Epilepsia - Editor's Choice
This issue is devoted largely to studies involving pediatric epilepsy issues. The Editors' Choice selections focus particularly on consequences and comorbidities of seizures in children.
Early developmental outcomes in children following convulsive status epilepticus: A longitudinal study
Martinos MM, Yoong M, Patil S, Chong WK, Mardari R, Chin RFM, Neville BGR, de Haan M, Scott RC
Convulsive status epilepticus (CSE) is associated with developmental impairments within 6 weeks of the acute event that continue to be present a year onward. This is also true of PFS cases that under-perform relative to controls despite mean scores within the clinically normal range. The absence of a change in performance from baseline to follow-up as well as the lack of a relationship between seizure characteristics and developmental outcomes supports the notion that premorbid abilities may be overshadowing any direct effects of CSE itself on outcome.
What predicts enduring intractability in children who appear medically intractable in the first 2 years after diagnosis?
Wirrell EC, Wong-Kisiel LC-L, Mandrekar J, Nickels, KC
Although a significant minority of children with early medical intractability ultimately achieved seizure control without surgery, those with an abnormal imaging study did poorly. For this subgroup, early surgical intervention is strongly advised to limit comorbidities of ongoing, intractable seizures. Conversely, a cautious approach is suggested for those with normal imaging, as most will remit with time.
Psychiatric symptoms in children prior to epilepsy surgery differ according to suspected seizure focus.
Salpekar JA, Berl MM, Havens K, Cushner-Weinstein S, Conry JA, Pearl PL, Yaun AL, Gaillard WD
The aim of this study was to assess psychiatric symptoms in children with medically refractory epilepsy and ascertain whether symptoms were associated with specific localization. The majority of the sample had psychiatric diagnoses and behavior problems, well beyond the level reported in chronic epilepsy populations. In addition, children with temporal lobe seizure foci had more CBCL behavioral problem categories rated in the clinically significant range, and also were more likely to have clinical diagnoses of depression. Routine psychiatric evaluation prior to epilepsy surgery may be important for pediatric patients with medically refractory epilepsy. Psychiatric illness, particularly depression, may be especially prominent for those with temporal lobe seizure foci.
May 2013 articles from Editor-in-Chief Simon Shorvon
SCN1A testing for epilepsy: Application in clinical practice.
Hirose S, Scheffer IE, Marini C, Jonghe P, Andermann E, Goldman AM, Kauffman M, Tan NCK, Lowenstein DH, Sisodiya SM, Ottman R, Berkovic SF for the Genetics Commission of the ILAE (2013)
This report is a useful reference guide for genetic testing of SCN1A in practice. Mutations in this gene are frequently found in Dravet syndrome (DS), and are sometimes found in genetic epilespy with febrile seizures plus (GEFS+), migrating partial seizures of infancy (MPSI), other infantile epileptic encephalopathies, and rarely in infantile spasms. The authors make recommendations for testing and note cautions in interpreting test results.
Examining factors related to accelerated long-term forgetting in epilepsy using ambulatory EEG monitoring
Fitzgerald Z, Thayer Z, Mohamed A, Miller LA (2013)
Accelerated forgetting is an interesting phenomenon which may well explain the often-noted discrepancy between a patient's complaint of memory loss and the apparent normality of conventional memory testing when memory is tested at relatively short intervals (e.g., 30 min). Such patients may show substantial loss over longer delay periods (e.g., days or weeks) when compared to healthy control subjects. This pattern of accelerated "long-term forgetting" (ALF) impacts on the patients' everyday lives, yet goes undetected by standard neuropsychological memory tests. Its pathophysiological basis is poorly understood.
By testing memory over a period of concurrent ambulatory EEG, the current study aimed to investigate possible factors contributing to ALF. Thirty-nine patients diagnosed with epilepsy or probable epilepsy underwent 5 days of continuous ambulatory electroencephalography (EEG). Subjects were taught 13-item word and design lists to criterion, and recall was tested at 30 minutes, 24 hours and 4 days. Subjects also completed questionnaires pertaining to everyday memory and mood.
This group analyses (excluding patients who experienced seizures during monitoring) indicated that patients who experienced generalized discharges during the 24hr to 4 day delay intervals showed higher rates of forgetting for nonverbal information. Those with focal discharges showed ALF between 30 minutes and 4 days for verbal information, while those with normal EEGs over the 4 days recording had no evidence of ALF. Surprisingly, mood and epilepsy variables (such as duration of disease or number of anticonvulsant medications) showed no significant correlation with ALF. Self-report of everyday memory functioning was related to recall at longer delays, but not at 30 minutes.
The findings indicated that ALF in epilepsy is associated with subclinical discharges rather than AEDs, mood or sleep disturbance. Measures of longer-term recall can reveal correlations with subjective everyday memory complaints that are not evident when recall is only tested at a standard (30 minutes) delay interval. This study is a useful contribution to this fascinating topic.
A systematic review of meta-analysis of the role of ABCC2 variants on drug response in patients with epilepsy
Grover S, Kukreti R (2013)
There is a lot of nonsensical discussion about 'drug resistance' — as if this phenomenon is likely to be due to a single mechanism. In this study, the authors performed a meta-analysis of published studies on the commonly reported genetic variants of ABCC2 as associated with drug response in patients with epilepsy (PWE). In their search of electronic databases, the authors found a total of eight reports, which included 1294 good responders and 1529 poor responders.
Although the authors concluded that the results of their meta-analysis indirectly suggested a possible role of the ABCC2 transporter, the associations were not significant. The authors suggest that further studies are warranted in different ethnic groups to investigate the effects of the ABCC2 haplotypic variants, with stratified analysis on the basis of different phonotypic covariates. I wonder, however, if such analyses will really yield significant new insights.