Susanne Aull-Watschinger

A functional polymorphism in the prodynorphin gene promotor is associated with temporal lobe epilepsy

The prodynorphin gene (PDYN) encoding the anticonvulsant peptide dynorphin is a strong candidate for a seizure suppressor gene and thus a possible modulator of susceptibility to temporal lobe epilepsy. We performed a case control association study in 155 patients with nonlesional temporal lobe epilepsy and 202 controls and found that PDYN promotor low‐expression L‐alleles confer an increased risk for temporal lobe epilepsy in patients with a family history for seizures. Irrespective of the familial background, L‐homozygotes display a higher risk for secondarily generalized seizures and status epilepticus.

Outcome predictors for surgical treatment of temporal lobe epilepsy with hippocampal sclerosis

Purpose: To study long‐term postoperative course and identify predictors for postoperative seizure control in patients with medically intractable temporal lobe epilepsy (TLE) associated with hippocampal sclerosis (HS), diagnosed by magnetic resonance imaging (MRI), and ascertained histopathologically. To compare patients becoming seizure‐free (i.e., cured from epilepsy) and patients experiencing prolonged seizure‐free periods interposed with recurring seizures.

Sexual auras: Predominance of epileptic activity within the mesial temporal lobe

The occurrence of sexual auras (SAs), defined as erotic feelings accompanied by sexual arousal and orgasm, was investigated in 244 consecutive patients with medically refractory focal epilepsy. All patients were evaluated with prolonged video/EEG monitoring, high-resolution MRI, and the Wada test. One female and two male patients with hippocampal sclerosis and /or atrophy experienced SAs. In accordance with the findings on interictal and ictal EEGs, the epileptogenic zone could be localized to the speech-dominant mesial temporal lobe in one case and to the non-speech-dominant mesial temporal lobe in two cases. All patients were treated by selective amygdalohippocampectomy. Our results indicate that: (1) SAs occur in men and women, (2) SAs occur predominantly in seizures originating from the nondominant temporal lobe (but may also be associated with seizure onset in the dominant hemisphere), and (3) SAs point toward a seizure onset in mesial temporal structures.

Combined electroencephalography and magnetoencephalography of interictal spikes in benign rolandic epilepsy of childhood

OBJECTIVE The neurogenesis and functional organization of the interictal spikes in benign rolandic epilepsy of childhood (BREC) still remains controversial. METHODS We performed a combined neuroelectric and neuromagnetic study in 24 consecutive patients with BREC using a 143-channel whole-head magnetoencephalography (MEG) system simultaneously with electroencephalography (EEG) recorded from 40 closely spaced scalp-EEG electrodes. Isopotential and isofield maps were calculated over the time window from 250ms before to 250ms after the maximum of the negative peak of the spike. We then performed principal component analysis (PCA) and spatio-temporal dipole modeling in order to estimate the number, location and temporal activity of sources. RESULTS EEG and MEG spikes were characterized by a stereotypical appearance both within and across patients showing a stable dipolar field distribution over the entire time window. The spikes were generated by a single tangential dipolar source located in the precentral gyrus with the positive pole directed frontally and the negative pole directed centro-temporally. CONCLUSIONS One source located in the precentral gyrus can adequately explain the spike complex in BREC. SIGNIFICANCE Simultaneous EEG and MEG provide comprehensive information on functional organization of spikes in BREC.

Is reoperation an option for patients with temporal lobe epilepsy after failure of surgery

PURPOSE Epilepsy surgery is the most efficacious therapeutic modality for patients with medically refractory focal epilepsies, but surgical failures remain a challenge to the epilepsy treatment team. The aim of present study was to evaluate the postoperative outcome of patients who underwent reoperation after a failed epilepsy surgery on the temporal lobe. METHODS We systematically analyzed the results of comprehensive preoperative evaluations before the first surgery, and before and after reoperation in 17 patients with drug resistant temporal lobe epilepsies. RESULTS Overall, 13 of 17 patients (76.5%) improved after reoperation: five patients (29.4%) were completely seizure free after reoperation (median duration 60months, range 12-72); six patients (35.3%) were seizure free at least 12month before observation points (median duration 120.5months, range 35-155) and two patients (11.8%) had a decrease in seizure frequency. Four patients (23.5%) remained unchanged with respect to seizure frequency and severity. There was no correlation between the improvement in seizure outcome after reoperation and other clinical data except of the history of traumatic brain injury (TBI). The patients who had no history of TBI improved after reoperation, compared to patients with TBI (p=0.044). The postoperative seizure outcome of patients with incongruent Video-EEG results before the first surgery (p=0.116) and before reoperation (p=0.622) was not poorer compared to patients with congruent Video-EEG results. CONCLUSIONS Reoperation can considerably improve the operative outcome of the first failed epilepsy surgery in patients with drug resistant temporal lobe epilepsies. Epilepsy centres should be encouraged to report the results of failed epilepsy surgeries.

The yield of routine electroencephalography in the detection of incidental nonconvulsive status epilepticus – A prospective study

OBJECTIVE Diagnosis of NCSE is challenging, because the clinical presentation ranges from minimally altered mental status to coma without tonic-clonic activity. According to the largest retrospective study to date the incidence of NCSE is about 0.2%. METHODS We prospectively investigated electroencephalography (EEG) recordings of 2514 consecutive patients that were referred to the Electrophysiology Unit of Department of Neurology, Vienna General Hospital between November 2009 and February 2011 (i.e. 16months). RESULTS The incidence of NCSE in our study population was 0.8%, i.e. the EEG of 19 patients fulfilled the criteria of NCSE. In 53% of these patients the NCSE was not suspected by treating physicians. A severely reduced level of consciousness was found in 78% of patients with a suspected NCSE and in 30% of patients with an unsuspected NCSE, although the results were not statistically significant (p=0.081). The delay between the admission to the hospital and diagnosis ranged between 0 and 51days. CONCLUSIONS NCSE was an unsuspected finding in more than half of the patients. Consciousness was severely impaired in only one third of these patients. SIGNIFICANCE These results highlight the importance of urgent EEG for the diagnosis of NCSE in patients even without significant impairment of consciousness.

Temporal evolution and prognostic significance of postoperative spikes after selective amygdala-hippocampectomy.

Summary The purpose of this study was to quantify the temporal evolution and to determine the prognostic significance of spikes on serial postoperative EEGs after selective amygdala-hippocampectomy. The authors performed postoperative EEGs 4 months, 1 year, and 2 years after surgery in 31 patients with unilateral mesial temporal lobe epilepsy. Spike frequency was determined ipsilateral to the resection (group I, no spikes; group II, 1 to 10 spikes; group III, 11 to 20 spikes; group IV, more than 21 spikes during the 30-minute recording). The temporal evolution of postoperative spike frequency was assessed, and these parameters were correlated with surgical outcome. Twenty-two patients showed spikes on postoperative EEG. Spike frequency decreased over time in 14 patients, while no changes or minimal changes occurred in seven patients, and spike frequency increased in one patient. Nine patients had no spikes. There was no correlation between occurrence, frequency, and temporal evolution of spikes with postoperative seizure control. The authors’ results demonstrate a progressive decrease of spike frequency during the postoperative period after selective amygdala-hippocampectomy, although occurrence, frequency, and temporal evolution of postoperative spikes had no implications on surgical outcome.

Field testing of ICHD-3 beta criteria of periictal headaches in patients with focal epilepsy – a prospective diary study

Background To date we are lacking prospective data for field testing of ICHD-3 beta criteria for periictal headache (PIH). Methods Patients with focal epilepsy diagnosed by means of prolonged video-EEG monitoring completed a paper-pencil diary for three months and recorded seizures and headaches on a daily basis. According to ICHD-3 beta, we classified PIH, defined as headache present on a day with at least one seizure, as “7.6 headache related to epileptic seizure”, “7.6.1 hemicrania epileptica” or “7.6.2 postictal headache”. In addition, we compared the ICHD-3 beta diagnoses to the diagnoses according to ICHD-2. Results Thirty two patients completed the diary. Data analysis included 2,668 patient days, 300 seizures and 37 episodes of PIH. Two of these episodes (5.4%) were classified as headache related to seizure, three (8.1%) fulfilled both the criteria of headache related to seizure and hemicrania epileptica and four (10.8%) were postictal headaches. Twenty eight episodes (75.7%) did not fulfil any of the ICHD-3 beta criteria of seizure-related headaches, mostly because headache onset was before seizure onset. Applying ICHD-2 criteria allowed only one single episode of PIH to be classified as postictal headache. Discussion Our study is the first to present prospective field testing data of the ICHD-3 beta criteria for three types of seizure-related headaches. The majority of PIH episodes do not fulfil any of these criteria. One quarter can be classified according to ICHD-3 beta, whereas purely clinical diagnosis of PIH is markedly restricted in ICHD-2 because of mandatory electroencephalographic evidence.

Psychoses in epilepsy: A comparison of postictal and interictal psychoses

We retrospectively analyzed data of patients with epilepsy (n=1434) evaluated with prolonged EEG monitoring in order to estimate the prevalence of postictal psychosis (PP) and interictal psychosis (IP), to investigate a potential association of psychosis subtype with epilepsy type, and to assess differences between PP and IP. The overall prevalence of psychosis was 5.9% (N=85); prevalence of PP (N=53) and IP (N=32) was 3.7% and 2.2%, respectively. Of patients with psychosis, 97.6% had localization-related epilepsy (LRE). Prevalence of psychosis was highest (9.3%) in patients with temporal lobe epilepsy (TLE). When comparing PP with IP groups on demographic, clinical, and psychopathological variables, patients with IP were younger at occurrence of first psychosis (P=0.048), had a shorter interval between epilepsy onset and first psychosis (P=0.002), and more frequently exhibited schizophreniform traits (conceptual disorganization: P=0.008; negative symptoms: P=0.017) than those with PP. Postictal psychosis was significantly associated with a temporal seizure onset on ictal EEG (P=0.000) and a higher incidence of violent behavior during psychosis (P=0.047). To conclude, our results support the presumption of a preponderance of LRE in patients with psychosis and that of a specific association of TLE with psychosis, in particular with PP. Given the significant differences between groups, PP and IP may represent distinct clinical entities potentially with a different neurobiological background.

Incidental epileptiform discharges in patients of a tertiary centre

OBJECTIVE This controlled study set out to assess the rate of incidental epileptiform discharges (ED) during routine EEG and the incidence of epilepsy within a 4-year follow-up period in patients without a history of epilepsy. METHODS We retrospectively analyzed electroencephalography (EEG) recordings of 1750 consecutive patients referred to the Department of Neurology at the Vienna General Hospital between January 1 and December 31, 2009. The incidence of epilepsy in patients with ED and no prior history of epilepsy was compared with a disease control group matched for gender and neuroimaging findings. RESULTS ED were identified in 26 (4%) of 629 patients without a history of epilepsy. Sixteen (62%) of these patients developed epilepsy during follow-up compared with five (19%) of the disease controls (p=0.01), yielding an adjusted odds ratio of 8.8 (95% CI 2.1-37.7) for developing epilepsy in patients with ED and no prior history of epilepsy. CONCLUSIONS Incidental ED during routine EEG significantly increase the likelihood of developing epilepsy. SIGNIFICANCE Patients with incidental ED should be specifically asked for any signs and symptoms suggestive of seizures, since they appear more prone to develop epilepsy.