Auditory evoked potentials and vestibular evoked myogenic potentials in evaluation of brainstem lesions in multiple sclerosis.

OBJECTIVE: The aim of this study was to determine the roles of magnetic resonance imaging (MRI), auditory evoked potentials (AEP) and vestibular evoked myogenic potentials (VEMP) in the evaluation of brainstem involvement in multiple sclerosis (MS). PATIENTS AND METHODS: Altogether 32 patients with the diagnosis of MS participated in the study. The following data was collected from all patients: age, gender, Expanded Disability Status Scale (EDSS) score, brainstem functional system score (BSFS) (part of the EDSS evaluating brainstem symptomatology), and involvement of the brainstem on the brain MRI. AEP and ocular VEMP (oVEMP) and cervical VEMP (cVEMP) were studied in all patients. RESULTS: BSFS, MRI, AEP, oVEMP and cVEMP involvement of the brainstem was evident in 9 (28.1%), 14 (43.8%), 7 (21.9%), 12 (37.5%) and 10 (31.0%) patients, respectively. None of the tests used showed statistically significant advantage in the detection of brainstem lesions. When combining oVEMP and cVEMP 18 (56.3%) patients showed brainstem involvement. This combination showed brainstem involvement in greater percentage than BSFS or AEP, with statistical significance (p=0.035 and p=0.007, respectively). CONCLUSION: VEMP is a reliable method in detection of brainstem involvement in MS. It is comparable with MRI, but superior to clinical examination or AEP.

[The effect of antiepileptic drug therapy on cognitive evoked potentials and reaction time]. / Utjecaj terapije antiepilepticima na kognitivne evocirane potencijale i brzinu motoricke reakcije.

UNLABELLED: It is well known that antiepileptic drugs have side effects on cognitive and behavioral functioning of the treated patients. AIM: Our goal was to investigate their effect on cognitive evoked potential peak latencies and patient reaction times to target stimuli for two different, acoustic and visual stimulating paradigms. Therefore, a control group of healthy subjects and three groups of patients treated with antiepileptic drugs (carbamazepine, phenobarbital) were compared. PATIENTS AND METHODS: Group 1 of 19 epileptic patients had undertherapeutic and group 2 of 16 patients had a therapeutic concentration of these drugs. Group 3 of 18 patients were treated with carbamazepine in therapeutic dose for nonepileptic reasons. The N1, P2, N2, P3a and P3b peak latencies as well as reaction time to the same target stimuli were analyzed. RESULTS AND DISCUSSION: Obtained for acoustic and visual stimulating paradigm in the control group showed no significant differences results suggesting it to be sufficient to use simple acoustic paradigm for screening. The hypothesis that antiepileptic drugs influence the parameters of cognitive evoked potentials when used as polytherapy was confirmed. The reaction time measured in the same groups showed statistically significant differences between healthy subjects and drug treated patients. The effect of antiepileptic drugs on peak latencies of cognitive evoked potentials was statistically significant, and an even greater effect was recorded on the reaction time of treated patients. CONCLUSION: The results obtained in the study were in accordance with our hypothesis that this neurophysiological method could be successfully used as a screening method to check the cognitive and motor state of antiepileptic medication.