Status Epilepticus and Periictal Imaging

Summary:  Peri- and postictal changes on both anatomic and functional imaging examinations have been recognized for many years. With the wide availability of magnetic resonance imaging and positron emission tomography, a growing range of recognized acute imaging findings have been described. Periictal and postictal findings can be classified as either local or remote, with respect to the site of maximal ictal EEG abnormality. Although many of the findings described are reversible, the factors that determine whether findings will resolve are incompletely understood. This article considers the range of findings that have been described, places them into the context of known or hypothesized pathophysiologic mechanisms, and considers their clinical significance. A framework is proposed for considering the relation between ictal duration and severity, the characteristics of imaging abnormalities, and the mechanism of their underlying pathophysiology.     

SPECT in the localisation of extratemporal and temporal seizure foci.

The yield of ictal, postictal, and interictal SPECT was compared in the localisation of seizure foci in 177 patients with partial epilepsy. In 119 patients with known unilateral temporal lobe epilepsy ictal SPECT (97% correct localisation) was superior to postictal SPECT (71% correct), which was better than interictal studies (48% correct). Similarly, in cases of known or suspected extratemporal epilepsy the yield of ictal SPECT studies was high (92%). By contrast, the yield of postictal studies was much lower (46%) and usually only very early postictal studies were diagnostic. Interictal SPECT was of little value. The accuracy of ictal SPECT in localising temporal lobe seizures is now well established. Extratemporal seizures are often brief and difficult to localise. This report shows that ictal SPECT also has a high diagnostic yield in a wide range of extratemporal epilepsies. The brevity of many extratemporal seizures means that true ictal SPECT examinations can be difficult to achieve, but the high diagnostic yield justifies the special organisational effort needed to obtain such studies.     

Role of immediate postictal diffusion-weighted MRI in localizing epileptogenic foci of mesial temporal lobe epilepsy and non-lesional neocortical epilepsy.

OBJECTIVE: To determine whether meaningful changes in signal intensity or in the apparent diffusion coefficient of water (ADC) in the ictal onset zone can be detected through immediate postictal and interictal diffusion-weighted magnetic resonance imaging (DWMRI) in patients with localization-related epilepsy. METHOD: In randomly selected 10 medial and lateral temporal lobe epilepsy (TLE) and four extratemporal epilepsy patients, DWMRI was performed immediately after a seizure and during the interictal period. All 14 patients were non-lesional except for hippocampal sclerosis detected on MRI. The mean time interval from seizure onset to postictal DWMRI was 81 min. Regions of interest (ROI) were selected in both the cortex, which was believed to be the ictal onset zone, and the corresponding anatomical region of the contralateral hemisphere in the postictal and interictal DWMRI. The mean ADC measured from all ROIs was compared. Ictal onset zones were determined by ictal electroencephalography (EEG) and seizure semiology. RESULTS: On visual inspection of postictal and interictal DWMRI, signal changes in the ictal onset zone could be identified in only one patient with medial TLE. The mean ADC values from the ictal onset zones were not significantly different from those of the corresponding contralateral regions of the cortices in both postictal and interictal DWMRI. However, the postictal ADC values of the epileptogenic foci of neocortical epilepsy or neocortical temporal portion of TLE without hippocampal sclerosis were decreased compared with interictal ones in whom both interictal and postictal DWMRIs were obtained (P = 0.028). CONCLUSION: Our results demonstrate that water diffusion can change even after a single seizure in non-lesional neocortical epilepsy.     

Episodic psychotic states in temporal lobe epilepsy: an investigation on their physiopathogenesis

The discussion here is about the direct relationship of epileptic seizures to episodic psychotic states. The episodic psychotic states were divided into three groups: interictal, ictal and postictal. In each group, one representative case was described and the neurophysiological pathogenesis discussed according to a recent research, mainly depth-electrode findings. It is believed that: interictal psychotic state--limbic paroxysmal discharges play an important role in its pathogenesis, according to the theory of Geschwindt and others; ictal psychotic state--repetitive auras develop to the psychotic state, and aura continua itself can be described as a psychotic state; and postictal psychotic state--the increased limbic discharges might be responsible for the psychotic state. The common neurophysiological cause in all the three groups is due to the increased epileptic discharges in the limbic system. It is concluded that the episodic psychotic states in temporal lobe epilepsies are possibly of an epileptic nature in themselves.     

Periictal sign of the cross or Signum Crucis as a lateralizing sign in focal epilepsies: Not only a right temporal lobe epilepsy feature

IntroductionThe sign of the cross (SC) is a catholic ritual that has been described as an automatism during the ictal phase in patients with right temporal lobe epilepsy.ObjectiveThe study aimed to describe the prevalence of the SC and analyze the characteristics of patients who presented this phenomenon during the video-electroencephalography (VEEG) admission in our Epilepsy department.MethodsThis is a retrospective analysis of 1308 recorded seizures; 14 patients presented the SC during the admission. Seizure semiology, electroencephalography (EEG), etiology, neuroimaging, and surgical findings were analyzed.ResultsA prevalence of 1.1% was found, and the sign was not only an ictal finding (21% was postictal) but also exclusive of patients with temporal lobe epilepsy (15% were extratemporal) in contrast to what has been reported so far. The localizing and lateralizing value of the ictal SC was low (sensitivity 75%, specificity 33.3%, positive predictive value 60%, negative predictive value 50% for a right temporal epileptogenic zone (EZ)) compared with other previously described signs. Regardless of the lateralization of the EZ, the sign was always performed with the right hand supporting the hypothesis of a possible learned behavioral automatism.ConclusionThe SC is a rare ictal or postictal manifestation that occurs in patients with temporal and extratemporal epilepsies without clear localizing and lateralizing value compared with previously described signs.     

The postictal psychosis of epilepsy: investigation in two patients

Patients with epilepsy have a higher incidence of psychosis. Epilepsy-related psychotic behaviors include a chronic interictal schizophreniform illness, an "alternating psychosis" which remits with seizure activity, and ictal or perictal psychotic behaviors. In addition, there is an uncommon and less understood psychosis characterized by brief psychotic episodes during the postictal period. This report describes two patients with postictal psychosis and correlates their behavior with the pattern of seizures, electroencephalographic discharges, and anticonvulsant and psychotropic medications. The findings suggest that postictal psychosis results from increased epileptiform activity and continued cerebral dysrhythmia, has a latency in onset and is not due to the immediate postictal delirium, and reflects an exacerbation of underlying psychopathological tendencies. This report further discusses the potential pathophysiological mechanisms and management of this disorder.     

Acute postictal psychosis: a stereo EEG study

An acute psychosis characterized by auditory hallucinations and paranoid delusions developed in a 19-year-old man with temporal lobe epilepsy after he had a cluster of seizures when antiepileptic drugs (AEDs) had been gradually discontinued. Continuous sterotactic depth and epidural EEG recordings confirmed that this was a postictal rather than an ictal event. Acute postictal psychosis is a self-limited condition phenomenologically distinct from ictal or postictal confusion.     

Single photon emission computed tomography findings in a case of alternating hemiplegia of childhood in relation to migraine

Single photon emission computed tomography (SPECT) was performed 3 times during attacks and performed 4 times during postictal periods on a case of alternating hemiplegia of childhood. Hyperperfusion of the corresponding hemisphere to hemiparesis was suggested by asymmetric increase RI uptake during the ictal scans, whereas interictal scans showed symmetric topography of cerebral blood flow. Manifestations except hemiplegia included loss of consciousness and vomiting. These manifestations and ictal SPECT findings are the same evidence as hemiplegic migraine. It suggests that these two disorders have a similar pathophysiology. There are two interesting findings regarding this patient. The first finding is magnetic resonance imaging showed progressive cerebellar atrophy. Second finding is interictal SPECT showed a progressive decrease of cerebral perfusion, especially in cerebellar hemispheres. These two findings suggest alternating hemiplegia of childhood may be a chronic progressive disorder.     

Episodic Psychotic States in Temporal Lobe Epilepsy: An Investigation on Their Physiopathogenesis

Abstract. The discussion here is about the direct relationship of epileptic seizures to episodic psychotic states. The episodic psychotic states were divided into three groups: interictal, ictal and postictal. In each group, one representative case was described and the neurophysiological pathogenesis discussed according to a recent research, mainly depth-electrode findings. It is believed that: 1) interictal psychotic state—limbic paroxysmal discharges play an important role in its pathogenesis, according to the theory of Geschwindt and others; 2) ictal psychotic state—repetitive auras develop to the psychotic state, and aura continua itself can be described as a psychotic state; and 3) postictal psychotic state—the increased limbic discharges might be responsible for the psychotic state. The common neurophysiological cause in all the three groups is due to the increased epileptic discharges in the limbic system. It is concluded that the episodic psychotic states in temporal lobe epilepsies are possibly of an epileptic nature in themselves.     

Lateralizing signs during seizures in focal epilepsy

This article reviews lateralizing semiological signs during epileptic seizures with respect to prediction of the side of the epileptogenic zone and, therefore, presurgical diagnostic value. The lateralizing significance of semiological signs and symptoms can frequently be concluded from knowledge of the cortical representation. Visual, auditory, painful, and autonomic auras, as well as ictal motor manifestations, e.g., version, clonic and tonic activity, unilateral epileptic spasms, dystonic posturing and unilateral automatisms, automatisms with preserved responsiveness, ictal spitting and vomiting, emotional facial asymmetry, unilateral eye blinking, ictal nystagmus, and akinesia, have been shown to have lateralizing value. Furthermore, ictal language manifestations and postictal features, such as Todd's palsy, postictal aphasia, postictal nosewiping, postictal memory dysfunction, as well as peri-ictal water drinking, peri-ictal headache, and ipsilateral tongue biting, are reviewed. Knowledge and recognition of semiological lateralizing signs during seizures is an important component of the presurgical evaluation of epilepsy surgery candidates and adds further information to video/EEG monitoring, neuroimaging, functional mapping, and neuropsychological evaluation.     

Respiratory changes with seizures in localization‐related epilepsy: Analysis of periictal hypercapnia and airflow patterns

Purpose: The rate of sudden unexpected death in epilepsy (SUDEP) approaches 9 per 1,000 patient‐years in patients with refractory epilepsy. Respiratory causes are implicated in SUDEP. We reported that ictal hypoxemia occurs in one‐third of seizures in localization‐related epilepsy. We now report on respiratory changes in the ictal/postictal period including changes in end‐tidal CO₂ (ETCO₂) that correlate directly with alveolar CO₂, allowing a precise evaluation of seizure‐related respiratory disturbances. Methods: One hundred eighty‐seven seizures were recorded in 33 patients with localization‐related epilepsy, with or without secondarily generalized convulsions, undergoing video‐electroencephalography (EEG) telemetry with recording of respiratory data. Results: The ictal/postictal ETCO₂ increase from baseline was 14 ± 11 mm Hg (11, ?1 to 50) [mean ± standard deviation (SD) (median, range)]. ETCO₂ peak was at or above 50 mm Hg with 35 of 94 seizures, 60 mm Hg with 15, and 70 mm Hg with five seizures. Eleven of the 33 patients had seizures with ETCO₂ elevation above 50 mm Hg. The duration of ictal/postictal ETCO₂ increase above baseline was 424 ± 807 s (154, 4 to 6225). The duration of ictal apnea was 49 ± 46 s (31, 6–222); most ictal apneic events were central. Oxygen desaturation to 60% or less occurred with 10 seizures, including five that did not progress to generalized convulsions. Respiratory rate and amplitude increased postictally. The peak ictal ETCO₂ change and duration of change were not associated with apnea duration or seizure duration. Peak ETCO₂ change was significantly associated with contralateral seizure spread. Conclusions: Severe and prolonged increases in ETCO₂ occur with seizures. Postictally, respiratory effort is not impaired. Ictally triggered ventilation–perfusion inequality from pulmonary shunting or transient neurogenic pulmonary edema may account for these findings.     

Combining advanced neuroimaging techniques in presurgical workup of non-lesional intractable epilepsy.

PURPOSE: The rationale for this case report is to assess the degree of congruency between the results of several advanced functional, metabolic, and structural neuroimaging techniques used in patients with MRI-negative focal epilepsy. METHODS: We investigated the presurgical evaluation and post-operative outcome of a patient with intractable, extratemporal epilepsy. Because the habitual seizures in this patient could be easily induced, six, advanced, neurodiagnostic techniques were successively applied (SISCOM, ictal FDG-PET, ictal fMRI, postictal diffusion-weighted imaging, voxel-based morphometry, and MRS imaging). RESULTS: The findings for the neuroimaging methods investigated, within the left central region, were fairly congruent. Subsequent, invasive EEG recordings revealed a seizure-onset zone at the site where most of the neuroimaging had shown abnormal findings. The surgical removal of the epileptogenic zone, as defined by concordant neuroimaging and SEEG data, resulted in seizure-free postoperative outcome. Histopathological findings revealed mild focal cortical dysplasia. CONCLUSION: Great efforts should be made to combine most of the advanced neuroimaging methods in the preoperative assessment of non-lesional epilepsy surgery candidates.     

Lateralization of cerebral blood flow in juvenile absence seizures

Cerebrovascular blood flow in absence seizures and flow patterns during the ictal period have not been thoroughly investigated. We aimed to evaluate cerebral blood flow changes in typical juvenile absence seizures during the ictal and postictal phases. Seizures were recorded in three patients (mean age: 21 ± 1 years) with multiple daily typical absence seizures. Simultaneous video electroencephalography and bilateral middle cerebral artery transcranial Doppler ultrasonography recordings were conducted during seizures. Basal, ictal, and postictal blood flow velocities were recorded bilaterally, and offline analyses were performed in relation with generalized spike and wave discharges. Total of 43 seizures were recorded. Ictal increase and postictal decrease of cerebral blood flow velocities were significant for both sides (P < 0.001). The interhemispheric asymmetry in the ictal velocity increase was significant (P < 0.05). The interhemispheric asymmetry in the postictal velocity decrease was not significant (P > 0.05). The blood flow velocity increase after seizure onset indicates a vascular coupling mechanism. A sudden and then a gradual decrease in blood flow velocity, which lasted even after the seizure ceased, might suggest a preventive mechanism to avoid excessive seizure duration or even an absence status epilepticus. Significant asymmetries in increase and a symmetrical decrease may support the cortical focus theory.     

Ictal headache: headache as first ictal symptom in focal epilepsy

Headache may be associated with seizures as a preictal, ictal, or postictal phenomenon, but it is often neglected because of the dramatic neurological manifestations of the seizure. Headache can also be the sole or predominant clinical manifestation of epileptic seizures, although this is a relatively rare condition. We describe two cases of focal symptomatic drug-resistant epilepsy with headache as the first ictal symptom. In both cases, the headache, which lasted a few seconds, was contralateral to the ictal discharge and did not have the clinical features of migraine. Ictal headache is a rare epilepsy symptom that can help to localize ictal EEG discharges. Recently, the term ictal epileptic headache has been proposed in cases in which headache is the sole ictal epileptic manifestation Diagnosis requires the simultaneous onset of headache with EEG-demonstrated ictal discharges.     

Proton magnetic resonance spectroscopic imaging for discrimination of absence and complex partial seizures

We performed proton magnetic resonance spectroscopic imaging of the temporal lobes between, during, and soon after nonconvulsive seizures in 20 patients with documented temporal lobe epilepsy, 5 patients with primary generalized epilepsy, and 2 patients with secondary generalized epilepsy. Our objective was to determine whether there were metabolic changes observable by magnetic resonance spectroscopic imaging during seizures and whether these changes were specific for focal or generalized nonconvulsive seizures. We found a significant increase in lactate to creatine plus phosphocreatine (lactate/creatine) values, reflecting an imbalance in energy supply and demand or an adaptation in response to ictal neuronal discharges, during and soon after complex partial seizures, but not during or soon after absence seizures associated with generalized epilepsy. In patients with temporal lobe epilepsy, the N-acetylaspartate resonance relative to creatine plus phosphocreatine was low in one or both temporal lobes, indicating neuronal loss or damage. This was not observed in patients with primary generalized epilepsy. The regions with abnormal lactate/creatine and N-acetylaspartate/creatine values corresponded to the epileptogenic focus as defined by clinical-electroencephalographic investigation. There was no change in the N-acetylaspartate/creatine values in the temporal lobes between the interictal, ictal, or postictal states. We conclude that (1) partial seizures are associated with abnormally high lactate levels, but absence seizures are not, and (2) no short-term changes of N-acetylaspartate occur during or soon after complex partial seizures or absence seizures. These findings may be related to the lack of postictal confusion in patients with absence seizures, as well as with the more benign course of primary generalized epilepsy with nonconvulsive attacks.     

Ictal headache: Headache as first ictal symptom in focal epilepsy

Headache may be associated with seizures as a preictal, ictal, or postictal phenomenon, but it is often neglected because of the dramatic neurological manifestations of the seizure. Headache can also be the sole or predominant clinical manifestation of epileptic seizures, although this is a relatively rare condition. We describe two cases of focal symptomatic drug-resistant epilepsy with headache as the first ictal symptom. In both cases, the headache, which lasted a few seconds, was contralateral to the ictal discharge and did not have the clinical features of migraine. Ictal headache is a rare epilepsy symptom that can help to localize ictal EEG discharges. Recently, the term ictal epileptic headache has been proposed in cases in which headache is the sole ictal epileptic manifestation Diagnosis requires the simultaneous onset of headache with EEG-demonstrated ictal discharges.     

Electrode manipulation automatism during temporal lobe seizures.

OBJECTIVE: To describe clinical characteristics and lateralizing value of peri-ictal electrode manipulation automatism (EMA) in patients with temporal lobe epilepsy (TLE) and compare our data with ictal manual automatisms described in the literature. METHODS: Two-hundred and five videotaped seizures of 55 consecutive patients with refractory TLE and postoperatively seizure-free outcome were analyzed and EMA (tugging, scratching or adjusting the electrodes and cables) were monitored. RESULTS: Twenty-eight (51%) patients showed EMA during 47 (23%) seizures. Ictal start was noted in 22 seizures and in 19/22 cases EMA finished before the end of seizure. Ictal EMAs were always associated with automotor seizure components. During 25 seizures, exclusively postictal EMAs were observed. Electrode manipulation was presented during 24/112 left-sided and 23/93 right-sided seizures (p = 0.742). Peri-ictal EMA was unilateral (completed by one hand) in 24/47 seizures (10 ictal, 14 postictal); it was done by the hand ipsilateral to the seizure onset zone in 17/24 and by contralateral hand in 7/24 cases (p = 0.064). We observed concomitant contralateral dystonic posturing during 3/10 seizures with unilateral ictal EMA. Unilateral hand automatism, temporally independent from the EMA appeared in 30 (64%) of the 47 seizures. CONCLUSION: Peri-ictal EMA is a frequent phenomenon but shows no lateralizing value in TLE. The mechanism of EMA is in many ways dissimilar from that of earlier described manual automatisms.     

Nose wiping: an unrecognized automatism in absence seizures.

Nose wiping is a well-known postictal automatism in complex partial seizures, considered very important for lateralization. We report a 24-year-old woman selected from 32 patients with video-EEG investigations of absence seizures. The patient, with normal examination and imaging findings, had typical absence seizures from the age of 5 years, which were controlled with either ethosuximide or valproate and worsened by carbamazepine. In two of her recorded typical absence seizures associated with generalized 3 Hz symmetric spike-wave discharges, she wiped her nose as an automatism in the ictal and post-ictal period. Our case showed that nose wiping could be associated with generalized seizures, in contrast to other recent reports.     

Frontal lobe partial seizures and psychogenic seizures: comparison of clinical and ictal characteristics.

Of all partial seizures, those of frontal lobe origin (FLPS) are most bizarre and are often mistaken for psychogenic seizures (PS). The reverse can also be true. To clarify the confusing clinical presentation of these different seizure types, we compared the clinical ictal characteristics of 63 FLPS in 11 patients with 29 PS in 12 patients. Patients with PS had significantly later age at onset and longer ictal duration. There was no statistically significant difference between the two groups with respect to history of psychiatric disorder, ictal pelvic thrusting, rocking of body, side-to-side head movements, or rapid postictal recovery, all of which previously have been reported as characteristic features of PS. Turning to a prone position during the seizure occurred only in FLPS. Nocturnal occurrence, short ictal duration, younger age at onset, stereotyped patterns of movements, and MRI and EEG abnormality suggested FLPS.