Examining Movement Specific Reinvestment and the Effects of Dual-task Training and Analogy learning on Walking by Older Fallers in Hong Kong: A Pilot Randomized Controlled Trial
Dr Wong, Wai Lung Thomson (Principal investigator)
Professor Masters Richard Stanley William (Co-Investigator)
Older Adults in Hong Kong, Elderly Falls, Movement Specific Reinvestment, Dual-task Training, Analogy Learning
Block Grant Earmarked for Research (104)
HKU Project Code
Seed Fund for Basic Research
Walking is the most common fall-related activity in older adults (Lai, Low, Wong, Wong, & Chan, 2009). Consequently, walking ability of older adults may be adversely affected after a fall incident (Hauer, Specht, Schuler, Bartsch, & Oster, 2002). Walking at a comfortable pace usually involves minimum attention despite the movement complexity (Sparrow, Bradshaw, Lamoureux, & Tirosh, 2002). Healthy adults are mostly capable of walking and executing a wide range of movement skills automatically (i.e., with little conscious effort), but may use conscious motor processing to assure the effectiveness of their movements when encountering difficulties. Conscious motor processing utilizes knowledge and strategies that are explicitly processed in working memory (Baddeley, 1994). The process of switching from automatic motor processing to conscious explicit motor processing has been called ‘reinvestment’ (Masters, 1992; Masters & Maxwell, 2008). Masters (1992) defined reinvestment as "an inward focus of attention in which an attempt is made to perform the skill by consciously processing explicit knowledge of how it works" (p. 343). Subsequently, the Movement Specific Reinvestment Scale (MSRS) was developed to measure an individual’s propensity for ‘reinvestment’ (Masters, Eves & Maxwell, 2005). The scale assesses two separate factors (i) movement self-consciousness and (ii) conscious motor processing. Higher scores represent a greater propensity for conscious monitoring and control of movements. Recently, Masters, Ling, Maxwell, and Wong (in preparation) developed and validated the MSRS in older Chinese adults in Hong Kong (MSRS-C: MSRS Chinese version). Previous extensive evidence suggests that people who are highly motivated to make successful movements or who are self-conscious about the way in which they move demonstrate an increased propensity for reinvestment in different disease groups, such as Stroke and Parkinson diseases (Masters, Polman, & Hammond, 1993; Orrell, Masters, & Eves, 2002; Fasotti & Kovacs, 1995; Stapleton, Asburn, & Stack, 2001; Grattan, Ghahramanlou, Aronoff, Wozniak, Kittner, & Price, 2001; Masters, Pall, MacMahon, & Eves, 2007). Wong, Masters, Maxwell, and Abernethy (2008) discovered that older fallers have a higher propensity to consciously process their movements than age-matched non-fallers. Besides, it was found that, in a logistic regression analyze, the conscious motor processing subscale of the MSRS-C can successfully predict previous fall status of the older adults, implying that reinvestment may be a risk factor for older falls. Conscious control of movements by internal focus of attention may lead to movement disruption, possibly by constraining or interfering with automatic motor control mechanisms (Wulf, Shea, & Park, 2001; McNevin, Shea, & Wulf, 2003). Focusing internally may not only have the effect of disrupting natural motor coordination but may also reduce the allocation of or interfere with the attention to negotiating the environment, further increasing the risk of falling of the older adults. These difficulties are likely to be exacerbated in demanding situations in which attentional capacity is further overloaded. Wong, Masters, Maxwell, and Abernethy (2009) found that older fallers have a higher tendency to divide their attention between the external environment and internal mechanisms of their movements while older non-fallers focus externally during walking. Efforts to attend both internal and external information by the older fallers may overload resources in the working memory (Baddeley, 1994), which may in return interfere with movement control. However, no research has investigated a potential intervention to reduce the propensity for reinvestment in older fallers. It will be highly influential if methods to reduce the predisposition to reinvest of older fallers during gait re-education by physiotherapists can be developed. One of the main aims of physiotherapy in geriatric rehabilitation is to improve, restore, or maintain the functional outcome of ambulation (Sullivan & Markos, 2000). Physiotherapist’s rehabilitation programs have been found to be effective in improving balance and motor abilities of older fallers (Steadman, Donaldson, & Kalra, 2003). Gait re-education is one of the main components of the physiotherapist’s training regime. As older adults with a high propensity to reinvest may have a higher risk of falling (Wong et al., 2008), the reduction of reinvestment during physiotherapy training in gait re-education may lead to improved rehabilitation outcomes. Methods to minimize the predisposition to reinvest during gait re-education can be derived from previous literature in implicit motor learning. Motor skills can be acquired implicitly and explicitly during learning (Berry & Broadbent, 1988). Implicit learning has been defined as a process in which knowledge is acquired largely independently of awareness of both the process and the products of acquisition (Sternberg, 1999). Conversely, explicit learning requires consciousness and learning of rules (Sternberg, 1999). Considerable evidence has accumulated to suggest that different methods of implicit learning can be used, which may reduce the propensity for reinvestment. A demanding cognitive dual task can be added concurrently during learning (dual-task training), since Masters (1992) suggested that the accumulation of accessible task relevant knowledge can be prevented by overloading working memory with another cognitive task, which promotes an implicit mode of learning. Silsupadol, Shumway-Cook, Lugade, van Donkelaar, Chou, Mayr, and Woollacott (2009) recommended that 4-weeks (3 sessions of 45 minutes training per week) dual-task walking and balance training by concurrent cognitive dual-tasks demonstrated a significant dual-task training effect. Moreover, Liao and Masters (2001) conducted a study of analogy learning, which showed that analogy learning shares the characteristics of implicit learning in acquiring a forehand topspin shot when playing table tennis. The skills were learned by using a metaphor (Masters, 2000) that provides a verbal representation of the task to be performed but with little verbal information or rules. Therefore, analogy may be useful to facilitate implicit learning in gait re-education. Advantages of implicit motor learning may be gained from learning with a concurrent cognitive secondary task (dual-task training) and analogy learning. In addition, those implicit learning strategies may reduce the propensity for reinvestment of older fallers by means of distracting them from reinvestment (e.g., learning with a concurrent cognitive dual-task) or by minimizing explicit rules accumulation during skill learning or relearning (analogy learning). Rehabilitation, by means of different forms of implicit motor learning, may be considered in daily rehabilitation, perhaps by modifying instructions to patients during rehabilitation and applying gait re-education with a concurrent cognitive secondary task or by analogy learning. For example, patients can be asked to walk with a counting backward task (dual-task training) or walk with their legs swing like a pendulum (analogy learning) during gait re-education. Objectives: The primary objective of the current proposed pilot study is to investigate the effects of single-task training, dual-task training and analogy learning during gait rehabilitation on reinvestment propensity and dual-task walking ability of older fallers in Hong Kong. We would also like to develop the culturally appropriate analogy in gait re-education.