Brook Galna

Background and aims: The use of wearable technology enables precise measurement of turning movements during walking. Cross-sectional studies have shown that a decline in turning can be detected in the early clinical and even preclinical stages of Parkinson's disease (PD). This prospective longitudinal study aims to quantify the change in turning performance among older adults and determine if turning performance predicts future PD diagnosis.

Methods: A total of 933 participants (mean age = 66.1 years) from the TREND study were included for this analysis over five 2-year intervals, with the development of clinically evident PD tracked. Participants walked up and down a 20-meter hallway for one minute at their preferred pace, wearing a digital device on their lower back to capture turning. Longitudinal trajectories of turning performance were modelled using random effects linear mixed models to establish the interval between initial turning changes and PD diagnosis. Cox regression was used to assess whether initial turning measures could predict the time to PD onset, controlling for age and sex.

Results: Of all participants, 23 were diagnosed with idiopathic PD, an average of 5.3 years after baseline assessment. Slower peak angular velocity at baseline was associated with a higher hazard of PD diagnosis, with deviations from controls emerging approximately 8.7 years before diagnosis (Figure 1). Other parameters showed no prediction value of PD diagnosis.
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Conclusion: Peak angular velocity during turning appears to be a promising marker for identifying and tracking motor progression in the pre-diagnostic phase of PD.

Disclosure: nothing to disclose.

Background: We investigated how commonly telehealth is used by people with MS, their satisfaction with telehealth during the COVID-19 period, and recommendations to improve their experiences with telehealth.

Methods: In October-December 2020 we surveyed Australians with MS. We collected demographic, disease- related and social health determinant data, data on telehealth use and experiences during the COVID-19 pandemic, and recommendations on telehealth improvements. We conducted univariate analysis to compare factors associated with telehealth use versus no use, established frequencies of experiences and suggestions for improvement, and conducted thematic analysis on free-text suggestions for improvement.

Results: Of the 1485 participants, 69.7% had used telehealth since the start of the COVID-19 pandemic, there were small differences in demographical, disease and social health determinants to explain telehealth use.Most participants who used telehealth had good or very good experiences (74.3%). Most common
suggestions to improve telehealth experiences was “guidance on preparing for telehealth sessions” (n = 545, 60%). Themes of expansion in telehealth availability and expansion to physical test and physical treatments were wanted by participants.

Conclusion: Persons with MS in Australia commonly used telehealth during the COVID-19 pandemic and were generally satisfied with their experiences. Implementing the suggested improvements will further optimise the use of telehealth.

Background:
We investigated how commonly telehealth is used by people with MS, their satisfaction with telehealth during the COVID-19 period, and recommendations to improve their experiences with telehealth.

Methods:
In October-December 2020 we surveyed Australians with MS. We collected demographic, disease-related and social health determinant data, data on telehealth use and experiences during the COVID-19 pandemic, and recommendations on telehealth improvements. We conducted univariate analysis to compare factors associated with telehealth use versus no use, established frequencies of experiences and suggestions for improvement, and conducted thematic analysis on free-text suggestions for improvement.

Results:
Of the 1485 participants, 69.7% had used telehealth since the start of the COVID-19 pandemic, there were small differences in demographical, disease and social health determinants to explain telehealth use . Most participants who used telehealth had good or very good experiences (74.3%). Most common suggestions to improve telehealth experiences was “guidance on preparing for telehealth sessions” (n = 545, 60%). Themes of expansion in telehealth availability and expansion to physical tests and physical treatments were wanted by participants.

Conclusion:
Persons with MS in Australia commonly used telehealth during the COVID-19 pandemic and were generally satisfied with their experiences. Implementing the suggested improvements will further optimise the use of telehealth.

Wearable technology allows an in-depth analysis of gait behaviour in free-living environments. This investigation aimed to use Alzheimer's disease as an example to apply the time series analysis technique of Statistical Parametric Mapping (SPM) to create daily gait profiles and test if they differed from cognitively intact controls. A framework of macro (habitual walking behaviours) and micro characteristics (spatiotemporal gait variables) characteristics were calculated on an hourly basis. SPM showed that select micro gait characteristics differed from controls at specific hours of the day. Therefore, the application of SPM may provide a more in-depth reflection of activity and gait time-dependent fluctuations than commonly used whole day values. Considering macro and micro gait hour-by- hour may have applications towards disease management, personalized care, monitoring medication and targeted interventions for people with a range of neurodegenerative diseases.

[Poster] BACKGROUND AND AIM: The ability to safely negotiate obstacles is important for independent mobility. Appropriate processing of visual information helps to identify and distinguish environmental obstacles and their location. Visual function is compromised in people with Parkinson’s disease (PD) with respect to appropriate observation of the environment and is linked to poorer attention[1] and impaired contrast sensitivity[2]. Together they may contribute to falls in PD during challenging tasks such as obstacle crossing[3]. The aim of this study was to determine the effect of obstacle contrast on visual behaviour and whether this was altered in PD. METHODS: Seventeen mild-to-moderate PD fallers (x̅[SD]age:71.1[8.2]y, 10♂) and 18 older adult non-fallers(x̅[SD]age:64.4[7.0]y, 9♂) participated. Participants began the walking trials with their eyes closed and when prompted opened their eyes and walked to the end of a 10-metre walkway. An obstacle of high or low contrast (HxWxD 15cmx60cmx2cm) was placed half way down the walkway and the presentation order was counterbalanced. Visual behaviour was monitored using a mobile eye-tracker (Dikablis) and contextual outcomes were extracted from the approach phase (Approach time[s], movement latency[s], time spent looking at the obstacle[%], time spent looking at the ground preceding the obstacle[%] and time spent looking at the ground past the obstacle[%]). Contrast sensitivity was measured binocularly (Mars CS chart). Group medians were used to complete non-parametric comparisons between groups and obstacle conditions. RESULTS: Contrast sensitivity was significantly reduced in PD (x̅[SD]:1.51[0.16] vs. 1.64[0.07],p=.006). There were no group differences in visual behaviour when negotiating the high contrast obstacle (p=.126), movement latency (p=.858) and the time spent looking at the ground past the obstacle (p=.143). There was a trend for PD to spend longer looking at the obstacle but this was not significant (p=.067). In the low contrast obstacle condition, PD took significantly longer during their approach to the obstacle (4.2s vs. 3.1s, p<.001) and spent longer looking at the obstacle as a proportion of the approach phase (51.5% vs. 22.7%, p=.025) compared to the older adults who spent proportionally more time looking at the ground beyond the obstacle (75.0% vs. 29%,p=.007). CONCLUSIONS: The clarity of obstacles influences visual behaviour. Our findings suggest that increased contrast improves visual behaviour in PD so that it becomes similar to older adults. When obstacle contrast was low, participants with PD prolonged their visual attention to the obstacle to gather sufficient information regarding the obstacle proximity and dimensions limiting their capacity to scan for future obstacles. Future studies will explore the manipulation of contrast within natural environments where the presence and location of trip hazards such as obstacles are not known. REFERENCES: [1]Galna 2012 BrainRes 1473 35-43 [2]Hwang 2013 J Neurosci 33 14989-14997 [3]Gazibara 2014 Geriatric Nursing 35 364-369

[Poster] INTRODUCTION: People with Parkinson’s disease (PD) commonly report visual problems, such as impaired eye movements [1,2]. Visual dysfunction can impact safe walking capability, particularly if task-relevant visual information is not gathered when walking. Limited research exists that has explored the location of gaze fixations when walking [3], which are important for appropriate visual input during locomotion. AIM: This study aimed to examine the task-relevance of fixation locations during various walking tasks in PD. METHOD: 40 control (68.8[8.8]y, 20m) and 38 PD participants (69.6[8.2]y, 23m) ; one with no additional stimuli and another with additional stimuli (either with visual cues or a high contrast obstacle to transverse) whilst wearing a mobile eye-tracking device. All walks were repeated under dual task (Wechsler digit span) conditions. The location of fixations was manually classified, coded as relevant/irrelevant to the task, and analysed using negative binomial regression. RESULTS: During single task walking, people with PD made significantly more fixations (p=.032) with the difference resulting from more irrelevant fixations (p=.014). Both groups had similar number and relevance of fixations with visual cues (p=.359). However, people with PD required more task-relevant fixations (i.e. looked at the obstacle/floor more) to complete both single task (p=.007) and dual task (p=.007) obstacle crossing trials. CONCLUSION: People with PD make more irrelevant fixations than controls when walking, which may contribute to impaired mobility and falls. High contrast obstacles and visual cues attract visual attention to relevant areas when walking, which may reduce falls risk. An increased frequency of task relevant fixations during both single and dual task obstacle negotiation indicated that home based modifications such as improving the saliency of trip hazards may redirect visual exploration even when attentional demands are high. Further work is required to examine fixations locations when walking in real-world environments which contain more visual distractors. REFERENCES: [1] Chan et al., (2005). Neuropsychologia, 43(5), pp.784-796. [2] Amador et al., (2006). Neuropsychologia, 44(8), pp.1475-1482. [3] Stuart et al., (2016). Neurosci Biobehav Rev, 62, pp.76-88.

[Poster] BACKGROUND AND AIM: Gait impairments are frequent among older adults and associated with fall risk. Intervention programmes aiming to reduce fall risk (e.g. balance exercise programs) usually focus on single risk factors (i.e. either motor or cognitive performance). The effects of interventions on free-living walking activity are still not clear and need to be explored. Recently, the V-TIME study showed that a six week multimodal intervention programme of treadmill training combined with a virtual reality component (TTVR) lowered the incidence of falls more than an intensity-matched intervention with treadmill training (TT) only [1]. The aim of this exploratory analysis was to examine the hypothesis that a lower fall risk due to the TTVR intervention would be mediated by change in volume, pattern and variability (macro gait outcomes) of free living walking activity. METHODS: 165 older adults (age: 74±7 years) including: 72 elderly fallers (EF), 24 people with mild cognitive impairment (MCI) and 69 people with Parkinson's disease (PD), who had fallen twice or more in the previous 6 months were assessed. Participants were randomly assigned to TT or TTVR interventions and tested at baseline and after the intervention (1 week, 1 month and 6 months) [1]. For each assessment free-living data were recorded for 7 days with an accelerometer (Axivity AX3) placed on the lower back. Macro gait outcomes representing the volume (% walking time, number of bouts per day, number of steps, mean bout length), pattern (alpha), and variability of free-living walking activity were extracted in MATLAB® (R2012a) [2]. General linear models were used to examine the effect of Group (EF vs PD vs MCI), Time and Intervention on macro gait, controlling for age and sex. RESULTS: Macro gait outcomes did not changed over time (main effect for Time p > 0.05). In addition, there were no significant Group x Time or Intervention x Time interactions. This suggests the lack of change was consistent between groups and intervention type. We repeated the analysis including different thresholds of bout length (bouts over 10 seconds and 60 seconds) with similar results. Significant group effects (EF vs PD vs MCI) showed that PD had more variable bout lengths compared to EF and MCI (p ≤ 0.016). CONCLUSIONS: This exploratory work showed that despite reducing the incidence of falls, a 6 week treadmill training intervention (with or without VR augmentation) did not change macro gait outcomes (volume, pattern and variability) in older adult fallers who managed to sustain free-living walking activity while reducing fall risk. Reduction in falls rate due to treadmill training does not seem to be mediated by a change in macro gait outcomes of free-living walking activity. REFERENCES: [1]Mirelman A et al, Lancet, 2016; 388(10050):1170-82 [2]Lord S et al, J Neurol., 2013; 260(12):2964-72