DOI: 10.17605/osf.io/v6uh5
title: Responses to Stochastic Electrical Vestibular Stimulation During Walking

description: - Participants: 
 Sixteen healthy participants (7 male, 9 female, Age: 23.5 ± 3.4 years, height: 1.71 ± 0.07 m, weight: 64.5 ± 13.2 kg).

- Electrical vestibular stimulation (EVS):
 Sampling rate: 1000Hz;
 Bipolar configuration;
 Zero-mean stochastic EVS (bandwidth: 0-25 Hz, amplitude: ± 5.0 mA, root mean square of 1.35 mA).

- Bipolar surface electromyography (EMG)
 Sampling rate: 1000 Hz (downsampled from 2048 Hz);
 Recorded from paraspinal muscles at eight vertebral levels (C7,T3, T5, T7, T9, T12, L2, L4) bilaterally. 

- Ground reaction force
 Sampling rate: 1000 Hz

- Kinematic
 Sampling rate: 50 Hz;
 Full body kinematic of a13-segments model including Calf left, Calf right, Foot left, Foot right, Head, Lower arm left, Lower arm right, Pelvis, Thigh left, Thigh right, Thorax, Upper arm left, Upper arm right (Kingma et al., 1996).

- Conditions
 Walking on the dual-belt treadmill at 2.8 km/h with a cadence of 78 steps/min for 8 min. 
 Conditions were defined by the presence of EVS (EVS and no-EVS), by the step width (preferred step width: PSW and narrow step width: NSW) and by head orientation (facing forward: HF and facing leftward: HL). 
 Trial 1 EVS, HF, PSW
 Trial 2 EVS, HL, PSW
 Trial 3 No EVS, HF, PSW
 Trial 4 No EVS, HL, PSW
 Trial 5 EVS, HF, NSW
 Trial 6 No EVS, HF, NSW

Data structure:
- Folder: EMG_GVS_GRF
 data.gvs -- EVS signal in mA (n x 1 vector)
 data.F -- combined GRF signals in N (n x 3 matrix)
 data.F (:,1) -- GRFx 
 data.F (:,2) -- GRFy
 data.F (:,3) -- GRFz 
 data.fs -- Sampling rate of signals in Hz
 data.t -- Time in seconds (n x 1 vector)
 data.event.lhs -- gait events, left heel strikes (m x 1 vector)
 data.event.rhs -- gait events, right heel strikes (m x 1 vector)
 data.event.lto -- gait events, left toe offs (m x 1 vector)
 data.event.rto -- gait events, right toe offs (m x 1 vector)
 data.emg -- EMG signals without filtering in mA (n x 32 matrix)
 data.emg(:,1:2) -- C7 Left 
 data.emg(:,3:4) -- T3 Left 
 data.emg(:,5:6) -- T5 Left 
 data.emg(:,7:8) -- T7 Left 
 data.emg(:,9:10) -- T9 Left 
 data.emg(:,11:12) -- T12 Left 
 data.emg(:,13:14) -- L2 Left 
 data.emg(:,15:16) -- L4 Left 
 data.emg(:,17:18) -- C7 Right
 data.emg(:,19:20) -- T3 Right 
 data.emg(:,21:22) -- T5 Right 
 data.emg(:,23:24) -- T7 Right 
 data.emg(:,25:26) -- T9 Right 
 data.emg(:,27:28) -- T12 Right 
 data.emg(:,29:30) -- L2 Right 
 data.emg(:,31:32) -- L4 Right 

- Folder: trajectory
 DBforces -- GRF, in N
 nor_F -- GRF normalized to the body weight, in BW%
 fs_analog -- sampling rate of GRF, in Hz
 fsopto -- sampling rate of the traj file, in Hz
 traj -- trajectories of all segments (13 segments, see traj.segment.name), in metres (m)
 
For more information about methods: 
- Li, Y. C., Bruijn, S. M., Lemaire, K. K., Brumagne, S., & van Dieën, J. H. (2024). Vertebral level specific modulation of paraspinal muscle activity based on vestibular signals during walking. The Journal of physiology, 602(3), 507–525. https://doi.org/10.1113/JP285831

- Li, Y. C., Lemaire, K. K., Bruijn, S. M., Brumagne, S., & van Dieën, J. H. (2025). The effect of head orientation on vestibular signal-based modulation of paraspinal muscle activity during walking. European journal of applied physiology, 125(2), 573–586. https://doi.org/10.1007/s00421-024-05620-1

- Kingma I, de Looze MP, Toussaint HM, Klijnsma HG & Bruijnen TBM (1996). Validation of a full body 3-D dynamic linked segment model. Human Movement Science 15, 833–860.