Teo, Wei Peng

Current literature lacks consolidated evidence for the impact of stimulation parameters on the effects of transcranial direct current stimulation (tDCS) in enhancing upper limb motor learning. Hence, we aim to synthesise available methodologies and results to guide future research on the usage of tDCS on upper limb motor learning, specifically in older adults and Parkinson’s disease (PD). Thirty-two studies (Healthy older adults, N = 526, M = 67.25, SD = 4.30 years; PD, N = 216, M = 66.62, SD = 6.25 years) were included in the meta-analysis. All included studies consisted of active and sham protocols. Random effect meta-analyses were conducted for (i) subjects (healthy older adults and PD); (ii) intensity (1.0, 1.5, 2 mA); (iii) electrode montage (unilateral anodal, bilateral anodal, unilateral cathodal); (iv) stimulation site (cerebellum, frontal, motor, premotor, SMA, somatosensory); (v) protocol (online, offline). Significant tDCS effect on motor learning was reported for both populations, intensity 1.0 and 2.0 mA, unilateral anodal and cathodal stimulation, stimulation site of the motor and premotor cortex, and both online and offline protocols. Regression showed no significant relationship between tDCS effects and density. The efficacy of tDCS is also not affected by the number of sessions. However, studies that reported only single session tDCS found significant negative association between duration with motor learning outcomes. Our findings suggest that different stimulation parameters enhanced upper limb motor learning in older adults and PD. Future research should combine tDCS with neuroimaging techniques to help with optimisation of the stimulation parameters, considering the type of task and population.

Background: Aging is becoming a major global challenge. Compared with younger adults, the older population has greater health needs but faces inadequate access to appropriate, affordable, and high-quality health care. Telehealth can remove geographic and time boundaries, as well as enabling socially isolated and physically homebound people to access a wider range of care options. The impacts of different telehealth interventions in terms of their effectiveness, cost, and acceptability in aging care are still unclear. Objective: This scoping review of systematic reviews aimed to provide an overview of the domains of telehealth implemented in aging care; synthesize evidence of telehealth’s feasibility, effectiveness, cost benefits, and acceptability in the context of aging care; identify gaps in the literature; and determine the priorities for future research. Methods: Guided by the methodological framework of the Joanna Briggs Institute, we reviewed systematic reviews concerning all types of telehealth interventions involving direct communication between older users and health care providers. In total, 5 major electronic databases, PubMed, Embase (Ovid), Cochrane Library, CINAHL, and PsycINFO (EBSCO), were searched on September 16, 2021, and an updated search was performed on April 28, 2022, across the same databases as well as the first 10 pages of the Google search. Results: A total of 29 systematic reviews, including 1 post hoc subanalysis of a previously published large Cochrane systematic review with meta-analysis, were included. Telehealth has been adopted in various domains in aging care, such as cardiovascular diseases, mental health, cognitive impairment, prefrailty and frailty, chronic diseases, and oral health, and it seems to be a promising, feasible, effective, cost-effective, and acceptable alternative to usual care in selected domains. However, it should be noted that the generalizability of the results might be limited, and further studies with larger sample sizes, more rigorous designs, adequate reporting, and more consistently defined outcomes and methodologies are needed. The factors affecting telehealth use among older adults have been categorized into individual, interpersonal, technological, system, and policy levels, which could help direct collaborative efforts toward improving the security, accessibility, and affordability of telehealth as well as better prepare the older population for digital inclusion. Conclusions: Although telehealth remains in its infancy and there is a lack of high-quality studies to rigorously prove the feasibility, effectiveness, cost benefit, and acceptability of telehealth, mounting evidence has indicated that it could play a promising complementary role in the care of the aging population.

Studies examining dual-task gait (DTG) have used varying conditions such as overground or treadmill walking, however it is not known whether brain activation patterns differ during these conditions. Therefore, this study compared oxyhaemoglobin (O2Hb) responses of the prefrontal cortex (PFC) during overground and treadmill walking. A total of 30 participants (14M/16F) were recruited in a randomized crossover study comparing overground and treadmill walking under single- and dual-task (STG and DTG) conditions. The DTG consisted of performing walking and cognitive (serial subtraction by 7’s) tasks concurrently. A portable 24-channel functional near-infrared spectroscopy system was placed over the PFC, corresponding the left and right dorsolateral PFC and frontopolar cortices (DLPFC and FPC) during overground and treadmill STG and DTG. Results showed a reduction in gait speed during DTG compared to STG on overground but not treadmill walking, while cognitive performance was maintained during DTG on both overground and treadmill walking. A reduction in O2Hb was seen in the FPC during DTG compared to a cognitive task only, and on the treadmill compared to overground walking. Increased activation was seen in the left and right DLPFC during DTG but did not differ between treadmill and overground walking. Our results support the concept of improved gait efficiency during treadmill walking, indicated by the lack of change in STG and DTG performance and concomitant with a reduction in FPC activation. These findings suggest different neural strategies underpinning treadmill and overground walking, which should be considered when designing gait assessment and rehabilitation interventions.

Parkinson’s disease (PD) is characterized by motor and cognitive deficits that negatively impact on activities of daily living. While dopaminergic medications are used to attenuate motor symptoms, adjuvant therapies such as acoustic-based non-pharmacological interventions are used as a complement to standard drug treatments. At present, preliminary studies of acoustic-based interventions such as rhythmic-auditory stimulation (RAS) and vibroacoustic therapy (VAT) suggest two competing hypotheses: (1) RAS may recruit alternative motor networks that may bypass faulty spatiotemporal motor networks of movement in PD; or (2) the use of RAS enhances BG function through entrainment of beta oscillatory activities. In this mini review article, we discuss the mechanisms underlying the role of acoustic-based interventions and how it may serve to improve motor deficits such as gait impairments and tremors. We further provide suggestions for future work that may use a combination of RAS, VAT, and physical therapy to improve motor function in PD.