Responses to Stochastic Electrical Vestibular Stimulation During Walking

- 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.