C.S.Y. Choi1, C.M. Capio2,1, T.W.L. Wong3,1, R.S.W. Masters4,1
1The University of Hong Kong, School of Public Health, Hong Kong, Hong Kong, 2The Education University of Hong Kong, Centre for Educational and Developmental Sciences, New Territories, Hong Kong, 3The Hong Kong Polytechnic University, Rehabilitation Sciences Department, Kowloon, Hong Kong, 4University of Waikato, Te Huataki Waiora School of Health, Hamilton, New Zealand
Background: Older adults have been known to have declining working memory capacity (WMC), which represents the ability to utilise stored information to perform goal-directed tasks without being disrupted by distractions. WMC decline could impact motor performance under cognitively demanding situations, such as when multi-tasking or being under pressure. In particular, older adults may face impaired motor performance when they have a high propensity for movement-specific reinvestment – i.e., the allocation of attention and application of explicit knowledge to consciously control and monitor movement performance. This needs verification, so that appropriate screening and intervention may mitigate the risks of movement failure among older adults.
Purpose: This study aimed to investigate the relationships of WMC and individual propensity for movement-specific reinvestment with the performance of a fine motor skill in older adults.
Methods: Each participant provided written informed consent prior to a 1-hour assessment session. The participants consisted of healthy older adults (N = 81, 72.15 ± 5.68 years old) with no history of neurological conditions, learning disabilities, psychiatric or attention deficit disorders. They scored at least 24/30 in the Mini-Mental State Examination-Chinese (Chiu et al., 1994).
The computerised Counting Span task (Case et al., 1982) was used to measure WMC; the Movement Specific Reinvestment Scale-Chinese (Wong et al., 2009) was used to measure the propensity for movement-specific reinvestment. Using a dual-task paradigm, each participant performed two subtests (i.e., simple and complex tasks) of the Purdue Pegboard test (Tiffin, 1960), in single-task (ST) and dual-task (DT) conditions. Median split on WMC and reinvestment data categorised participants into low/high WMC and low/high reinvestor groups. Motor performances were analysed using mixed-model analysis of variance, followed by Bonferroni-corrected post-hoc tests.
The computerised Counting Span task (Case et al., 1982) was used to measure WMC; the Movement Specific Reinvestment Scale-Chinese (Wong et al., 2009) was used to measure the propensity for movement-specific reinvestment. Using a dual-task paradigm, each participant performed two subtests (i.e., simple and complex tasks) of the Purdue Pegboard test (Tiffin, 1960), in single-task (ST) and dual-task (DT) conditions. Median split on WMC and reinvestment data categorised participants into low/high WMC and low/high reinvestor groups. Motor performances were analysed using mixed-model analysis of variance, followed by Bonferroni-corrected post-hoc tests.
Results: Motor performance was poorer in DT compared to ST conditions in simple (F(1,74) = 16.07, p < .001, ηp2 = .18) and complex (F(1,74) = 48.41, p < .001, ηp2 = .40) tasks across all participants. In the simple task, participants who have both low WMC and high reinvestment propensity performed significantly poorer in both ST and DT conditions, compared to the other participants (p’s < .05). In the complex task, participants who have both low WMC and high reinvestment propensity performed significantly poorer in both ST and DT conditions (p’s < .05) compared to those with low WMC and low reinvestment propensity.
Conclusion(s): In older adults, dual-tasking appeared to lead to a deterioration in motor performance. Those with low WMC were found to display poorer fine motor performance compared to those with high WMC, but only when they had a high reinvestment propensity.
Implications: The current findings suggest that individual propensity for reinvestment should also be considered because it could differentiate the motor performance of older adults who have impaired cognitive resources. In practice, the combination of low WMC and high reinvestment propensity in older adults could signal that motor performance might be compromised. Screening the individual reinvestment propensity of older adults who appear to have compromised WMC may inform interventions that could prevent the negative consequences of movement failures (e.g., falls, movement dependence).
Funding, acknowledgements: This was funded in part by the General Research Fund of the Hong Kong Research Grants Council (RGC No. 17603318).
Keywords: Older adults, Working memory capacity, Reinvestment
Topic: Older people
Did this work require ethics approval? Yes
Institution: University of Hong Kong /Hospital Authority Hong Kong West Cluster
Committee: Institutional Review Board
Ethics number: UW 17-228
All authors, affiliations and abstracts have been published as submitted.
