JMIR Publications

ABSTRACT

Background:

Pulse characteristics have long served as biomarkers of physical health. However, the relationship between pulse waveforms and psychological well‑being remains understudied, in part because acquiring high‑quality pulse recordings outside clinical or laboratory environments is both costly and technically challenging.

Objective:

This study aims to fill this gap by utilizing smartphone photoplethysmography to extract fingertip pulse features, thereby allowing remote, real time monitoring of mental health without the need for hospital or laboratory infrastructure. The study also provides the first comprehensive analysis across three domains of digital pulse waveform features, thereby linking digital pulse waveforms to psychological variables.

Methods:

Data were collected from 113 participants using fingertip videos captured by a smartphone application developed by the research team. The structured signal processing pipeline transformed raw video frames into 43 quantitative pulse waveform features, encompassing time domain, frequency domain, and curvature-domain metrics.

Results:

Regression and correlation analyses demonstrated that smartphone derived waveform features reliably predicted psychological states and emotional profiles. Curvature and frequency domain metrics exhibited significant associations with indices of psychological distress, whereas time domain metrics reflected short term emotional variability. No feature group demonstrated a significant relationship with measures of positive mental well being. These associations persisted after adjusting for conventional physiological covariates (blood pressure, sex, and height), highlighting the independent predictive validity of digital pulse waveform metrics.

Conclusions:

These results confirm that smartphone photoplethysmography can reliably capture pulse waveforms and assess psychological health parameters. However, low signal quality in user-operated recordings may limit the method's acceptance. Additionally, since arterial stiffness resulting from chronic psychological stress develops gradually, this technique is expected to be more sensitive in middle-aged and older cohorts.