A cross-sectional study to assess dual-task interference in postural control in people with lower limb amputation.

Background: In people with lower limb amputation (LLA), the loss of limb structures and peripheral motor and sensory systems result in significant mobility challenges, including impaired postural stability.

Objective: The primary objective of this study was to evaluate the dual-task interference (DTI) on postural control and dual-task interference on cognition during static and dynamic balance in people with LLA and compare the same with controls. The secondary objective of this study was to compare the DTI on postural control and DTI on cognition between LLA of different etiology.

Design: Cross-sectional observational study METHODOLOGY: Fifteen people with unilateral LLA and 15 age and gender-matched controls participated in this study at a tertiary care hospital. The outcome measures used were anterior-posterior stability index (APSI), medial-lateral stability index, and overall stability index (OSI) using Biodex Balance System and a cognitive task parameter, namely correct response rate in serial seven subtraction test. Quantitative variables were compared using a Wilcoxon rank-sum test. Spearman's correlation test was used to establish the correlation between the DTI on cognition and the DTI on postural control.

Results: DTI on postural control during static balance was significantly higher in people with LLA than controls (APSI, OSI). No significant difference was observed in DTI on postural control during dynamic balance. No significant difference was observed in DTI on cognition during static and dynamic balance. A significant negative correlation was observed between DTI on cognition and DTI on postural control (APSI) during static balance people with LLA.

Significance: In people with unilateral LLA, the addition of a cognitive task results in significant deterioration of sagittal plane postural control during static balance but not during dynamic balance due to the over-allocation of resources to a cognitive task.