TABLE 1.
Summary of Key Studies using the Minimal Model
| Study (published reference) | Model Version & Features | Subject Pool & Study Conditions | Summary of Findings |
|---|---|---|---|
| Belozeroff et al. (2002) | Original Minimal Closed-loop Model | OSA subjects studied in wakefulness before and after long-term CPAP therapy; comparison of compliant vs. non-compliant subjects | RCC and ABR gains increased while DER (direct effect of respiration) and CID (circulatory dynamics) gains decreased in compliant subjects; CID gain showed a tendency to increase in non-compliant subjects |
| Belozeroff et al. (2003) | Original Minimal Closed-loop Model | OSA subjects and normal controls studied during wakefulness in supine & standing postures | Reduced ABR and RCC gains, but higher CID gain in OSA subjects; both groups show decreases in ABR and RCC gains and increases in CID gain with change in supine to standing |
| Jo et al. (2003) | Original Minimal Closed-loop Model | OSA subjects and healthy controls studied during wakefulness and sleep under bilevel pressure ventilation (used to broaden bandwidth of breathing pattern) | RCC and ABR gains lower in OSA subjects vs normal controls; RCC gain unchanged with sleep in both groups; ABR gain increased with sleep in normals but remained unchanged in OSA subjects |
| Jo et al. (2007) | Nonlinear dynamics added to RCC and ABR components; assumed interaction assumed interaction between RCC and ABR gains | OSA subjects and normal controls studied during wakefulness and sleep under bilevel pressure ventilation bilevel pressure ventilation (used to broaden bandwidth of breathing pattern) | Nonlinear ABR gain and magnitude of interaction between ABR and RCC lower in OSA subjects in all sleep-wake states |
| Blasi et al. (2002, 2006) | Time-varying dynamics incorporated into all components of minimal closed-loop model | Responses to acoustically- induced arousals studied in normal and OSA subjects during NREM and REM sleep | RCC gain increased during arousal in NREM but not in REM sleep; ABR gain increased transiently during arousal in both sleep states but subsequently fell below pre-arousal levels. No significant changes in RCC and ABR gains with arousal in OSA subjects. |
| Chaicharn et al. (2009) | Original and Time-Varying Versions of Minimal Closed-loop Model | Pediatric subjects with OSA and age-matched healthy controls studied during wakefulness | ABR gain lower in OSA subjects, but no differences with controls in gains of other model components; Postural change from supine to standing led to decreases in ABR gain in controls only. |