Table 1.
Methodology of the VR studies in PD-FOG
| Author, year |
Participants (age and gender data if stated in the article) |
Country where study was conducted |
Hoehn and Yahr stage (range) (mean/standard deviation if range is not stated) |
UPDRS- Part III score |
FOG categorization before the VR paradigm |
Medications | Dopaminergic state during VR paradigm |
VR paradigm methodology ** |
FOG definition in the VR paradigm |
|---|---|---|---|---|---|---|---|---|---|
| Naismith and Lewis, 2010 [10] | 12 PD • Age 65.6/4.7 |
Australia | 1-4 | 37.8 | Not done | Three not medicated, 4 on levodopa monotherapy (1 had bilateral STN DBS), 2 on levodopa with entacapone, 2 on dopamine agonist monotherapy, 1 on levodopa and dopamine agonist therapy | ON | First person perspective of a three-dimensional virtual environment with hands used to control stepping movements. Environment constructed using asoftware development kit by ID Software (Mesquite, TX, USA) | Responses falling 2 SD outside of the mean step latency |
| Shine et al., 2011 [11] | 1 PD-FOG • 61 year-old male |
Australia | Not stated | OFF: 33.0 ON: 23.0 |
FOG-Q | Levodopa, catechol-O-methyltransferase inhibitor, dopamine agonist | OFF and ON (14 days apart) | The task from Naismith and Lewis, 2010 with foot pedals. | Footsteps falling 1.5 SD outside the mean step latency |
| Shine et al., 2013 [12] | 24 PD-FOG • Age 69.5/7.3 14 PD-nFOG • Age 64.0/8.2 |
Australia | PD-FOG: 2.5–3 PD-nFOG: 1-2 |
PD-FOG: 39.8 PD-nFOG: 23.5 |
FOG-Q-item 3, Timed Up-and-Go | Two not medicated, 6 on dopamine agonist monotherapy, 30 on levodopa: 14 on additional entacapone, 20 on additional dopamine agonist, 2 on apomorphine infusion, 1 on apomorphine infusion and amantadine, 6 s/p DBS | OFF | The task from Shine et al., 2011 | Epochs greater than twice the modal footstep latency |
| Shine et al., 2013 [13] | 14PD-FOG • Age 63.2/7.0 15 PD-nFOG • Age 63.4/8.3 |
Australia | PD-FOG: 2.2/0.3 PD-nFOG: 1.9/0.5 |
PD-FOG: 31.9 PD-nFOG: 29.1 |
FOG-Q- item 3, MDS-UPDRS III-item 14, Timed Up-and-Go | Not stated | OFF | The task from Shine et al., 2011 | Epochs greater than twice the modal footstep latency |
| Shine et al., 2013 [14] | 18 PD-FOG • Age 66.8/8.2 |
Australia | 2-4 | 39.2 | FOG-Q-item 3, Timed Up-and-Go | Not stated | OFF | The task from Shine et al., 2011 | Epochs greater than twice the modal footstep latency |
| Shine et al., 2013 [15] | 10 PD-FOG • Age 67.1/6.4 10 PD-nFOG • Age 66.3/6.2 |
Australia | PD-FOG: 2.3/0.9 PD-nFOG: 2.7/0.6 |
PD-FOG: OFF 32.5 ON 26.2 PD-nFOG: OFF 23.9 ON 19.7 |
FOG-Q-item 3, Timed Up-and-Go | Not stated | OFF and ON (average of four weeks apart) | The task from Shine et al., 2011 | Epochs greater than twice the modal footstep latency |
| Matar et al., 2013 [16] | 36 PD-FOG • Age 66.2/9.6 37 PD-nFOG • Age 63.2/8.8 18 HC • Age 69.3/7.6 |
Australia | 1-4 | PD-FOG: 29.4 PD-nFOG: 21.0 |
FOG-Q-item3 | Not stated | ON | The task from Shine et al., 2011 | Not defined |
| Gilat et al., 2013 [17] | 17 PD-FOG • Age 66.1/6.5 11 PD-nFOG • Age 63.4/8.1 |
Australia | PD-FOG: 1.9/0.4 PD-nFOG: 1.8/0.6 |
PD-FOG: OFF 32.4 ON 24.2 PD-nFOG: OFF 22.2 ON 12.5 |
FOG-Q-item 3, clinical observation | Not stated | OFF and ON (average of nine weeks apart) | The task from Shine et al., 2011 with only wide doorways as environmental cue, and only direct “Walk” and “Stop” cues | Epochs greater than twice the modal footstep latency |
| Matar et al., 2014 [18] | 27 PD-FOG • Age 65.8/1.8 14 PD-nFOG • Age 62.6/7.9 |
Australia | PD-FOG: 2.3/0.9 (mean/standard error) PD-nFOG: 1.8/0.1 (mean/standard error) |
PD-FOG: 34.7 PD-nFOG: 24.1 |
FOG-Q-item 3, standardized gait assessment incorporating rapid turns | Not stated | OFF and ON (at least two weeks apart) | The task from Shine et al., 2011 with only direct “Walk” and “Stop” cues | Not defined |
| Gilat et al., 2015 [19] | 17 PD-FOG • Age 67.4/6.2 10 PD-nFOG • Age 64.8/4.1 |
Australia | PD-FOG: 2-3, PD-nFOG: 2-2.5 |
PD-FOG: 37.2 PD-nFOG: 30.1 |
FOG-Q-item 3 | Not stated | OFF | Task from Shine et al., 2011 including 90° turns without any environmental cues and with only direct “Walk” and “Stop”cues | Epochs greater than twice the modal footstep latency |
| Georgiades et al., 2016 [20] | 31 PD-FOG • Age 66.2/6.5 • 24 male/7 female 23 PD-nFOG • Age 64.7/6.8 • 18 male/5 male 15 HC • Age 64.8/5.1 • 6 male/9 female |
USA | PD-FOG: 2.2/0.4 PD-nFOG: 2.0/0.5 |
*PD-FOG: 25.8 PD-nFOG: 22.8 |
FOG-Q-item 3, MDS-UPDRS III-item 10 and 11 | Not stated | OFF | The task from Shine et al., 2011 | Epochs greater than twice the modal footstep latency |
| Ehgoetz Martens et al., 2018 [6] | 41 PD-FOG • Age 67.5/6.4 • 32 male/9 female 20 included in the fMRI analysis • Age 66.5/5.3 • 17 male/3 female |
Australia | Not stated | *All participant s: 33.9 Participants included in the fMRI analysis: 34.2 | FOG-Q-item 3, clinical observation | Not stated | OFF | The task from Shine et al., 2011 | Epochs greater than twice the modal footstep latency |
PD: Parkinson’s disease patients, PD-FOG: Parkinson’s disease patients with freezing of gait, PD-nFOG: Parkinson’s disease patients without freezing of gait, HC: healthy controls, fMRI: functional magnetic resonance imaging, UPDRS: Unified Parkinson’s Disease Rating Scale, FOG: freezing of gait, MDS-UPDRS: Movement Disorders- Unified Parkinson’s Disease Rating Scale, VR: virtual reality, FOG-Q: Freezing of gait questionnaire, NFOG-Q: New freezing of gait questionnaire, SD: standard deviation. Age is reported as mean/standard deviation. UPDRS scores are reported as mean.
*
MDS-UPDRS part III was used
**
All studies used the environment constructed by a software development kit by ID Software (Mesquite, TX, USA) for the VR paradigm.