over one month. Head CT scan showed a left middle cerebral artery infarct involving the posterior part of the temporal lobe. In September 1995, a second stroke occurred. Head CT scan revealed a recent right middle cerebral artery infarct within the posterior part of temporal cortex. Auditory agnosia was diagnosed. Auditory evoked potentials recording showed bilateral dysfunction of central auditory pathways mainly over the right hemisphere. Clinical data and evoked potentials suggest that auditory agnosia might be related to the right temporal lobe damage. This later is involved in linguistic processes as suggested by positron emission tomography studies.