Multi-Parameter Infrared Thermographic Assessment of Human Facial Responses to Nominal 8 Hz Acoustic Stimulation

This record contains the full manuscript entitled "Multi-Parameter Infrared Thermographic Assessment of Human Facial Responses to Nominal 8 Hz Acoustic Stimulation." The study presents a pilot experimental investigation evaluating whether a nominally generated 8 Hz acoustic stimulus is associated with measurable changes in human facial thermal dynamics using infrared thermography. A custom-developed software platform (Thermal Dynamics Pro v1.0) was used to perform automated multi-parameter analysis of thermal video recordings, integrating thermal statistics, spectral analysis (FFT and PSD), texture analysis (GLCM, LBP, Fractal Dimension), Structural Similarity Index (SSIM), Optical Flow motion analysis, Sliding Window Principal Component Analysis (PCA), bootstrap confidence intervals, and permutation testing. The experimental protocol consisted of three phases: Baseline: 1 minute without stimulation. Exposure: 2 minutes during nominal 8 Hz acoustic stimulation. Recovery: 2 minutes recorded approximately 30 minutes after exposure. The analysis identified several consistent image-derived changes during exposure, including: Slight increase in mean thermal intensity (+0.09%). More than 60% reduction in the coefficient of variation (CV), indicating increased thermal stability. Emergence of a dominant thermal oscillation near 0.060 Hz during exposure. Progressive increase in Structural Similarity Index (SSIM). Distinct phase separation using Sliding Window PCA. Persistent separation of the Recovery phase from Baseline, consistent with a prolonged hysteresis-like response. The observed oscillatory component falls within the frequency range commonly associated with low-frequency vasomotor oscillations reported in thermographic literature. However, the present work does not establish a biological mechanism or causal relationship. Instead, it demonstrates reproducible image-derived changes that justify further physiological investigation. Because this is a single-subject pilot study, all statistical analyses should be interpreted as exploratory rather than confirmatory. The findings are intended to generate hypotheses for future controlled studies involving larger cohorts, sham stimulation, calibrated acoustic measurements, and direct physiological monitoring. This record includes the complete manuscript describing the experimental design, analytical methodology, statistical framework, results, discussion, limitations, and recommendations for future research. Software used: Thermal Dynamics Pro v1.0 Programming environment: Python (Streamlit, OpenCV, SciPy, Scikit-image, Plotly) Author: Eng.