2025 Posters & Presentations

Gait differences in overground walking between real and immersive virtual environments - Abh Homagain (2025)

Abhishesh Homagain Poster

Homagain, A., & Ehgoetz Martens, K. (2025). Gait differences in overground walking between real and immersive virtual environments.

Abstract

Purpose

Increasing evidence has shown the benefit of virtual reality (VR) based gait training and physical rehabilitation for various movement related disorders. Usage of non-immersive VR and treadmills in past research has shown conflicting results with work that uses immersive VR and overground walking. Important aspects of gait such as variability are also scarce in research comparing gait in VR and non-VR environments. This study aimed to investigate the influence of an immersive VR environment on overground gait whilst also measuring the impact of VR on gait variability.

Results

Greater cadence, step length, and velocity were observed in the real environment compared to the virtual environment. Greater double stance time (%), step time, and step width variability (%CV) were observed in the virtual environment. Moderate-to-strong correlations were observed in gait parameters between the environments.

Conclusion

The immersive VR environment showed a slower more cautious gait compared to the real environment. However, overall gait behavior is still maintained in the virtual environment, such that fast walks in the real environment continue to be fast in the virtual environment and vice versa. The absence of visual feedback of limbs could contribute to these results and future work should investigate how incorporating feedback may influence these differences in gait.

Enhancing Patient-and Clinician-Reported Outcome Measures for Freezing of Gait in Parkinson's Disease through Patient Engagement

Abstract

Freezing of gait (FOG) in Parkinson’s disease (PD) continues to be a major challenge for people with PD, caregivers, clinicians, and researchers alike. Limited treatment options reflect a paucity of research demonstrating efficacious therapeutics partly due to the lack of standardized Clinician Reported Outcomes (ClinRO) or Patient Reported Outcomes (PRO) to appropriately quantify changes in FOG severity. To meet this need, a working group of the International Consortium of FOG (ICFOG) was formed to develop a FOG ClinRO and PRO. Subsequently, a Patient Advisory Committee (PAC)  was assembled to provide consultation and feedback on the ClinRO and PRO. 
Here we describe the development process and patient engagement that shaped the development of these new tools that are currently being validated. The initial ClinRO was composed of 6 timed gait tests and the initial PRO had 8 items evaluating the impact of FOG on physical, social and emotional contexts in daily life. Based on the experiential knowledge from the PAC, the ClinRO expanded to 8 tests and the PRO expanded to 16 items. Additionally, the PAC revised the PRO Likert scale, reworded the FOG lay definition, and provided several examples to include in each PRO item that related to daily situations that FOG makes more difficult. The PAC also revised the dual-task procedure in the ClinRO, as well as specified guarding instructions, and adjusted the grading scale for scoring FOG severity. The validation testing is now in process, recruiting 105 individuals with PD and FOG and 35  individuals with PD without FOG across 7 international sites (sponsored by Michael J Fox Foundation).
In conclusion, multi-stakeholder perspectives, particularly persons with lived experiences, provided several insights into how to define FOG, how it meaningfully impacts daily life, how to maximally provoke FOG in clinical settings, and how to measure its severity, while also highlighting the importance of the caregiver perspective. These insights have been instrumental in guiding this ongoing ClinRO and PRO development research.

Ehgoetz Martens, K., Horak, F., Howe, E., Ginis, P., Gilat, M., Mancini, M., Mammen, J., Adams, J., McKay, L., Nonnekes, J., Almeida, Q., LeWitt, P., Fietzek, U., Herman, T., Muller, M., Peterson, D., Plotnik, M., Potter-Nerger, M., Revuelta, G., … Hausdorff, J. (n.d.). Enhancing Patient-and Clinician-Reported Outcome Measures for Freezing of Gait in Parkinson's Disease through Patient Engagement.

Characterizing Performance of Different Subtypes of Freezers on the New Clinician Reported Outcome for Freezing of Gait (FOG)

Abstract

There is accumulating evidence that Parkinson’s Disease with Freezing of Gait (PD+FoG) is linked to autonomic nervous system (ANS) dysfunction. Vagally mediated HRV, a marker of ANS, serves as an indicator of frontal brain control over cognition and emotion. In healthy adults, higher HRV is correlated to improved attention and executive function whereas low HRV is associated with a rigid, less adaptable ANS and poorer cognitive function. Meanwhile, reduced resting HRV in Freezers during the OFF state can predict FoG presence during clinical assessment, but its associations with cognition are unknown. As FoG severity increases, set-shifting function becomes more impaired. Given FoG’s link to set-shifting deficits, we aim to assess vagally mediated HRV’s relationship with cognitive performance in PD+FoG. Heart rate (HR)  was recorded during a 1-min stance in 12 freezers in their OFF-state (Bittium Faros™ 360). Cognitive assessments (MoCA and Trail-Making Test) were completed after intake of their dopaminergic medication.

HRV was calculated using time-domain measures:

  • Root Mean Square of successive differences (RMSSD): rapid, beat-to-beat changes primarily indicating parasympathetic activity.
  • Standard Deviation of Normal-to-Normal (NN) intervals (SDNN): overall HRV influenced by sympathetic and parasympathetic activity.
No significant cognitive–HRV link has been found in Freezers to date, despite prior associations in healthy individuals. This is possibly due: Protocol: 1-minute of standing HR may not be sufficient to represent HRV dynamics and therefore the protocol will be extended to 4 minutes. Cognitive Profile: While the TMT-B primarily assesses set-shifting within executive function, inhibitory control, measured by a Stroop Test, might relate more strongly to HRV5. Sample Size: Ongoing recruitment aims to overcome sample size limitations that may be limiting detection of subtle HRV-cognition relationships. Reduced HRV predicts FoG presence but may not reflect executive dysfunction severity in Freezers. This nuanced role of HRV in PD warrants further exploration, particularly given HRVs established influence across different cognitive domains in broader populations.

Pinto, Arthur, et al. Investigating the Association Between Heart Rate Variability and Cognitive Flexibility. ICFOG, 2025.