Decreased fractional anisotropy in the middle cerebellar peduncle in children with epilepsy and/or attention deficit/hyperactivity disorder: A preliminary study q Nina Bechtel a, * , Maja Kobel a , Iris-Katharina Penner a , Markus Klarhöfer b , Klaus Scheffler b , Klaus Opwis a , Peter Weber c a Department of Cognitive Psychology and Methodology, University of Basel, Basel, Switzerland b Division of Radiological Physics, University Hospital Basel, Basel, Switzerland c Division of Neuropediatrics and Developmental Medicine, University Children’s Hospital Basel, Basel, Switzerland article info Article history: Received 26 January 2009 Revised 2 April 2009 Accepted 4 April 2009 Available online 1 May 2009 Keywords: Epilepsy Attention deficit/hyperactivity disorder Diffusion tensor imaging Middle cerebellar peduncle abstract Children with epilepsy are at increased risk for attention deficit/hyperactivity disorder (ADHD). It has been shown that the cerebellum plays a major role in the pathophysiology of ADHD. We aimed to clarify whether children with combined epilepsy/ADHD have the same neurocerebellar pathophysiology as chil- dren with developmental ADHD. Eight boys with combined epilepsy/ADHD, 14 boys with developmental ADHD, and 12 healthy boys were investigated using diffusion tensor imaging generating fractional anisotropy (FA) maps. Healthy controls exhibited more FA in the left and in the right middle cerebellar peduncle compared with children with combined epilepsy/ADHD, and more FA in the right middle cer- ebellar peduncle compared with children with developmental ADHD. Our data show deficient cerebellar connections in both patient groups and endorse the crucial role of the cerebellum in the pathophysiology of ADHD. Our results suggest that ADHD seen in epilepsy might have the same cerebellar pathology as in developmental ADHD. Ó 2009 Elsevier Inc. All rights reserved. 1. Introduction Epilepsy is one of the most frequent chronic childhood diseases with a prevalence of 0.5 to 1% [1]. In addition to the problems asso- ciated with treating the epileptic disorder, social, emotional, and school problems are relevant in determining the long-term out- come of children with epilepsy. Teachers estimate that more than 50% of pupils with epilepsy have learning disabilities [2,3]. This could be a result of the brain dysfunction that causes the epilepsy or a result of attention problems. Although attention problems and learning disabilities in children with epilepsy could exist indepen- dently, attention problems are one of the best predictors of aca- demic performance in children with epilepsy [4]. Numerous studies have confirmed the clinical observation that children with epilepsy have an increased incidence of attention deficit/hyperac- tivity disorder (ADHD) with an overrepresentation of the predom- inantly inattentive subtype [5–8]. This stands in contrast to clinically derived samples of children with ADHD, in whom the combined subtype predominates [9]. It has to be mentioned though that the diagnostic criteria are not homogenous in these studies and the validity and reliability of subtype diagnosis are subject to debate [10,11]. The prevalence of ADHD is estimated to be around 5% in the general population [12], and it is characterized by three clusters of symptoms: inattention, hyperactivity, and impulsivity. Besides behavioral symptoms, patients with ADHD exhibit cognitive symp- toms that may interfere with academic progress [13] and disrupt activities of daily living, leading to clear reductions in quality of life of the affected children and their families [14]. Although knowl- edge of the neuroanatomical substrates of ADHD is increasing because of a growing body of evidence from imaging studies, the etiology and neurobiology of ADHD still remain unclear due to the heterogeneity of the findings. One of the most consistently reported features of ADHD leading to increasing interest in the pathogenesis of the disease is structural anomalies in the cerebel- lum. The core function of the cerebellum is traditionally viewed as the regulation of motor control [15,16]. However, during past dec- ades, results from clinical, neuroanatomical, and neuroimaging studies of healthy controls and patients indicated strongly that the cerebellum is also involved in cognitive and affective processes. In more detail, the cerebellum has been reported to be involved in executive functions such as set shifting [17], Stroop interference [18], temporal information processing [19], planning [20], and ver- bal working memory [21]. Each of these cognitive domains has been shown to be deficient in children with ADHD [22,23]. 1525-5050/$ - see front matter Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2009.04.005 q This study was supported by the Swiss National Science Foundation (Grant 3200B0-113897). * Corresponding author. Address: Department of Cognitive Psychology and Methodology, University of Basel, Missionsstrasse 60/62, 4055 Basel, Switzerland. Fax: +41 61 267 35 26. E-mail address: nina.bechtel@unibas.ch (N. Bechtel). Epilepsy & Behavior 15 (2009) 294–298 Contents lists available at ScienceDirect Epilepsy & Behavior journal homepage: www.elsevier.com/locate/yebeh