Simultaneous recording of absence seizures with video tape and electroencephalography. A study of 374 seizures in 48 patients.

Forty-eight patients, 4 to 24 years of age, with recurring absence seizures were studied prospectively for twenty-seven months. Each patient and his EEG were recorded simultaneously by a multicamera videotape technique and each recording was repeatedly viewed and described in writing by two observers who subsequently resolved any differences by joint viewing. From the 48 patients, 374 clinical absence seizures were recorded and classified according to the International Classification of Epileptic Seizures. Automatisms accompanied at least one attack in 88 per cent of the patients. Mild clonic components occurred in 71 per cent, and decreased postural tone in 41 per cent. Only one patient experienced an attack comprising only "blank staring" accompanied by unawareness and amnesia, but 40 per cent of patients exhibited this type of attack in addition to more complex absence attacks. Seizures of ten seconds or less in duration occurred among 85 per cent of patients. Each of the 374 seizures were readily classified according to the International Classification, but simple absence constituted only 9-4 per cent of the seizures. The others most often contained, in order of prevalence, either automatisms, mild clonic components, or decreased postural tone, or a combination of two or more of these features. The relationship between increased duration of the seizures and the occurrence of automatisms was significant. The findings are discussed in relation to differential diagnosis and mechanisms of automatisms. Absence seizures differ from complex partial (temporal lobe, psychomotor) seizures because an aura does not precede the abruptly beginning absence attack, the seizure usually lasts less than ten seconds, and mental clarity returns instantly at the end of the seizure.     

额叶癫痫发作录像脑电图特点分析

目的通过录像脑电图观察额叶癫痫的临床特征、发作期及发作间歇期的脑电图特点。方法使用录像脑电图（ｖｉｄｅｏＥＥＧ,ＶＥＥＧ）对５０例确诊为额叶癫痫的患者进行常规及长时间记录,对其中１７例（２０次）癫痫发作的临床表现及脑电图所见进行分析。结果额叶癫痫常见的发作形式有：姿势性发作,具有额叶癫痫特点的自动症;复杂部分性发作时伴发声、偏转或表情的变化,有时出现发作性情绪改变或强迫思维等少见症状。其发作特点为：持续时间短,发作相对较频繁,无明显发作后意识障碍。发作间歇期脑电图有时可无阳性所见,典型的临床发作及发作时ＶＥＥＧ记录到的额部爆发性节律有助于诊断。本组９例儿童期起病的额叶癫痫患者,以夜间频繁的躯体自动症发作为主,检查均未发现相应的脑器质性病变。脑电图睡眠描记可见频繁的额部导联癫痫样放电。临床治疗观察预后良好,提示可能为一组儿童原发性部分发作型癫痫综合征。结论额叶癫痫是一组较为特征性的癫痫综合征,临床并不少见,及时而正确的诊断有助于治疗。     

Focal akinetic seizures as documented by electroencephalography and video recordings.

In three patients with focal epilepsies, focal akinetic seizures that were characterized by ictal paresis of the contralateral arm during preserved consciousness were recorded with EEG and video. MRI and ictal/interictal EEG revealed a frontal or central focus in all patients. Focal akinetic seizures are probably due to epileptic activation of negative motor areas.     

Short-term outpatient EEG video with induction in the diagnosis of psychogenic seizures

To analyze the yield of short-term outpatient EEG video monitoring, the authors reviewed data on all patients who underwent this procedure at their center. All patients were suspected of having psychogenic nonepileptic seizures (PNES) on clinical grounds. The total number of cases of short-term outpatient EEG video monitoring was 74. In 49 (66%) cases, the suspected diagnosis of PNES could be confirmed, thereby obviating the need for prolonged inpatient EEG video monitoring.     

The value of combined ambulatory cassette-EEG and video monitoring in the differential diagnosis of intractable seizures.

OBJECTIVE: To evaluate the ability of combined ambulatory cassette-EEG and video monitoring (ACV) to establish a diagnosis in patients with attacks of unknown nature and its impact on their treatment. METHODS: We evaluated ACV in 125 consecutive patients with attacks of unknown nature. Most had intractable attacks suspected of being non-epileptic. Antiepileptic drugs (AEDs) were discontinued or reduced at the start of the procedure. The median duration of monitoring was 3 days (range 1-10). The ACV results and patient records were reviewed, and patients were called for additional follow-up when feasible. RESULTS: Attacks were recorded in 101 patients. They were epileptic in 20 patients, psychogenic in 60, both in 3, and of unknown nature in 18 (usually subjective episodes). The study resulted in AED discontinuation at discharge in 46 patients with recorded psychogenic seizures and 6 with recorded attacks of unknown nature. Three-quarters of patients followed up were free of attacks or improved. CONCLUSIONS: ACV was effective in providing a diagnosis in two-thirds of patients. If psychogenic seizures are suspected in patients on AEDs, ACV may provide the diagnosis and may help exclude epilepsy, without the need for standard EEG-CCTV, which can then be reserved for patients undergoing presurgical evaluation.     

Cassette electroencephalography in the evaluation of neonatal seizures

Three-channel cassette electroencephalographic (EEG) recording for up to 24 hours was obtained from 37 neonates with clinically diagnosed or suspected seizures but no seizure activity on routine EEG. EEG seizures were recorded in seven patients, five of whom had experienced clinical seizures in the 24 hours prior to cassette EEG recording. EEG seizures were detected in only one of nine neonates with recurring clinical episodes believed unlikely to be seizures and in only one of 18 without recent clinical events. Cassette EEG can enhance the detection and differentiation of seizures in neonates with persistent clinical episodes but is of low yield otherwise.     

Interobserver reliability of video recording in the diagnosis of nocturnal frontal lobe seizures

BACKGROUND: Nocturnal frontal lobe seizures (NFLS) show one or all of the following semeiological patterns: (1) paroxysmal arousals (PA: brief and sudden recurrent motor paroxysmal behavior); (2) hyperkinetic seizures (HS: motor attacks with complex dyskinetic features); (3) asymmetric bilateral tonic seizures (ATS: motor attacks with dystonic features); (4) epileptic nocturnal wanderings (ENW: stereotyped, prolonged ambulatory behavior). OBJECTIVE: To estimate the interobserver reliability (IR) of video-recording diagnosis in patients with suspected NFLS among sleep medicine experts, epileptologists, and trainees in sleep medicine. METHODS: Sixty-six patients with suspected NFLS were included. All underwent nocturnal video-polysomnographic recording. Six doctors (three experts and three trainees) independently classified each case as "NFLS ascertained" (according to the above specified subtypes: PA, HS, ATS, ENW) or "NFLS excluded". IR was calculated by means of Kappa statistics, and interpreted according to the standard classification (0.0-0.20 = slight agreement; 0.21-0.40 = fair; 0.41-0.60 = moderate; 0.61-0.80 = substantial; 0.81-1.00 = almost perfect). RESULTS: The observed raw agreement ranged from 63% to 79% between each pair of raters; the IR ranged from "moderate" (kappa = 0.50) to "substantial" (kappa = 0.72). A major source of variance was the disagreement in distinguishing between PA and nonepileptic arousals, without differences in the level of agreement between experts and trainees. CONCLUSIONS: Among sleep experts and trainees, IR of diagnosis of NFLS, based on videotaped observation of sleep phenomena, is not satisfactory. Explicit video-polysomnographic criteria for the classification of paroxysmal sleep motor phenomena are needed.     

Use of clobazam for the treatment of refractory complex partial seizures.

Clobazam (CLB) add-on therapy was attempted in 183 patients with intractable complex partial seizures in whom conventional benzodiazepines had been successfully discontinued before initiation of CLB. Although complete remission was initially achieved in 61, tolerance developed in almost half (49.2%) within the first 3 months, whereas 23 out of 31 patients (74.2%) who remained seizure free for the first 3 months continued to be so over the next 3 months. CLB add-on therapy proved to be significantly more effective when concurrent GTC occurred more often than yearly. In the current series, no frank psychotic episodes were elicited among the 61 patients who achieved complete suppression of long-standing complex partial seizures, which was in agreement with previous studies. From these results, we believe that CLB is an effective, safe, and inexpensive medication for add-on therapy in difficult to treat focal epilepsies, especially without concurrent use of conventional benzodiazepine compounds.     

Mathematical models of patterns of seizures. Their use in the evaluation of drugs

The analysis of the results of many well-designed, double-blind trials of anticonvulsant drugs has been unsophisticated. We draw attention to the nonrandom occurrence of seizures, which negates the simple comparison of average seizure frequency. We propose a method of taking into account clustering of seizures when deciding on the appropriate length of follow-up after introducing a new treatment. Deterministic and nondeterministic models were used to show why there may be reasons for sometimes using more than one drug in the treatment of epilepsy.     

The role of quantitative ictal SPECT analysis in the evaluation of nonepileptic seizures.

Nonepileptic seizures may represent difficult diagnostic problems. Identifying their presence and frequency is critical for determining appropriate treatment. The authors investigated the value of quantitative perfusion changes as measured by ictal single-photon emission tomography (SPECT) difference images in differentiating nonepileptic from epileptic seizures. Eleven patients with a clinical suspicion of nonepileptic events had ictal and interictal technetium-99m hexamethylpropylene amine SPECT scans during continuous audiovisual surface electroencephalogram (EEG) monitoring. The authors analyzed perfusion difference images based on registration, normalization, and subtraction of ictal and interictal SPECT images. The difference images were registered to each patient's magnetic resonance imaging scan to anatomically localize ictal perfusion changes. Three of 11 patients also carried the diagnosis of epilepsy and were taking antiepileptic medication. Five patients were taking antiepileptic drugs, but the diagnosis of epilepsy was not confirmed. In all patients, continuous video EEG monitoring revealed no ictal EEG findings. In nine of these patients, visual interpretation of ictal SPECT was suggestive of localized increased (n = 6) or decreased perfusion (n = 3). In all patients, however, no blood flow changes were noted on quantitative SPECT analysis with injections performed during the seizure-like event, suggesting the diagnosis of pseudoseizures. The authors' results suggest that quantitative ictal SPECT analysis is a useful tool in the diagnosis of nonepileptic seizures.     

Use of caffeine to lengthen seizures in ECT

During a course of ECT, seizure duration may become too brief for clinical benefit. Use of higher-energy stimuli may lengthen seizures but may also increase the risk of toxicity, and it is not possible when maximum settings are reached. The authors present the cases of six drug-free depressed inpatients whose seizure durations in ECT declined despite maximum settings on three different ECT devices. In all cases, pretreatment with caffeine lengthened seizures (mean increase = 107%), and clinical improvement followed. Caffeine was well tolerated, even in patients with cardiovascular diseases.     

Use of routine and video electroencephalography

The routine EEG continues to be a pivotal diagnostic study in the evaluation of patients with suspected seizure disorders. The identification of potentially epileptiform alterations is important in the classification of the epilepsy and in determining the presence of an epileptic syndrome. The electroclinical correlation observed during long-term EEG monitoring may be used for diagnostic classification and surgical localization. Confirmation of a seizure disorder may be a priority before initiating antiepileptic drug therapy in selected patients. Finally, recognition of the ictal EEG pattern is necessary in evaluating patients with intractable seizure disorders for surgical treatment.     

Neuroethological evaluation of audiogenic seizures in hemidetelencephalated rats

Wistar-derived male rats were tested for audiogenic seizure (AS) susceptibility, and classified into sensitive (S) and resistant (R) groups. Rats from group R underwent unilateral ablation of the telencephalon, or were detelencephalated (HD), or sham-lesioned, and were tested for audiogenic susceptibility one month and one year after surgery. It was found that previously AS-resistant, HD-operated animals developed generalized tonic-clonic convulsions upon high intensity (110.8 dB) acoustic stimulation, with higher severity and shorter latencies than the susceptible, non-operated control animals. Sham-lesioned R animals maintained their previous resistance to AS. HD-lesioned R animals also presented asymmetric motor patterns, such as gyrating and barrel-rolling behavior, always oriented towards the side contralateral to the lesion. HD-lesioned S animals presented an increase in the severity of seizures, as well as a shortening of the latencies of the running (procursive) and convulsive phases of the seizures. This effect was more marked one year after surgery. Contralateral barrel-rolling behavior was also observed in these animals. The fact that seizure severity increases and latency decreases with time after lesion seems to indicate a role for denervation hypersensitivity and other cerebral plasticity phenomena in explaining the effects of HD lesions on AS. The fundamental neural structures involved appear to be those related to sensorimotor coordinating systems (substantia nigra/pontine-mesencephalic reticular formation and substantia nigra/superior colliculus), the acoustic pathways (inferior colliculus) and their projections to the superior colliculus and reticular formation.