Measurement performance
The results of the clinical validations and studies carried out on each variable, with the reference method each was compared against.
Each measured variable has been the subject of clinical validations and scientific studies, compared against an established reference method. The table below reports their results as published.
| Variable | Sample size | Measuring range | Accuracy target | Performance | Inclusive population | Studies and medical grade | Gold standard |
|---|---|---|---|---|---|---|---|
| Heart rate (HR) | 1163 | 40–130 bpm | ≤ 3 bpm | 96 % | Caucasian, north African, African (Europe), phototype I to VI | Controlled clinical trial — CE certified Class IIa | ECG, 3-lead |
| Respiratory rate (RR) | 1163 | 5–30 brpm | ≤ 3 brpm | 95 % | Caucasian, north African, African (Europe), phototype I to VI | Controlled clinical trial — CE certified Class IIa | Piezoelectric belt |
| Heart-rate variability (HRV, RMSSD) | 1163 | 5–200 ms | ≤ 20 ms | 91,5 % | Caucasian, north African, African (Europe), phototype I to VI | Database collected during our clinical investigation, retrospective cross-sectional study | ECG, 3-lead |
| Stress level | 1163 | 1–5 | ≤ 1 | 95,9 % | Caucasian, north African, African (Europe), phototype I to VI | Database collected during our clinical investigation, retrospective cross-sectional study | ECG, 3-lead |
| High blood pressure risk | 1297 | Normotensive — medium — high hypertensive | Derived metric classification | 84 % | Caucasian, north African, African (Europe), phototype I to VI | Database collected during our clinical investigation, retrospective cross-sectional study | Blood pressure cuff monitor |
| Cardiovascular health score | 4240 | 1–100 | Derived metric classification | 76 % | Caucasian, African, Hispanic (USA), phototype I to VI | Retrospective cross-sectional study | Medical cohort |
| Visual age | 7000 | 20–70 apparent age in years | ≤ 10 years apparent age | 93,6 % | Caucasian, north African, African (Europe), phototype I to VI | Retrospective cross-sectional study | Mean value of 10 expert estimations of apparent age |
| Body mass index estimated from the face (Face to BMI) | 70000 | 20–33 kg/m² | ≤ 4 kg/m² | 84,2 % | Caucasian, north African, African, Hispanic (USA & Europe), phototype I to VI | Retrospective cross-sectional study | Weight (kg) and height (m) |
How to read the table
Performance means agreement with the reference method, on the population of the study and inside the measuring range shown on the same row. It is not a promise attached to any one measurement. The accuracy target is the threshold the study set for itself, and the performance column is the share of measurements that reached it.
The measuring range says what was studied. A value outside the range on a row was not part of that study.
The population column says who took part. Phototype refers to the Fitzpatrick scale, which covers the range of skin tones. The geographic terms are those of the study groups.
For any single measurement, the conditions still decide the outcome: light, stillness, framing. Conditions for a good measurement sets them out.