The effect of different cognitive domains on dual-task cost of gait in cognitive impaired elderly

Objective: For persons with dementia performance of a cognitive task during a motor task is associated with impaired gait stability and increased fall risk. While gait with and without dual tasking has often been the object studies, few studies have investigated the relationship between different cognitive domains and gait stability. Methods: Seventeen elderly with impaired cognition, who underwent neuropsychological examination, participated (77.2±6.7 years). Four cognitive domains were assessed: 1) attention and psychomotor speed; 2) executive functioning; 3) memory; 4) visuospatial and constructive abilities (fourteen cognitive variables). To assess gait, participants walked for three minutes at self-selected pace, once under single (ST) and once under dual task (DT) condition (letterfluency). While walking, trunk accelerations were registered from which parameters were calculated that quantify gait stability. To examine differences in gait parameters between ST and DT conditions, t-tests were applied. Dual-task cost (DTC) was calculated for all gait parameters as:(DT-ST) /ST). Partial least squares regression analysis was applied to examine the effects of neuropsychological tests, representing the cognitive domains, on DTC. Significant components and contributions of cognitive variables were examined by means of their loads. Results: A significant effect of dual tasking was observed for all gait variables: walking speed, stride time variability and the accelerometer data that quantify trunk variability. PLS analyses revealed a combination of 4 components to account for the variance, of DTC with R-values ranging between 0.67-0.87. Analysis of the weight revealed not only an association with gait deficits and executive function, but also with memory and visual spatial and constructive abilities. Conclusion: More insight in the relation between different cognitive functions with motor function might be of importance for the early diagnosis of dementia or mild cognitive impairments, since a decline in gait control and dual tasking even occurs in preclinical stages before cognitive decline occurs