ORIGINAL ARTICLE Impact of Tactile Dysfunction on Upper-Limb Motor Performance in Children With Unilateral Cerebral Palsy Megan L. Auld, PhD, Roslyn N. Boyd, PhD, G. Lorimer Moseley, PhD, Robert S. Ware, PhD, Leanne M. Johnston, PhD ABSTRACT. Auld ML, Boyd RN, Moseley GL, Ware RS, Johnston LM. Impact of tactile dysfunction on upper-limb motor performance in children with unilateral cerebral palsy. Arch Phys Med Rehabil 2012;93:696-702. Objective: To determine the relationship between tactile function and upper-limb function in children with unilateral cerebral palsy (CP). Design: Cross-sectional study. Setting: Assessments were performed in community or hos- pital venues or in participants’ homes. Participants: Recruitment information was sent to 253 pos- sible participants with unilateral CP (aged 8 –18y), and N=52 participated (median age [interquartile range], 12y [9 –14y]; Gross Motor Functional Classification System level I=34; II=18; Manual Abilities Classification Scale level I=36; II=16). Interventions: Not applicable. Main Outcome Measures: Tactile assessment included 1 test of registration, 5 tests for spatial perception, and 1 test for texture perception. Upper-limb motor function was assessed using 2 unimanual tests, the Melbourne Unilateral Upper Limb Assessment (MUUL) and Jebsen-Taylor Test of Hand Function (JTTHF), and 1 bimanual test, the Assisting Hand Assessment (AHA). Results: Tactile registration and all tests of spatial perception were moderately related to the MUUL, JTTHF, and AHA (P.001). Texture perception was not related to upper-limb motor function. Regression analysis showed that single point localization, a unilateral tactile spatial perception test, contrib- uted most strongly to unimanual capacity (29% explained variance in MUUL and 26% explained variance in JTTHF), whereas double simultaneous, a bilateral tactile spatial percep- tion test, contributed most strongly to bimanual performance (33% for the AHA). Conclusions: Spatial tactile deficits account for approxi- mately 30% of the variance in upper-limb motor function in children with unilateral CP. This emphasizes the need for routine tactile assessment and targeted treatment of tactile spatial deficits in this population. Key Words: Arm; Cerebral palsy; Hemiplegia; Perception; Rehabilitation; Sensation; Touch. © 2012 by the American Congress of Rehabilitation Medicine I NTERVENTIONS FOR children with unilateral cerebral palsy (CP) have traditionally focused on training upper-limb performance and reducing motor impairments associated with muscle spasticity, weakness, and contracture. However, recent studies have begun to examine impairments in tactile registra- tion and perception 1-3 and their potential impact on unimanual capacity 4,5 and bimanual performance. 1,6 In recent years, spe- cific tactile deficits, such as spatial tactile discrimination, tex- ture perception, and object recognition, have been identified in children with dystonia 7 and diplegia. 8,9 Although information is increasing, systematic analysis of how tactile and motor deficits interact in children with unilateral CP is lacking. In children with unilateral CP, tactile impairment disrupts uni- manual function including grasp, anticipatory control, and grip-lift tasks with the involved hand. 4,5,10 Where tactile deficits are pres- ent in the impaired hand, sensory information from previous performance of a grip-lift task with the less impaired hand can be used to facilitate anticipatory scaling of the same object in the impaired hand. 4 This indicates that initially impaired anticipatory control is not due to disturbed motor output, but rather to sensory disturbances in the impaired hand that lead to a poor representa- tion of the object’s physical properties. 4,5 Grasp dysfunction in the impaired hand is, therefore, proposed to result from an inability to appropriately integrate tactile input with subsequent motor output of the same hand. 11,12 However, this proposal is based on a limited repertoire of tactile assessments—Semmes-Weinstein monofila- ments a (SWM), 13 two-point discrimination (2PD), 14 and Manual Form Perception 15 —and, as such, the mechanisms that link tactile registration and perception to unimanual capacity and bimanual performance are not fully explained. That is, performance in different tactile domains may impact upper-limb motor function to different degrees. From the Division of Physiotherapy, School of Health and Rehabilitation Sciences (Auld, Johnston), Queensland Cerebral Palsy and Rehabilitation Research Centre, School of Medicine (Boyd), and School of Population Health (Ware), The University of Queensland, Brisbane; Cerebral Palsy League, Brisbane (Auld, Johnston); The Sansom Institute for Health Research, University of South Australia, Adelaide (Mose- ley); Neuroscience Research Australia, Sydney (Moseley); and Queensland Chil- dren’s Medical Research Institute, Royal Children’s Hospital, Brisbane (Ware), Australia. Supported by an Australian Postgraduate Award and Queensland Government Smart State PhD Scholarship; a Senior Research Fellowship from the National Health and Medical Research Council (NHMRC) of Australia (no. 571090); a Career Development grant from the NHMRC of Australia (grant no. 473840); a Smart State Fellowship from the Queensland Government; and a grant from the Mayne Bequest and the University of Queensland Foundation, Brisbane, Australia. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organi- zation with which the authors are associated. Correspondence to Megan L. Auld, PhD, Division of Physiotherapy, School of Health and Rehabilitation Sciences, The University of Queensland, QLD, Australia 4072, e-mail: mauld@uq.edu.au. Reprints are not available from the author. In-press corrected proof published online on Feb 24, 2012, at www.archives-pmr.org. 0003-9993/12/9304-00699$36.00/0 doi:10.1016/j.apmr.2011.10.025 List of Abbreviations AHA Assisting Hand Assessment CP cerebral palsy ICC intraclass correlation coefficient JTTHF Jebsen-Taylor Test of Hand Function MACS Manual Abilities Classification Scale MUUL Melbourne Unilateral Upper Limb Assessment SWM Semmes-Weinstein monofilaments 2PD two-point discrimination 696 Arch Phys Med Rehabil Vol 93, April 2012