Vestibular evoked myogenic potentials in multiple sclerosis

Vestibular evoked myogenic potential [VEMP] is an otolith-mediated, short-latency reflex recorded from the sternocleidomostoid muscle in response to intense auditory clicks used for evaluation of the vestibulo-spinal pathway. This study aimed at shedding light on the sensitivity of VEMPs in detection of occult vestibular pathway lesions in patients suffering from multiple sclerosis [MS]. VEMPs were recorded from 25 MS patients. Clinical data were evaluated for possible brain stem affection, their EDSS scores were recorded. All patients underwent visual evoked potential [VEP], brainstem auditory evoked potential [BAEP], somatosensory evoked potential [SSEP] studies and magnetic resonance imaging [MRI]. VEMPs were also recorded in 25 age and sex matched controls as well. VEMPs showed abnormal P13 and N23 waves in 56% of Patients, VEP in 56%, BAEPs in 44%, SSEPs in 28% and MRI in 80%. MRI showed better sensitivity in detecting brain stem plaques yet patients with normal MRI had abnormal VEMPs and BAEPs and VEMPs had nearly equal sensitivity in detecting brainstem plaques in symptomatizing group; however VEMPs were more sensitive than BAEPs in non symptomatizing group. Also we found no significant correlation between VEMPs and MRI or BAEPs. VEMPs is a simple, non-invasive, safe and quick method, which should be considered as a complementary neurophysiological tool for evaluation of possible brainstem dysfunction

Predictors of medically intractable childhood epilepsy: clinical, electroencephalographic and neuroimaging factors

Predicting which children are destined to develop medically intractable seizures would be very helpful in developing treatment strategies that would be more aggressive than in children with easily controlled epilepsy. Little is known about the natural history, particularly the time course of development, of refractory epilepsy. To identify clinical, electroencephalographic [EEC] and neuroradiological factors associated with both seizure control and medical intractability in children with epilepsy and to be acquainted with predictors of uncontrolled seizures. A case-control study to identify predictors of medically intractable epilepsy in children. Cases were children who had an average of one seizure or more a month over a 2-year period and who, during that time, had failed trials of at least three different anti-epileptic drugs [AEDs]. Controls were children who had epilepsy, who had been seizure-free for >/= 2 years, and who had never, before becoming seizure-free, met the definition for intractable epilepsy. Features of clinical findings, EEG and Magnetic Resonance Imaging [MR1] were compared in 20 children with well controlled seizures and 40 with intractable epilepsy using contingency 2x2 tables for inference of associations, odds ratios, predictive values, sensitivity and specificity. Logistic regression -was performed for multivariate analysis. Strong associates of clinical factors with intractability included: age at onset; duration of epilepsy; multiple types of seizures; complex partial, simple partial, tonic, atonic and myoclonic seizures; initial seizure frequency; history of status epilepticus; history of febrile seizures; duration of fit at onset; lapse of time before treatment; receiving more than one A ED; a symptomatic etiology of the seizures, and abnormal magnetic resonance imaging [MRl] of the brain. Strong associates were noted between intractability and several EEG factors: abnormal EEG background including diffuse slowing, asymmetry and high frequency spikes. These factors were predictors of refractory epilepsy. With multiple logistic regression, independent predictors of intractability included: early risk factors, complex partial seizures and multi-focal or focal epileptic discharges with secondary generalization. There are a number of clinical, EEG and neuroradiological features that can be identified early in the course of childhood epilepsy that are predictive of outcome. These findings will need to be verified in a prospective study