Semiautomated electric source imaging determines epileptogenicity of encephaloceles in temporal lobe epilepsy.

OBJECTIVE: We aimed to assess the ability of semiautomated electric source imaging (ESI) from long-term video-electroencephalographic (EEG) monitoring (LTM) to determine the epileptogenicity of temporopolar encephaloceles (TEs) in patients with temporal lobe epilepsy. METHODS: We conducted a retrospective study involving 32 temporal lobe epilepsy patients with TEs as potentially epileptogenic lesions in structural magnetic resonance imaging scans. Findings were validated through invasive intracerebral stereo-EEG in six of 32 patients and postsurgical outcome after tailored resection of the TE in 17 of 32 patients. LTM (mean duration = 6 days) was performed using the 10/20 system with additional T1/T2 for all patients and sphenoidal electrodes in 23 of 32 patients. Semiautomated detection and clustering of interictal epileptiform discharges (IEDs) were carried out to create IED types. ESI was performed on the averages of the two most frequent IED types per patient, utilizing individual head models, and two independent inverse methods (sLORETA [standardized low-resolution brain electromagnetic tomography], MUSIC [multiple signal classification]). ESI maxima concordance and propagation in spatial relation to TEs were quantified for sources with good signal quality (signal-to-noise ratio > 2, explained signal > 60%). RESULTS: ESI maxima correctly colocalized with a TE in 20 of 32 patients (62.5%) either at the onset or half-rising flank of at least one IED type per patient. ESI maxima showed propagation from the temporal pole to other temporal or extratemporal regions in 14 of 32 patients (44%), confirming propagation originating in the area of the TE. The findings from both inverse methods validated each other in 14 of 20 patients (70%), and sphenoidal electrodes exhibited the highest signal amplitudes in 17 of 23 patients (74%). The concordance of ESI with the TE predicted a seizure-free postsurgical outcome (Engel I vs. >I) with a diagnostic odds ratio of 2.1. SIGNIFICANCE: Semiautomated ESI from LTM often successfully identifies the epileptogenicity of TEs and the IED onset zone within the area of the TEs. Additionally, it shows potential predictive power for postsurgical outcomes in these patients.

Seizures as a Struggle between Life and Death: An Existential Approach to the Psychosocial Impact of Seizures in Candidates for Epilepsy Surgery.

INTRODUCTION: Mental health comorbidities such as depression and anxiety are common in epilepsy, especially among people with pharmacoresistant epilepsy who are candidates for epilepsy surgery. The Psychology Task Force of the International League Against Epilepsy advised that psychological interventions should be integrated into comprehensive epilepsy care. METHODS: To better understand the psychological impact of epilepsy and epileptic seizures in epilepsy surgery candidates, we analysed interviews with this subgroup of patients using Karl Jaspers' concept of limit situations, which are characterised by a confrontation with the limits and challenges of life. These are especially chance, randomness, and unpredictability, death and finitude of life, struggle and self-assertion, guilt, failure, and falling short of one's aspirations. RESULTS: In 43 interviews conducted with 15 people with drug-resistant epilepsy who were candidates for epilepsy surgery, we found that these themes are recurrent and have a large psychosocial impact, which can result in depression and anxiety. For some people, epileptic seizures appear to meet the criteria for traumatic events. CONCLUSION: Understanding epilepsy and seizures as existential challenges complements the neurobiological explanations for psychological comorbidities and can help tailor psychological interventions to the specific needs of people with epilepsy, especially those who are candidates for surgical treatment.

"What is this strange sensation?" A qualitative exploration of metaphors used to verbalise hard-to-describe experiences by people with epilepsy.

Mental health comorbidities are frequent in epilepsy. Consequently, psychotherapy is becoming increasingly important. To address the psychological needs of people with epilepsy (PwE) it is essential to understand the subjective experiences of seizures better. There is little research on how people report seizures, and which psychological representations they have. We conducted a thematic analysis based on 42 (micro-phenomenological) interviews with 15 participants on their experiences of seizures. In these interviews, we identified three categories of seizure descriptions: (1) phenomena related to the body and emotions; (2) the moments that are difficult to describe; and (3) the use of figurative language and metaphors. Paroxysmal physical and psychological sensations were often reported spontaneously by the participants. The moments that were difficult to describe were expressed, among other things, through the use of paradoxes or the report of a 'strange' feeling and led participants to use figurative language. As these metaphors can reveal important information about people's subjective experiences, they were analyzed in detail. We identified the three main types of metaphors that the participants used most frequently: (1) perception, (2) nature, and (3) battle. The theme of battle was most frequently used in different forms and was closely related to the metaphors from the fields of perception and nature, thus representing a key point in the personal experience of seizures. These findings can contribute to developing psychotherapeutic approaches for the treatment of seizure disorders.

Effects of cenobamate on cognitive performance of epilepsy patients.

PURPOSE: Cenobamate (CNB) is a new antiseizure medication (ASM) for the treatment of focal epilepsy in adults. While efficacy of CNB was confirmed in controlled clinical trials, its effects on cognition are unclear. Cognitive adverse effects of ASM affect quality of life and retention rate. Therefore, we investigated whether the adjunctive treatment with CNB is associated with changes in cognitive performance. METHOD: Efficacy and tolerability of CNB were investigated in an observational study. Fifty patients with pharmacoresistant focal epilepsy aged 18 to 71 years (Mdn = 37.5 years) were tested before (T0) and after reaching the first target dose of CNB, usually after three months (T1). Cognitive performance was assessed using the EpiTrack©, a change-sensitive screening tool for attention and executive functions. RESULTS: The median CNB dose at T1 was 125 mg/day (range: 50 - 250 mg/day). Most patients received 2-3 concomitant ASMs. Individual test scores remained stable in 72%, significantly improved in 16%, and significantly deteriorated in 12% of the patients from T0 to T1. The total group showed a significant improvement in EpiTrack scores (p < .01). Changes in EpiTrack performance from T0 to T1 occurred independently of CNB dose, changes in the total drug load or reduction in seizure frequency. CONCLUSION: Most of the patients showed stable or improved cognitive performance. Thus, there is preliminary evidence that adjunctive CNB is not associated with an increased risk of cognitive side effects for the majority of patients. These findings need to be confirmed in controlled trials encompassing higher doses.

Diagnostic yield and limitations of in-hospital documentation in patients with epilepsy.

OBJECTIVE: To determine the diagnostic yield of in-hospital video-electroencephalography (EEG) monitoring to document seizures in patients with epilepsy. METHODS: Retrospective analysis of electronic seizure documentation at the University Hospital Freiburg (UKF) and at King's College London (KCL). Statistical assessment of the role of the duration of monitoring, and subanalyses on presurgical patient groups and patients undergoing reduction of antiseizure medication. RESULTS: Of more than 4800 patients with epilepsy undergoing in-hospital recordings at the two institutions since 2005, seizures with documented for 43% (KCL) and 73% (UKF).. Duration of monitoring was highly significantly associated with seizure recordings (p < .0001), and presurgical patients as well as patients with drug reduction had a significantly higher diagnostic yield (p < .0001). Recordings with a duration of >5 days lead to additional new seizure documentation in only less than 10% of patients. SIGNIFICANCE: There is a need for the development of new ambulatory monitoring strategies to document seizures for diagnostic and monitoring purposes for a relevant subgroup of patients with epilepsy in whom in-hospital monitoring fails to document seizures.

Detection of interictal epileptiform discharges in an extended scalp EEG array and high-density EEG-A prospective multicenter study.

OBJECTIVES: High counts of averaged interictal epileptiform discharges (IEDs) are key components of accurate interictal electric source imaging (ESI) in patients with focal epilepsy. Automated detections may be time-efficient, but they need to identify the correct IED types. Thus we compared semiautomated and automated detection of IED types in long-term video-EEG (electroencephalography) monitoring (LTM) using an extended scalp EEG array and short-term high-density EEG (hdEEG) with visual detection of IED types and the seizure-onset zone (SOZ). METHODS: We prospectively recruited consecutive patients from four epilepsy centers who underwent both LTM with 40-electrode scalp EEG and short-term hdEEG with 256 electrodes. Only patients with a single circumscribed SOZ in LTM were included. In LTM and hdEEG, IED types were identified visually, semiautomatically and automatically. Concordances of semiautomated and automated detections in LTM and hdEEG, as well as visual detections in hdEEG, were compared against visually detected IED types and the SOZ in LTM. RESULTS: Fifty-two of 62 patients with LTM and hdEEG were included. The most frequent IED types per patient, detected semiautomatically and automatically in LTM and visually in hdEEG, were significantly concordant with the most frequently visually identified IED type in LTM and the SOZ. Semiautomated and automated detections of IED types in hdEEG were significantly concordant with visually identified IED types in LTM, only when IED types with more than 50 detected single IEDs were selected. The threshold of 50 detected IED in hdEEG was reached in half of the patients. For all IED types per patient, agreement between visual and semiautomated detections in LTM was high. SIGNIFICANCE: Semiautomated and automated detections of IED types in LTM show significant agreement with visually detected IED types and the SOZ. In short-term hdEEG, semiautomated detections of IED types are concordant with visually detected IED types and the SOZ in LTM if high IED counts were detected.

Electrode placement for SEEG: Combining stereotactic technique with latest generation planning software for intraoperative visualization and postoperative evaluation of accuracy and accuracy predictors.

BACKGROUND: Intracranial recordings with stereoelectroencephalography (SEEG) aims at defining the epileptogenic zone in patients with pharmacoresistant epilepsy. Currently used techniques for depth electrode implantation include stereotactic frame-based and navigated frameless applications, both either conventional or robot-assisted. Safety and diagnostic effectiveness depend on accuracy of implantation. OBJECTIVE: To evaluate the planning experience, accuracy of stereotactic electrode placement as well as accuracy predictors with the use of latest generation planning software. METHODS: Retrospective study of 15 consecutive patients who received depth electrodes using the Leksell stereotactic frame, after planning with Elements (Brainlab, Munich, Germany). For each electrode, we calculated the entry point error (EPE) as lateral deviation and target point error (TPE) both as lateral deviation and distance to tip. Multivariate regression analysis and computation of 95% confidence intervals using the bootstrap method were applied for statistical analysis and evaluation of accuracy predictors. RESULTS: The mean EPE, lateral deviation at TP and distance to tip at TP were 0.6 ±0.5 mm, 1.1 ±0.7 mm and 1.5 ±0.8 mm respectively. Order of implantation (1-6 vs. >6) is predictor for distance to tip at TP and length of electrode predictor for the lateral deviation at TP. Localization of electrode generally did not correlate to error, but insular electrodes were significantly less accurate than lobar ones. CONCLUSION: Combination of frame-based stereotaxy with latest generation planning software may offer a better planning and implantation experience. Accuracy predictors should be analyzed and be considered for the improvement of accuracy and safety of SEEG implantation methods.

Electrocorticographic and neurochemical findings after local cortical valproate application in patients with pharmacoresistant focal epilepsy.

Because oral pharmacological treatment of neocortical focal epilepsy is limited due to common systemic side effects and relatively low drug concentrations reached at the epileptic foci locally, application of antiepileptic agents directly onto the neocortical focus may enhance treatment tolerability and efficacy. We describe the effects of cortically applied sodium valproate (VPA) in two patients with pharmacoresistant neocortical focal epilepsy who were selected for epilepsy surgery after a circumscribed epileptic focus had been determined by invasive presurgical evaluation using subdural electrodes. Local VPA modified epileptic activity as electrocorticographically recorded from the chronic focus in both patients. In addition, VPA induced local increase of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) in cortical tissue samples, whereas the excitatory glutamate was possibly decreased. In this clinical pilot study, we could show antiepileptic effects of cortically applied VPA in humans by electrocorticographic and neurochemical parameters.

Can commercially available wearable EEG devices be used for diagnostic purposes? An explorative pilot study.

Electroencephalography (EEG) is a core element in the diagnosis of epilepsy syndromes and can help to monitor antiseizure treatment. Mobile EEG (mEEG) devices are increasingly available on the consumer market and may offer easier access to EEG recordings especially in rural or resource-poor areas. The usefulness of consumer-grade devices for clinical purposes is still underinvestigated. Here, we compared EEG traces of a commercially available mEEG device (Emotiv EPOC) to a simultaneously recorded clinical video EEG (vEEG). Twenty-two adult patients (11 female, mean age 40.2 years) undergoing noninvasive vEEG monitoring for clinical purposes were prospectively enrolled. The EEG recordings were evaluated by 10 independent raters with unmodifiable view settings. The individual evaluations were compared with respect to the presence of abnormal EEG findings (regional slowing, epileptiform potentials, seizure pattern). Video EEG yielded a sensitivity of 56% and specificity of 88% for abnormal EEG findings, whereas mEEG reached 39% and 85%, respectively. Interrater reliability coefficients were better in vEEG as compared to mEEG (ϰ = 0.50 vs. 0.30), corresponding to a moderate and fair agreement. Intrarater reliability between mEEG and vEEG evaluations of simultaneous recordings of a given participant was moderate (ϰ = 0.48). Given the limitations of our exploratory pilot study, our results suggest that vEEG is superior to mEEG, but that mEEG can be helpful for diagnostic purposes. We present the first quantitative comparison of simultaneously acquired clinical and mobile consumer-grade EEG for a clinical use-case.

Simultaneous Frame-assisted Stereotactic Placement of Subdural Grid Electrodes and Intracerebral Depth Electrodes.

BACKGROUND AND STUDY AIMS: In complex cases of drug-resistant focal epilepsy, the precise localization of the epileptogenic zone requires simultaneous implantation of depth and subdural grid electrodes. This study describes a new simple frame-assisted method that facilitates the simultaneous placement of both types of intracranial electrodes. MATERIAL AND METHODS: Ten consecutive patients were evaluated and divided into two groups. Group A included patients with simultaneous frame-assisted placement of depth and subdural grid electrodes. In group B, depth electrodes were implanted stereotactically; grid electrodes were implanted in a separate surgery. RESULTS: The placement of the subdural grid was accurate as individually designed by the epileptologists in all five patients from group A. In group B, one patient showed a slight and another one a significant deviation of the subdural grid position postoperatively. The mean surgical time in group A was shorter (280±62 minutes) compared with the mean duration of the surgical procedures in group B (336±51 minutes). CONCLUSION: The frame-assisted placement of subdural grid electrodes facilitates the surgical procedure for invasive video-electroencephalography monitoring in complex cases of drug-resistant focal epilepsy in which a combination of depth electrodes and subdural grid electrodes is needed, by reducing the surgical time and guaranteeing highly accurate electrode localizations.

Histopathology of 3 Tesla MRI-negative extratemporal focal epilepsies.

BACKGROUND: Information about the histopathology in 3 Tesla MRI negative extratemporal epilepsies is relatively limited. Most common histopathological findings in earlier (mixed 1.5 or 3 Tesla) MRI-negative series are focal cortical dysplasia (FCD), gliosis or normal findings. These series mostly use the older Palmini criteria for classification and grading. We focus on histopathology of only 3 Tesla MRI-negative extratemporal epilepsies according to the current ILAE criteria and investigate potential correlation to seizure outcome 1 year postoperatively. MATERIALS AND METHODS: Sixteen substrates of 3 Tesla MRI-negative extratemporal epilepsies were examined in two steps. Standard stains and immunohistochemical reactions and Palmini criteria were used prospectively during the initial examination. Retrospectively, all specimens were re-examined and re-evaluated. Phospho-6 and calretinin stains and ILAE criteria were used during the review examination. RESULTS: Initial examination revealed 5 FCDs Palmini 1b, two 1a, five 2a and 4 cases of gliosis. The review examination according to ILAE criteria revealed 6 FCDs type IIa, 2 FCDs Ib and 7 mild malformations of cortical development (mMCD) type II. None of our cases was labelled as isolated gliosis after the review examination. The incidence of FCD, after the review examination per ILAE criteria, was reduced to 56%; versus 75% per Palmini. CONCLUSIONS: In "true" 3 Tesla MRI-negative extratemporal epilepsies, incidence of FCD may be lower than in earlier MRI-negative series that included weaker MRI-field. Furthermore, consistent review examination may confirm the diagnosis of mMCD type II as substrate in cases diagnosed as "gliosis" or "normal" in the past.

The oxymoron of image-guided resection in 3 T MRI-negative extratemporal epilepsy: Technique and postoperative results.

OBJECTIVE: We share our experience with extratemporal MRI-negative epilepsies that received "image-guided" resection with the use of neuronavigation after invasive presurgical video-EEG monitoring. We describe and discuss our technique of image generation, navigation system registration, and surgical resection. In addition, we evaluate seizure outcome with respect to the preoperatively planned versus achieved resection. PATIENTS AND METHODS: Seven patients with 3 T MRI-negative extratemporal epilepsy received navigation-guided resective surgery. The resection plan was based on electrophysiological data from intracranial EEG recordings. For each case a resection segment was created in the neuronavigation device in a systematic manner. We compared the preoperatively planned segment to the achieved resection and looked for correlation with postoperative seizure outcome according to Engel classification, at last follow-up (mean 2.4 years, range 1-4 years). RESULTS: Mean volume of planned resections was 23.8 ±â€¯15.3 cm3 and of achieved resections 17 ±â€¯10.4 cm3. There was complete overlap with planned resection in 4 patients and partial overlap in 3. Postoperative seizure outcome was class I in 4 patients (57%), IIIA in 1 patient and IVB in 2 patients. Three patients reached seizure-freedom (Engel IA). Volume of planned resection, volume difference of planned versus achieved resection and level of overlap (complete versus partial) did not significantly correlate to seizure outcome. CONCLUSION: The use of neuronavigation for planning and executing a tailored resection in MRI-negative extratemporal epilepsy is elaborate but can be an effective procedure.

Histopathology of 3 Tesla MRI-negative temporal lobe epilepsies.

INTRODUCTION: Histopathology of MRI-negative temporal lobe epilepsies (TLE) shows heterogeneous findings. The use of either 1.5 or 3 Tesla MRI for the selection of MRI-negative cases and use of older classification systems instead of the current ILAE classification system may account for this heterogeneity. We focus on histopathology of 3 Tesla MRI-negative TLE according to ILAE criteria and investigate potential correlation to seizure outcome 1 year postoperatively. MATERIALS AND METHODS: Twenty specimens (9 neocortical, 11 hippocampal) from eleven 3 Tesla MRI-negative patients with TLE were examined in two steps. Standard stains and immunohistochemical reactions as well as Palmini and Wyler criteria were used prospectively during the initial examination. Retrospectively, all specimens were re-examined and re-evaluated. Phospho-6 and calretinin stains and the ILAE criteria were used during the review examination. RESULTS: Initial examination revealed 7 focal cortical dysplasias (FCDs) Palmini type 1, two cases of cortical gliosis, 4 cases of hippocampal sclerosis (HS) Wyler grade 1 and seven cases of hippocampal gliosis. The review examination according to ILAE criteria revealed 4 FCDs type I and 5 mild malformations of cortical development. All hippocampal specimens showed "no HS/gliosis only" after the review examination. Histopathology showed no correlation to seizure outcome. DISCUSSION: This is the first histopathological study to include only 3 Tesla MRI-negative cases. The use of ILAE criteria lead to the diagnosis of "no HS/gliosis only" of all hippocampal specimens, a finding not in line with previously reported series. The spectrum of diagnoses within neocortical specimens showed accordingly more mild findings.

3 Tesla MRI-negative focal epilepsies: Presurgical evaluation, postoperative outcome and predictive factors.

OBJECTIVE: To investigate presurgical diagnostic modalities, clinical and seizure outcome as well as predictive factors after resective epilepsy surgery in 3 Tesla MRI-negative focal epilepsies. PATIENTS AND METHODS: This retrospective study comprises 26 patients (11 males/15 females, mean age 34±12years, range 13-50 years) with 3 Tesla MRI-negative focal epilepsies who underwent resective epilepsy surgery. Non-invasive and invasive presurgical diagnostic modalities, type and localization of resection, clinical and epileptological outcome with a minimum follow-up of 1year (range 1-11 years, mean 2.5±2.3years) after surgery as well as outcome predictors were evaluated. RESULTS: All patients underwent invasive video-EEG monitoring after implantation of intracerebral depth and/or subdural electrodes. Ten patients received temporal and 16 extratemporal or multilobar (n=4) resections. There was no perioperative death or permanent morbidity. Overall, 12 of 26 patients (46%) were completely seizure-free (Engel IA) and 65% had a favorable outcome (Engel I-II). In particular, seizure-free ratio was 40% in the temporal and 50% in the extratemporal group. In the temporal group, long duration of epilepsy correlated with poor seizure outcome, whereas congruent unilateral FDG-PET hypometabolism correlated with a favorable outcome. CONCLUSIONS: In almost two thirds of temporal and extratemporal epilepsies defined as "non-lesional" by 3 Tesla MRI criteria, a favorable postoperative seizure outcome (Engel I-II) can be achieved with accurate multimodal presurgical evaluation including intracranial EEG recordings. In the temporal group, most favorable results were obtained when FDG-PET displayed congruent unilateral hypometabolism.

Schizophrenia Associated with Epileptiform Discharges without Seizures Successfully Treated with Levetiracetam.

BACKGROUND: Schizophrenia-like disorders can be divided into endogenic or primary, idiopathic, polygenetic forms, and different secondary, organic subgroups [e.g., (para)epileptic, immunological, degenerative]. Epileptic and paraepileptic explanatory approaches have a long tradition due to the high rate of electroencephalography (EEG) alterations in patients with schizophrenia. CASE PRESENTATION: We present the case of a 23-year-old female patient suffering, since the age of 14 years, from a fluctuating paranoid-hallucinatory syndrome with formal thought disorder, fear, delusions of persecution, auditory, visual, and tactile hallucinations, as well as negative and cognitive symptoms. Laboratory measurements showed increased titers of antinuclear antibodies (ANAs) in the context of ulcerative colitis. While there was no clear history or evidence of epileptic seizures, the EEG showed generalized 3 Hz polyspike wave complexes. Under treatment with levetiracetam, the symptoms disappeared and the patient was able to complete vocational training. CONCLUSION: The schizophrenia-like symptoms associated with epileptiform discharges but not overt seizures and the good response to antiepileptic treatment could be interpreted in the context of a (para)epileptic pathomechanism. The EEG alterations might be due to a polygenetic effect due to different genes. Mild immunological mechanisms in the framework of ulcerative colitis and increased ANA titers might have supported the network instability. This case report illustrates (1) the importance of EEG screenings in schizophrenia, (2) a potential pathogenetic role of epileptiform discharges in a subgroup of patients with schizophrenia-like symptoms, and (3) that antiepileptic medication with levetiracetam could be a successful treatment alternative in schizophrenia-like disorders with EEG alterations.

Local brain activity persists during apparently generalized postictal EEG suppression.

OBJECTIVES: Postictal generalized EEG suppression (PGES) frequently occurs after generalized convulsive seizures (GCS) and may be involved in the pathophysiology of sudden unexpected death in epilepsy (SUDEP). It is usually determined using conventional scalp EEG which is likely to miss cerebral activity in deeper brain structures. Here, we examined intracranial EEG activity after GCS to unravel the pattern and extent of local brain activity during apparent PGES on scalp EEG (s-PGES). METHODS: We retrospectively reviewed electroencephalographic data of people with chronic epilepsy who had GCS during presurgical video-EEG monitoring using simultaneous intracranial and scalp EEG (10-20 system) electrodes. RESULTS: Twenty-five GCS (20 with s-PGES) of 15 patients with an average number of 88±42 intracranial electrode contacts were included. The majority of GCS with s-PGES (18 of 20) displayed persisting or reemerging intracranial EEG activity during apparent PGES on scalp EEG. Three patterns were identified: Pattern 1 (11 GCS, 6 patients) consisted of continuous local interictal activity; Pattern 2 (5 GCS, 5 patients) displayed suppressed EEG activity at all intracranial contacts in the early phase of s-PGES, but reemerging local brain activity before s-PGES dissolved; and Pattern 3 (2 GCS, 2 patients) showed persistent local ictal activity during s-PGES. Persisting intracranial EEG activity at PGES onset on scalp EEG was present in 10±14% (range: 0 to 42%) of all intracranial contacts and mostly in the temporal lobe. CONCLUSIONS: Our results reveal that, during apparently generalized postictal EEG suppression, local brain activity persists or reemerges in most GCS. Possible implications of this localized neuronal activity in the context of SUDEP are discussed in the paper.

Electroencephalographic findings in schizophreniform and affective disorders.

OBJECTIVE: Pathological findings in electroencephalography (EEG) are discussed as a possible marker of organic mental disorders and a therapeutic response to anticonvulsive medication under these conditions. METHODS: We compared the prevalence of EEG abnormalities in 100 patients with schizophrenia, 100 patients with schizoaffective disorder, 51 patients with acute polymorphic psychotic disorder, 100 patients with bipolar disorder, 100 patients with unipolar major depression and 76 healthy control subjects with the findings of a previous study using well-diagnosed, large control samples (13,658 pilots and aircrew personnel). RESULTS: We detected an increased number of pathological EEG findings with intermittent rhythmic delta or theta activity in 7% of patients with schizophrenia, 7% of patients with schizoaffective disorder, 5.9% of patients with acute polymorphic psychosis, 6% of patients with bipolar disorder, 4% of unipolar depressed patients and 3.9% of the own control group, compared to 1% of strictly controlled healthy subjects. One-sided logistic regression revealed an association between pathological EEGs and the diagnosis of schizophrenia (Wald W = 3.466, p = 0.0315), schizoaffective disorder (W = 3.466, p = 0.0315) and bipolar disorder (W = 2.862, p = 0.0455). CONCLUSIONS: We suggest that the previously developed local area network inhibition model for a potential paraepileptic pathomechanism can explain the relevance of such findings in different psychiatric disorders.