Violence and Epilepsy: A Close Relation Between Violence and Postictal Psychosis

Summary: Purpose: We investigated the incidence of well-directed violent behavior and suicide attempts in patients with temporal lobe epilepsy, with special attention to postictal psychosis.
Methods: We compared 57 episodes of postictal psychosis with 62 episodes of acute interictal (or alternative) psychosis and with 134 complex partial seizures. All patients were matched for age and for age at onset of seizures.
Results: The incidence of well-directed violent behavior against human beings was significantly higher (23%) during postictal psychotic episodes than during acute interictal episodes (5%) and postictal confusion (1%). Suicide attempts were also more frequent during postictal psychosis (7%) than during either acute interictal psychosis (2%) or postictal confusion (0%).
Conclusions: Our study showed that well-directed violent and self-destructive behavior was not a feature of epileptic psychosis in general but a specific hallmark of postictal psychosis.     

Postictal Psychosis: A Comparison with Acute Interictal and Chronic Psychoses

Summary: We studied 30 patients with postictal psychosis and compared them with 33 patients with acute interictal psychosis and 25 patients with chronic psychosis. All patients had either complex partial seizures (CPS) or EEG temporal epileptogenic foci. Patients with postictal psychosis had a high incidence of psychic auras and nocturnal secondarily generalized seizures. The most striking feature that distinguished postictal psychosis from both acute interictal and chronic psychoses was phenomenological: the relatively frequent occurrence of grandiose delusions as well as religious delusions in the setting of markedly elevated moods and feeling of mystic fusion of the body with the universe. In addition, postictal psychosis exhibited few schizophreniform psychotic traits such as perceptual delusions or voices commenting. Reminiscence, mental diplopia, and a feeling of impending death were also fairly frequent complaints of patients with postictal psychosis. Interictal acute psychosis and chronic epileptic psychosis were psychopathologically similar. Although acute interictal and chronic epileptic psychoses could simulate schizophrenia, postictal psychosis results in a mental state quite different from that of schizophrenic psychosis.     

Prediction of Surgical Outcome by Interictal Epileptiform Abnormalities During Intracranial EEG Monitoring in Patients with Extrahippocampal Seizures

PURPOSE: Ictal intracranial EEG recordings obtained during continuous preoperative monitoring are often used to localize the region of seizure onset for purposes of surgical resection in patients with extrahippocampal seizures. Whether interictal epileptiform abnormalities during long-term monitoring can predict surgical outcome in this group is not established. METHODS: Intracranial EEGs of patients who underwent extrahippocampal resective epilepsy surgery were reviewed for interictal epileptiform abnormalities before medication discontinuation or first seizure occurrence. Interictal abnormalities were categorized as within or beyond the confines of surgical resection. We correlated these findings with the region of seizure onset, the pathologic substrate, and surgical outcome (by using Engel criteria) at 1-year minimum follow-up. RESULTS: Of 13 patients with interictal epileptiform abnormalities, six patients had interictal epileptiform discharges extending beyond the confines of surgical resection. These patients all had poor surgical outcome even if the region of electrographic seizure onset was resected. Seven patients had focal interictal epileptiform discharges, the entire extent of which were resected. All had good outcomes. All patients with structural lesions had focal interictal epileptiform abnormalities and good surgical outcomes. The spatial extent of interictal epileptiform discharges varied among patients with nonstructural lesions. However, those whose regions of interictal epileptiform abnormality were included in surgical resection also had good surgical outcome. CONCLUSIONS: The presence of interictal epileptiform discharges extending beyond the area of resection correlates with poor surgical outcome in patients with extrahippocampal epilepsy. In contrast, patients with focal interictal epileptiform discharges included in surgical resection have good surgical outcomes.     

Speech During Partial Seizures: Intracranial EEG Correlates

Vocalization during a seizure may help predict the location of seizure onset or identify structures ultimately involved in the seizure. Spontaneous vocalization during seizures was studied retrospectively in 22 patients with refractory complex partial seizures evaluated with bilateral intracranial electrodes. Of 22 patients, 12 vocalized during seizures. Seizures were as likely to originate from language-dominant (6/12) as from language-nondominant mesial temporal cortex (6/12). Fluent speech frequently occurred as seizure activity was recorded from language-dominant temporal lobe neocortex (6/12 seizures). Of the patients with well-localized seizure onsets who did not speak (6/10), seizures arose from both language-dominant and -nondominant mesial temporal cortex. We conclude that the presence or absence of vocalizations during a seizure does not reliably indicate the anatomic regions in which the seizure begins or spreads.     

Intracranial EEG substrates of scalp EEG interictal spikes

PURPOSE: To determine the area of cortical generators of scalp EEG interictal spikes, such as those in the temporal lobe epilepsy. METHODS: We recorded simultaneously 26 channels of scalp EEG with subtemporal supplementary electrodes and 46 to 98 channels of intracranial EEG in 16 surgery candidates with temporal lobe epilepsy. Cerebral discharges with and without scalp EEG correlates were identified, and the area of cortical sources was estimated from the number of electrode contacts demonstrating concurrent depolarization. RESULTS: We reviewed approximately 600 interictal spikes recorded with intracranial EEG. Only a very few of these cortical spikes were associated with scalp recognizable potentials; 90% of cortical spikes with a source area of >10 cm(2) produced scalp EEG spikes, whereas only 10% of cortical spikes having <10 cm(2) of source area produced scalp potentials. Intracranial spikes with <6 cm(2) of area were never associated with scalp EEG spikes. CONCLUSIONS: Cerebral sources of scalp EEG spikes are larger than commonly thought. Synchronous or at least temporally overlapping activation of 10-20 cm(2) of gyral cortex is common. The attenuating property of the skull may actually serve a useful role in filtering out all but the most significant interictal discharges that can recruit substantial surrounding cortex.     

Psychosis in epilepsy patients

Summary   Epileptic psychoses reflect a fundamental disruption in the fidelity of mind and occur during seizure freedom or during or after seizures. The psychotic symptoms in epilepsy share some qualities with schizophrenic psychosis, such as positive symptoms of paranoid delusions and hallucinations. Psychotic syndromes in epilepsy are most common but not exclusively associated with temporal lobe epilepsy. De Novo psychosis following epilepsy surgery is rare. Forced normalization—psychosis associated with dramatic reduction of epileptiform activity or seizures is described in small series only. Ictal and postictal psychosis can be prevented with seizure control, but postictal and chronic interictal psychoses require multidisciplinary and psychopharmacologic management.     

Intracranial EEG in temporal lobe epilepsy: location of seizure onset relates to degree of hippocampal pathology

PURPOSE: To determine whether the specific location of electrographic seizure onset in the temporal lobe is related to hippocampal pathology in temporal lobe epilepsy (TLE). METHODS: Consecutive presurgical patients with scalp EEG-video evidence of TLE and no or mild hippocampal atrophy (HA) on magnetic resonance imaging (MRI) were prospectively studied by using depth and subdural strip electrode recordings to identify the site of the initial ictal discharge (IID). Thirty-four patients had either no or mild HA (HA- group). Four additional patients with moderate or marked HA (HA+ group) who required depth and strip electrodes served as a comparison group. Hippocampal pathology was assessed by MRI volumetrics and histopathologic grade of sclerosis (HS). RESULTS: Thirty-eight patients were investigated. In the HA- group, 10 patients had lobar ictal EEG onsets in the hippocampus (HF), medial paleocortex (MPC), and lateral neocortex (LNC); eight cases had regional IIDs in both HF and MPC; 12 persons had IIDs completely outside the HF; three cases lacked depth electrodes, and only one case (3%) had an IID confined to the HF. By contrast, three (75%) of four HA+ cases had IIDs confined to the HF (p = 0.002). Similarly, in 12 patients with low-grade HS, IIDs confined to the HF area were seen significantly less often than in six cases with high-grade HS (p = 0.025). CONCLUSIONS: In this study of a large number of patients with no to mild and a smaller group with moderate to marked HA and HS, the location of seizure onset in the temporal lobe was related to the degree of hippocampal pathology. Absence of HA and low-grade HS was each associated with IIDs in both the hippocampus and medial (with or without lateral) temporal cortex, or only the MPC or LNC. Marked HA and high-grade HS both were associated with IIDs restricted to the HF.     

Non-linear analysis of intracranial human EEG in temporal lobe epilepsy.

OBJECTIVE: Intracranial EEG recordings from patients suffering from medically intractable temporal lobe epilepsy were analyzed with the aim of characterizing the dynamics of EEG epochs recorded before and during a seizure and comparing the classification of the EEG epochs on the basis of visual inspection to the results of the numerical analysis. METHODS: The stationarity of the selected EEGs was assessed qualitatively. The coarse-grained correlation dimension and coarse-grained correlation entropy were used for the non-linear characterization of the EEG epochs. RESULTS: High-pass filtering was necessary in order to make the majority of the epochs appear stationarity beyond a time scale of about 2 s. It was found that the dimension of the ictal EEGs decreased with respect to the epochs containing ongoing (interictal) activity. The entropy of the ictal recordings however increased. A scaling of the entropy was applied and it was found that the scaled entropy of the ictal EEG decreased, consistent with the increased regularity of the ictal EEG. The coarse-grained quantities discriminated well between EEG epochs recorded prior to and during seizures at locations displaying ictal activity and classification improved by including the linear autocorrelation time in the analysis. CONCLUSIONS: It is concluded that ictal and non-ictal EEG can be well distinguished on the basis of non-linear analysis. The results are in good agreement with the visual analysis.     

Ictal Behaviors During Nonepileptic Seizures Differ in Patients with Temporal Lobe Interictal Epileptiform EEG Activity and Patients Without Interictal Epileptiform EEG Abnormalities

Summary: Purpose: Ictal behaviors during psychogenic non-epileptic seizures (NES) vary considerably among individuals, and can closely resemble common semiologies of epileptic seizures (ES). We tested the hypothesis that behaviors during NES in patients who have temporal spikes would more closely resemble behaviors during ES in patients with temporal lobe epilepsy than would behaviors during NES in patients who do not have EEG spikes.
Methods: We identified 20 patients who had interictal temporal EEG spikes and EEG-video recorded NES (Study Group), 133 patients with temporal EEG spikes and recorded ES, without NES (Epileptic Group), and 24 patients with recorded NES and no epileptiform EEG abnormalities, without ES (Nonepileptic Group).
Results: The hypothesis was supported with regard to ictal motor behaviors. Motionless staring or complex automatisms occurred mainly during NES in the Study Group and during ES in the Epileptic Group. In contrast, convulsive movements or flaccid falls were most common during NES in the Nonepileptic Group. Duration of unresponsiveness was longer, and there were fewer postictal states in NES both in the Study and Non-epileptic Groups. Unresponsiveness was briefer and postictal states were more consistent in ES in the Epileptic Group, however.
Conclusions: Stereotyped motor activities during NES presumably represent learned behaviors. Processes underlying acquisition of ictal behaviors of NES probably differ in patients with interictal epileptiform EEG abnormalities compared to those without. Prior experiences and temporal lobe dysfunctions that are associated with epilepsy, and psychological characteristics that are unrelated to interictal epileptic dysfunctions, may determine ictal behaviors during NES.     

Postictal mania versus postictal psychosis: differences in clinical features, epileptogenic zone, and brain functional changes during postictal period

PURPOSE: To clarify the differences between postictal mania (PIM) and postictal psychosis (PIP). METHODS: Five patients with PIM were compared to 17 patients with PIP, with respect to clinical, epileptological, electrophysiological, and neuroimaging features. PIM was distinguished from PIP by the symptoms observed in the postictal period based on the ICD-10 criteria. RESULTS: Postictal manic episodes lasted for a longer period than postictal psychotic episodes. Patients with PIM had more recurrent postictal episodes than patients with PIP. The age at onset of epilepsy in patients with PIM was older than that in patients with PIP. PIM was associated with frontal lobe and temporal lobe epilepsies, whereas PIP was associated with temporal lobe epilepsy. The estimated epileptogenic zone was on the language dominant side in PIM, whereas there was no predominant hemispheric laterality in PIP. Electroencephalography (EEG) performed during the early period of postictal manic and psychotic episodes showed decreased frequency of interictal epileptiform discharges in both PIM and PIP. Single-photon emission computed tomography (SPECT) during postictal manic and psychotic episodes showed increased perfusion in the temporal and/or frontal lobes in both PIM and PIP. Three patients with PIM showed increased perfusion during postictal episodes on bilateral or the language nondominant side, which were contralateral to the estimated epileptogenic zone, whereas three patients with PIP showed increased perfusion on the areas, which were ipsilateral to the estimated epileptogenic zone. CONCLUSIONS: PIM has a distinct position among the mental disorders observed in the postictal period.     

Preeminence of extrahippocampal structures in the generation of mesial temporal seizures: evidence from human depth electrode recordings

PURPOSE: To examine the intralimbic localization and morphology of mesial temporal seizure onsets and to correlate the findings with patterns of initial seizure spread and the presence or absence of clinical manifestations. METHODS: Eighteen patients with temporal lobe epilepsy were investigated with intracranial depth electrodes implanted in the amygdala (AM), anterior hippocampus (HP), and parahippocampal gyrus (PH). Focal and regional ictal-onset morphologies were classified as rhythmic limbic spiking <2 Hz (RLS), spike-and-wave activity >2 Hz (S/W), rhythmic polyspike activity >13 Hz (RPS), and rhythmic sharp activity <13 Hz (RS). RESULTS: Onset morphologies in 389 total seizures (260 regional + 129 focal) were 50% RPS, 35% RS, 11% RLS, and 4% S/W. Focal AM or HP onsets (30% and 58% of focal onsets, respectively) were more likely to show RLS, whereas RPS was more common in regional onsets. Most patients showed two or more different morphologies and focal onsets at more than one ipsilateral limbic site. Seizure propagation and clinical manifestations were significantly more common with AM or PH onsets (both 67% clinical seizures): only 23% of focal HP onsets resulted in clinical seizures. CONCLUSIONS: (a) There is substantial inter- and intrapatient variability in the morphology and localization of mesial temporal seizure onsets, which suggests that the epileptogenic temporolimbic system may be conceptualized as a dynamic network containing a multiplicity of potential ictal generators; (b) Seizures beginning in the AM or PH are more likely to propagate and give rise to clinical manifestations than are focal-onset HP seizures, which suggests that inhibitory circuits within the HP may function to prevent seizure spread.     

Recognition of the Various Expressions of Anxiety, Psychosis, and Aggression in Epilepsy

Summary:  Anxiety, psychosis, and aggressive behavior are among the frequent comorbid psychiatric disorders identified in patients with epilepsy. Often the clinical manifestations of these disorders vary according to their temporal relation relative to seizure occurrence. Thus, postictal symptoms of anxiety or psychosis differ in severity, duration, and response to treatment with interictal symptomatology. Psychiatric symptomatology in epilepsy can appear concurrently with the seizure disorder and improve or remit on the abolition of epileptic activity. We refer to these as paraictal psychiatric phenomena. Such is the case of aggressive disturbances associated with gelastic seizures caused by hypothalamic hamartomas. In this article, three case studies are presented to illustrate the importance of distinguishing psychiatric symptoms of anxiety, psychosis, and aggression, with respect to their temporal relation with seizure occurrence.     

Intracranial EEG seizure-onset patterns in neocortical epilepsy

PURPOSE: We investigated neocortical seizure-onset patterns recorded by intracranial EEG with regard to anatomic location, pathologic substrate, and prognostic value for surgical outcome. METHODS: Seizure onset was analyzed in 53 neocortical resective epilepsy surgery patients. Anatomic location was divided into temporal and extratemporal. Pathologic substrate was classified as developmental, mature, and negative or non-specific gliosis. Onset frequency was categorized by visual analysis into tradition EEG frequency bands. Spatial extent was divided into focal (fewer than four contacts) and regional (more than five contacts). Waveform at seizure onset was divided into several types based on their morphology. Onset features were examined with respect to anatomic location, pathologic substrate, and surgical outcome. RESULTS: Seizure-onset frequency was significantly related to spatial distribution and to anatomic location. Extratemporal and regional onset were more commonly in the gamma range, and temporal and focal onset in the beta frequency range or slower. Waveform could be categorized into five different patterns, of which low voltage fast activity (LVFA) was the most common form (57%). LVFA and rhythmic alpha-theta spike activity were more common in developmental than in mature pathology, whereas rhythmic sinusoidal waves at onset were found in only mature substrates. Waveform pattern showed a possible correlation with surgical outcome (p = 0.097): LVFA and rhythmic sinusoidal waves onset patterns were associated with favorable outcome more often (40.4%) than the other three patterns (6.3%). Slow onset suggested poor outcome in the subgroup of developmental pathology (p = 0.062). CONCLUSIONS: Certain electrographic seizure-onset features are associated with specific substrates and outcomes, whereas others reflect the anatomic location and its connections independent of the pathology.     

The clinical usefulness of ictal SPECT in temporal lobe epilepsy: the lateralization of seizure focus and correlation with EEG

PURPOSE: To analyze the relationship between ictal electroencephalography (EEG) and ictal single-photon emission computed tomography (SPECT) and to evaluate the diagnostic usefulness of ictal SPECT as an independent presurgical evaluation technique. METHODS: Sixty-eight patients with temporal lobe epilepsy who underwent temporal lobectomy with good surgical outcome were included in this study. Ictal SPECT was performed during video-EEG monitoring. The ictal EEG was analyzed in 5-second intervals from the initiation of the ictal rhythm. Lateralized EEG dominance was determined by the amplitude, frequency, or regional patterns of ictal rhythm for each 5-second interval. The total ictal EEG was divided into three periods: preinjection (maximum, 30 seconds), the initial part of the postinjection period (30 seconds), and the latter part of the postinjection period (30 to 60 seconds). The results of ictal SPECT were compared with the lateralized EEG dominance of each period and at seizure onset. RESULTS: Fifty-four of 68 ictal EEGs correctly lateralized seizure focus ipsilateral to the side of surgery. Ictal SPECT correctly lateralized the epileptogenic temporal lobe in 61 of 68 patients (mean injection time, 29.8 seconds from onset). Multivariate analysis indicated that only the EEG dominance of the preejection period correlated significantly with the concordant hyperperfusion of ictal SPECT. Correct lateralization of ictal SPECT occurred in 10 of 14 patients with nonlateralized ictal EEG. CONCLUSIONS: Preinjection neuronal activity seems to be important for the accurate interpretation of the hyperperfused patterns of ictal SPECT. Ictal SPECT is an independent and confirmatory presurgical evaluation technique.     

An investigation of EEG dynamics in an animal model of temporal lobe epilepsy using the maximum Lyapunov exponent

Analysis of intracranial electroencephalographic (iEEG) recordings in patients with temporal lobe epilepsy (TLE) has revealed characteristic dynamical features that distinguish the interictal, ictal, and postictal states and inter-state transitions. Experimental investigations into the mechanisms underlying these observations require the use of an animal model. A rat TLE model was used to test for differences in iEEG dynamics between well-defined states and to test specific hypotheses: 1) the short-term maximum Lyapunov exponent (STL_max), a measure of signal order, is lowest and closest in value among cortical sites during the ictal state, and highest and most divergent during the postictal state; 2) STL_max values estimated from the stimulated hippocampus are the lowest among all cortical sites; and 3) the transition from the interictal to ictal state is associated with a convergence in STL_max values among cortical sites. iEEGs were recorded from bilateral frontal cortices and hippocampi. STL_max and T-index (a measure of convergence/divergence of STL_max between recorded brain areas) were compared among the four different periods. Statistical tests (ANOVA and multiple comparisons) revealed that ictal STL_max was lower (p < 0.05) than other periods, STL_max values corresponding to the stimulated hippocampus were lower than those estimated from other cortical regions, and T-index values were highest during the postictal period and lowest during the ictal period. Also, the T-index values corresponding to the preictal period were lower than those during the interictal period (p < 0.05). These results indicate that a rat TLE model demonstrates several important dynamical signal characteristics similar to those found in human TLE and support future use of the model to study epileptic state transitions.     

Timing,Distribution, and Relationship Between Nonpsychotic and Subthreshold Psychotic Symptoms Prior to Emergence of a First Episode of Psychosis

Prospective population studies suggest that psychotic syndromes may be an emergent phenomenon—a function of severity and complexity of more common mental health presentations and their nonpsychotic symptoms. Examining the relationship between nonpsychotic and subthreshold psychotic symptoms in individuals who later developed the ultimate outcome of interest, a first episode of psychosis (FEP), could provide valuable data to support or refute this conceptualization of how psychosis develops. We therefore conducted a detailed follow-back study consisting of semistructured interviews with 430 patients and families supplemented by chart reviews in a catchment-based sample of affective and nonaffective FEP. The onset and sequence of 27 pre-onset nonpsychotic (NPS) or subthreshold psychotic (STPS) symptoms was systematically characterized. Differences in proportions were analyzed with z-tests, and correlations were assessed with negative binomial regressions. Both the first psychiatric symptom (86.24% NPS) and the first prodromal symptom (66.51% NPS) were more likely to be NPS than STPS. Patients reporting pre-onset STPS had proportionally more of each NPS than did those without pre-onset STPS. Finally, there was a strong positive correlation between NPS counts (reflecting complexity) and STPS counts (β = 0.34, 95% CI [0.31, 0.38], P < 2 e-16). Prior to a FEP, NPS precede STPS, and greater complexity of NPS is associated with the presence and frequency of STPS. These findings complement recent arguments that the emergence of psychotic illness is better conceptualized as part of a continuum—with implications for understanding pluripotential developmental trajectories and strengthening early intervention paradigms.     

The Relationship Between Sleep and Epilepsy in Frontal and Temporal Lobe Epilepsies: Practical and Physiopathologic Considerations

Summary: Purpose: The influence of sleep on the incidence of seizures and the reciprocal effects of epilepsy on sleep were analyzed in 30 patients with intractable partial seizures, all candidates for surgery.
Methods: The patients were classified into two groups of 15 patients according to the documented site of the epileptogenic zone: frontal lobe epilepsy (FLE) and medial temporal lobe epilepsy (TLE). Frequency and waking-sleep distribution of seizures were evaluated by continuous video-EEG monitoring for 5 days, under defined antiepileptic drug (AED), sleep, and sleep deprivation regimens. Sleep organization was analyzed by polysomnography prior to the presurgical protocol.
Results: Significant differences were found between the two groups in sleeping-waking distribution of seizures under varied conditions, and in the quality of sleep organization. In FLE patients, seizures most often occurred during sleep, although sleep organization was normal. In TLE patients, most seizures occurred while patients were awake, and sleep organization was characterized by a low efficiency index. The difference in seizure distribution between FLE and TLE persisted under all conditions investigated, i.e., after AED discontinuation and sleep deprivation.
Conclusions: Sleep recording may be useful for diagnosis of FLE, and monitoring after sleep deprivation for that of TLE. We speculate that sleep-related seizures in FLE may depend on interaction between frontal lobe areas with the thalamus cortical synchronization system and the acetylcholine regulatory system of waking.