THREE-DIMENSIONAL GAIT ANALYSIS Use of the Gait Deviation Index and spatiotemporal variables for the assessment of dual task interference paradigm Danielli Souza Speciali, PT a , Elaine Menezes de Oliveira, PT b , Nadia Maria dos Santos, PT b , Fernando Vieira Pereira, PT, PhD b , Ame´rica Cristina Fracini, PT c , Thiago Yukio Fukuda, PT, PhD d,e , Claudia Santos Oliveira, PT, PhD a , Joa ˜o Carlos Correa, PT, PhD a , Paulo Roberto Garcia Lucareli, PT, PhD a, * a Universidade Nove de Julho, Department of Rehabilitation Science, Motion Analysis Laboratory, Sa˜o Paulo, Brazil b Universidade Federal de Sa˜o Paulo, Department of Neurology, Sa˜o Paulo, Brazil c Hospital das Clı´nicas da Faculdade de Medicina da Universidade de Sa˜o Paulo, Department of Rehabilitation Science, Sa˜o Paulo, Brazil d Irmandade Santa Casa de Miserico´rdia (ISCMSP), Physical Therapy Department, Sa˜o Paulo, Brazil e Centro Universita´rio Sa˜o Camilo (CUSC), Sa˜o Paulo, Brazil Received 14 October 2011; received in revised form 10 March 2012; accepted 12 March 2012 KEYWORDS Parkinson’s disease; Gait Index; Cognition; Biomechanics; Physical therapy Summary Three-dimensional gait analysis (3DGA) is an important element in the quantitative evaluation of gait in subjects with Parkinson’s disease (PD). Indexes, such as the Gait Deviation Index (GDI), have recently been proposed as a summary measure of gait. The aim of the present study was to investigate the effectiveness of the GDI and spatiotemporal variables in the quan- tification of changes in gait during a dual-task (DT) exercise. Fourteen patients with idiopathic PD and nine healthy subjects (CG) participated in the study. All subjects walked under two conditions: free walking and DT walking. The GDI was computed from the 3DGA data. The results show gait impairment during DT, a significant difference between groups regarding GDI and an interaction effect involving the group, side and task factors. The CG and PDG were different independent of interference and side, but interference was only different for the PDG group. The results also demonstrate that the GDI should be an appropriate outcome measure for the evaluation of the effects of DT on patients with Parkinson’s disease. ª 2012 Elsevier Ltd. All rights reserved. * Corresponding author. Universidade Nove de Julho, UNINOVE, Av. Francisco Matarazzo, 612, A ´ gua Branca, 05001-100 Sa˜o Paulo, Brazil. Tel.: þ55 (11) 3665 9325. E-mail address: paulolucareli@uninove.br (P.R.G. Lucareli). + MODEL Please cite this article in press as: Speciali, D.S., et al., Use of the Gait Deviation Index and spatiotemporal variables for the assessment of dual task interference paradigm, Journal of Bodywork & Movement Therapies (2012), doi:10.1016/j.jbmt.2012.03.001 1360-8592/$ - see front matter ª 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.jbmt.2012.03.001 Available online at www.sciencedirect.com journal homepage: www.elsevier.com/jbmt Journal of Bodywork & Movement Therapies (2012) xx,1e9