Nesibe Cakmak


Background: Dual-task training (DTT), utilized in motor-motor (M-DTT) and/or cognitive-motor (C-DTT) forms, has been identified as an effective and safe approach to improve balance in people with Parkinson’s disease (pwPD). Studies which investigate the superiority of the effectiveness of M-DTT and CDTT interventions, however, are lacking. To determine superiority there is a need to design a randomized control trial (RCT). This PhD study, therefore, had two aims. Firstly, to design home-based M-DTT and C-DTT interventions for improving upright balance in people with mild to moderate PD. Secondly to test the feasibility and acceptability of the interventions, outcome measures, and the design of an anticipated future RCT to investigate the superiority of the effectiveness of these DTT interventions on balance. Methods: Three linked work packages (WP) were implemented: WP1- Scoping review to inform the proposed feasibility RCT in terms of the content and combination of DTT interventions and outcome measures used to treat balance impairments in pwPD. WP2- A pre-trial stage qualitative study was held using semi-structured individual interviews and focus groups with six pwPD, two supporters of pwPD, and two physiotherapists to inform intervention design and balance assessment methods of the feasibility RCT. Transcribed data were analysed using the framework analysis method. WP3- A feasibility RCT of six people with mild to moderate PD tested the acceptability and the feasibility of the home-based, non-supervised M-DTT and C-DTT interventions and the trial design. Interventions were delivered as 30- minute-sessions, three times/week over 6 weeks. Qualitative research (semi-structured interviews post-intervention) was embedded into the feasibility trial. Feasibility outcomes were attendance and adherence to the intervention and safety (by recording of adverse events and number of falls/near falls). Acceptability of interventions were assessed with twice-weekly 5-point Likert scale, self-scored enjoyment and difficulty, and interviews. Acceptability of overall trial design was assessed with interviews. Signals of effectiveness of each intervention on balance function were assessed using the MiniBESTest and body sway data. Results: WP1 – The scoping review showed that the delivery form of DTT, task combinations and task types within DTT, training characteristics and the balance assessment methods used for evaluation varied. Only one qualitative study explored participants’ perceptions regarding DTT interventions, confirming the need for further qualitative studies. One study, which had methodological limitations, explored the superiority of M- DTT and C-DTT in improving balance in pwPD. Therefore, there is a clear need for further studies to determine any difference between M-DTT and C-DTT with regard to balance outcomes in these individuals. WP2 – The qualitative findings showed that the acceptability of DTT is influenced by factors such as enjoyment and level of task challenge. Home setting was considered acceptable if the right number of sessions and session durations were provided. Despite the inconvenience of travel, pwPD found face-to-face assessments in a research clinic acceptable. WP3 – The feasibility study results indicate that both M-DTT and C-DTT are safe. Attendance and adherence rates were high. Both interventions were acceptable, although improvements are required in the content and technical aspects of the training programs/session movies. The assessments were generally well-received and acceptable. No statistical analysis for balance-related data was conducted due to the small sample size and imbalance between groups. On an individual level, both M-DTT and C-DTT demonstrated promising effects on the MiniBESTest and standing balance. While M-DTT led to improved MiniBESTest scores, neither group exhibited a clinically meaningful change in MiniBESTest outcomes. Conclusions: The findings from each work-package provide important information to inform a future powered RCT investigating superiority of two DTT interventions.

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