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Frengopoulos C.1, Payne M.2, Viana R.2, Hunter S.2,3
1Western University, Health & Rehabilitation Science, London, Canada, 2Western University, Schulich School of Medicine & Dentistry, Physical Medicine & Rehabilitaiton, London, Canada, 3University of Western Ontario, Physical Therapy, London, Canada
Background: Balance and walking are complex processes that involve the coordination of motor and sensory systems through higher-order cognitive processes. Lower extremity amputation (LEA) may challenge these processes through the forced learning of new motor patterns for mobility, or through disease processes that result in impaired sensation or cognition. These challenges may impact the acquisition of motor skills required to be independent in daily activities with a prosthesis. It is established that cognition plays a role in functional mobility following LEA. However, cognition, balance and mobility have merely been studied in isolation in this population. To better understand the role of cognition in functional mobility, individuals must be observed performing simultaneous cognitive and motor tasks through use of the dual-task paradigm. The dual-task paradigm is relevant to daily activities as most involve the multi-tasking of cognitive and motor tasks. There is currently no reliable dual-task assessment protocol to evaluate the interaction of cognition and mobility in those with LEA.
Purpose: The objective is to determine the test-retest reliability and minimal detectable change of a dual-task functional mobility assessment protocol for use in the LEA population.
Methods: Cross-sectional study of 39 individuals with below knee amputations (BKA). Of these individuals, 20 have amputations of non-vascular etiology (NV; age=55.8±14.1, 89.5% male, MoCA=26.8±2.0) and 19 have amputations due to dysvascular disease (DV;age=60.2±8.0, 85.0% male, MoCA=26.2±2.2). Individuals were stratified based on etiology as processes associated with dysvascular disease may interact with cognition and impact dual-task performance. Functional mobility was measured using the L Test of functional mobility (L Test). The L Test times an individual as they rise to standing, walk 10 meters in an L-shape, turn 180° and walk back 10 meters in an L-shape, before sitting back down. Dual-task testing paired the L Test with the secondary cognitive task of counting backwards by 3s from a number between 100 and 150. The Montreal Cognitive Assessment (MoCA) was used to evaluate cognition. Test-retest reliability was determined using intra-class correlation coefficient (ICC). Two measures of absolute reliability were also calculated: the standard error of measurement (SEM) and the minimum detectable change (MDC95). Bland and Altman plots were used to measure agreement between initial and retest assessments.
Results: For the NV etiology group, the dual-task L Test had a test-retest reliability value of 0.93 (95% CI, 0.80-0.97); SEM was 1.43 seconds and MDC95 was 3.96 seconds. The values for the DV etiology group were ICC=0.96 (95% CI, 0.87-0.99), with SEM of 2.10 seconds and MDC95 of 5.82 seconds. For both groups, Bland-Altman plots demonstrated agreement between initial and retest assessments.
Conclusion(s): The proposed dual-task functional mobility assessment protocol has demonstrated excellent test-retest reliability in both dysvascular and non-vascular etiology BKA groups. It has also established values for absolute reliability, making novel contributions to the LEA literature.
Implications: This study has created, and established reliability values for, a dual-task functional mobility assessment protocol that can now be used clinically and in research settings to assess the interaction between cognition and functional mobility in the LEA population.
Funding acknowledgements: Faculty of Health Sciences Research Development Fund (SWH)
Frederick Banting and Charles Best Canada Graduate Scholarships - Master's Award (CF)
Frederick Banting and Charles Best Canada Graduate Scholarships - Master's Award (CF)
Topic: Musculoskeletal: peripheral
Ethics approval: This study was approved by Western University Health Science Research Ethics board (HSREB#107472).
All authors, affiliations and abstracts have been published as submitted.
