Advanced HRV Analysis — Oura Digital Twin

DFA alpha-1 (RMSSD-Epoch Proxy)

Abnormal

nan

Applied to RMSSD epochs (not RR intervals) — ref ~1.0 (not directly comparable) | 95% KI: (nan, nan)

Sample Entropy

Low

1.5534

Healthy: 1.5-2.5 | normal

Toichi CVI (vagal)

Low

1.2385

Healthy: 3.255

Allostatic Load

Elevated

4/7

moderate

Baevsky SI

Normal

11.94

Normal: <150 | normal

Cosinor Amplitude

Low

6.85bpm

Healthy: 15-25 bpm | Acrophase: 09:47

RQA Determinism

Low

0.2416

Healthy: >0.6 | severely_reduced_determinism

Nightly HR CV

Normal

7.91%

Mean: 84.7 bpm | moderate_variability

1. Proxy Frequency Spectrum (Lomb-Scargle)

Note: Analysis based on 5-minute RMSSD epochs (not beat-to-beat RR intervals). Nyquist frequency is limited to ~0.00167 Hz, so the table below uses proxy bands across the accessible spectrum only. These labels are heuristic and do not support standard LF/HF physiology claims.

Band	Power	Proportion	Interpretation
Lower proxy band	0.0	8.0%	Lowest third of accessible RMSSD-epoch spectrum
Mid proxy band	0.0	72.6%	Middle third of accessible RMSSD-epoch spectrum
Upper proxy band	0.0	19.4%	Upper third of accessible RMSSD-epoch spectrum
Upper/lower proxy ratio	3.744		Heuristic spectral balance only; not a standard sympathovagal index

2. Multiscale Entropy (MSE)

Pattern: High entropy preserved - possible inflammatory pattern

Low-scale mean: 1.5974 | High-scale mean: 1.8007

Costa et al. 2005: Healthy systems show high entropy across all scales. Neuropathic disease shows decline at high scales.

3. Recurrence Quantification Analysis (RQA)

Metric	Value	Interpretation
Recurrence Rate (RR)	0.0011	Proportion of recurrent states
Determinism (DET)	0.2416	Reduced predictability
Laminarity (LAM)	0.0763	Degree of intermittency
Diagonal Entropy	0.6017	Complexity of diagonal lines

Severely reduced determinism - consistent with autonomic neuropathy

4. RMSSD-Epoch DFA (Proxy)

Note: DFA is originally designed for beat-to-beat RR-interval time series. Applied here to 5-minute RMSSD epochs as a proxy. Reference values from RR-interval studies; RMSSD-epoch DFA values are not directly comparable.

Parameter	Value	95% CI	Reference (RR-interval literature)
alpha-1 (short-term)	nan	(nan, nan)	~1.0 (RR-interval ref; proxy may differ)
alpha-2 (long-term)	nan	(nan, nan)	~1.0 (RR-interval ref; proxy may differ)
alpha (full)	nan	-	~1.0 (RR-interval ref)

nolds not installed - DFA cannot be computed

5. Approximate Entropy (ApEn) and Sample Entropy (SampEn)

Metric	Value	Parameters	Healthy Reference
ApEn	1.5808	m=2, r=0.9472	~1.0-1.5
SampEn	1.5534	m=2, r=0.9472	~1.5-2.5

Normal complexity

6. Hjorth Parameters

Parameter	Value	Description
Activity	22.4290 ms²	Signal variance (power)
Mobility	0.8538	Mean frequency (low = monotonous signal)
Complexity	1.8925	Rate of frequency change

7. Baevsky Stress Index (SI)

Component	Value
AMo (mode amplitude)	13.2%
Mo (mode)	8.25 ms
MxDMn (range)	67.0 ms
SI (scaled)	11.94

Normal stress level
Reference (Baevsky 2002): Normal <150, Moderate 150-500, High >500, Pathological >1000

8. Toichi CVI/CSI (Vagal/Sympathetic Index)

Parameter	Patient	Healthy Reference	% of Normal
SD1 (vagal)	2.859 ms	30 ms	9.5%
SD2 (sympathetic)	6.056 ms	60 ms	10.1%
CVI	1.2385	3.255	-
CSI	2.1181	2.0	-

CVI=1.24 (healthy ref: 3.26) - severely reduced vagal tone. CSI=2.12 (healthy ref: 2.0) - normal balance.

9. Cosinor Circadian Analysis (Heart Rate)

Parameter	Value	Reference
MESOR	93.37 bpm	60-80 bpm (healthy)
Amplitude	6.85 bpm	15-25 bpm
Acrophase	09:47	14:00-17:00
R²	0.1449	>0.3 for significant rhythm

Flattened circadian rhythm

10. HR Complexity (Permutation and Spectral Entropy)

Metric	Value	Healthy Reference
Permutation Entropy (PE)	0.9787	>0.85
Spectral Entropy (SE)	0.7179	>0.80

Normal ordinal pattern complexity

11. Night-to-Night HR Variability

Parameter	Value
Number of Nights	77
Mean Nocturnal HR	84.7 bpm
SD Nocturnal HR	6.7 bpm
CV	7.91%
Min-Max	69.8 - 113.9 bpm
Trend	declining trend (-0.17 bpm/night)

12. Wearable Allostatic Load Score

4 / 7 MODERATE

Biomarker	Value	Threshold	Status
Hr Avg Sleep	84.7 bpm	> 80 bpm	EXCEEDED
Hrv Rmssd	10.1 ms	> 15 ms	EXCEEDED
Sleep Efficiency	72.4 %	< 85 %	EXCEEDED
Temp Deviation	0.189 °C	> 0.5 °C	OK
Spo2	96.07 %	< 95 %	OK
Deep Sleep Pct	18.0 %	< 10 %	OK
Rem Sleep Pct	11.9 %	< 15 %	EXCEEDED

Moderate allostatic load (4/7)

Clinical Summary

Key Findings:
Advanced analysis of 5,986 RMSSD epochs and 29,263 heart rate measurements confirms severe autonomic dysfunction in this post-hsct patient.

Key Metrics:

DFA alpha-1 (RMSSD-Epoch Proxy) = nan (RR-interval ref ~1.0; proxy may differ): nolds not installed - DFA cannot be computed
SampEn = 1.5534 (RR-interval ref 1.5-2.5; RMSSD-epoch may differ): Normal complexity
Toichi CVI = 1.2385 (reference 3.255): Severely reduced vagal tone
Cosinor amplitude = 6.85 bpm (reference 15-25): Flattened circadian rhythm
Allostatic load score = 4/7: moderate
RQA determinism = 0.2416: Severely reduced determinism - consistent with autonomic neuropathy

Clinical Interpretation:
Combined analyses show a pattern consistent with severe autonomic neuropathy with both parasympathetic failure (low CVI, low SampEn, low SD1) and chronodisruption (low cosinor amplitude). MSE pattern (inflammatory) and DFA findings support loss of fractal dynamics. The high allostatic load (4/7) indicates systemic physiological stress exceeding adaptive capacity.

Analysis based on Oura Ring Gen 4 data (Jan-Mar 2026). RMSSD epochs are 5-minute intervals during sleep. DFA and SampEn are computed from RMSSD epochs (proxy) - not beat-to-beat RR intervals. Reference values from RR-interval studies are not directly comparable. Frequency domain values are approximations based on Lomb-Scargle periodogram, not beat-to-beat analysis, and should be interpreted as relative indicators. Population norms for RMSSD are from controlled clinical 5-minute recordings; consumer wearable nocturnal values may differ.