Faculty Bibliography

PURPOSE: This study examined the association of depression with laterality of epilepsy surgery in patients with temporal lobe epilepsy before standard lobectomy. METHODS: Forty-nine patients presented for EEG telemetry for localization of epilepsy and eventual temporal lobectomy. Patients underwent routine neuropsychiatric evaluation blinded for epileptic focus, including ratings on depression. Patients were grouped according to right (n = 25, M = 10/F = 15) and left (n = 24, M = 13/F = 11) temporal lobectomy. Analysis of variance included side of surgery as grouping variable and sex, general depressive, cognitive depressive, and vegetative depressive symptoms as dependent variables. Chi2 analyses included categoric variables of sex, handedness, education, neuropathologic findings, and current affective disorders. t Tests were performed on variables of age, epilepsy duration, and cognitive function. RESULTS: Right and left temporal epilepsy groups did not differ with regard to sex, handedness, age, duration of epilepsy, education, cognitive function, and neuropathology. Patients with right temporal epilepsy rated higher on general, cognitive. and vegetative depression scores. Women scored higher on general, cognitive, and vegetative depression scores. Current affective disorders were more common in the right temporal epilepsy group. CONCLUSIONS: Depression ratings and diagnoses were more prominent in patients with right temporal lobe epilepsy and in women in particular. The strength of this laterality finding lies in the selection of patients, as all underwent epilepsy surgery. The finding on gender difference partly reflects the higher incidence of depression in women and needs further exploration. The laterality finding contrasts with recent findings in epilepsy, stroke, and trauma that associate depression with left hemispheric lesions. However, our results are consistent with findings in electrically hyperactive lesions such as gelastic and dacrystic epilepsy

PURPOSE: Valproate (VPA) triples the half-life of lamotrigine (LTG), and combined use may be difficult. The adverse effect (AE) profile of this combination needs clarification. METHODS: We prospectively recorded our experience in adding LTG to VPA-containing regimens in 108 patients. Data collected included medications, seizure types and syndromes, and AEs. Patients were followed up to 27 months, until a stable dose was reached, or until LTG was discontinued. Patient management was not altered by this study. There were 60 patients with partial-onset seizures, 30 with generalized onset, and 12 with the Lennox-Gastaut syndrome. In 37, LTG was added to VPA monotherapy, and in 71, to VPA and other drugs. The median starting dose of LTG in our adult patients was 20.8 mg/day. RESULTS: LTG was added successfully in 86 (80%) patients. It was discontinued in 22 (20%): seven because of rash, seven for other AEs, and nine for other reasons. Rash occurred in 14 (13%) but caused discontinuation of LTG in only seven. We found a rash rate of 14.2% and a discontinuation rate because of rash of 8.7% among 310 patients in whom LTG was added to drug regimens not including VPA. Other AEs included fatigue (12%), gastrointestinal (GI) symptoms (9%), dizziness, headache, and insomnia (3% each). Serious AEs were hallucinations (two patients), hepatic enzyme elevations (two patients), irritability (one patient), and low white blood cell count (one patient). Whether LTG was added to VPA monotherapy or polytherapy made no difference in overall AE rate. CONCLUSIONS: LTG can be added to VPA with an acceptable incidence of side effects. LTG-induced rashes are no more common with VPA than with other drugs when LTG is added at very low initial dosages. Rashes are potentially serious and should be evaluated promptly

Electrical stimulation of the vagus nerve, a recently available option for patients with refractory epilepsy, has demonstrated safety and efficacy. We report four patients with refractory epilepsy who experienced ventricular asystole intraoperatively during initial testing for implantation of the vagus nerve stimulator. Acute intraoperative vagus nerve stimulation may create ventricular asystole in humans. Extracorporeal cervical vagus nerve stimulation testing with continuous EKG monitoring intraoperatively before generator implantation is warranted

Prediction of post-surgical seizure relief and potential cognitive deficits secondary to anterior temporal lobectomy (ATL) are important to pre-surgical planning. Although the intracarotid amobarbital test (IAT) is predictive of post-ATL seizure outcome, development of non-invasive and more precise means for determining post-ATL seizure relief are needed. We previously reported on a technique utilizing functional MRI (fMRI) to evaluate the relative functional adequacy of mesial temporal lobe structures in preparation for ATL. In the present study, we report follow-up outcome data on eight temporal lobe epilepsy (TLE) patients 1-year post-ATL who were evaluated pre-surgically using IAT and fMRI. Functional memory lateralization using fMRI predicted post-ATL seizure outcome as effectively as the IAT. In general, asymmetry of functional mTL activation favouring the non-epileptic hemisphere was associated with seizure-free status at 1-year follow-up. Moreover, when combined, fMRI and IAT provided complementary data that resulted in improved prediction of post-operative seizure control compared with either procedure alone

Vigabatrin (VGB) is a structural analogue of the inhibitory neurotransmitter gamma-amino butyric acid (GABA), which produces its antiepileptic effect by irreversibly inhibiting the degradative enzyme GABA-transaminase. This produces an increase in central nervous system (CNS) GABA levels. VGB is among the few antiepileptic drugs (AEDs) that was synthesized with a specific targeted mechanism in mind and was subsequently demonstrated to function by that mechanism. Tiagabine, a GABA reuptake blocker, is the only other 'designer drug' among the currently available AEDs. Therefore, VGB is among the few AEDs for which the mechanism of action is well understood. Recently, safety issues have been raised with regard to the use of vigabatrin. This article reviews the mechanism of action, pharmacokinetics, safety, and efficacy of VGB