Effect of interictal epileptiform discharges on EEG-based functional connectivity networks

ObjectiveFunctional connectivity networks (FCNs) based on interictal electroencephalography (EEG) can identify pathological brain networks associated with epilepsy. FCNs are altered by interictal epileptiform discharges (IEDs), but it is unknown whether this is due to the morphology of the IED or the underlying pathological activity. Therefore, we characterized the impact of IEDs on the FCN through simulations and EEG analysis.MethodsWe introduced simulated IEDs to sleep EEG recordings of eight healthy controls and analyzed the effect of IED amplitude and rate on the FCN. We then generated FCNs based on epochs with and without IEDs and compared them to the analogous FCNs from eight subjects with infantile spasms (IS), based on 1340 visually marked IEDs. Differences in network structure and strength were assessed.ResultsIEDs in IS subjects caused increased connectivity strength but no change in network structure. In controls, simulated IEDs with physiological amplitudes and rates did not alter network strength or structure.ConclusionsIncreases in connectivity strength in IS subjects are not artifacts caused by the interictal spike waveform and may be related to the underlying pathophysiology of IS.SignificanceDynamic changes in EEG-based FCNs during IEDs may be valuable for identification of pathological networks associated with epilepsy.     

Five-Year Outcome After Epilepsy Surgery in Nonmonitored and Monitored Surgical Candidates

Summary: Purpose : We wished to compare outcome 5 years after temporal lobectomy in 28 patients selected for surgery on the basis of interictal EEG patterns with that in 46 patients who underwent EEG-video monitoring studies as part of their preoperative evaluation during the same era.
Methods : The 28 nonmonitored patients had interictal EEG patterns that demonstrated a consistent, unilateral, anterior-midtemporal epileptiform focus, without discordant findings from other studies. Outcomes were assessed for years 4 and 5 after operation.
Results : Twenty-six of 28 (92.9%) nonmonitored patients were seizure-free or had at least 75% reduction in seizures. Twenty-nine of 46 (63.0%) monitored patients were seizure-free or had at least 75% reduction in seizures. Preoperative interictal EEGs of 29 of these patients showed independently localized bitemporal, ex-tratemporal, midposterior temporal, or diffuse epileptiform patterns. The remaining 17 monitored patients had preoperative strictly unilateral anterior-midtemporal interictal discharges, and their outcome was comparable to the nonmonitored group, with 15 (88.8%) seizure-free or with at least 75% reduction in seizures.
Conclusions : A proportion of candidates for epilepsy surgery can be selected without ictal recordings provided that interictal EEGs demonstrate consistent unilateral anterior-midtemporal epileptiform discharges and that other data are not discordant.     

电刺激黑质对脑干伤害性单位放电的影响

本实验采用单细胞外记录神经元单位放电的方法，在Ｗｉｓｔａｒ大鼠上观察到网状巨细胞核。一区伤害性神经元５７个，其中伤害兴奋性神经元（ＮＥＮ）４２个，伤害抑制性神经元（ＮＩＮ）１５个。电刺激黑质对ＮＥＮ（２９）和ＮＩＮ（８的放电呈抑制作用，其反应百分率分别由刺激黑质第１分钟时的１．０±２．１％和－２０．４±６．２％，降到第５分钟时的－８３．６±１２．３％和－６５．４±１０．７％（Ｐ＜０．０１）。刺激黑质对少数ＮＥＮ（１３）和ＮＩＮ（７）的放电有兴奋作用，其值分别由第］分钟时的２０．５±７．３％和１．０±３．４％，升高到第５分钟时的７４．５±１０．７％和２１，５±８．６％（Ｐ＜０．０５）。氟哌啶醇注入ＰＡＧ腹外侧部可阻断刺激黑质的效应，这提示从黑质到网状巨细胞核α－区存在着一条痛调制通路，而且这种通路的递质是多巴胺能的。     

吗啡抑制大鼠多觉型伤害性感受器持续放电

作利用复合致痛剂引起大鼠尾部皮肤多觉型伤害性感受器（ＰＭＮ）持续性放电模型，经股静脉注入吗啡（４ｍｇ／ｋｇ），显抑制ＰＭＮ持续性放电。吗啡抑制ＰＭＮ放电５０％的潜伏期为１０±４．５ｍｉｎ，抑制时程超过３０ｍｉｎ。纳络酮１ｍｇ／ｍｇ ｉｖ，可翻转吗啡的抑制作用。在慢性吗啡耐受大鼠，吗啡几乎失去其抑制作用。吗啡引起的ＰＭＮ放电数变化不呈一致关系。小剂量吗啡（１ｍｇ／ｋｇ）注入支配感受野皮肢的尾动脉     

原发全身性癫痫遗传流行病学研究

本文报道１００例原发全身性癫痫家系的遗传流行病学研究结果。先证者一级亲属患病率为６．８６％，二级亲属为１．０３％；分别是对照组一级亲属的１３．８３倍和２．０８倍。原发全身性癫痫的遗传度为：一级亲属０．７５２１±０．０６７８，二级亲属０．３５９２±０．０７４６；加权平均０．５７４３±０．０５０２。说明遗传因素起重要作用。发病年龄影响因素分析表明：原发全身性癫痫有一定年龄依从性。ＥＥＧ家系分析显示，该型癫痫一级亲属癫痫样放电明显高于对照组一级亲属，提示癫痫样放电的遗传倾向。     

电刺激杏仁核对猫丘脑后核内脏大神经诱发放电的抑制作用

本文使用条件—检验刺激技术,研究了电刺激杏仁皮质内侧核对猫丘脑后核内脏大神经诱发放电的影响。电刺激杏仁皮质内侧核抑制丘脑后核的中等和长潜伏期内脏大神经诱发放电呈现两种形式:即时抑制和迟发抑制。前者可能是通过从杏仁核到丘脑后核的神经通路产生的,静脉注射纳洛酮可消除这种抑制,提示有鸦片样物质的参与。后者可能涉及神经—体液性因素。结果提示,杏仁核参与抑制内脏痛。     

Lateralizing value of interictal spikes on overnight sleep-EEG studies in temporal lobe epilepsy

PURPOSE: To determine the lateralizing value of interictal epileptiform discharges (IEDs) recorded during overnight sleep-EEG studies in temporal lobe epilepsy. Because IEDs are more prevalent in non-rapid eye movement (NREM) sleep than in wakefulness, overnight sleep-EEG recordings may contribute additional lateralizing information to the epilepsy surgery evaluation beyond daytime EEGs. METHODS: Twenty-four subjects with medically refractory temporal lobe epilepsy underwent continuous overnight sleep-EEG recordings. Subjects were seizure free > or =24 h before study and receiving stable doses of medication. The IED foci recorded on overnight studies were compared with daytime EEGs, interictal samples, and ictal recordings during long-term monitoring, brain magnetic resonance images (MRIs), and surgical outcome. RESULTS: (a) In all 24 subjects, including 13 without IEDs on daytime EEGs, temporal IEDs were present during NREM sleep and were exclusively or predominantly (>95%) unilateral in 15 and bitemporal in nine. (b) Unilateral NREM IEDs were concordant with surface or depth ictal-onset regions in 14 subjects, even if MRIs were normal (three subjects) or surface ictal-onset regions were bilateral (five subjects). Eleven of 12 subjects with unilateral concordant NREM IEDs who have undergone surgery are seizure free. (c) Bitemporal IEDs were associated with postoperative seizures in all subjects with normal MRIs or widespread MRI abnormalities. However, all subjects with bitemporal IEDs and MRI hippocampal abnormalities concordant with ictal-onset regions had good to excellent surgical outcomes. CONCLUSIONS: When combined with other investigations, IEDs recorded on overnight studies add prognostic data to the epilepsy surgery evaluation not provided by daytime EEGs.     

Unusual ‘Spike-wave stupor’ in a patient with manic-depressive psychosis treated with amitriptyline

Summary Spike-wave stupor was observed in a 58-year-old male patient with manic-depressive psychosis. Almost continuous atypical spike-wave activity was seen in conjunction with a stuporous episode with stereotyped automatism. Intravenous diazepam ended both the electroencephalographic epileptiform discharges and the clinical stupor. Before and during this episode the patient was treated with an average-dose amitriptyline monotherapy. There was no family history of epileptic seizures. The patient had had electroconvulsive therapy. The history suggests that the analeptic property of amitriptyline induced the spike-wave stupor in this patient.

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Zusammenfassung Während eines Stupors mit stereotypen Bewegungsabläufen und Reihensprechen, der im Rahmen einer depressiven Phase eines an einer manisch-depressiven Psychose erkrankten 58jährigen Patienten auftrat, wurde eine nahezu kontinuierliche unregelmäßige spike-wave- und sharp-wave-Aktivität im EEG abgeleitet. Der spike-wave-Stupor konnte durch eine intravenöse Applikation von Diazepam in seiner klinischen und elektroenzephalographischen Ausprägung rasch unterbrochen werden. Vor und während der stuporösen Attacke wurde der Patient mit Amitriptylin als Monotherapie in üblicher Dosierung behandelt. Die Eigen- und Familienanamnese ergab keinen Hinweis auf das Vorliegen einer Epilepsie. Epileptische Anfälle hatte der Patient nur aus therapeutischen Gründen im Rahmen einer Elektroschocktherapie. Die Analyse des Falles läßt in der analeptischen Wirkung von Amitriptylin die Ursache für das Auftreten des spike-wave-Stupors erkennen.

     

Frequency of bitemporal independent interictal epileptiform discharges in temporal lobe epilepsy

PURPOSE: Bitemporal interictal epileptiform discharges (IEDs) occur in < or =42% of scalp EEGs in patients with temporal lobe epilepsy (TLE) studied with routine EEGs or partial analysis of long-term recordings. METHODS: Twenty-eight patients with TLE demonstrating exclusively unilateral temporal IEDs on routine EEGs underwent 24-h continuous recording. The entire record was visually inspected for epileptiform discharges. We used continuous EEG to assess the significance of long-term recording in detecting bilateral IEDs. RESULTS: Twenty-two patients had left temporal IEDs; 21 had right temporal IEDs. Seventeen (61%) patients had IEDs originating from both the right and left temporal lobes. The probability of detecting bilateral independent IEDs was correlated with the duration of continuous EEG recording. There was no correlation between the number of IEDs originating from one side and the probability of detecting independent IEDs on the other side. The frequencies of IEDs were not correlated with the length of time since onset of epilepsy. CONCLUSIONS: The findings suggest that when long-term recordings are performed, the incidence of bilateral discharges in TLE is higher than previously reported in the literature and supports the view that TLE is commonly a bilateral disease.     

An Attempt to Stem the Tide: Exploring the Effect of a 90-Day Transitional Care Intervention on Readmissions to an Acute Male Psychiatric Unit in South Africa

Introduction

Pressure on inpatient beds often results in premature discharges, which may precipitate early readmission. This has prompted an increased interest in transitional care interventions to bridge the gap between in- and outpatient care to reduce such readmissions. Our study aimed to assess the effect of a Transitional Care Service (TCS) on readmission rates in a high pressure inpatient service which utilizes a premature discharge policy to address bed pressures.