Data for: Effects of vestibular stimulation on gait stability when walking at different step widths

Read me - Effects of vestibular stimulation on gait stability when walking at different step widths

In this folder you will find the data (folders named Data) and analysis (folder named software) belonging to the manuscript “Effects of vestibular stimulation on gait stability when walking at different step widths”(Magnani et al. 2021). To re-run the analysis, create a folder, and put the file subject_numbers.m, as well as the contents of data.zip and software.zip in that top level folder. Next, navigate to the “software” folder, and run scripts C_main_all_outcomes_paper2 and E_main_stats_paper2.

The following subject numbers were included in the analysis: 4 5 6 8 12 14 16 17 18 19 20 21 22 23 (see also subject_numbers.m, which includes explanation of why some subjects were excluded). We had problems with dust due to reconstruction in nearby labs, so some of the kinematic data was simply not useable.

The scripts were written for data from 12 conditions, being analyzed the conditions numbered 1 2 5 6 7 8 :

Steady state walking under vestibular stimulation (control, EVS)

Steady state walking (control, no-EVS)

Stabilization frame walking under vestibular stimulation (frame, EVS)

Stabilization frame walking (frame, no-EVS)

Narrow-base walking under vestibular stimulation (narrow, EVS)

Narrow-base walking (narrow, no-EVS)

Wide-base walking under vestibular stimulation (wide, EVS)

Wide-base walking (wide, no-EVS)

Stabilization frame ML walking under vestibular stimulation looking to the left side (left_frame, EVS)

Stabilization frame ML (left_frame, no-EVS)

Stabilization frame AP/ML walking under vestibular stimulation looking to the left side (left_frame_AP, EVS)

Stabilization frame AP/ML walking looking to the left side (left_frame_AP, no- EVS)

Below we describe the most important contents:

Folders

Content

Data.zip

Data of all participants. Each subject has a separate subfolder.

These subfolders contain 1 excel files (used to match the conditions with the corresponding data files), as well as the pointer file corresponding to the pointer used during the measurement, needed to digitize the bony landmarks and the muscles names.

Each subject subfolder has the following subfolders:

OPTO

Optotrak and force plate files

.ndf (motion capture data)

.afp (force plate data)

.hs calculated heelstrikes, as done in B_main_heelstrikes.m

EMG

EMG data stored at .mat and .bin files (not used in current manuscript)

Software

=VU 3D model=

Contains general functions for the analysis of our kinematic and force plate data.

Functions

Functions written specifically for the analysis of this dataset, including some unused functions

Local Dynamic Stability

Functions written specifically for the local dynamic stability.

(Bruijn 2017).

Results

Contains storage of some intermediate results.

The figures folder includes all

A_main_check_kin

Scripy used to check the kinematics

B_main_heelstrikes

Script to identify gait events were identified from center of pressure data (Roerdink et al. 2008), results are stored in .hs files in subject data folder

C_main_all_outcomes_paper2

Script to calculate all outcomes

E_main_stats_paper2

Scripts of the statistical analysis, which also creates the figure files as seen in the manuscript.

figure1.eps

Mean values of stride width and stride width variability (represents figure 2 from paper)

figure2.eps

Mean values of step time and step time variability (represents figure 3 from paper)

figure3.eps

Mean values and standard deviation of local divergence exponent and center of mass variability (represents figure 4 from paper)

figure4.eps

Mean values of R2 (percentage of explained variance in foot placement) and the residual variance in foot placement (represents figure 5 from paper)

ANOVA.csv

ANOVA results for each variable

Posthocs_condition.csv

Posthoc results of the condition effect

Posthocs_interaction.csv

Posthoc results of the interaction effect

Settings_rina.xls

The setting of pointer, markers, and segments. 

Stimulationfig.pdf

Figure of the electrical stimulation signal (corresponds to figure 1 from paper)

Svs_5mA_0-25Hz_2000Hz_120s.txt

File containing the random electrical vestibular stimulation from the zero-mean low-pass filtered (25 Hz cutoff, zero lag, fourth-order Butterworth) white noise, the peak amplitude of 5mA, root mean square (RMS) of ~ 1.2 mA, range frequency between 0 to 25Hz, and intensity of 2000Hz for 120 seconds of duration.

Svs_5mA_0-25Hz_2000Hz_480s.txt

File containing the electrical vestibular stimulation from the zero-mean low-pass filtered (25 Hz cutoff, zero lag, fourth-order Butterworth) white noise, the peak amplitude of 5mA, root mean square (RMS) of ~ 1.2 mA, range frequency between 0 to 25Hz, and intensity of 2000Hz for 480 seconds of duration.

Bruijn SM (2017) Local Dynamic Stability. https://zenodo.org/record/1181937#.Y1Fj7i0w354

Magnani RM, van Dieen JH, Bruijn SM (2021) Effects of vestibular stimulation on gait stability when walking at different step widths. bioRxiv 459650:. https://doi.org/https://doi.org/10.1101/2021.09.09.459650

Roerdink M, Coolen BH, Clairbois BHE, et al (2008) Online gait event detection using a large force platform embedded in a treadmill. J Biomech 41:2628–32. https://doi.org/10.1016/j.jbiomech.2008.06.023