Gait performance during simple cognitive dual task in patients with Parkinson's disease

Abstract

Objective: To examine gait performance in people with Parkinson’s disease (PD) under simple and complex cognitive dual task conditions.

Background: Patients with PD were found to elicit difficulty in walking while performing a dual cognitive task, e.g. calculation. Calculation is relatively complex because it activates working memory. We therefore examine whether gait performance will be affected while performing a simple cognitive task of naming a picture which requires object identification.

Methods: Twenty two patients with PD (mean age 61.3 years) and 22 healthy control subjects (mean age 60.5 years) were compared when they walked: 1) at a self-selected natural speed (Walk0); 2) while naming the picture on a screen (Walkpicture); 3)while saying out loudly the serial subtractions of three, starting from 100 (Walkcalculation). Velocity, stride length and cadence were recorded by GAITRite.

Results: During Walk0, PD patients had significantly reduced velocity (by 15.2%) and stride length (by 11.0%) when compared with control subjects (p50.000). When dual tasks were added, both groups significantly decreased their speed compared with Walk0 (p50.000). PD patients decreased by 17.4% and 25.8%, and control subjects by 6.4% and 15.8% respectively in Walkpicture and Walcalculation. For the stride length, a significant groups x task interaction was found under dual task condition (p50.004), implying that PD patients and control subjects had different magnitude of reduction. PD patients decreased by 13.5% and 15.1% while control subjects only decreased by 4.8% and 7.4% for Walkpicture and Walcalculation respectively. For cadence, both groups had small but significant reduction during dual task conditions when compared with Walk0.

Conclusions: The addition of a concurrent task influenced gait performance in control subjects and patients with PD. However, PD patients had more deterioration in stride length than control subjects under dual task conditions. The similar gait deterioration in PD patients during simple dual task of naming a picture and complex task of calculation suggests that even a small distraction of attention could have affected their walking performance. This finding further confirms that walking is not automatic in PD patients.