SAFE-PD - Stepping to Avoid Fall Events in Parkinson’s disease

INTERVENTION: Participants allocated to the intervention group will receive volitional and reactive step training. Volitional step training will involve playing home‐based exergames for 80+ minutes per week for 12 weeks. The training involves a custom‐built software, operating on a supplied personal computer and stepping mat. Stepping games will be used to train balance and step reaction time, as well as executive functions. A research assistant will visit each participant’s home to install the system and instruct how to use the equipment. Participants will also receive a follow‐up home visit in the following week to ensure safe use and progression of training. The training will be recommended to be split between 3 or 4 sessions per week and will be monitored via data transfer to a web application. Participants who do not engage in the minimum weekly training dose (80 minutes) for two consecutive weeks will be contacted by telephone to encourage adherence and also address any barriers to participation. Intensity and complexity of training will be progressed as performance improves by increasing the level of difficulty of the games. Additional visits and telephone support will be provided for those participants experiencing difficulties. Reactive step training sessions will be undertaken monthly starting week 4. Participants will visit NeuRA to undertake three individual sessions (one per month, 120 minutes in total) with each session focusing on balance recovery progressively from 1) slips, 2) trips and 3) mix of trips and slips. The order of the first two session (trips or slips) will be randomized. A novel trip‐ and slip‐perturbation system built on a 10‐m walkway consisting of 50cm x 50cm wooden decking tiles will be used. Participants will be secured with a ceiling‐mounted full body harness to avoid any contact with the ground. Participants will practise recovering their balance to trip and slip events. Gait speed during this training will be progressed from 50 to 100% of usual speed using music or metronome with beat corresponding to target cadence. A slip is induced by a movable tile on two hidden low‐friction rails with linear bearings that result in a slide of 10‐70cm upon foot contact. A trip is induced using a 7‐14cm height tripping board that flips up from the walkway at mid‐swing using a foot detection sensor. An exercise physiologist and an assistant will supervise each reactive step training session, ensure participants safety, adherence and individualize the training protocol. The tripping board and the slipping tile are undetectable and can be moved to various locations along the walkway so that predictive adaptation (e.g. changing gait with prediction) will be minimized and reactive stepping responses can be specifically trained. CONDITION: Falls Parkinson's disease PRIMARY OUTCOME: Perturbation‐induced falls incidence will be assessed on the slip and trip walkway (Okubo et al., 2018). The choice stepping reaction time test standard version (Lord et al., J Gerontol A Biol Sci Med Sci, 2001) SECONDARY OUTCOME: Anteroposterior sway to maximal balance range ratio will be assessed with eyes open and on the floor (Menant et al., Mov Disord, 2011). A sway meter that consists of a 40cm‐long rod with a vertically mounted pen at its end will be attached at waist level. Arm movements during the slip and trip trials will be assessed using the vicon 3D motion analysis system with the full‐body 38‐marker model.. ; ; The choice stepping reaction time inhibitory version The coordinated stability test ; (Lord et al., J Am Geriatr Soc, 1996), The Falls Efficacy Scale‐International ; (Schoene et al., Age Ageing, 2013) The Trail‐making Test (Wechsler, 1981) will be assessed using an iPad app NeuRA Trails. INCLUSION CRITERIA: • Have been diagnosed with Parkinson’s disease (according to UK PD Society Brain Bank ; Extrapolated centre of mass (Hof et al., 2005) during the slip and trip trials (baseline and post‐intervention) will be assessed using the vicon 3D motion analysis system with the full‐body 38‐marker model.. Ground reaction forces during the slip and trip trials will be measured using AMTI and Kistler force plates. Haemodynamic changes in the brain, Prefrontal Cortex (Maidan et al., 2016) will be measured with functional near‐infrared spectroscopy (fNIRS) while participants perform the volitional stepping and gait adaptability tests. Haemodynamic changes in the brain, Primary Motor Cortex (Maidan et al., 2016) will be measured with functional near‐infrared spectroscopy (fNIRS) while participants perform the volitional stepping and gait adaptability tests. Haemodynamic changes in the brain, Supplementary Motor Area (Maidan et al., 2016) will be measured with functional near‐infrared spectroscopy (fNIRS) while participants perform the volitional stepping and gait adaptability tests. Knee extension strength will be measured using a digital dynamometer attached to the participant's leg using a webbing strap and affixed to a crossbar position behind the participant (Lord et al., J Am Geriatr Soc 1994). Margin of stability (Hof et al., 2005) during the slip and trip trials (baseline and post‐intervention) will be assessed using the vicon 3D motion analysis system with the full‐body 38‐marker model.. Postural sway on foam (Lord et al., J Am Geriatr Soc 1994). A sway meter that consists of a 40cm‐long rod with a vertically mounted pen at its end will be attached at waist level. Range of trunk sway during the slip and trip trials will be assessed using the vicon 3D motion analysis system with the full‐body 38‐marker model.. Real life fall incidence will be ascertained using monthly falls calendars or email (Lamb et al., J Am Geriatr Soc, 2005). Step length during the slip and trip trials will be assessed using the vicon 3D motion analysis system with the full‐body 38‐marker model.. ; (Yardley et al., 2005) The gait adaptability test using projected obstacles and targets appearing at short notice on a walkway (Caetano et al., Gait Posture, 2016). The simple reaction time test (Lord et al., J Am Geriatr Soc 1994). A hand‐held electronic timer and a light as the stimulus and a switch will be used. The Stroop Stepping Test Criteria); • Being stable on anti‐Parkinsonian medications for >= 1 month • Living independently in the community or retirement village; • Able to communicate in English language