The Effects of Augmented Reality Visual Cues on Turning in Place in Parkinson's Disease Patients With Freezing of Gait

Abstract

Background: Turning in place is particularly bothersome for patients with Parkinson's disease (PD) experiencing freezing of gait (FOG). Cues designed to enforce goal-directed turning are not yet available. Objectives: Assess whether augmented reality (AR) visual cues improve FOG and turning in place in PD patients with FOG. Methods: Sixteen PD patients with FOG performed a series of 180 • turns under an experimental condition with AR visual cues displayed through a HoloLens and two control conditions (one consisting of auditory cues and one without any cues). FOG episodes were annotated by two independent raters from video recordings. Motion data were measured with 17 inertial measurement units for calculating axial kinematics, scaling, and timing of turning. Results: AR visual cues did not reduce the percent time frozen (p = 0.73) or the number (p = 0.73) and duration (p = 0.78) of FOG episodes compared to the control condition without cues. All FOG parameters were higher with AR visual cues than with auditory cues [percent time frozen (p = 0.01), number (p = 0.02), and duration (p = 0.007) of FOG episodes]. The AR visual cues did reduce the peak angular velocity (visual vs. uncued p = 0.03; visual vs. auditory p = 0.02) and step height (visual vs. uncued p = 0.02; visual vs. auditory p = 0.007), and increased the step height coefficient of variation (visual vs. uncued p = 0.04; visual vs. auditory p = 0.01) and time to maximum head-pelvis separation (visual vs. uncued p = 0.02; visual vs. auditory p = 0.005), compared to both control conditions. Conclusions: The AR visual cues in this study did not reduce FOG, and worsened some measures of axial kinematics, and turn scaling and timing. Stimulating goal-directed turning might, by itself, be insufficient to reduce FOG and improve turning performance. Trial Registration: This study was registered in the Dutch trial registry (NTR6409; 2017-02-16).

Holocue: A Wearable Holographic Cueing Application for Alleviating Freezing of Gait in Parkinson's Disease

“…Participants indeed stated that they had trouble with stepping onto or over cues (see Supplementary Material 2 ), for which unnatural head postures were required to see the nearby holographic cues during the targeted step or crossing maneuver. As such, the small mixed-reality field of view thus limited the action relevance of holographic cues and their immediate effect on FOG, which could also have played a role in previous studies showing null effects with related technology and cueing applications ( 19 , 27 , 30 , 31 ). Interestingly, mixed-reality field of view and wearer comfort have allegedly already strongly improved with the latest generation of mixed-reality headsets, such as HoloLens 2 and Magic Leap 1 and 2.…”

“…Previous studies in controlled lab environments examining the effect of holographic visual cues on FOG showed no demonstrable effect during walking (19,30) or turning (31), which may be attributable to the overall low occurrence of FOG observed in the lab (30). Another limitation in previous research on wearable cueing devices is the absence of a control condition without the wearable (19,30,31), leaving the influence of potential unfamiliarity effects of the wearable (e.g., distraction) on FOG unexplored. Mixed-reality headsets are currently quite heavy (e.g., HoloLens 1 weighs 579 g) and uncomfortable (19) and can therefore divert attention.…”

“…The aim of this study is to explore the potential immediate effect of Holocue's on-demand patient-tailored holographic visual cues, as a means to alleviate FOG in free-living environments in PD patients suffering from "ON state" FOG, for whom currently no evidence-based medication or stimulation is available to alleviate FOG (3,29). Previous studies in controlled lab environments examining the effect of holographic visual cues on FOG showed no demonstrable effect during walking (19,30) or turning (31), which may be attributable to the overall low occurrence of FOG observed in the lab (30). Another limitation in previous research on wearable cueing devices is the absence of a control condition without the wearable (19,30,31), leaving the influence of potential unfamiliarity effects of the wearable (e.g., distraction) on FOG unexplored.…”

Effectiveness of Augmented Reality for Lower Limb Rehabilitation: A Systematic Review

“…Palacios-Navarro et al [ 38 ] aimed to determine the effects of an AR-based mole stomping game on the gait function of Parkinson patients, and they also found that the 30-minute game with 4 sessions per week for 5 weeks is effective to improve the completion time score and walk function. However, some conflicting and equivocal results have been proposed by Janssen et al [ 39 ]. In their study, the acute effects of AR-based visual cues on freezing of gait and turning in place of Parkinson patients were assessed, and the results showed that the AR-based visual cues did not reduce freezing of gait and even worsen some gait kinematics and turning in place.…”

The Microsoft HoloLens 2 Provides Accurate Measures of Gait, Turning, and Functional Mobility in Healthy Adults

“…The HL system has been examined as a rehabilitation tool in the clinical arena and utilized to provide digital content to individuals with PD, with the aim of improving spatio-temporal measures of gait, turning, and improvements in balance stability [44][45][46][47].…”