Factors associated with the dual-task cost of walking in people with Parkinson's disease.

BACKGROUND: Walking skills are negatively affected in people with Parkinson's disease (PwPD) when performing dual-tasks. However, the factors that contribute to this negative dual-task cost (DTC) remain unclear. PURPOSE: This study was planned to investigate the factors associated with the DTC of walking in PwPD. METHODS: Seventy-seven PwPD were included. Single task walking speed and dual-task walking speed were assessed with the 10-Meter Walking Test (10MWT). The following tests were used in the assessments: the Unified Parkinson's Disease Rating Scale (UPDRS) for clinical symptoms, the Single Leg Stance Test (SLST) for static balance, the Four-Square Step Test (FSST) for dynamic balance, the Trail Making Test (TMT) for attention, the Symbol Digit Modalities Test (SDMT) for processing speed, the Word List Generation Test (WLGT) for verbal fluency, the Hospital Anxiety and Depression Scale (HADS) for anxiety and depression, the Falls Efficacy Scale-International (FES-I) for fear of falling, the Freezing of Gait Questionnaire (FOGQ) for freezing of gait, and the International Physical Activity Questionnaire (Short Form) (IPAQ-SF) for level of physical activity. RESULTS: Dual-task 10MWT scores of PwPD were significantly worse than single-task 10MWT scores (p < .001). Multiple linear regression analysis revealed that only SDMT (Β = -0.361, p < .001), dual-task 10MWT (Β = 0.294, p = .001), and TMT-B (Β = 0.338, p = .001) determined the DTC in PwPD. CONCLUSION: Dual-tasking has a negative impact on walking in PwPD and this DTC is associated with processing speed, dual-task walking speed and attention.