Abstracts

Rationale: Multiple Subpial Transection (MST) has been used to stop presumed autonomous epileptic foci that have been associated with language or other cognitive regression in childhood epilepsies such as Landau-Kleffner Syndrome (LKS). This current study draws from children seen in a specialist clinic over a period of years and compares the outcome of children who underwent MST (12) with a control group (21) who had similar presentations and evaluation for surgery, but did not proceed to MST.Methods: Inclusion criteria were patients with LKS or other epileptic encephalopathy who showed resistance to medical intervention and so underwent presurgical investigations for MST. 9 had LKS. Groups were compared across a range of variables at the time of surgical evaluation and at follow-up. The non-surgery group was slightly older (mean age at baseline assessment 8.8yr versus 7.3yrs) and cognitively more preserved (non-verbal IQ 75.2 versus 63.1; receptive language 34.8 versus 15.5; expressive language 32.8 versus 15.2). Control children were routinely given 6 weeks high dose prednisolone with a weaning dose for 6 weeks, followed by weekly use of up to 4mg/kg for several years if there was benefit.Results: MST was associated with sustained improvement in EEG abnormality in 3 cases, but in 9 cases the EEG either did not improve, or abnormalities returned within 6 months. MST was complicated by an extradural haematoma in one child which led to an acquired hemiplegia. Both MST and Control Groups showed improvement over time and in both cases this increased with time from initial surgical assessment (Table 1). There was no evidence of accelerated recovery in the MST group in the year following surgery except for behaviour, with some suggestion of continued advantage in the long term (e.g. Strength and Difficulties Questionnaire at outcome showed a near significant difference for overall difficulties (0.051) and attention and hyperactivity (0.062) and also a borderline significant score for (0.049) for impact of the child s difficulties on their everyday life). Final assessment suggested similar levels of recovery in both groups (Table 2), although there was a wide range of outcome for individuals within groups. Conclusions: MST did not consistently stop epileptiform discharges in this group of children. There appeared to be a subtle benefit for behaviour, but long term outcome did not differ significantly between the MST and Control groups. MST was complicated by acquired hemiplegia in one child. The present study is the first to use a control group in the investigation of behavioural, communication and quality of life outcomes in LKS patients who undergo MST. As no significant difference was found between the two groups it is argued that MST as a form of intervention in LKS remains an experimental procedure. There was no external funding.