Evaluating a Mat-Based Biometric Vibration System for Sleep and Daily Recovery

Eyes-closed 15-minute, supine resting EEG using a 24-channel Smarting Mobi system. Preprocessing: 0.5-30 Hz band-pass, ocular SSP, ±100 µV artifact rejection, common-average reference; clean data segmented into 10-s epochs. Outcome is band power in Theta (4-8 Hz), Alpha (8-13 Hz), Beta (13-30 Hz), averaged across all electrodes and epochs (units: power; may be log-transformed for analysis). Higher values indicate stronger oscillatory activity in each band. Primary analysis compares Post-Baseline change between groups.

From the same 15-minute, eyes-closed, supine EEG. Frequency-domain Granger causality computed per 10-s epoch; spectra averaged within Theta (4-8 Hz), Alpha (8-13 Hz), Beta (13-30 Hz). Connectivity summarized across all electrodes via: (a) Global directed strength (mean of all non-diagonal influences; unitless; higher = stronger overall directed connectivity); (b) Nodal inflow and outflow (sum of incoming vs. outgoing influences for each electrode; unitless; higher = stronger received/sent influence); and (c) Pairwise directed influence (value for each electrode pair; unitless). Primary analysis compares Post-Baseline change between groups, with band-specific follow-ups.

Heart rate variability measured during a 15-minute, eyes-closed, supine rest in the lab. Inter-beat intervals captured with Optimal HRV; processed in Kubios (artifact correction; 4 Hz resampling; files with >5% corrected beats excluded; spectral estimates with 300-s windows, 50% overlap). Outcomes reported as:

• RMSSD (ms): Root mean square of successive differences. Higher = greater parasympathetic (vagal) activity.
• HF power (0.15-0.40 Hz, ms²): High-frequency power. Higher = greater parasympathetic activity.

Primary analysis compares change (Post - Baseline) between groups for each metric; an exploratory composite (mean of RMSSD and HF z-scores) may be reported to summarize parasympathetic tone.

RMSSD and HF recorded (i) during the 15-min home session (vibration vs quiet rest), (ii) 15 min before bedtime, and (iii) 15 min after waking. Outcomes are trajectories and group differences over time (linear mixed-effects). Benefit onset (threshold) will be explored via segmented regression/GAM change-point. Operational definition (pre-specified exploratory): first of two consecutive session-day recordings where RMSSD exceeds each participant's Baseline median by ≥0.10 log-units (~10% increase), sustained thereafter.

Pittsburgh Sleep Quality Index (0-21). Higher scores = worse sleep quality. Outcome is change in global score; report also % with PSQI >5 (poor sleep), if applicable.

Perceived Stress Questionnaire total (0-30). Higher scores = more perceived stress. Outcome is change in total score.

Six-item state anxiety scale (range 6-24). Higher scores = greater current anxiety. Outcome is change in total score.

BRUMS subscales scored 0-16 each. Higher = more of the construct (Tension, Fatigue); higher Vigor = more energy. Outcomes are changes in each subscale.

Trail Making Test Part A and Part B completion times (seconds) nd error counts for each part. Errors include sequencing mistakes. Lower times and fewer errors indicate better performance. Primary metric: Change in TMT-B completion time and B-A (set-shifting cost) from Baseline to Post between groups, considering the amount of errors.

Valence and arousal rated 1-9 (single-item pictorial scales). Higher valence = more pleasant; higher arousal = more activated. Outcomes: pre-session levels and pre-session to morning change.

Session completion rate (% of prescribed sessions), missed-session streaks, and proportion of analyzable HRV/EEG files. Descriptive stats; between-group comparisons by t-test or Wilcoxon as appropriate.