Validating Lyfas as a reliable mental health screening and monitoring instrument: a step towards mobile health application during COVID-19 Pandemic

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Subhagata Chattopadhyay Rupam Das


COVID-19 has disturbed mental health to a great extent. Lockdowns, re-infections in fully vaccinated people, frequent mutations of the virus, working from home, shutting of school colleges, contradictory information flying in the air, and so on are some serious predisposing factors in deteriorating the mental health. The Indian Govt. has granted the telemedicine model of healthcare in the country. Mobile health (mHealth) adds to it effectively and Lyfas is such a smartphone-based instrument that works using the principle of arterial photoplethysmography and photochromatography. It captures short (120 sec) heart rate variability (HRV) and the allied optical biomarkers that surrogate for the cardiovascular autonomic modulation, which is influenced by mental health issues. The study aims to validate Lyfas optical biomarkers (SD1/SD2, LF/HF, pNN50, and HRVscores) and a set of physical parameters e.g., age, HR, BP – systolic and diastolic, and serum cortisol in addressing the mental health state. A total of RTPCR positive 1130 adults (Male 541, Female 589) within the age group of 27-68 yrs. participated in the study. Till the participants became RTPCR negative (average time of 14 days), the Depression-Anxiety-Stress Screening-21 (DASS-21) and Covid Screening Scale (CSS)-based monitoring is done once daily to note the distress levels, and Lyfas tests are taken thrice daily simultaneously. The average of all scores constructs the experimental data. Internal consistency (Cronbach’s α), normality test (Shapiro Wilkis test), and Spearman’s correlations (ρ) and their respective statistical significance (p<0.05, CI: 95%) are computed. The study concludes that Lyfas biomarkers show strong correlations with that of the DASS-21 and CSS scores. Physical parameters are also corroborative to the result.

Keywords: COVID-19, Lyfas, Optical biomarkers, Depression Anxiety Stress Scale-21, Stress Scale (CSS), Shapiro Wilkis test, Cronbach’s alpha, Spearman’s correlation, Bland Altman’s reliability assessment

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CHATTOPADHYAY, Subhagata; DAS, Rupam. Validating Lyfas as a reliable mental health screening and monitoring instrument: a step towards mobile health application during COVID-19 Pandemic. Medical Research Archives, [S.l.], v. 10, n. 3, mar. 2022. ISSN 2375-1924. Available at: <>. Date accessed: 25 june 2024. doi:
Research Articles


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