Sleep Architecture as Health Signal

HENRIK AVG SLEEP

Short

6.0hrs

Target: 7-9 hrs

MITCHELL AVG SLEEP

Below target

6.7hrs

Target: 7-9 hrs

HENRIK EFFICIENCY

Abnormal

79.0%

11% nights below 75%

MITCHELL EFFICIENCY

Abnormal

82.8%

10% nights below 75%

HENRIK DEEP SLEEP

Normal

15.0%

Norm: 13-23%

MITCHELL DEEP SLEEP

Normal

18.8%

Norm: 13-23%

Oura Ring Gen 4 sensor data — not clinical measurementsN=1 case study — not validated for clinical decisionsHEV diagnosed Mar 18; interpret findings cautiously in this Day 20 post-ruxolitinib window

Sleep Architecture Over Time

Sleep Efficiency Trends

Sleep Timing Analysis

Benchmark Comparison

Metric	General Norms	Henrik (post-HSCT)	Mitchell (post-Stroke)
Deep Sleep %	13 - 23	15.0 (z=-0.6)	18.8 (z=+0.2)
REM Sleep %	20 - 25	11.9 (z=-4.2)	17.2 (z=-2.1)
Efficiency %	85 - 100	79.0 (z=-1.8)	82.8 (z=-1.3)
Total Hours	7 - 9	6.0 (z=-2.0)	6.7 (z=-1.3)

Recovery Trajectory

Statistical Comparison

Metric	Henrik	Mitchell	p-value	Cohen's d	Cliff's Δ	95% CI (median diff)
Deep Sleep %	15.0	18.8	p<0.001 ***	-0.66 (medium)	-0.38 (medium)	[-5.2, -2.2]
REM Sleep %	11.9	17.2	p<0.001 ***	-1.26 (large)	-0.66 (large)	[-7.2, -4.4]
Light Sleep %	52.1	46.8	p<0.001 ***	+0.83 (large)	+0.45 (medium)	[+2.5, +6.7]
Awake %	20.9	17.2	p<0.001 ***	+0.60 (medium)	+0.50 (large)	[+3.8, +6.0]
Efficiency	79.0	82.8	p<0.001 ***	-0.60 (medium)	-0.50 (large)	[-6.0, -4.0]
Total Hours	6.0	6.7	p<0.001 ***	-0.70 (medium)	-0.42 (medium)	[-1.2, -0.6]
Bedtime Hour	24.9	23.9	p<0.001 ***	+0.72 (medium)	+0.43 (medium)	[+0.8, +1.5]

* p<0.05, ** p<0.01, *** p<0.001 · CI = bootstrap 95% confidence interval for median difference (Henrik - Mitchell)

Clinical Interpretation

Henrik (post-HSCT): REM sleep (11.9%) is below population norms (20.0-25.0%), suggesting possible autonomic interference with dream-stage cycling.
Henrik (post-HSCT): Sleep efficiency (79%) is below the recommended 85% threshold.
Henrik (post-HSCT): Average daily sleep debt of 62 minutes below the 7-hour target, accumulating chronic sleep restriction.
Henrik (post-HSCT): Efficiency trend is statistically improving (+0.35%/week, p=0.002).
Henrik (post-HSCT): High bedtime variability (SD=110 min) suggests inconsistent sleep schedule, which may impair circadian entrainment.
Mitchell (post-Stroke): REM sleep (17.2%) is below population norms (20.0-25.0%), suggesting possible autonomic interference with dream-stage cycling.
Mitchell (post-Stroke): Sleep efficiency (83%) is below the recommended 85% threshold.
Mitchell (post-Stroke): Efficiency trend is statistically declining (-0.06%/week, p=0.000).
Mitchell (post-Stroke): High bedtime variability (SD=77 min) suggests inconsistent sleep schedule, which may impair circadian entrainment.
Deep sleep percentage differs significantly between patients (p=0.000, Cohen's d=-0.66, medium effect).
Sleep efficiency differs significantly (p=0.000, Cohen's d=-0.60, medium effect).

Methodology & Limitations

Data Source

Sleep architecture data from Oura Ring wearable sensors (oura_sleep_periods table, type='long_sleep'). Durations are recorded in seconds by the Oura API and converted to hours/percentages for analysis.

Architecture Percentages

Computed as stage_duration / (total_sleep_duration + awake_time) × 100, ensuring all stages sum to 100% of time in bed.

Statistical Tests

Mann-Whitney U: Non-parametric test for distribution differences (does not assume normality)
Cohen's d: Standardized mean difference (pooled SD); |d| < 0.2 = negligible, < 0.5 = small, < 0.8 = medium, else large
Cliff's delta: Non-parametric effect size based on rank ordering
Bootstrap CI: 5,000-iteration bootstrap for median difference confidence interval
Linear regression: Ordinary least squares for efficiency trend
Spearman rank correlation: Monotonic trend detection for recovery trajectory

Bedtime Handling

Bedtime hours past midnight are encoded as 24+ (e.g., 00:30 = 24.5) to avoid discontinuities in variability and midpoint calculations.

Population Norms

General (age 30-39): Deep 13-23%, REM 20-25%, Efficiency ≥85%, Total 7-9h (Ohayon et al. 2004, Hirshkowitz et al. 2015)
Post-HSCT: Deep 8-15%, REM 10-18%, Efficiency 70-82% (Jim et al. 2014, Rischer et al. 2020)
Post-stroke: Deep 10-18%, REM 12-20%, Efficiency 72-85% (Leppavuori et al. 2002, Duss et al. 2018)

Limitations

N=2 case study: findings are descriptive, not generalizable
Oura Ring is a consumer wearable, not a polysomnograph; sleep staging has known accuracy limitations
Different observation windows and data density between patients
No control for confounders (medications, environment, activity levels)
Population norms are age-adjusted approximations, not individual-level standards