C. Helmstaedter

Evidence of brain abnormality in patients with psychogenic nonepileptic seizures

Markers of brain abnormalities in patients with psychogenic nonepileptic seizures (PNES) were studied to explore whether physical brain disorder is associated with an increased risk of PNES. Evidence of epileptiform EEG changes, MRI abnormalities, and neuropsychological (NPS) deficits was obtained from the records of 329 consecutive patients in whom the diagnosis of PNES was established at our center between 1991 and 2001. Two hundred six patients had PNES alone, and 123 PNES and epilepsy (PNES+E). In the PNES-only group, at least one marker of brain disorder was detected in 22.3% of patients (epileptiform potentials in 8.7%, MRI changes in 9.7%, NPS deficits in 9.7%). The actual prevalence of abnormalities is likely to be higher because 54.9% of the patients with only psychogenic seizures did not undergo MRI or neuropsychological testing. Evidence of brain abnormality was found more frequently in the PNES+E group (epileptiform potentials in 70.7%, MRI changes in 60.2%, NPS deficits in 52.8%). Although markers of brain abnormality were detected much less commonly in the PNES than in the PNES+E group, they were still found in a substantial proportion of patients with PNES alone. This suggests that physical brain disease plays a role in the development of PNES. Markers of physical abnormality were not more common in the right hemisphere.

Efficacy and cognitive side effects of tiagabine and topiramate in patients with epilepsy

OBJECTIVE Whereas the efficacy of the newer antiepileptic drugs (AEDs) is well established, there remain questions regarding their cognitive side effects. Therefore, we performed a comparative open randomized trial with TPM and TGB as add-on therapy, with particular consideration of cognition, mood, and health-related quality of life (HRQOL). METHODS Forty-one patients with refractory epilepsy were randomly assigned to one of the two treatment groups (TPM vs TGB) and received neuropsychological testing at baseline (T1), after titration (3 months, T2), and during the maintenance phase (another 3 months, T3). Tests included measures of intelligence, attention, working memory, episodic memory, language, and self-report questionnaires regarding mood and HRQOL. Twenty patients (8 TPM, 12 TGB) discontinued the trial for different reasons (no group difference). RESULTS Seizure outcome (intention-to-treat analysis) was comparably good in both groups (8.1% seizure free, 29.7% seizure reduction>50%). From baseline to after the titration paired sample t tests revealed significant deterioration in verbal fluency, language comprehension, working memory, and visual block tapping under TPM and a deterioration in verbal memory (delayed free recall) in the TGB group. These functions remained stable in the maintenance phase. Self-report measures initially indicated concerns about AED side effects in both groups and concerns about worse cognitive functioning and depression under TPM. In the maintenance phase the TGB group reported feeling a lack of energy, whereas patients on TPM demonstrated improvement on all QOLIE scales on a descriptive level. CONCLUSION This study demonstrates the comparable efficacy of TPM and TGB. Consistent with previous reports, TPM but not TGB appears to be associated with persistent negative cognitive side effects on frontal lobe-associated functions, the degree of which may be estimated by the fact that this effect was observed with a very small sample size. In contrast, in patients taking TPM, initially negatively affected HRQOL returns to baseline in the long run on a descriptive level. The latter finding may be interpreted in accordance with the observation that objective performance and subjective self-report under TPM can be dissociated.

Neuropsychological Outcome in Children after Frontal Lobe Epilepsy Surgery

We investigated the neuropsychological performance of children with frontal lobe epilepsy (FLE, n = 12) before and 1 year after surgery. Children with temporal lobe epilepsy (TLE, n = 12) were included as control group. Preoperatively, children with FLE had a significantly higher IQ than children with TLE, but were significantly more often impaired in manual motor coordination. Postoperatively, both groups improved in attention, short-term and long-term memory, and manual coordination, although the latter was not significant. Neuropsychological outcome in FLE patients was not better in seizure-free patients than in patients with continuing seizures. To avoid deterioration in language functions of patients in whom surgery involved left area 44, correspondence of results in cortical stimulation and intracarotid amytal test may be essential. All in all, our data indicate a favorable cognitive outcome in children 1 year after frontal lobe surgery.

Quantitative and qualitative evaluation of patterns of cerebral language dominance: An amobarbital study.

As a part of presurgical evaluation, 173 patients received bilateral intracarotid amobarbital tests for determination of cerebral language dominance. Language testing during intracarotid amobarbital procedures (IAP) consisted of the following tasks: automatic speech, sentence comprehension, body commands, naming, repetition, reading, and spontaneous speech. Patterns of cerebral language dominance were evaluated and discussed on five levels of analysis: (1) quantification of language dominance on the basis of a lateralization index derived from the total language scores in each IAP; (2) determination of five dominance subpatterns (left or right dominant, strongly bilateral, and incomplete left or right dominant) according to quantification performed on level (1) and clinical judgement; (3) qualitative differentiation of three kinds of bilaterality (positive, negative, and general) according to total language performance in left and right IAP; (4) analysis of grouped linguistic subfunctions extracted from performance in specific IAP subtests; (5) extraordinary individual case histories. The distribution of lateralization indices revealed only partially continuous degrees of lateralization, especially between the left-dominant and bilateral subgroups. As for the clinically oriented classification, incomplete left dominance is frequent (16.2%), while incomplete right dominance does not occur at all. Atypical dominance patterns are mostly correlated to bilateral and/or extratemporal foci. Concerning grouped subfunctions, a rotated factor matrix statistic yields an analysis of clusters of IAP subtests, where functions involving expressive language capacities are separated from those that are purely receptive. Further analyses of bilaterality subpatterns suggest that there are mainly four bilaterality phenomena, namely interhemispheric dissociation, double representation, unilateral representation of subfunctions, and partial representation of subfunctions in either hemisphere. Application of these differentiations to individual cases yields additional evidence that can be used in patient selection for operation in order to avoid postoperative neuropsychological deficits, especially in candidates for extratemporal surgery. In conclusion, a multilevel analysis of IAP language data is recommended since it permits a detailed account of varieties of language dominance patterns and contributes to more adequate presurgical decision-making in planned operations in cognitively relevant brain areas.

Different effects of left anterior temporal lobectomy, selective amygdalohippocampectomy, and temporal cortical lesionectomy on verbal learning, memory, and recognition

In the present study, we investigated whether left hemisphere temporolateral resections and left selective amygdalohippocampectomy (SAH), have different effects on verbal learning, memory, and recognition. We evaluated patients who underwent standard two-thirds anterior temporal lobectomy including the hippocampus (TL, n = 22), SAH (n = 21), or temporolateral lesionectomy (TCL, n = 16). Patients with TL and SAH were matched with regard to temporomesial seizure onset and hippocampal pathology. Results were as follows: There were no preoperative group differences on any parameter of verbal learning and memory, but all groups showed impairment as compared with healthy subjects. Postoperatively, both TL and SAH led to a significant deterioration in measures of free recall (after distraction and a delay) and recognition. TL also led to a significant deterioration of immediate recall. No significant change in performance was observed after TCL. Seizure outcome did not account for these results. We conclude that left temporolateral and temporomesial resections have different qualitative rather than different quantitative effects on verbal memory in that they differentially affect short- and long-term aspects of verbal memory. The good neuropsychological outcome of pure lesionectomy (TCL) indicates that the postoperative loss in memory after TL and SAH is largely a function of the resection of still functioning tissue. Consequently, the data favor performance of individually tailored resections restricted to already nonfunctioning or malfunctioning brain tissue. Especially for mesial temporal lobe epilepsy, the surgical consequence would be to restrict the resection to mesiobasal structures.

Positive and negative psychotropic effects of levetiracetam

OBJECTIVES The goals of this study were to observe behavioral changes in patients receiving levetiracetam (LEV), a newer antiepileptic drug (AED), and to answer the question of whether LEV exerts a specific effect on impulse control and aggression. METHODS We asked 288 consecutive patients with epilepsy on LEV (90% polytherapy, mean dose=2689 mg) and 135 relatives whether LEV caused a positive or negative behavioral change. Forty-three patients on other AEDs served as a control group. Ratings were related to patient characteristics, efficacy, dose, drug load, bidirectional ratings of change in behavioral domains, and questionnaires on personality (Fragebogens zur Persönlichkeit bei zerebralen Erkrankungen) and impulsivity (Barratt Impulsiveness Scale-11). RESULTS LEV was rated as very effective by 40% of the patients. In contrast to only 9% of the controls, a considerable number of patients reported a behavioral change while taking LEV (12% very negative, 25% negative, 16% positive, 6% very positive). Negative ratings were due to loss of self-control, restlessness, sleep problems, and, most importantly, aggression. Positive ratings were due to increased energy, vigilance, and activation. Increases in psychomotor speed, concentration, and remote memory indicated subjectively experienced positive effects on cognition. The proxy reports indicated reliable self-reports. Reported change was not related to type of epilepsy, co-therapy, dose, drug load, or psychiatric history. Negative effects were, however, associated with poorer seizure control, mental retardation, indicators of an organic psychosyndrome, and nonplanning impulsiveness. CONCLUSION The results indicate that LEV exerts a dose-independent stimulating effect that can be positive or negative. Aggression is a prominent feature. Lack of efficacy, mental retardation, and presumably also pre-intake disposition (organic psychosyndrome, impulsivity) may be helpful in predicting whether additional activation under LEV will be positive or negative.

Interhemispheric dissociation of expressive and receptive language functions in patients with complex-partial seizures: an amobarbital study.

Bilateral intracarotid amobarbital procedures (IAP) were performed in 144 patients with medically intractable complex-partial seizures. As a result of language testing, 29 patients (20.1%) were found to have bilateral language representation to different degrees. In four (2.8%) of these patients--all right-handers with early onset of epilepsy and/or evidence of early brain damage--there was strong evidence of an interhemispheric dissociation of expressive and receptive language functions. Two of these patients had circumscribed temporal foci (one left, one right), and receptive language functions were represented in the hemisphere contralateral to the focus. One patient with a right frontal focus showed left-hemisphere dominance for expressive functions, while the fourth patient exhibited left-hemisphere dominance for receptive functions associated with a right temporo-parietal focus. It is argued that in these four cases the circumscribed functional and/or structural impairments have led to a shift of the anatomically associated language functions to the opposite hemisphere (rather than to neighboring regions of the same hemisphere). These findings substantiate the hypothesis that in special circumstances the anterior (expressive) language area can be located in one hemisphere and the posterior (receptive) area in the other.

EpiTrack: Tracking cognitive side effects of medication on attention and executive functions in patients with epilepsy

RATIONALE Achievement of maximum seizure control with preservation or even improvement of patients cognitive capabilities is the major aim of epilepsy therapy. EpiTrack is a brief screening tool for the tracking of cognitive side effects of antiepileptic drugs. Test selection was based on recent studies on the effects of topiramate on cognition and retrospective inspection of results from patients with antiepileptic drug (AED) side effects. METHODS The 15-minute screening tool comprises six subtests: the Trail-Making Test (parts A and B), a test of response inhibition, digit span backward, written word fluency, and a maze test. These tests were standardized in 220 healthy subjects, 100 of whom were reevaluated after 5.3 months to obtain information on reliability and practice effects. Criterion validity was determined by correlation to other neuropsychological measures. For a first clinical evaluation, the impact of epilepsy (seizures) and medication on EpiTrack scores was evaluated cross-sectionally in 184 consecutive inpatients with chronic epilepsy. RESULTS According to the normative data, we developed an easy scoring scheme assigning test scores on a 7-point scale. The EpiTrack is suitable for patients between 18 and 60 years of age. Age corrections were included for patients between 40 and 60 years. EpiTrack scores on subtests for both controls and patients were submitted to principal component analysis. VARIMAX rotation yielded a two-factor solution (verbal/visuo-spatial) that accounted for 63.8% of the total variance in controls. In the patient group, only one factor emerged accounting for 54.7% of variance. EpiTrack correlates with global scores of attention (r=0.85) and language (r=0.67) (Ps<0.001). At a cutoff score of 25, only 2.7% of the controls were classified as impaired, while impairment was indicated in 48.4% of the patients. The score is sensitive to monthly frequency of complex partial seizures and to number of AEDs. It shows negative cognitive effects of valproate and topiramate given in mono/polytherapy. CONCLUSION EpiTrack is a promising 15-minute screening tool for the detection and tracking of cognitive side effects of AEDs and adverse effects of seizures in patients with epilepsy. Future application will show its value in prospective follow-up studies on AED side effects.

Neuropsychological course of voltage-gated potassium channel and glutamic acid decarboxylase antibody related limbic encephalitis

Autoantibodies (abs) to glutamic acid decarboxylase (GAD) and to voltage‐gated potassium channels (VGKC) induce distinct courses of limbic encephalitis, related to MRI findings, seizure outcome and cognition.

The validity of the Child Behavior Checklist for children with epilepsy.

The validity of the Child Behavior Checklist (CBCL) for patients with epilepsy has been questioned, because several items may reflect seizure semiology rather than habitual behavior. This study compared a standard version of the CBCL with an adjusted version that excluded those ambiguous items. Participants were 58 pediatric patients with epilepsy who were assessed preoperatively and 1 year after successful surgical treatment. Before surgery, the adjusted version indicated significantly lower values for the scales Attention Problems, Thought Problems, and Total Problems than the standard version. After surgery, the difference between the standard and adjusted versions and the scores for the ambiguous items were unchanged, although all patients were completely seizure free at that time. Elevated scores on the ambiguous items thus probably reflect real behavioral problems and are not due to confusion with seizure semiology. The results support the CBCL as a valid assessment tool in children with epilepsy.