Cognitive Progression in Epilepsy Michael Seidenberg & Dalin T. Pulsipher & Bruce Hermann Received: 14 August 2007 / Accepted: 27 September 2007 # Springer Science + Business Media, LLC 2007 Abstract The issue of cognitive progression in people with epilepsy is of considerable interest and has important clinical and theoretical implications. In this paper, we review recent studies in both the adult and childhood epilepsy literature which have included a longitudinal test– retest design to examine this question. Several important methodological issues of this literature are highlighted and areas which require more investigation are identified. Keywords Cognitive progression . Longitudinal . Epilepsy . Children . Adults Introduction Epilepsy is the third most prevalent chronic neurological disorder, affecting approximately 1% of the population (Hauser 1990). The potential impact of epilepsy on cognition has been the subject of interest dating back to ancient times, and systematic investigation of this issue can be found beginning in the early part of the 20th century. It is now generally acknowledged that a subset of people with epilepsy manifest some degree of cognitive impairment, and considerable research efforts have been devoted to characterizing the extent and nature of the impairment, and to identifying the associated risk factors (Devinsky and Tarulli 2002; Elger et al. 2004; Oyegbile et al. 2004). A related but distinct question relates to the presence and extent of continued cognitive decline over time. This issue is commonly referred to as “progression,” and has been the focus of investigation at the molecular, physiologic, and cellular level (Pitkanen and Sutula 2002). From a neuro- psychological perspective, the issue of progression entails the possibility that continued cognitive decline is evident among people with epilepsy over the course of the disorder. To date, research relevant to the issue of progression has relied primarily on cross-sectional designs, which have obvious limitations for inferring change or progression. The most direct method is through longitudinal designs that specifically retest the same subject cohort over a specified interval of time. Despite the importance of the progression issue, there have been a decidedly limited number of studies using a longitudinal design in the investigation of cognitive change in epilepsy. Dodrill (2004) surveyed the published literature of cognitive longitudinal studies in both children and adults with epilepsy. He listed 13 studies of adults dating back to 1942 and nine studies with children dating back to 1924. Based on this review, Dodrill concluded that there was evidence for “losses in mental abilities over time” which was more evident among children than adults. Neverthe- less, he cautioned that additional investigation was neces- sary and stressed the need for including a control group to account for potential developmental and aging changes, and the importance of recording information about interval and lifetime seizure activity. The purpose of the current review is to provide an updated examination and discussion of recently published longitudinal studies of cognitive progression in epilepsy. This review includes both child and adult papers published since Dodrill’ s review in 2004. Similar to the Dodrill Neuropsychol Rev DOI 10.1007/s11065-007-9042-x M. Seidenberg : D. T. Pulsipher Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA B. Hermann University of Wisconsin School of Medicine and Public Health, Madison, WI, USA M. Seidenberg (*) Department of Psychology, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60069, USA e-mail: michael.seidenberg@rosalindfranklin.edu