A Case of Epilepsy Characterized by Spike-Wave Stupor Followed for Long Period

Abstract: A 34-year-old housewife with nonconvulsive status epilepticus was followed up for 20 years since the initial fit. She maintained some contact with reality during the stupor and recalled the episode to some extent, while the EEG showed continuous spike-wave complexes. During the clinical course, the main type of seizures was spike-wave stupor, of which the maximum frequency was several times a week in the hospital and the duration was many minutes to several hours, and also secondarily generalized convulsive seizures occurred approximately once a month. The lasting control of spike-wave stupor was not achieved in spite of the various medications for the long follow-up period. The ictal EEGs of spike-wave stupor always showed the frontal origin. The meaning of the term "nonconvulsive status epilepticus" in this case was briefly discussed.     

Cerebral Blood Flow During Spike-Wave Discharges

Summary We used the ¹³³xenon method to assess cerebral blood flow (CBF) during generalized spike-wave discharges in a patient with an uncommon form of generalized epilepsy with persistent spike-wave discharges. CBF measurements were made under four conditions with repeated measures: normal EEG, continuous theta state, continuous spike-wave state at rest, and continuous spike-wave discharges during performance of a cognitive activation task. CBF was mildly reduced (5.7%) during the theta state and decreased further (12%) in the spikewave state. Although globally diminished, CBF was less decreased in the frontal lobes and more decreased in the parietal lobes during spike-wave discharges. CBF increased to baseline levels during the cognitive activation task. The decrease in CBF suggested that the generalized spike-wave discharges caused a net decrease in cortical metabolic demand and neuronal activity. The differences in lobar CBF during spike-wave discharges may reflect lobar disparities in neuronal firing patterns. The theta state noted is novel and intermediate between normal and spike-wave.     

Effects of clonazepam on self-induced photoparoxysmal responses

A 5-year-old girl exhibited daily episodes of repetitive blinking lasting 5–10 s. Electroencephalography (EEG) revealed marked photoparoxysmal responses (PPR) at 3–20 Hz of photic stimulation and diffuse spike-wave bursts during sleep. A 24-h video EEG identified 11 episodes of repetitive blinking, 3 of which resulted in widespread spike-wave discharges. These suggested that the behavior of the patient represented self-induction of PPR. Valproate sodium was ineffective in decreasing PPR, as revealed by EEG, and the frequency of blinking episodes, but clonazepam attenuated PPR and significantly decreased the blinking behavior.     

Ipsilateral blinking seizures during left fronto-temporal ictal pattern on scalp EEG.

We report an infant with left eye blinking seizures accompanying a left (ipsilateral) fronto-temporal scalp EEG ictal pattern. The epileptogenic lesion was a left frontal encephalomalacia along the ventriculo-peritoneal shunt tract. The shunt was inserted for treatment of communicating hydrocephalus. This case illustrates the lateralizing value of the ictal blinking. Review of the literature suggests that seizures with unilateral blinking are likely to be produced by activation of ipsilateral trigeminal fibers innervating subdural intracranial structures and pial vessels in temporal and frontal lobes. Ipsilateral blinking could also be produced by activation of the ipsilateral cerebellar hemisphere.     

Spike-Wave Stupor

Five cases of spike-wave stupor are presented. One case occurred in association with cerebrovascular disease and another in association with the Vogt-Koyanagi syndrome. A third case had repeated episode of spike-wave stupor as the only sign of a seizure disorder. A fourth case was characterized by behavior quite similar to catatonic schizophrenia and was so diagnosed. These atypical cases are contrasted with a case more typical of petit mal status as reported in the literature. Thus while spike-wave stupor is usually superimposed on a chronic centrencephalic seizure disorder, it must be recognized as a syndrome that can arise from a variety of etiological mechanisms. Detailed clinical and EEG investigation is necessary for an understanding of the mechanisms involved in any individual case.     

睡眠中失神发作的儿童失神癫痫的临床特点(附1例报告)

目的 探讨睡眠中失神发作的儿童失神癫痫(CAE)的临床特征.方法 回顾性分析1例睡眠中失神发作的CAE患儿的临床资料.结果 本例患儿以反复愣神为主要表现,同时伴有睡眠中突然睁眼、茫然无视及轻微眨眼等症状,同期视频EEG均为全导广泛性3 Hz棘慢波阵发.空腹CSF检查及头颅MRI正常.先后给予丙戊酸、拉莫三嗪及左乙拉西坦...     

Non-verbal auditory agnosia with EEG abnormalities and epilepsy; an unusual case of Landau-Kleffner syndrome]

A case of unusual Landau-Kleffner syndrome was reported. She was an 8 year-old girl and showed non-verbal agnosia, diffuse EEG abnormalities and convulsions. Her responses to both verbal and non-verbal sounds remained inconsistent and unstable. When a continuous spike-wave complexes on EEG was detected, she paid no attention to any sound in spite of her fair consciousness. Auditory brainstem response and magnetic resonance imaging of her brain were normal. Auditory agnosia was correlated well with EEG abnormalities, and valproic acid and clonazepam were effective for EEG improvement. After the EEG improvement, clinical responses to sounds recovered well; firstly she could pay attention to sounds and then she could distinguish between verbal and non-verbal sounds. Finally, she could speak a few words after the learning letters.     

Late-onset, "Gastaut type", childhood occipital epilepsy: an unusual evolution.

We report on two girls and one boy with clinical and electroencephalographic features of late-onset childhood epilepsy with occipital paroxysms of the "Gastaut type", showing an unusual evolution. Neurological examination and brain imaging were normal in all three. At the age of 7.5 years, eight years and ten years respectively, the three children presented with episodes of visual symptoms when awake, and in one of them, the seizures were occasionally followed by oculocephalic deviation. The interictal EEG showed bilateral occipital spike-wave activated by eye closing. In two patients, the occipital seizures had been immediately followed by typical absences, since onset; in the other patient, five months after onset. The ictal EEG showed irregular bilateral occipital spike-wave discharges during the visual symptoms, followed by generalized spike-wave activity during the typical absences. The typical absences were activated by hyperventilation; the EEG did not show continuous spikes and waves during slow sleep. These three patients, with typical electroclinical features of "Gastaut type", childhood occipital epilepsy, demonstrated an evolution which, to our knowledge, has not been previously described. We investigated whether this unusual, age-dependent evolution was due to secondary bilateral synchrony or if these electroclinical features represent two types of idiopathic epileptic syndromes in the same patients.     

Epileptiform EEG Activity of the Centromedian Thalamic Nuclei in Children with Intractable Generalized Seizures of the Lennox-Gastaut Syndrome

Centromedian thalamic nuclei (CM) epileptiform EEG activities were recorded in children with intractable generalized seizures of Lennox-Gastaut syndrome (LGS) through implanted recording-stimulating electrodes used for seizure control. Ictal CM epileptiform activities were consistently correlated to widespread surface cortical EEG activities and symptoms in all patients and all types of generalized seizures; i.e., fast spike discharges at CM correlated at onset of tonic and tonic-clonic generalized seizures; slow (1-2 Hz) spike-wave complex discharges at CM correlated for atypical absence seizures; slow polyspike-wave complex discharges correlated for myoclonic seizures; and spike bursts and suppression patterns correlated for combined tonic-atonic-myoclonic seizures. Ictal EEG activities occurred simultaneously at right and left CM and surface at onset of all seizure types, with the exception of myoclonic seizures where CM complete discharges and individual spike-wave complexes significantly lead those of the surface. Brief tonic-atonic spasms clinically undistinguishable from "real" epileptic seizures showed no EEG counterparts at CM and surface. Interictal CM spike-wave complete discharges and individual spike-wave complexes showed variable amplitude-temporal patterns. Amplitude emphasis on CM and frontopolar regions was observed in most of complete discharges, however, and phase shifts between CM and frontopolar regions were observed in individual spike-wave complexes.     

A case of Panayiotopoulos syndrome showing an atypical course

We describe herein a patient with Panayiotopoulos syndrome (PS) showing an atypical course. The patient initially had seizures typical of this syndrome from 3 to 5 years of age. EEG showed right occipital high-amplitude sharp and slow-wave complexes followed by brief generalized discharges of slow waves. Sequential EEGs obtained from 5 to 11 years of age showed both multifocal discharges and generalized spike and wave complexes. With these changes in EEG findings, the patient experienced various types of seizures. The seizures were frequent and showed oculocephalic deviation followed by absence, atonic seizures, generalized tonic clonic convulsions and clonic seizures of the eyelids, which were observed between 7 and 10 years of age. Antiepileptic drugs were only partially effective for these seizures. Ictal EEG recorded at 8 years of age revealed high-voltage slow waves from the bilateral frontal and occipital regions prior to diffuse high-amplitude spike-wave bursts. At 9 years of age, magnetoencephalography (MEG) revealed the calculated dipoles of the preceding bifrontal spike-wave discharges to be in the frontal areas, while those of the following generalized spike-wave bursts were in the bilateral mid-temporal areas. In PS, reportedly, dipoles of multifocal epileptic discharges are usually located in the occipital and Rolandic areas. The unique clinical evolution in our case may be associated with the unusual frontal localization of dipoles detected by MEG.     

Visual evoked potentials during spontaneously occurring spike-wave discharges in rats.

Flash evoked visual potentials (VEPs) were recorded in freely moving WAG/Rij rats. These rats show spontaneously occurring spike-wave discharges in the EEG, interpreted as absence-like seizures. VEPs recorded during the presence of spike-wave discharges were compared with those obtained during normal states of vigilance as quiet wakefulness, slow-wave sleep and REM sleep. Almost similar VEPs were recorded during wakefulness and REM sleep, whereas during slow-wave sleep the second positive peak (P2) was considerably larger. In comparison with normal sleep-wake states, VEPs during spike-wave discharges showed unique changes, such as a decrease in the N1 amplitude, an increase of the P4 amplitude and an enhanced afterdischarge. Other characteristics were similar to those seen during slow-wave sleep, such as an increase of the P2 amplitude and a diminished P2-N3-P3 complex. These findings indicate sensory alterations during a spike-wave discharge. As expressed in the decrease of N1, afferent information cannot enter the thalamus during the rhythmic oscillatory mode. Such alterations may underlie the lowered responsiveness to external stimuli during spike-wave activity.     

Acquired epileptic frontal syndrome as long-term outcome in two children with CSWS

Continuous spikes and waves during slow sleep (CSWS) are a well-known EEG pattern that can be associated with cognitive and behavioural deterioration. We present the long-term clinical, neuropsychological and EEG follow-up of two patients who developed CSWS during childhood. In both the CSWS onset was followed immediately by rapid cognitive and behavioural deterioration. Later the CSWS fragmented or fluctuated and the spike-wave discharges diminished and this was associated with progressive clinical improvement. At the same time bilateral frontal EEG abnormalities appeared awake and in sleep. After the initial period of rapid cognitive and linguistic improvement both patients stabilised. The latest neuropsychological assessment showed a frontal syndrome. The presence of frontal EEG abnormalities superimposed on CSWS, their persistence after CSWS resolution and, in addition, the finding of subtle frontal-type neuropsychological alterations early in recovery may indicate poor long-term outcome.     

Ictal HMPAO-Single Photon Emission Computed Tomography Findings in Reading Epilepsy in a Japanese Boy

Summary: Reading epilepsy is rare. We report a 14-year-old right-handed Japanese boy who had had jaw jerking only while reading since age 12 years. The episodes occurred every time he read an English textbook and some-times during prolonged reading of a Japanese textbook. The jaw jerking evolved to generalized tonic-clonic seizures (GTCS) on only two occasions during prolonged reading aloud. Routine EEGs showed no abnormality. After a few minutes of reading, however, the EEG showed bilateral 2-Hz, 150-μ V spike-wave complexes with left frontotemporal accentuation, accompanied by jaw jerking. Ictal single photon emission computed tomography (SPECT) with [^99mTc]hexamethylpropylene amine oxime (HMPAO) showed focal hyperperfusion of the frontal lobes bilaterally and of the left temporal area. Interictal SPECT and magnetic resonance imaging (MRI) were normal. The combination of valproate (VPA) and clonazepam (CZP) almost eliminated his symptoms. Ictal SPECT is a useful technique for seizure localization in reading epilepsy.     

Electrocortical and behavioral responses produced by acute electrical stimulation of the human centromedian thalamic nucleus

Incremental, desynchronizing and spike-wave electrocortical responses and concomitant symptoms to acute electrical stimulation of the centromedian thalamic nucleus (CM) were studied in 12 patients with intractable complex partial and tonic-clonic generalized seizures. Low-frequency (6/s), 320–800 μA stimulation of the caudal-basal and central portions of CM elicited incremental recruiting and augmenting-like responses with a bilateral regional scalp distribution, with emphasis at the ipsilateral frontal (recruiting) and central (augmenting) regions, while ventral-basal CM stimulation elicited primary-like responses with a focal distribution at the ipsilateral parietal region. High-frequency (60/s), 320–800 μA stimulation of caudal-basal and central, but not ventral-basal CM, elicited EEG desynchronization and a slow negative shift of the EEG baseline with scalp distribution similar to that showed by recruiting- and augmenting-like responses. Neither incremental nor desynchronization EEG responses were accompanied by evident patient sensory or motor responses. Low-frequency (3/s), high-intensity (30 V = 2400 μA) combined stimulation of the right CM and left non-specific mesencephalic ascending pathways elicited a response similar to the typical absence attack with all EEG and clinical ingredients: S1, S2, P1 and W components of the individual spike-wave complex and generalized spike-wave discharges followed by sleep spindle EEG afterdischarges, accompanied by motionless stare, 3/s eye blinking, lip smacking and total failure to respond to visual stimuli in patients under a simple responding task.     

Correlation between periodic sharp wave complexes and diffusion-weighted magnetic resonance images in early stage of Creutzfeldt-Jakob disease: A report of two cases

We evaluated the correlation between the periodic sharp wave complexes (PSWC) on EEG and the spreading lesions on diffusion-weighted (DW) magnetic resonance images (MRI) in two cases of Creutzfeldt-Jakob disease (CJD). In Case 1, DW-MRI showed increased signal intensity in bilateral caudate, bilateral parietal, and right temporo-occipital cortex at 7 weeks after onset. EEG showed PSWC of 1 Hz frequency at 8 weeks after onset. Source localization analysis of the PSWC was conducted by low resolution electromagnetic tomography (LORETA), and localized the source in the cortex of bilateral parietal lobes and mesial frontal lobe, predominantly on the right side. At 10 weeks after onset, the PSWC source spread to bilateral parietal and frontal lobes, and the same spread was also observed for the lesion depicted on DW-MRI. In Case 2, DW images showed high signal intensity in the right parietal cortical lesion at 4 weeks after onset. PSWC of 2 Hz frequency were seen in the routine EEG, and the source was localized in bilateral frontal lobes and right parietal lobe at 7 weeks after onset. The lesions on DW images also spread to bilateral frontal and parietal lobes. Nine weeks after onset, the source of PSWC extended to the right frontal lobe and bilateral parietal lobes, while the lesions on DW images progressed to the right temporal lobe and bilateral fronto-parieto-occipital lobes. Spreading DW-MRI lesions may correlate with the appearance of PSWC.     

Hypomotor seizures in infants and children

PURPOSE: Hypomotor seizures (characterized by diminished behavioral activity with indeterminate level of consciousness) have been identified as an important seizure type in infants. Our goal was to investigate further the clinical and EEG features of hypomotor seizures. METHODS: We retrospectively reviewed 110 hypomotor seizures from 34 patients recorded with video-EEG. RESULTS: Twenty-seven (79%) patients were younger than 48 months, and seven (21%) were aged 4 to 15 years. Seventy-one (64%) seizures had regional or lateralized EEG onset, arising predominantly from temporal or parietal lobe regions. The other 39 (35%) seizures had generalized onset, usually with abrupt onset of diffuse rhythmic high-amplitude theta activity or diffuse electrodecrement and only rarely (two patients) with slow spike-wave complexes or 3-Hz spike-wave complexes. Hypomotor seizures with generalized EEG onset were significantly shorter than those with regional or lateralized onset (p = 0.01, GEE model). Unsustained head or eye movements and subtle mouth automatisms were commonly seen in hypomotor seizures with either focal or generalized onset. Seventeen percent of hypomotor seizures with focal onset evolved to include version of head and eyes or jerking of one arm, whereas 2% of generalized hypomotor seizures evolved to a cluster of spasms. CONCLUSIONS: Hypomotor seizures may be either focal or generalized. Regional EEG onsets were most often temporal or parietal, suggesting that focal hypomotor seizures may be a bland form of "complex partial" seizures with no or minimal automatisms, seen predominantly in infants. Generalized hypomotor seizures were rarely associated with an ictal pattern of generalized spike-wave complexes, suggesting a different mechanism from absence seizures seen later in life.     

Spike-wave stupor in a patient with metabolic disorder.

We report a 79-year-old woman with a decreased level of consciousness. Investigation revealed an elevated serum ammonia and a portal-systemic shunt on angiography. Thus, her symptoms were thought to be due to metabolic encephalopathy. Her electroencephalogram (EEG) showed bilaterally synchronous runs of three-phase waves consistent with the triphasic waves typically seen in metabolic encephalopathy. However, after intravenous administration of diazepam, the EEG abnormalities improved; indicating that her decreased consciousness was of epileptic etiology, consistent with spike-wave stupor. Therefore, even in the presence of a clearly defined metabolic disorder, triphasic waves on the EEG may not be due to metabolic encephalopathy; they may reflect an epileptic state precipitated by the metabolic disorder.     

Multiple focal cortical dysplasias presenting with intractable epilepsy: case report]

A 14-year-old female, who had intractable epilepsy associated with multiple focal cortical dysplasias (FCD), was reported. She developed intractable epilepsy at the age of 7 and was diagnosed as having frontal lobe epilepsy based on the seizure semiology and interictal EEG. MRI revealed multiple lesions in the right frontal, bilateral occipital and left parietal lobes. EEG demonstrated that ictal discharge was preceded by spike on the right frontal region and FDG-PET showed hypometabolic area in the right frontal lobe. Chronic subdural electrode recordings from the right frontal lobe indicated that ictal onset zone was located around the right frontal lesion, especially frontal tip and base, and these areas including the lesion were resected. Postoperatively, residual seizure was noted although seizure frequency was decreased. It is well known that, postoperatively, satisfactory seizure outcome can be obtained in patients with FCD. However, further investigation in terms of surgical indication and strategies for multiple FCD should be needed.     

Information processing during two types of EEG activity.

A 15-year-old girl whose EEG contained frequent bursts of generalized sub-clinical spikewave activity was examined on a paced serial-choice response task with simultaneous EEG control. The task was carried out at three different speeds and three different information loads. Performance was compared during paroxysms of spike-wave activity and during normal EEG background activity. Four parameters of performance were compared, each parameter being somewhat differently affected by spike-wave activity. "Response ambiguity" was significantly increased in the presence of spike-wave activity, with a corresponding decrease in the amount of "information transmitted". The "absolute rate" at which information could be transmitted in relation to presentation rate was consequently reduced during spike-wave activity, the effect being most marked at the intermediate speed of presentation (1 signal/2 sec). However, when signals were presented very slowly (1/4 sec) the child's "relative information transmitted" during spike-wave activity approached that achieved under normal background conditions. Thus, accuracy of performance per se is not critically affected by spike-wave; rather it is the rate at which signals can be handled. Spike-wave may therefore be conceptualized as a form of "neural noise" whose effect is to reduce a subject's channel capacity.     

Absence attacks with secondary bilateral synchrony]

Three cases with petit mal absence attacks with secondary bilateral synchrony were presented. The interictal EEG showed unilateral focal epileptic discharges in the frontal area with normal background activity. The ictal EEG disclosed 3-Hz generalized symmetrical spike-wave patterns preceded by unilateral focal discharges, which were elicited by hyperventilation. None of the three cases had abnormal neurological findings or abnormal CT findings. All three cases had normal psychomotor development. One case had a history of febrile convulsions. The ictal manifestations were as follows; impairement of consciousness without any other signs in one case, with decreased posture tone in the second, and automatism in the third. The authors suggest that there can be petit mal absence with 3-Hz generalized spike-wave discharges induced by secondary bilateral synchrony.