Short post-injection seizure duration is associated with reduced power of ictal brain perfusion SPECT to lateralize the seizure onset zone

BACKGROUND

The aim of this study was to assess the impact of the post-injection electrical seizure duration on the identification of the seizure onset zone (SOZ) in ictal brain perfusion SPECT in presurgical evaluation of drug-resistant epilepsy.

METHODS

176 ictal SPECT performed with 99mTc-HMPAO (n = 140) or -ECD (n = 36) were included retrospectively. Visual interpretation of the SPECT images (together with individual MRI and statistical hyperperfusion maps) with respect to lateralization (right, left, none) and localization (temporal, frontal, parietal, occipital) of the SOZ was performed by 3 independent readers. Between-readers agreement was characterized by Fleiss' κ. An ictal SPECT was considered "lateralizing" if all readers agreed on right or left hemisphere. It was considered "localizing" if it was lateralizing and all readers agreed on the same lobe within the same hemisphere. The impact of injection latency and post-injection seizure duration on the proportion of lateralizing/localizing SPECT was tested by ANOVA with dichotomized (by the median) injection latency and post-injection seizure duration as between-subjects factors.

RESULTS

Median [interquartile range] (full range) of injection latency and post-injection seizure duration were 30 [24, 40] (3-120) s and 50 [27, 70] (-20-660) s, respectively. Fleiss' κ for lateralization of the SOZ was largest for the combination of early (< 30 s) injection and long (> 50 s) post-injection seizure duration (κ = 0.894, all other combinations κ = 0.659-0.734). Regarding Fleiss' κ for localization of the SOZ in the 141 (80.1%) lateralizing SPECT, it was largest for early injection and short post-injection seizure duration (κ = 0.575, all other combinations κ = 0.329-0.368). The proportion of lateralizing SPECT was lower with short compared to long post-injection seizure duration (estimated marginal means 74.3% versus 86.3%, p = 0.047). The effect was mainly driven by cases with very short post-injection seizure duration ≤ 10 s (53.8% lateralizing). Injection latency in the considered range had no significant impact on the proportion of lateralizing SPECT (p = 0.390). The proportion of localizing SPECT among the lateralizing cases did not depend on injection latency or post-injection seizure duration (p ≥ 0.603).

CONCLUSIONS

Short post-injection seizure duration is associated with a lower proportion of lateralizing cases in ictal brain perfusion SPECT.

Expert opinion on diagnosis and management of epilepsy-associated comorbidities

Apart from seizure freedom, the presence of comorbidities related to neurological, cardiovascular, or psychiatric disorders is the largest determinant of a reduced health-related quality of life in people with epilepsy (PwE). However, comorbidities are often underrecognized and undertreated, and clinical management of comorbid conditions can be challenging. The focus of a comprehensive treatment regimen should maximize seizure control while optimizing clinical management of treatable comorbidities to improve a person's quality of life and overall health. A panel of four European epileptologists with expertise in their respective fields of epilepsy-related comorbidities combined the latest available scientific evidence with clinical expertise and collaborated to provide consensus practical advice to improve the identification and management of comorbidities in PwE. This review provides a critical evaluation for the diagnosis and management of sleep-wake disorders, cardiovascular diseases, cognitive dysfunction, and depression in PwE. Whenever possible, clinical data have been provided. The PubMed database was the main search source for the literature review. The deleterious pathophysiological processes underlying neurological, cardiovascular, or psychiatric comorbidities in PwE interact with the processes responsible for generating seizures to increase cerebral and physiological dysfunction. This can increase the likelihood of developing drug-resistant epilepsy; therefore, early identification of comorbidities and intervention is imperative. The practical evidence-based advice presented in this article may help clinical neurologists and other specialist physicians responsible for the care and management of PwE.

Temporal lobe epilepsy with GAD antibodies: neurons killed by T cells not by complement membrane attack complex

Temporal lobe epilepsy (TLE) is one of the syndromes linked to antibodies against glutamic acid decarboxylase (GAD). It has been questioned whether 'limbic encephalitis with GAD antibodies' is a meaningful diagnostic entity. The immunopathogenesis of GAD-TLE has remained enigmatic. Improvement of immunological treatability is an urgent clinical concern. We retrospectively assessed the clinical, MRI and CSF course as well as brain tissue of 15 adult patients with GAD-TLE who underwent temporal lobe surgery. Brain tissue was studied by means of immunohistochemistry, multiplex fluorescent microscopy and transcriptomic analysis for inflammatory mediators and neuronal degeneration. In 10 patients, there was a period of mediotemporal swelling and T2 signal increase; in nine cases this occurred within the first 6 years after symptom onset. This resulted in unilateral or bilateral hippocampal sclerosis; three cases developed hippocampal sclerosis within the first 2 years. All CSF studies done within the first year (n = 6) revealed intrathecal synthesis of immunoglobulin G. Temporal lobe surgeries were done after a median disease duration of 9 years (range 3 weeks to 60 years). Only two patients became seizure-free. Brain parenchyma collected during surgery in the first 6 years revealed high numbers of plasma cells but no signs of antibody-mediated tissue damage. Even more dense was the infiltration by CD8+ cytotoxic T lymphocytes (CTLs) that were seen to locally proliferate. Further, a portion of these cells revealed an antigen-specific resident memory T cell phenotype. Finally, CTLs with cytotoxic granzyme B+ granules were also seen in microglial nodules and attached to neurons, suggesting a CTL-mediated destruction of these cells. With longer disease duration, the density of all lymphocytes decreased. Whole transcriptome analysis in early/active cases (but not in late/inactive stages) revealed 'T cell immunity' and 'Regulation of immune processes' as the largest overrepresented clusters. To a lesser extent, pathways associated with B cells and neuronal degeneration also showed increased representation. Surgically treated patients with GAD-TLE go through an early active inflammatory, 'encephalitic' stage (≤6 years) with CTL-mediated, antigen-driven neuronal loss and antibody-producing plasma cells but without signs of complement-mediated cell death. Subsequently, patients enter an apparently immunologically inactive or low-active stage with ongoing seizures, probably caused by the structural damage to the temporal lobe. 'Limbic encephalitis' with GAD antibodies should be subsumed under GAD-TLE. The early tissue damage explains why immunotherapy does not usually lead to freedom from seizures.

No Evidence to Favor 99mTc-HMPAO or 99mTc-ECD for Ictal Brain Perfusion SPECT for Identification of the Seizure Onset Zone

PURPOSE

Ictal brain perfusion SPECT with the tracer 99mTc-HMPAO or 99mTc-ECD is widely used for identification of the epileptic seizure onset zone (SOZ) in presurgical evaluation if standard pointers are uncertain or inconsistent. For both tracers, there are theoretical arguments to favor it over the other for this task. The aim of this study was to compare the performance of ictal brain perfusion SPECT between 99mTc-HMPAO and 99mTc-ECD in a rather large patient sample.

PATIENTS AND METHODS

The study retrospectively included 196 patients from clinical routine in whom ictal perfusion SPECT had been performed with stabilized 99mTc-HMPAO (n = 110) or 99mTc-ECD (n = 86). Lateralization and localization of the SOZ were obtained by the consensus of 2 independent readers based on visual inspection of the SPECT images.

RESULTS

The 99mTc-HMPAO group and the 99mTc-ECD group were well matched with respect to age, sex, age at first seizure, duration of disease, seizure frequency, history of previous brain surgery, and findings of presurgical MRI. The proportion of lateralizing ictal SPECT did not differ significantly between 99mTc-HMPAO and 99mTc-ECD (65.5% vs 72.1%, P = 0.36). Sensitivity of ictal perfusion SPECT (independent of the tracer) for correct localization of the SOZ in 62 patients with temporal lobe epilepsy and at least worthwhile improvement (Engel scale ≤ III) 12 months after temporal epilepsy surgery was 63%.

CONCLUSIONS

This study does not provide evidence to favor 99mTc-HMPAO or 99mTc-ECD for identification of the SOZ by ictal perfusion SPECT.

Predicting the outcome of epilepsy surgery by covariance pattern analysis of ictal perfusion SPECT

Previous studies on the utility of specific perfusion patterns in ictal brain perfusion SPECT for predicting the outcome of temporal lobe epilepsy surgery used qualitative visual pattern classification, semi-quantitative region-of-interest analysis or conventional univariate voxel-based testing, which are limited by intra- and inter-rater variability and/or low sensitivity to capture functional interactions among brain regions. The present study performed covariance pattern analysis of ictal perfusion SPECT using the Scaled Subprofile Model for unbiased identification of predictive covariance patterns. Methods: The study retrospectively included 18 responders to temporal lobe epilepsy surgery (Engel I-A at 12 months follow-up) and 18 non-responders (≥ Engel I-B). Ictal SPECT images were analyzed with the Scaled Subprofile Model blinded to group membership for unbiased identification of the 16 covariance patterns explaining the highest proportion of variance in the whole data set. Individual expression scores of the covariance patterns were evaluated for predicting seizure freedom after temporal lobe surgery by ROC analysis. Kaplan-Meier analysis including all available follow-up data (up to 60 months after surgery) was also performed. Results: Amongst the 16 covariance patterns only one showed a different expression between responders and non-responders (P = 0.03). This 'favorable ictal perfusion pattern' resembled the typical ictal perfusion pattern in temporomesial epilepsy. The expression score of the pattern provided an area of 0.744 (95%-confidence interval 0.577-0.911, P = 0.004) under the ROC curve. Kaplan-Meier analysis revealed a statistical trend towards longer seizure freedom in patients with positive expression score (P = 0.06). The median estimated seizure free time was 48 months in patients with positive expression score versus 6 months in patients with negative expression score. Conclusion: The expression of the 'favorable ictal perfusion pattern' identified by covariance analysis of ictal brain perfusion SPECT provides independent (from demographical and clinical variables) information for the prediction of seizure freedom after temporal lobe epilepsy surgery. The expression of this pattern is easily computed for new ictal SPECT images and, therefore, might be used to support the decision for or against temporal lobe surgery in clinical patient care.

European Expert Opinion on ANT-DBS therapy for patients with drug-resistant epilepsy (a Delphi consensus)

INTRODUCTION

Although deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) represents an established third-line therapy for patients with drug-resistant focal epilepsy, guiding reports on practical treatment principles remain scarce.

METHODS

An Expert Panel (EP) of 10 European neurologists and 4 neurosurgeons was assembled to share their experience with ANT-DBS therapy. The process included a review of the current literature, which served as a basis for an online survey completed by the EP prior to and following a face-to-face meeting (Delphi method). An agreement level of ≥71 % was considered as consensus.

RESULTS

Out of 86 reviewed studies, 46 (53 %) were selected to extract information on the most reported criteria for patient selection, management, and outcome. The Delphi process yielded EP consensus on 4 parameters for selection of good candidates and patient management as well as 7 reasons of concern for this therapy. Since it was not possible to give strict device programming advice due to low levels of evidence, the experts shared their clinical practice: all of them start with monopolar stimulation, 79 % using the cycling mode. Most (93 %) EP members set the initial stimulation frequency and pulse width according to the SANTE parameters, while there is more variability in the amplitudes used. Further agreement was achieved on a list of 7 patient outcome parameters to be monitored during the follow-up.

CONCLUSIONS

Although current evidence is too low for definite practical guidelines, this EP report could support the selection and management of patients with ANT-DBS.

Electrical Stimulation of the Anterior Thalamus for Epilepsy: Clinical Outcome and Analysis of Efficient Target

OBJECTIVE

Deep brain stimulation (DBS) of the anterior thalamic complex (ANT) is an adjunctive therapy for pharmacoresistant epilepsy. To define the most efficient target in DBS for epilepsy, we investigate clinical data, position of leads, usability of atlas data compared to electric field modeling based on programming parameters.

METHODS

Data from ten consecutive patients who underwent ANT-DBS were analyzed. The mammillothalamic tract (MTT), an internal landmark for direct stereotactic targeting, was segmented from MRI. Centers of stimulation were determined and their positions relative to ventricles and the MTT were analyzed. Two 3D thalamus atlases were transformed to segmented patient's thalami and proportions of activated nuclei were calculated.

RESULTS

Our data indicate higher response rates with a center of stimulation 5 mm lateral to the wall of the third ventricle (R² for reduction of focal seizure frequency and distance to the wall of the third ventricle = 0.48, p = 0.026). For reduction of focal seizures, a strong positive correlation with the dorsal distance to the midcommissural plane was found (R² = 0.66, p = 0.004). In one 3D atlas, stimulation of internal medullary lamina (IML) correlated strongly positive with response rates, which, however, did not reach statistical significance (R² = 0.69, p = 0.17 for tonic-clonic seizures). All electrical fields covered the diameter of the MTT. The position of the MTT in the thalamus was highly variable (range: x-coordinate 4.0 to 7.3 mm, y-coordinate -1.3 to 5.1 mm in AC-PC space).

CONCLUSIONS

The distance of the active contact to the lateral wall of the third ventricle, MTT and the ventrodorsal distance to midcommissural plane appear to be relevant for optimal target planning. For reduction of focal seizure frequency, we found best response rates with a center of stimulation 5 mm lateral to the wall of the third ventricle, and a lead tip 10 mm dorsal of the midcommissural plane.

Face memory in MRI-positive and MRI-negative temporal lobe epilepsy

PURPOSE

Effects of MRI-positive (MRI(+)) as compared to MRI-negative (MRI(-)) temporal lobe epilepsy (TLE) on face memory are not yet known.

METHODS

We studied 24 MRI(-) (11 right/13 left) and 20 MRI(+) (13 right/7 left) TLE patients, 12 generalized epilepsy patients, and 12 healthy subjects undergoing diagnostic workup with 24-72-h Video-EEG-monitoring. Twenty faces were shown, and had to be recognized from 40 faces immediately and after a 24-h delay.

RESULTS

MRI(+) and MRI(-) right TLE (RTLE) patients showed deficits in face recognition compared to controls or generalized epilepsy, consistent with right temporal lobe dominance for face recognition. MRI(+) RTLE patients had deficits in both immediate and delayed recognition, while MRI(-) RTLE patients showed delayed recognition deficits only. The RTLE groups showed comparable delayed recognition deficits. Separate analyses in which the MRI(+) group included patients with hippocampal sclerosis only, did not alter results. Furthermore, MRI(-) RTLE had a worse delayed recognition than MRI(-) left TLE (LTLE). On the other hand, MRI(+) RTLE did not differ from MRI(+) LTLE in delayed recognition. Combining MRI(-) and MRI(+) TLE groups, we found differences between RTLE and LTLE in delayed, but not immediate face recognition.

CONCLUSIONS

Our results suggest that a delayed recognition condition might be superior to immediate recognition tests in detecting face memory deficits in MRI(-) RTLE patients. This might explain why former studies in preoperative patients did not observe an immediate face recognition dominance of the right temporal lobe when combining MRI(-) and MRI(+) TLE patients. Our data further point to an important role of the right mesial temporal region in face recognition in TLE.

Sex differences in face recognition memory in patients with temporal lobe epilepsy, patients with generalized epilepsy, and healthy controls

The influence of sex on face recognition memory was studied in 49 patients with temporal lobe epilepsy, 20 patients with generalized epilepsy, and 32 healthy controls. After learning 20 faces, serially presented for 5 seconds each, subjects had to recognize the 20 among 40 faces (including 20 new faces) immediately and 24 hours later. Women had better face recognition than men, with no significant differences between groups. Women's advantage was due mainly to superior delayed recognition. Taken together, the results suggest that sex has a similar impact on face recognition in patients with epilepsy and healthy controls, and that testing delayed face recognition raises sensitivity for sex differences. The influence of sex on face recognition in patients with epilepsy should be acknowledged when evaluating individuals or comparing groups.

Epilepsy increases vulnerability of long-term face recognition to proactive interference

Proactive interference (PI) decreases short- and long-term memory in healthy subjects. Neurological patients exhibit a heightened PI effect on short-term memory. It is, however, not known if PI affects long-term memory in neurological patients. We analyzed whether epilepsy heightens the negative effect of PI on long-term face memory. PI was induced by a list of 20 faces learned 24 hours prior to a target list of 20 faces. We tested immediate and 24-hour recognition for both lists. Twelve healthy controls and 42 patients with generalized epilepsy or temporal lobe epilepsy (TLE) were studied. PI led to a decrease in 24-hour recognition in patients with generalized epilepsy and TLE but not in controls. Thus, PI may cause long-term memory disturbances in epilepsy patients. PI was also associated with decreased short-term memory, but only in right TLE. This confirms the dominant role of the right temporal lobe in short-term face memory.

[The attitude of medical students to psychiatric patients]

Numerous studies conducted during the past decades indicate that the public's attitude toward the mentally ill is strongly prejudiced. Since the attitude of the general public also has an effect on community-based psychiatric care, we must ask how public opinion might be influenced. One possible approach could be through so called key community leaders--those who are highly respected in society because of their competence in a particular area. Doctors belong to this group of people. For this reason we questioned medical students, as future key community leaders, with respect to their attitudes toward the mentally ill within the framework of their first contact with psychiatric patients during their studies. In order to make a direct comparison possible, we interviewed a sample of the Mannheim population who live in a part of the city where a variety of complementary facilities have been set up. The comparison shows that medical students do not have a more positive attitude toward the mentally ill; in fact, in certain areas they have an even more negative attitude toward the mentally ill than the general population has. We were not able to establish what effect teaching has with respect to changing attitudes.

[Using natural helping systems]

Professional psychiatric help alone is not sufficient especially in the treatment of chronic mental illness. One must offer additional support also known as social support or social network. Informal helpers are family members, friends, civilian helpers, self-help groups with contracts to media and political levels and so on. In spite of different aims they have a great deal in common such as free-of-charge help, assistance to professional helpers not as their substitutes, and being in touch with normal everyday life. Any tensions between professional and informal helpers should be relieved in a constructive manner. Support by informal carers must also be assessed although it is difficult to find the correct approach, since so many variables are involved. The significance of promoting a social network for mental health becomes particularly evident in view of the reduction of the social network in persons suffering from schizophrenia.

[Alcohol consumption and its significance in therapeutic residences for psychiatric patients]

We conducted a study on alcohol consumption habits in the five therapeutic homes for the mentally ill in Mannheim. Through assessment by their case managers we obtained data from 136 residents. Frequent alcohol use is currently reported in 12.5%. This group of frequent alcohol users is characterized by a higher proportion of men, higher age at entry into the institution and a lower dosage of neuroleptic medication. No significant relation is found with regard to the age at onset of disease, the rehospitalisation rate and the general life satisfaction. Severe problems through alcohol use are seen only isolated but in all clients with an earlier diagnosis of alcohol abuse. According to our results alcohol abuse in therapeutic homes is reported less frequently than in other populations of chronic mentally ill clients. It might be suspected that mentally ill patients with additional alcohol problems are not adequately provided with housing in the complementary care system. Verification is needed whether through the development of specific offers this deficit can be regressed.

[Leisure and social contact clubs for psychiatric patients--an assessment of club members]

55 visitors from five recreation and social clubs for mentally ill clients have been described, related to some sociographic data including the number of times the club is frequented, the duration of membership in the club as well as the source of information. They were asked to give their opinions on the frequency and the duration of the meetings and the quality of the clubrooms, the care and the programmes. They give the reasons for attending the clubs and the resulting main effects. They make wishes and complaints about the clubs. The results of the questioning are compared to the description of tasks and aims of clubs as seen from the professional point of view in order to find conformities and/or differences. On the whole a consensus is to be seen. Differences can be ascertained, where the professional aim is mainly of therapeutic nature. Such a target does not meet the needs of the visitors. For them the social aspect is of main importance in a surrounding offering protection, acceptance, understanding and support.

Effect of vigabatrin (GVG) on serotonin (5-HT) uptake and release of human platelets in vitro

In platelets from healthy persons the effect of gamma-vinyl-GABA (GVG) on 5-HT uptake, storage, release and the kinetic parameters Km and Vmax of platelet 5-HT high affinity uptake was investigated in vitro. 5-HT uptake, storage and release in response to increasing GVG concentrations (0-7.74 mM) at a constant incubation time (60 min) and in dependence on time (0-90 min) at a constant GVG concentration (7.74 mM) remained unchanged. Concerning the high affinity 5-HT uptake, GVG (7.74 mM) caused a slight decrease of Vmax from 83.3 +/- 35.0 (SD) pmol 5-HT/10(8) pl./min to 77.0 +/- 33.4 (SD) pmol 5-HT/10(8) pl./min and a significant elevation of Km from 4.2 +/- 1.1 (SD) x 10(-7) M to 6.7 +/- 1.8 (SD) x 10(-7) M (P < 0.002) to about 160% of the control. This means a competitive inhibition of 5-HT uptake induced by GVG. Altogether, the effects of GVG on platelet 5-HT transport appear to be weak. An alteration of the platelet 5-HT system was demonstrated only at therapeutically nonrelevant high GVG concentrations. If platelets represent a model for 5-HT transport processes in presynaptic serotonergic neurons it is concluded that GVG has no effect on serotonergic activity.

Psychopathology and psychotherapy in chronic physically ill patients

Within the scope of psychosomatic medicine somato-psychic diseases are of great importance theoretically as well as practically, especially in view of problems dealing with the patient's attitude toward his illness and his coping with the disease. Among the somato-psychic illnesses chronic physical diseases are of primary interest. The knowledge of their general and specific psychological and psychopathological symptoms are of great importance for a better understanding of these patients and in view of a favourable direction in therapy. This is demonstrated in the form of extracts with three groups of the chronic physically ill: (1) hemophiliacs; (2) patients on regular hemodialysis treatment and following renal transplantation, and (3) diabetics.