The dual-task interference, motor and cognitive, during gait in patients with Parkinson s disease.

Abstract

The capacity to perform dual task is highly advantage and it is a condition for a functionally efficient life. Parkinson's disease (PD) patients show more difficulty in performing dual task then healthy individuals, due to the postural instability. While doing dual task, walking and cognitive task, PD patients present lack of automaticity and gait pattern alterations. The most common cognitive task used in experimental settings is the inverse counting or object naming, which presents a motor component, to speak. Few studies measured the performance on the secondary task and used a cognitive task without a motor component. In this context, the main questions driven this study are: how neurologically healthy individuals and PD patients change the spatial and temporal gait parameters facing dual task with different demands? Which one of the secondary task, motor, cognitive or combined, has more influence in the subjects gait parameters? What level of relationship between executive functions, attention and abstraction in the behavioral variables? Therefore, the aims of this study are: a) to identify the gait behavior changes under dual task conditions (motor, cognitive and motor-cognitive); b) to compare the locomotor behavior and the performance on the secondary task between PD patients and neurologically healthy individuals. c) to observe the relationship between behavioral variables and other assessments separately for each group. Thirty idiopathic PD patients, classified in Stages 1 to 3 of the Hoehn & Yahr scale and 30 neurologically healthy individuals (control group, matched by age, gender, and anthropometric features) will participate. Subject will be invited to walk on his self-paced speed a 8m long pathway under the following experimental conditions: a) control = only walk; b) walk and hold a tray; c) walk, hold a tray and to balance a golf ball inside in a hole in the tray center; d) walk, hold a tray and to realize the fifth Stroop test part presented in the tray; and e) walk, hold a tray, to balance a golf ball inside in a hole in the tray center and to realize the fifth Stroop test part presented in the tray. Five trials for each condition, totally randomized, will be performed. PD patients will participate in ON status of medication. The spatial and temporal gait variables, the performance on the Stroop test, the tray inclination and will be compared between groups by means of the analysis of variance with two factors (group and condition) with condition been treated as repeated measure. The relationship between the behavioral variables and other assessment will be observed by means of Pearson correlation test. The 0.05 significance level will be kept in all statistical analysis.