NCT07905378|Not Yet Recruiting
Validation of Wearable Core Body Temperature-Based Circadian Rhythm Digital Biomarkers
Calera
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Calera
Sponsor study identifier
Secondary identifiers
OTHER_GRANT · National Research Foundation of Korea (NRF)
observational
200
0 countries
N/A
Study Start
November 1, 2026
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
Primary Completion
December 31, 2027
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
Study Completion
December 31, 2027
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
This single-site prospective observational study aims to validate wearable-derived circadian and behavioral rhythm biomarkers using continuous core body temperature and raw accelerometry measurements and to explore longitudinal changes in circadian and rest-activity rhythms in psychiatric inpatients. The study consists of two complementary substudies. Study 1 will enroll 150 outpatients and community participants, including 75 patients with major depressive disorder or bipolar I/II disorder and 75 healthy controls. Participants will simultaneously wear a CALERAResearch core body temperature sensor and a Fitbit Charge 6 for approximately 7 days. Agreement between Fitbit-derived circadian and sleep/activity rhythm features and CALERAResearch-derived core body temperature and raw accelerometry markers will be evaluated. A subset of 50 participants will undergo a second measurement at least 1 month later to assess test-retest reliability. Study 2 will enroll 50 psychiatric inpatients irrespective of final diagnosis. Participants will continuously wear CALERAResearch and Fitbit devices from shortly after admission through the inpatient observation period, with CALERAResearch sensors replaced approximately every 5-7 days. Longitudinal changes in core body temperature rhythms, rest-activity rhythms, and physiological-behavioral rhythm alignment will be examined in relation to changes in psychiatric symptoms.
Registry-reported information. Elapsed time and enrollment totals alone do not measure study progress or recruitment pace.
December 31, 2027
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
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Dates and qualifiers reported by the registry. Estimated dates do not confirm that a milestone has occurred.
October 11, 2026
Actual (reported)October 29, 2026
Actual (reported)November 1, 2026
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
December 31, 2027
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
December 31, 2027
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
Circular Correlation Between Fitbit Sleep-Derived eDLMO and CALERAResearch-Derived CBT Trough Midpoint
The relationship between estimated dim light melatonin onset (eDLMO), derived from sleep timing data collected using Fitbit Charge 6, and the core body temperature (CBT) trough midpoint measured using CALERAResearch will be evaluated in Study 1 participants. One circadian phase estimate will be derived for each marker during the 7-day monitoring period. The relationship between the two phase markers will be quantified using the circular-circular correlation coefficient (r), accounting for the 24-hour periodicity of clock time. The coefficient is dimensionless and ranges from -1 to 1, with values closer to 1 indicating stronger positive circular correlation.
Day 1 through Day 7
Circular Correlation Between Fitbit Heart Rate Cosinor Phase and CALERAResearch-Derived CBT Trough Midpoint
The relationship between the acrophase estimated from 24-hour cosinor fitting of heart rate data collected using Fitbit Charge 6 and the core body temperature (CBT) trough midpoint measured using CALERAResearch will be evaluated in Study 1 participants. One phase estimate will be derived for each marker during the 7-day monitoring period. The relationship between the two phase markers will be quantified using the circular-circular correlation coefficient (r), accounting for the 24-hour periodicity of clock time. The coefficient is dimensionless and ranges from -1 to 1, with values closer to 1 indicating stronger positive circular correlation.
Adults aged 19-75 years with DSM-5 major depressive disorder, bipolar I disorder, or bipolar II disorder. Participants will simultaneously wear CALERAResearch and Fitbit Charge 6 devices for approximately 7 days for validation of circadian and behavioral rhythm biomarkers. A subset may undergo repeat measurement after at least 1 month.
Adults aged 19-75 years with no history of psychiatric diagnosis or treatment and no major mood disorder identified on structured diagnostic assessment. Participants will simultaneously wear CALERAResearch and Fitbit Charge 6 devices for approximately 7 days. A subset may undergo repeat measurement after at least 1 month.
Adults aged 19-75 years admitted to the psychiatric inpatient unit for psychiatric treatment. Enrollment is transdiagnostic and does not require a specific final diagnosis at study entry. Participants will undergo repeated CALERAResearch and Fitbit monitoring during the inpatient observation period.
This study will enroll 200 adults aged 19-75 years at Korea University Anam Hospital. Study 1 will include 75 outpatients with major depressive disorder, bipolar I disorder, or bipolar II disorder and 75 healthy control participants without a history of psychiatric diagnosis or treatment and without a major mood disorder identified on structured diagnostic assessment. Participants in Study 1 will undergo concurrent monitoring with CALERAResearch and Fitbit devices for approximately 7 days, and a subset of 50 participants will undergo repeat monitoring after an interval of at least 1 month. Study 2 will include 50 patients admitted to the psychiatric inpatient unit for psychiatric treatment, regardless of final psychiatric diagnosis at the time of enrollment. These participants will undergo repeated wearable monitoring during the inpatient observation period.
Heon-Jeong Lee, Professor
Korea University Anam Hospital
First Submitted
October 11, 2026
First Posted
October 29, 2026
Study Start
November 1, 2026
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
Primary Completion
December 31, 2027
Stress Management With Real-time Bio-signal Biofeedback
Day 1 through Day 7
Mean Absolute Difference in Phase Changes Between Fitbit Sleep-Derived eDLMO and CALERAResearch-Derived CBT Trough Midpoint
Agreement in circadian phase changes between Fitbit sleep-derived estimated dim light melatonin onset (eDLMO) and CALERAResearch-derived core body temperature (CBT) trough midpoint will be evaluated in 50 Study 1 participants undergoing repeat monitoring. For each marker, the signed circular phase change between the first and second monitoring periods will be calculated. Agreement will be quantified as the mean absolute circular difference between these phase changes, expressed in hours. Lower values indicate closer agreement in the direction and magnitude of phase changes, independent of systematic differences in absolute phase timing.
First 7-day monitoring period (Days 1-7) and second 7-day monitoring period (an average of 3 months after baseline)
Mean Absolute Difference in Phase Changes Between Fitbit Heart Rate Cosinor Phase and CALERAResearch-Derived CBT Trough Midpoint
Agreement in circadian phase changes between the acrophase derived from 24-hour cosinor fitting of Fitbit Charge 6 heart rate data and the CALERAResearch-derived core body temperature (CBT) trough midpoint will be evaluated in 50 Study 1 participants undergoing repeat monitoring. For each marker, the signed circular phase change between the two monitoring periods will be calculated. Agreement will be quantified as the mean absolute circular difference between these phase changes, expressed in hours. Lower values indicate closer agreement in the direction and magnitude of phase changes, independent of systematic differences in absolute phase timing.
First 7-day monitoring period (Days 1-7) and second 7-day monitoring period (an average of 3 months after baseline)
Mean Absolute Difference in Sleep Midpoint Between Fitbit Charge 6 and CALERAResearch
Day 1 through Day 7
Rate of Longitudinal Change in CALERAResearch-Derived Core Body Temperature Trough Midpoint
From study enrollment through study completion, an average of 3 weeks
Rate of Longitudinal Change in CALERAResearch-Derived Core Body Temperature Rhythm Amplitude
From study enrollment through study completion, an average of 3 weeks
Rate of Longitudinal Change in CALERAResearch-Derived Rest-Activity Rhythm Interdaily Stability
From study enrollment through study completion, an average of 3 weeks
Rate of Longitudinal Change in Absolute CBT-to-Rest/Sleep Phase Difference
From study enrollment through study completion, an average of 3 weeks
Contact the study team to confirm eligibility.
Planned date reported by the registry; this milestone is not confirmed as achieved.
Study Completion
December 31, 2027
EstimatedPlanned date reported by the registry; this milestone is not confirmed as achieved.
Last Updated
October 29, 2026
Record last verified: 2026-10
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