Motor learning in children with spina bifida: Intact learning and performance on a ballistic task MAUREEN DENNIS, 1–3 DERRYN JEWELL, 1 KIM EDELSTEIN, 1 MICHAEL E. BRANDT, 4 ROSS HETHERINGTON, 3,5 SUSAN E. BLASER, 6 and JACK M. FLETCHER 7 1 Brain and Behaviour Program, The Hospital for Sick Children, Toronto, Ontario, Canada 2 Department of Surgery, University of Toronto, Toronto, Ontario, Canada 3 Department of Psychology, University of Toronto, Toronto, Ontario, Canada 4 Center for Computational Biomedicine, University of Texas Health Science Center, Houston, Texas 5 Community Health Systems Resource Group, The Hospital for Sick Children, Toronto, Ontario, Canada 6 Department of Radiology, The Hospital for Sick Children, Toronto, Ontario, Canada 7 Department of Psychology, University of Houston, Houston, Texas (Received January 13, 2006; Final Revision May 26, 2006; Accepted May 30, 2006) Abstract Learning and performance on a ballistic task were investigated in children with spina bifida meningomyelocele (SBM), with either upper level spinal lesions ( n 5 21) or lower level spinal lesions ( n 5 81), and in typically developing controls ( n 5 35). Participants completed three phases (20 trials each) of an elbow goniometer task that required a ballistic arm movement to move a cursor to one of two target positions on a screen, including (1) an initial learning phase, (2) an adaptation phase with a gain change such that recalibration of the ballistic arm movement was required, and (3) a learning reactivation phase under the original gain condition. Initial error rate, asymptotic error rate, and learning rate did not differ significantly between the SBM and control groups. Relative to controls, the SBM group had reduced volumes in the cerebellar hemispheres and pericallosal gray matter (the region including the basal ganglia), although only the pericallosal gray matter was significantly correlated with motor adaptation. Congenital cerebellar dysmorphology is associated with preserved motor skill learning on voluntary, nonreflexive tasks in children with SBM, in whom the relative roles of the cerebellum and basal ganglia may differ from those in the adult brain. ( JINS, 2006, 12, 598–608.) Keywords: Cerebellum, Hydrocephalus, Meningomyelocele, Motor skills, Adaptation, Magnetic resonance imaging INTRODUCTION Individuals with spina bifida meningomyelocele (SBM), the most common and severe form of spina bifida, have deficits in upper (Grimm, 1976) as well as lower limb con- trol. Individuals with hydrocephalus, most with SBM, have impairments in persistent motor control, strength, balance, and fine motor skills (Hetherington & Dennis, 1999). Although it might be supposed that impaired motor perfor- mance would be associated with deficient motor learning, recent evidence suggests that SBM need not prevent suc- cessful acquisition of new motor skills. According to Doyon and Benali (2005), motor learning involves motor sequence learning (i.e., gradual acquisition of movements into a smoothly executed behavior) and motor adaptation (i.e., the ability to respond to changes in the environment). From examinations of these two domains, it appears that the motor control deficits in individuals with SBM do not entail motor learning deficits. Edelstein et al. (2004) demonstrated preserved motor sequence learning in individuals with SBM on a mirror drawing task, even when task performance was poor. Intact motor adaptation in indi- viduals with SBM was demonstrated on a task requiring prism adaptation to distorted visual information (Colvin et al., 2003). Children with SBM have difficulty visually tracking targets using smooth pursuit eye movements (Sal- man et al., 2005), conjugate eye movements serving to sta- bilize the image of a moving target on the fovea for high definition vision (Leigh & Zee, 1999). Nevertheless, the Correspondence and reprint requests to: Maureen Dennis, Ph.D., Brain and Behaviour Program, Department of Psychology, The Hospital for Sick Children, 555 UniversityAvenue, Toronto, ON, M5G 1X8, Canada. E-mail: maureen.dennis@sickkids.ca Journal of the International Neuropsychological Society (2006), 12, 598–608. Copyright © 2006 INS. Published by Cambridge University Press. Printed in the USA. DOI: 10.10170S1355617706060772 598