The Secondary Effects of Antiepileptic Drugs (AEDs) in Children and Their Implications on Augmentative and Alternative Communication (AAC) Processes: A Best-Evidence Synthesis

Abstract

This study uses a best-evidence synthesis method to investigate the secondary effects of various antiepileptic drugs (AEDs) and their implications on augmentative and alternative communication (AAC) processes. Epilepsy is a common serious neurological disorder, a concomitant condition in individuals with severe developmental and intellectual disabilities, who often need AAC because of little or no functional speech. The most common treatment modality for seizures is the use of AEDs which are associated with debilitating adverse effects. Adverse effects of these drugs may be associated with cognitive impairment, can aggravate age-related cognitive deficits, increase hyperactivity, other behavior problems, cause motor deficits and reduce the quality of life for children. Keeping in mind that children with disabilities require specialized planning and training of communication intervention programs it becomes even more crucial that interventionists know about other important aspects, such as medications that might impair their learning and/or performance. There is a need for synthesizing and evaluating the existing evidence on cognitive and behavioral effects of AEDs and its possible interference with AAC. The amount of available research literature focusing on clinical studies and understanding the secondary effects of AEDs is expansive, and captures a vast array of treatment approaches as well as different theoretical paradigms. Within this extensive literature little research has been published with respect to children. Without deriving and synthesizing empirical evidence from this extensive body of research, very few conclusions can be drawn about the effect of these drugs on the AAC user and changes and modifications that the field of AAC has to take-on. The purpose of this study is threefold--first, to understand the secondary effects that AEDs have on integral processes; second, to investigate specific short-term and long-term secondary effects of AEDs on children; and third, to derive implications for AAC intervention and performance. This study uses a best-evidence synthesis (Slavin, 1986) approach which incorporates the best features of a meta-analysis and retains insightful features indigenous to traditional systematic reviews. The methodology for conducting this best-evidence synthesis consisted of the following key elements: (1) conducting a comprehensive literature search; (2) selecting appropriate studies for synthesis based on an a priori inclusion and exclusion criteria; (3) organizing the literature; (4) categorization of studies based on their levels of evidence; (5) coding the studies; (6) appraising the studies for their methodological quality; (7) conducting the analyses of the data and interpreting the results of these analyses; and (8) literature synthesis. The search resulted in 113 articles from which 37 articles were selected based on a priori inclusion criteria and those that were high in methodological quality. The selected 37 studies were then categorized and coded. Each study was additionally appraised for its methodological quality, based on its design. Inter-rater agreement was calculated for the inclusion of studies, coding process, and appraising the studies for their methodological quality. For prospective cohort studies which provided data across time, effect sizes were used to characterize short-term and long term outcomes using a meta-analysis. In addition, individual studies typical of good quality are described as a narrative synthesis based on their level of evidence. Results have shown several secondary effects caused by the six chosen drugs. Implication for AAC performance and assessment has been detailed and gaps in research identified. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone [phone]. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]