Memory outcome one year after stereotactic interstitial radiosurgery in patients with epilepsy due to hypothalamic hamartomas

Epileptic seizures caused by hypothalamic hamartomas (HHs) are highly pharmacoresistant. Resective surgical approaches have shown some efficacy in controlling seizures; however, they bear a significant risk of postoperative mnemonic deterioration due to the close anatomical proximity of the HHs to structures essential for memory functions. We report on cognitive outcome in 26 patients with structural epilepsy due to HHs one year after interstitial radiosurgery. Individually, deteriorations occurred more frequently in declarative memory functions (in 20 to 50% of the patients), whereas more than 80% of the patients revealed stable or even improved performance in attentional functions. Preoperative better memory functions were associated with higher risk of postoperative performance decline. After radiosurgery, half of the patients showed more than 50%, and some up to 90%, of seizure reduction. Hypothalamic hamartoma volumes were significantly reduced at follow-up. Transient radiogenic edema found in 10/26 patients was not associated with further cognitive decline after radiosurgery. These results are highly relevant for therapeutic decisions and patient consultation on timing and choice of nonmedical treatment options for HHs.

Flashbulb memories in patients with temporal lobe epilepsy

PURPOSE

Flashbulb memories (FMs) are vivid and stable autobiographical memories associated with learning surprising news of high emotional impact. Patients with temporal lobe epilepsy (TLE) can have autobiographical memory deficits. This is the first investigation of FMs in TLE applying a consistency measure of FM quality controlling for confabulation.

METHOD

A sample of 12 patients with TLE and a matched group of 15 healthy controls (HCs) were tested on an FM test including a retest procedure. Scores of FM consistency were obtained by comparing answers across both testing occasions.

RESULTS

In patients with TLE, FM consistency scores were significantly lower than in HCs. Exploratory subgroup analyses revealed FM deficits in both patients with left TLE and patients with right TLE compared with HCs.

CONCLUSION

The present study indicates that the FMs of patients with TLE are less consistent than those of healthy control subjects. Future investigations with larger samples are desirable, especially regarding separate analyses of patients with left TLE and patients with right TLE.

Memory outcome after hippocampus sparing resections in the temporal lobe

BACKGROUND AND OBJECTIVE

Epilepsy surgery within the temporal lobe of the language dominant hemisphere bears the risk of postoperative verbal memory decline. As surgical procedures have become more tailored, the question has arisen, which type of resection within the temporal lobe is more favourable for memory outcome. Since the hippocampus (HC) is known to play an essential role for long-term memory, we examined whether HC sparing resections help to preserve verbal memory functions.

METHODS

We retrospectively analysed neuropsychological data (prior to and 1 year after surgery) of patients undergoing either HC sparing resections (HC-S, N=65) or resections including the hippocampus (HC-R, N=62).

RESULTS

Prior to surgery, the HC-R group showed worse memory performance as compared to HC-S patients. Both patient groups revealed further deterioration over time, but in verbal learning HC-R patients demonstrated a stronger decline. Predictors for verbal learning decline were left-sided surgery, better preoperative performance, higher age at surgery, hippocampus resection, and lower preoperative IQ. In patients with spared HC, resection of the left-sided parahippocampal gyrus was rather accompanied by a decline in verbal learning performance. For visual memory, better preoperative performance best predicted deterioration after surgery. Seizure outcome was comparable between the two groups (HC-S: 66%, HC-R: 65% Engel 1a).

CONCLUSIONS

Temporal lobe resections within the language dominant hemisphere can be accompanied by a decline in verbal memory performance, even if the HC is spared. Yet, HC sparing surgery is associated with a benefit in verbal learning performance. These results can help when counselling patients prior to epilepsy surgery.

Validation of a German version of the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E)

INTRODUCTION

Goal of the present study was the validation of a German version of the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E).

METHODS

197 adult epilepsy patients completed the NDDI-E (185 completed both the NDDI-E and BDI). 95 patients received psychiatric consults.

RESULTS

33 patients received a diagnosis of major depression according to ICD-10 criteria. Internal consistency of the NDDI-E was .83. Receiver operating characteristics (ROC) showed an area under the curve of 0.92. Applying a cutoff score of ≥14 resulted in both sensitivity and specificity of 0.85. In the subsample with psychiatric consult, at the same optimal cutoff, sensitivity was 0.92, and specificity was 0.86. Further analyses showed a high concurrent validity with the BDI.

DISCUSSION

The German version of the NDDI-E constitutes a brief and reliable depression screening instrument for epilepsy patients.

Who needs a Wada test? Present clinical indications for amobarbital procedures

INTRODUCTION

The Wada test has been the gold standard for testing cerebral language localisation during presurgical investigation in the past decades. However, during the last few years a shift has occurred in epilepsy surgery programmes towards the use of non-invasive methods, predominantly functional MRI (fMRI). However, Wada tests are still performed, albeit in a considerably smaller number of patients at many epilepsy centres.

METHODS

A retrospective monocentric analysis of remaining clinical indications for performing a Wada procedure was undertaken. The clinical data of patients who participated in Wada tests (42 hemispheric and 8 superselective procedures) during recent years were retrospectively evaluated.

RESULTS

Reasons for conducting a Wada test were (1) a patient's inability to perform the fMRI task due to agitation, mental disablement, or perceptual impairment, (2) validation of atypical, inconclusive or not clearly lateralised language activation shown with fMRI, (3) evaluation of propagation of ongoing interictal bilateral epileptiform EEG activity, (4) region selective testing of language and other cognitive functions, or (5) assessment of motor localisation. Patients who were not able to perform the fMRI task or in whom fMRI did not provide interpretable results were significantly younger (p<0.05).

CONCLUSION

It is argued that fMRI is eligible to replace Wada tests in the majority of patients who are compliant with clearly lateralised language localisation, but in patients who are agitated or mentally impaired as well as in the case of the above-mentioned specific clinical indications and bilateral fMRI activations, Wada tests still provide additional information. Additionally, non-invasive methods less sensitive to movement artefacts are discussed as possible alternatives for these patients.

Preoperative depressive symptoms predict postoperative seizure outcome in temporal and frontal lobe epilepsy

OBJECTIVE

Recent research has pointed to the possibility of a bidirectional relationship between seizure frequency in epilepsy and depressive symptoms. The study described here investigated the relationship between preoperative depressive symptomatology and postoperative seizure outcome in a sample of patients with temporal (TLE) and frontal (FLE) lobe epilepsy.

METHODS

A retrospective analysis was conducted on the data from 115 eligible patients with TLE (N=97) and FLE (N=18) and resections limited to one cortical lobe who were evaluated preoperatively and 1year after epilepsy surgery with respect to depressive symptoms (Beck Depression Inventory, BDI) and seizure outcome. The latter was assessed in terms of actual total seizure frequency as well as a dichotomous variable (seizure free vs. not seizure free) for the 1-year outcome. Repeated-measures analyses of variance and regression analyses were applied.

RESULTS

Seizure-free patients had significantly lower BDI scores preoperatively as well as postoperatively than patients who were not seizure free. In the regression analyses, the preoperative BDI score was a significant predictor of postoperative seizure frequency as well as seizure freedom. When only patients with TLE were analyzed, the results for the association between preoperative BDI and postoperative seizure frequency and seizure freedom remained consistent.

CONCLUSION

The present results provide evidence for a statistical bidirectionality of the relationship between depressive symptoms and postoperative seizure status in a mixed sample of patients with TLE and FLE. Possible reasons for this bidirectional association include an underlying common pathology in both depression and epilepsy, for example, structural changes or functional alterations in neurotransmitter systems.

The impact of extratemporal epilepsy surgery on quality of life

Quality of life (QOL) with respect to seizure outcome, cognitive performance, and depressive symptoms was analyzed in 21 adult patients undergoing extratemporal epilepsy surgery (EXTLE). The Subjective Handicap of Epilepsy questionnaire was administered before and 1 year after surgery. Additionally, cognitive performance, depressive symptoms (Beck Depression Inventory), and seizure frequency were assessed. After surgery, seizure frequency decreased and various aspects of QOL significantly improved. Improvements in the domain of Work and Activities correlated with a reduction in complex partial seizure frequency. Alterations in the subscale change correlated with a decrease in simple partial seizure frequency. The present results provide detailed evidence that patients with extratemporal epilepsy benefit from epilepsy surgery.

Ribbon synapses of the mammalian retina contain two types of synaptic bodies--ribbons and spheres

The present paper reports that the synaptic bodies of the retinal ribbon synapses in rat, guinea pig, golden hamster and mouse are a heterogeneous population of organelles. In addition to the well-known synaptic ribbons sensu stricto which consist of a platelike electron-dense central structure surrounded by electron-lucent synaptic vesicles, there are what is termed synaptic spheres, in which the core is not platelike, but round to oval. In rat retinae procured at day, ribbons outnumbered spheres by a factor of 4. At night spheres were not seen in photoreceptor cells. Spheres, like ribbons, may lie some distance from the synaptic site, perhaps indicating transit from their site of origin to the synapse. At night ribbons are longer than at daytime. In addition to the previously described connecting stalks between synaptic vesicles and the electron-dense ribbons, the presence of filamentous stalks between adjacent synaptic vesicles is described. The latter stalks, depending on their presence or absence, may influence the position of the synaptic vesicles in relation to the synaptic body and/or the presynaptic membrane. It is concluded that the plasticity of retinal synapses cannot be fully appreciated unless the temporal changes of ribbons, spheres and the connecting stalks are taken into consideration.