EEG in childhood absence epilepsy.

We performed a longitudinal clinico-electroencephalographic study of 23 children who were diagnosed as having absence epilepsy on their initial visits to our facility and we analysed those factors which lead to an unfavourable prognosis. SUBJECTS AND METHODS: We divided the 23 patients into three groups according to their clinical courses: Group A: eight patients who responded well to the therapy and became seizure free without relapse of epileptic discharges on EEGs; Group B: thirteen patients who suffered from relapse of epileptic discharges on EEGs despite clinical seizure cessation; Group C: two patients who continued to suffer from seizures. RESULTS: (1) Fifty-six percent of all patients had focal epileptic discharges, including a surprising 63% of patients in Group A. (2) "Lead in" in the ictal EEGs and automatisms during seizures were most commonly observed in patients in Group B, although there were no significant differences between the three groups. (3) The epilepsy of one patient in Group C evolved into complex partial seizures or absence status during her clinical course. She seemed to suffer from so-called "frontal absence", despite the fact that her initial EEG did not show any focal abnormalities. (4) Patients in Group B were treated with lower AED dosages than those in Group A. In addition, one patient in Group C was treated irregularly. CONCLUSION: We conclude that it is not uncommon for patients with absence epilepsy to show focal abnormalities on EEGs and clinical ictal automatisms. Thus, the existence of clinical ictal automatisms and focal signs in electroencephalographic features are not sufficient indicators of the final outcome. Furthermore, it appears that regular and adequate drug therapy is important for a favourable prognosis.     

Pseudoseizures caused by hyperventilation resembling absence epilepsy

During the 4-year period, 1982-1986, 18 patients presented to the Children's Hospital, Camperdown, Sydney, with the following features: (1) Recurrent "absences" clinically indistinguishable from childhood absence epilepsy, (2) Normal clinical examination, (3) Electroencephalogram (EEG) demonstrating normal waking background and sleep activity. On hyperventilation, "absences" occurred, characterized on EEG by a marked build-up of paroxysmal slow-wave activity unassociated with evidence of epileptic activity. We designate these attacks "pseudoseizures caused by hyperventilation resembling absence epilepsy." Individual cases demonstrated a variety of other symptoms consistent with the hyperventilation syndrome. There was an identifiable environmental stress in 13 of the 18 cases. Follow-up of 13 patients after a mean period of 20 months revealed that only two children continued to have occasional absences, associated with a clear history of breathing up when upset. Treatment did not influence outcome. On repeat hyperventilation with EEG and respiratory monitoring, five of the 13 had pseudoseizures. There was no indication that susceptibility to these episodes was associated with an abnormal CO2 response. It is postulated that the occurrence of pseudoseizures is related to cerebrovascular immaturity and an excessive vasoconstrictor response to a given level of CO2.     

Periventricular nodular heterotopia and childhood absence epilepsy.

A young female presented with an epileptic syndrome resembling childhood absence epilepsy, a normal neurologic examination, generalized 3-Hz spike-and-wave discharges, and clinical absences. Her seizures responded to treatment with valproic acid. Other abnormalities in her electroencephalogram prompted neuroimaging studies, which demonstrated periventricular nodular heterotopia. Review of published reports confirmed this presentation to be atypical of this developmental lesion. The authors describe their patient and discuss this unexpected association and the relevant reports briefly.     

Thalamic atrophy in childhood absence epilepsy

PURPOSE: Patients with childhood absence epilepsy (CAE) have normal clinical magnetic resonance imaging (MRI) studies. The presence of abnormalities in corticothalamic networks has been suggested to be the functional basis of absence seizure generation. We assessed whether structural grey and white matter volume changes of these areas occurred in patients with absence seizures by using optimized voxel-based morphometry (VBM). METHODS: We recruited 13 patients with a clinical and EEG diagnosis of CAE (mean age at examination, 17 +/- 8 years) and compared them with a consecutive series of 109 controls (mean age, 29 +/- 9 years). The 3 tesla MRI examination included a 3D T(1)-weighted sequence, which was analyzed with an optimized VBM protocol using the SPM2 package. The threshold was set at p < 0.05, corrected for multiple comparisons. RESULTS: Compared with controls, CAE patients showed areas of grey matter decrease in both thalami and in the subcallosal gyrus. White matter decrease was found in the extranuclear subcortical area and in the white matter of the basal forebrain. Grey and white matter increase was restricted to small clusters of cortical and subcortical areas. CONCLUSIONS: Evidence exists of subcortical grey and white matter volume reduction in CAE patients. Bilateral thalamic atrophy may be either a result of damage from seizures (as in hippocampal sclerosis) or a reflection of a primary underlying pathology as the cause of absence seizures.     

Ictal and interictal SPECT findings in childhood absence epilepsy.

The purpose of this study was to investigate the informative value of single photon emission tomography (SPECT) in relation to the pathophysiological functioning of the brain during absence seizures and the origin of ictal discharges in idiopathic generalized epilepsies (IGEs). Six patients with childhood absence epilepsy (CAE) were selected for the study and two consecutive SPECT sessions were performed concomitant with EEG recordings revealing normal results and during hyperventilation (HV) studies where the ictal discharges were induced either alone or accompanied by clinical absence seizures. All six patients had ictal discharges in their EEGs during HV and two of them also had clinical absences. SPECT findings during HV revealed an overall increase in the cerebral blood flow (CBF) with significantly higher values as compared to the baseline data. There was no indication for any focal origin in either the interictal or the ictal SPECT findings. Results of the study were supportive for the concept of subcortical origin for the absence seizures and they were also promising for the diagnostic value of ictal SPECT in epileptic cases with undetermined origin as to whether they were localization-related or generalized.     

Coexistence of childhood absence and rolandic epilepsy

The coexistence of absence and rolandic epilepsy is extremely rare. This coexistence has been attributed to either the treatment or an atypical course of the disease. However, for some authors, this issue remains controversial. We report the case of a 9-year-old girl presenting with both absence seizures and focal seizures consistent with rolandic epilepsy.     

Pharmacological treatment of childhood absence epilepsy

This review discusses current pharmacological treatment of childhood absence epilepsy (CAE). The key to successful treatment is the correct diagnosis of the epileptic syndrome, hence the initial part of the paper discusses the definition, diagnostic criteria and epidemiology. This is followed by a detailed analysis of pharmacological agents used in the treatment of CAE. The characteristics of old and new anticonvulsants used in the treatment of CAE are also reviewed. For each of the drugs, the mechanism of action, usual dose, common side effects and recommendations for treatment are also discussed. A separate section focuses on instances when anticonvulsants may exacerbate seizures. Particular emphasis is given to the evidence currently available, on which clinical practice needs to be based.     

Ezogabine treatment of childhood absence epilepsy

Generalised‐onset absence seizures can be resistant to treatment with currently available antiepileptic drugs. Ezogabine (retigabine), a potassium channel opener, is approved for the treatment of focal‐onset seizures. This is a case report of an adult with childhood absence epilepsy whose daily absence seizures ceased with adjunctive ezogabine. A 59‐year‐old woman, with a history of typical absence seizures since the age of 6 years, had multiple seizures daily despite trials of over 11 antiepileptic drugs. While taking lamotrigine and zonisamide, ezogabine at 50 mg daily was added. The dose was slowly increased and once a total dose of only 200 mg/day was reached, she became seizure‐free for three months. After subsequently discontinuing zonisamide, absence seizures returned. Further increasing the ezogabine to 400 mg/day, in addition to lamotrigine, did not restore seizure freedom, but adding back zonisamide at half dose again reduced their frequency. Ezogabine at low dose, added to lamotrigine and zonisamide, led to sustained absence seizure freedom. The return of seizures after zonisamide discontinuation suggests that the seizure freedom may have been the result of the different mechanisms of action of the antiepileptic drugs.     

Benign myoclonic epilepsy in infancy followed by childhood absence epilepsy

Benign myoclonic epilepsy in infancy (BMEI) is a rare syndrome included among idiopathic generalized epilepsies (IGE) and syndromes with age-related onset. Recently, it has been shown that a few patients with BMEI later had other epilepsy types mainly IGE but never childhood absence epilepsy (CAE).We report a patient who at 11 months of age showed isolated myoclonic jerks occurring several times a day. The ictal video-EEG and polygraphic recording revealed generalized discharge of spike-wave (SW) lasting 1–2 s associated with isolated bilateral synchronous jerk involving mainly the upper limbs controlled by valproic acid (VPA).At 6 years and 8 months the child developed a new electroclinical feature recognized as CAE. The ictal EEG disclosed a burst of rhythmic 3 Hz generalized SW.Our case is the first patient with BMEI reported in the literature who later developed a CAE.This finding suggests a common neurobiological and genetic link between different age-related epileptic phenotypes.     

Symptoms of anxiety and depression in childhood absence epilepsy

Childhood absence epilepsy (CAE) has been recently linked to a number of cognitive, behavioral, and emotional disorders. Identification of affective disorders (anxiety and depression) presents unique challenges in pediatric populations, and successful early intervention may significantly improve long-term developmental outcomes. The current study examined the specific anxiety and depression symptoms children with CAE experience, and explored the role of disease factors in the severity of their presentation. Forty-five subjects with CAE and 41 healthy matched controls, ages 6-16 years, participated in the study. The Behavior Assessment System for Children (BASC) was completed by parents, and the Anxiety and Depression subscales were used to characterize problems. Item analysis within the subscales revealed that children with CAE demonstrated higher rates of symptoms of anxiety (nervousness and thought rumination) and depression (sadness and crying), as well as more general psychosocial problems including isolation and low self-esteem. Disease duration, intractability, and medication effects were not associated with higher rates of affective problems in this limited patient sample. Screening of patients with CAE for comorbid psychiatric disorders early by focusing on specific symptom profiles unique to this population may enhance overall treatment and developmental outcomes.     

Attention and executive functions profile in childhood absence epilepsy

Childhood absence epilepsy (CAE) has been associated with executive functions and attention deficits. To clarify the issue of neurocognitive impairments in CAE, we investigated whether specific executive functions and attention deficit patterns were present in a well-defined group of children with CAE who were taking valproic acid. Participants included 15 children with CAE and 15 healthy controls aged 8–15 years and matched for sex, age and IQ. We compared the performances of the two groups in the following neuropsychological domains: planning and problem solving (TOL), verbal fluency (FAS and CAT), verbal short-term memory (DSF), verbal working memory (DSB), visuospatial memory (Corsi Block Tapping Test) and sustained and divided attention (TMT-A and TMT-B). No differences were found between the two groups on measures of intellectual functioning, verbal short-term memory and visuospatial memory. By contrast, significant differences were found in total time of planning task, phonological and category fluency and sustained and divided attention. Future studies that systematically examine different aspects of attention and executive functions are needed to outline a clear and specific neuropsychological profile in CAE.     

Long-term prognosis for childhood and juvenile absence epilepsy

Abstract. Purpose: To analyse prognostic factors for long term seizure remission in patients with childhood (CAE) and juvenile absence epilepsy (JAE). Study design: A retrospective analysis of a hospital based prevalence cohort. Methods: The cohort consisted of 163 patients (104 females, 59 males) treated at the Universitätsklinik für Neurologie, Innsbruck between 1970 and 1997. All had absences according to the ILAE classification. Follow up was in 1999 to 2000. We assessed multiple clinical and EEG factors as predictors of outcome and compared a classification according to the predominant pattern of seizure recurrence (pyknoleptic, PA or non pyknoleptic absence, NPA) with the ILAE classification with respect to prognosis. Results: The mean age at seizure onset was 10.9 years (range, 3 to 27); age at follow up was 36.7 years (range, 13 to 81); duration of follow up was 25.8 years (range, 3 to 69). Sixty four patients (39 %) had CAE and 64 (39 %) JAE, while 35 (22%) had typical absences but could not be clearly defined as either CAE or JAE, and were therefore called the overlap group. Patients with JAE or patients in the overlap group developed more often generalized tonic clonic seizures (GTCS) (p<0.001) and myoclonic attacks (p<0.05) during the course of the disease. At follow up 36 (56 %) of patients with CAE, 40 (62%) with JAE and 19 (54 %) of the overlap group were seizure free for at least two years (p=ns). When classified according to the predominant absence pattern at seizure onset 42 (51%) patients with PA and 53 (65%) with NPA were in remission (p=ns). In a stepwise binary logistic regression analysis the pattern of absence (PA or NPA) together with the later development of additional seizure types (myoclonias or GTCS), but not the CAE/JAE classification was predictive for long term lack of remission with a correct prediction of 66% of all patients. Conclusion: Only 58% of patients with absences were in remission after a long term follow up. CAE and JAE are closely related syndromes with large overlap of the age of onset. A classification according to the predominant seizure pattern at onset, together with later development of myoclonic attacks or GTCS is useful in predicting seizure remission in absence epilepsies.     

Paroxysmal tonic upgaze of childhood with co-existent absence epilepsy.

Paroxysmal tonic upgaze (PTU) is a childhood oculomotor syndrome of unclear etiology characterized by episodic tonic upward eye deviation with neck flexion. Neuroimaging findings are often normal and the electroencephalography during episodes is typically normal. We describe a 2-year-old boy who presented with macrocephaly, hypotonia, developmental delay and episodes of eye fluttering, head nodding and unresponsiveness. Video-EEG captured absence seizures and he was treated with valproate, which led to improvement of his seizures. However, two weeks after treatment, he developed paroxysmal episodes of "eyes up and chin down" movements lasting for hours at a time which were captured by home video. The episodes were relieved by sleep and exacerbated by fever, stress and even tactile stimulation. Increasing the dose of valproate resulted in increased frequency of the episodes. A repeat video-EEG disclosed the non-epileptic nature of these events. Discontinuation of valproate dramatically decreased the episodes. This case illustrates that paroxysmal tonic upgaze of childhood may co-exist with early onset absence epilepsy. Furthermore, valproate treatment may be associated with the development or unmasking of PTU suggesting that the pathophysiology of PTU may involve abnormal GABA neurotransmission. [Published with videosequences].     

Sequential occurrence of benign partial epilepsy and childhood absence epilepsy in three patients

We first report 3 patients who experienced absence epilepsy (mean age at onset: 6.3 years; range: 4–9) 1–4 years after recovering from an electroclinical picture characteristic of benign childhood partial epilepsy (BCPE). All patients were put on monotherapy with sodium valproate, and their long-term course was excellent with remission of absences and normalization of EEG recordings. The exceptionality of our observation favors the hypothesis that BCPE and absence epilepsy are distinct entities.     

儿童期失神癫痫静息态脑网络改变的脑电图联合功能磁共振成像研究

目的采用静息态功能磁共振(fMRI)脑网络分析技术对儿童失神发作时静息态脑网络的改变进行观察,旨在发现癫癎发作时患儿认知功能受损情况。方法根据病例选择标准,共纳入12例诊断明确的失神发作患儿,采用同步脑电图-fMRI技术采集17对弥漫性棘慢波综合发放和无发放状态下fMRI数据;以独立成分分析法分别观察丘脑、默认网络、背侧注意网络、中央执行网络和感知觉网络等7个静息态脑网络在不同状态下的表现情况。结果配对t检验及相关分析结果提示,在弥漫性棘慢波综合发放状态下丘脑表现为脑电活动同步性增强,且其强度与弥漫性棘慢波综合发放持续时间呈正相关(r=0.890,P=0.000);默认网络(r=-0.706,P=0.000)、背侧注意网络(r=-0.829,P=0.000)、中央执行网络(r=-0.905,P=0.000)等负责高级认知功能处理的静息态脑网络则表现为脑电活动同步性降低,并与弥漫性棘慢波综合发放持续时间呈负相关。而低级的感知觉网络的改变与弥漫性棘慢波综合发放无显著相关关系(P>0.05)。结论本研究首次验证丘脑可能与儿童期失神癫癎弥漫性棘慢波综合发放有关,并首次提出,除默认网络功能外,儿童失神发作还可表现为注意力及执行控制能力等高级认知功能受损,而低级感知觉功能虽可能受累但不明显。这一发现有益于对儿童失神发作时意识受损的病理生理学机制的理解。     

Recurrence of childhood absence epilepsy as pyknolepsy in adolescence

A developmentally normal adolescent boy with a history of childhood absence epilepsy presented with recurrence of pyknolepsy after a seven-year period of remission. The characteristics of his EEG showed the same 3-Hz generalised spike-wave discharge as in his previous EEG in childhood. To our knowledge, this is the first case report describing recurrence of childhood absence epilepsy as pyknolepsy in an adolescent. [Published with video sequences].