Pharmacological interventions for epilepsy in people with intellectual disabilities

Abstract

Background: The development of epilepsy in a person with intellectual disabilities is a common occurrence. In view of the fact that seizures in intellectually disabled people are often complex and refractory to treatment and that antiepileptic medication may have a profound effect upon behaviour in this patient group, it is evident that good quality randomised controlled trials are needed in this population.

Objectives: The aim of our study was to assess the data available from randomised controlled trials of antiepileptic drug interventions in people with epilepsy and intellectual disabilities.

Search strategy: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 4), MEDLINE OVID (1966 to October 2006), PsychInfo OVID (1806 to October 2006) and EMBASE OVID (1980 to April 2005).

Selection criteria: Randomised controlled trials (RCTs) of pharmacological interventions for people with epilepsy and a learning disability. RCTs where inadequate methods of allocation concealment had been used were also included.

Data collection and analysis: Two review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information. Outcome measures included the following.(1) Retention on treatment.(2) Seizure freedom.(3) Reduction in seizure frequency.(4) Seizure severity scales.(5) Global rating scales.(6) Behavioural outcomes.(7) Cognitive outcomes.(8) Adverse effects.(9) Quality of life.

Main results: Data were heterogenous and a descriptive analysis is presented. This review confirms that in the majority of cases where antiepileptic drugs (AEDs) were trialled in this population, moderate reduction in seizure frequency and occasional seizure freedom were obtained. In general it seems reasonable to say that AEDs proven effective in the general epilepsy population are also effective in refractory epilepsy in people with intellectual disability. It is not possible to comment on relative efficacy between medications making clinical choice decisions difficult. Clinical decision is also likely to be guided by concern over side effects. The quality of the studies does not aid clinicians greatly to this respect. In general it seems that in trial settings patients continue on treatment, in the majority of cases, and placebo groups often experience less in the way of side effects. Where side effects are experienced they appear similar to those seen in non-intellectual disability studies. One area of key concern is that of behavioural exacerbation. The majority of studies are unhelpful due to lack of or non-reliable measures in this area. However, where measured, little obvious impact on behaviour is seen in terms of behaviour disorder.

Authors' conclusions: In summary this review broadly supports the use of AEDs to reduce seizure frequency in people with refractory epilepsy and intellectual disability. The evidence suggests that side effects are similar to those in the general population and that behavioural side effects leading to discontinuation are rare but that other effects are under researched.