Dual-Task Cost Effects on Static Posture Control Parameters and Choice Reaction Time in Individuals With and Without Intellectual Disabilities.

This study aimed to evaluate the effect of age and intellectual disability (ID) on postural balance parameters, dual-task cost (DTC), and choice reaction time (CRT). Fifty-eight individuals with ID and 55 peers without ID performed a postural stance balance task under two conditions: a single task with eyes open and dual task involving an additional cognitive task (light sequence). Four postural balance parameters (total displacement, total sway area, mediolateral, and anteroposterior dispersion), cost of the dual task ([DTC%] = [(single-task performance - dual-task performance)/single-task performance] × 100), and CRT were recorded, calculated, and analyzed. All postural control parameters reflected poorerperformance during the dual-task condition, nevertheless, DTC was significantly higher only in individuals with ID and only for the total sway area, F(1, 111) = 5.039, p = .027, and mediolateral dispersion, F(1, 111) = 6.576, p = .012. CRT was longer in individuals with ID compared with the individuals without ID, F(1, 111) = 94.979, p ≤ .001, while age did not have a significant effect on the DTC nor on the CRT, F(1, 111) = 0.074, p = .786. In conclusion, an additional cognitive task during the postural balance task had a detrimental effect on various postural balance parameters, leading to increased DTC in terms of total sway area, mediolateral dispersion, and prolonged CRT in individuals with ID.