Every figure on this site, traced back to where it came from.
Grouped by the page that uses them. Nothing here is a lifted conclusion from a single paper unless stated as one; where a claim is a synthesis across sources, that's noted on the page itself.
Page 01 & 03 · assessment cadence and decline speed
42 CFR § 483.20, Resident Assessment · admission, significant-change, quarterly, and annual assessment schedule
42 CFR § 483.30(c), Physician Services · required visit frequency and the 10-day timeliness window
Hawkins, N. M. et al., 2024, Heart · COPD exacerbation and short-term cardiovascular decompensation risk
Möller, J. et al., 2005, Journal of Epidemiology & Community Health (SHEEP study) · acute work-stress trigger and 24-hour MI risk
de Zwart, P. L. et al., 2018, Epidemiology and Psychiatric Sciences · minimal duration of a depressive episode
Tong, Z. et al., 2025, Innovation in Aging · one-year pre-frail to frail progression rate
Gill, T. M., Gahbauer, E. A., Allore, H. G. & Han, L., 2006, Archives of Internal Medicine · frailty transitions across infrequent assessment intervals
Daltrey, A. et al., 2022, Journal of the American Medical Directors Association · detection gap in residential aged care deterioration
Page 04 · fatigue
Nylander, M. et al., 2024, Multiple Sclerosis Journal · vocal acoustic validity against the Modified Fatigue Impact Scale
Knoop, V. et al., 2021, Ageing Research Reviews · meta-analysis of fatigue and mortality, disability, and physical decline
Appels, A., Kop, W. & Schouten, E., 2000, Behavioral Medicine · fatigue subscale as the strongest independent MI predictor
Anderson, J. et al., 2022, PLOS ONE · fatigue and feeling unwell predicting 30-day heart failure readmission
Page 04 · stress
Oesten, S. et al., 2023, IEEE EMBS International Conference on Biomedical and Health Informatics · acoustic prediction of cortisol under the Trier Social Stress Test
Baird, A. et al., 2021 · speech-based prediction of cortisol trajectories
Lanas, F. et al., 2007, Circulation (INTERHEART Latin America) · persistent psychosocial stress and acute MI
Parker, H. W. et al., 2022, American Journal of Preventive Medicine · allostatic load and all-cause and cardiovascular mortality, meta-analysis
Page 04 · hydration
Mahalingam, S. & Boominathan, P., 2016, The Laryngoscope · surface vocal-fold hydration and acoustic measures
Alves, M. et al., 2017, Journal of Voice · systematic review of systemic hydration and voice
Rodgers, K. et al., 2025, PLOS One · confirmed systemic dehydration with no detectable acoustic signature, rodent model
Pendlebury, S. T. et al., 2015, BMJ Open · admission dehydration and delirium risk
Dworsky, J. Q. et al., 2019, The American Surgeon · geriatric events including dehydration and hospital outcomes
Hooper, L. et al., 2015, Cochrane Database of Systematic Reviews · reliability of bedside dehydration tests in older adults
Munk, T. et al., 2021, Clinical Nutrition ESPEN · clinician detection rate of lab-confirmed dehydration
Page 04 · energy and vitality
Flint, A. J. et al., 1992, Journal of Psycholinguistic Research; 1993, Journal of Psychiatric Research · acoustic markers of psychomotor retardation in depression
Andersen, C. H. et al., 2021, Journal of Psychosomatic Research · SF-36 Vitality and all-cause mortality, Copenhagen Aging and Midlife Biobank
Zaslavsky, O. et al., 2017, Journals of Gerontology Series A · vitality-derived frailty item and mortality and falls
Page 05 & our internal validation
Bögemann, S. A. et al., 2023, BMC Psychology (DynaM-INT protocol) · individually calibrated thresholds in just-in-time stress intervention
Amplifier Health internal validation study, 2025 · 7 participants, 10 days, 210 assessments, corporate wellness setting