The diagnostic value of earlier and later components of Vestibular Evoked Myogenic Potentials (VEMP) in multiple sclerosis

AIM OF THE STUDY

To evaluate the ability of VEMP to disclose spatial dissemination of Multiple Sclerosis.

MATERIALS AND METHODS

Forty-six MS patients with auditory and/or vestibular symptoms were studied. Patients were divided in two groups. Group 1 included 24 patients with brainstem MRI findings, and Group 2 included 22 patients without MRI findings. VEMP and BAEP have been recorded and assessed.

RESULTS

Abnormal p13n23 wave was observed in 50%, while unilateral absence or bilateral delay of the n34p44 in 43% of the patients. The overall diagnostic value considering abnormal cases suggested by both first and second VEMP waves was increased to 71%. Statistically significant differences revealed between patients and controls for p13 latency (p=0.018). The p13n23 was abnormal in 7 patients, although MRI scanning did not reveal brainstem lesions. In 9 out of 18 MS patients suffering from unilateral hearing loss, n34p44 was present in the unaffected ears and absent in the affected side, although p13n23 was normal.

CONCLUSION

Abnormal VEMP imply the presence of lesions undetected by MRI neuroimaging, which verifies the diagnostic value of the method. Unilateral absence of n34p44 complex was related with sensorineural hearing loss, supporting the hypothesis that n34p44 is of cochlear origin.

Auditory event related potentials in patients with epilepsy on sodium valproate monotherapy

OBJECTIVES

The effects of antiepileptic drugs on event related potentials (ERPs) have been studied, but with contradictory results. In this study we examine the effect of sodium valproate (VPA) on ERPs in patients with epilepsy.

MATERIALS AND METHODS

Auditory event related potentials were recorded in 40 patients with idiopathic generalized epilepsy, 20 on monotherapy with sodium valproate (VPA), 20 on monotherapy with carbamazepine and 20 age and sex matched controls. All subjects performed a simple auditory discrimination task in which a target tone was presented on 20% of the trials.

RESULTS

Mean P3 latency of the VPA group was significantly prolonged but not in carbamazepine group and healthy controls.

CONCLUSION

We conclude that VPA monotherapy has an effect on P300 latency in patients with epilepsy. This difference might be attributed to effects of treatment with VPA and may clarify in the future the mechanism of P300.