How Encephalopathy Impacts Language Ability: A Scoping Review of the Linguistic Abilities of Adults with Developmental and Epileptic Encephalopathy

Background and Objectives: Developmental and epileptic encephalopathy refers to a group of conditions where patients experience abnormal development due to various causes as well as frequent epileptiform discharges that ultimately contribute, in an independent and additive fashion, to cognitive and linguistic impairments. The language and cognition outcome of these patients in adulthood has been understudied. This paper aims to present a scoping review of linguistic abilities in adults with developmental and epileptic encephalopathy to determine the extent to which language outcomes in adulthood and their relation to cognitive outcomes have been studied. Design: Two online databases were searched and the methodological framework by Arksey & O’Malley (2005) was adopted. Results: Out of the 27 selected studies, only 13 exclusively examined adults, 15 were group studies, 5 were case studies and 7 were case series. A total of 9 out of the 15 group studies provided individual results for adults. Twenty-two studies included a follow-up examination. Twenty-three studies addressed the relationship between language and cognition. The selected studies indicate the presence of language impairments, which are nevertheless differentially manifested in the syndromes under investigation, whereas individual variability is also reported. Aspects of cognition seem to correlate with linguistic abilities. Conclusions: In sum, despite variability in linguistic abilities, language deficits constitute a significant aspect of the clinical profile of many adults with developmental and epileptic encephalopathy, a finding that should be taken into account for the treatment protocols of these individuals.