Arousal responses to respiratory events during sleep: the role of pulse wave amplitude

Abstract

The study aims at assessing the changes in electroencephalography (as measured by the A-phases of cyclic alternating pattern) and autonomic activity (based on pulse wave amplitude) at the recovery of airway patency in patients with obstructive sleep apnea syndrome. Analysis of polysomnographic recordings from 20 male individuals with obstructive sleep apnea syndrome was carried out in total sleep time, non-rapid eye movement and rapid eye movement sleep. Scoring quantified the combined occurrence (time range of 4 s before and 4 s after respiratory recovery) or separate occurrence of A-phases (cortical activation), and pulse wave amplitude drops (below 30%) to apneas, hypopneas or flow limitation events. A dual response (A-phase associated with a pulse wave amplitude drop) was the most frequent response (71.8% in total sleep time) for all types of respiratory events, with a progressive reduction from apneas to hypopneas and flow limitation events. The highly significant correlation in total sleep time (r = 0.9351; P < 0.0001) between respiratory events combined with A-phases and respiratory events combined with pulse wave amplitude drops was confirmed both in non-rapid eye movement (r = 0.9622; P < 0.0001) and rapid eye movement sleep (r = 0.7162; P < 0.0006). In conclusion, a dual cortical and autonomic activation is the most common manifestation at the recovery of airway patency. The significant correlation between A-phases and relevant pulse wave amplitude drops suggests a possible role of pulse wave amplitude as a marker of cerebral response to respiratory events.

Short-Term Impact of Sleep Apnea/Hypopnea on the Interaction Between Various Cortical Areas

“…Previous reports have stated that A-phases, which represented cortical activation, were found in this process. 45 This finding is in agreement with the results of our study.…”

Benzodiazepines Associated With Acute Respiratory Failure in Patients With Obstructive Sleep Apnea

“…Fourth, cyclic alternating pattern (CAP) in electroencephalography is the marker of a sleep instability that reflects the brain’s effort to preserve the structure of sleep (Parrino et al, 2012, 2014). The occurrence of CAP was verified to be significantly correlated with the apneas, hypopneas or flow limitation events in OSA patients (Bosi et al, 2018). BZD use in OSA patients may decrease the CAP rate in non-rapid eye movement sleep which results in less resilience to adverse respiratory events.…”

Causality of cortical and cardiovascular activity during cyclic alternating pattern in non-rapid eye movement sleep

“…In their studies on HRV during CAP in healthy subjects and patients with nocturnal front lobe epilepsy (NFLE), Dorantes-Mendez et al [23,24] demonstrated a comparable significant shift towards the low-frequency components of HRV with a more pronounced shift in A3-phases than in A1-and A2-phases. Furthermore, a study on the relation between EEG changes defined by A-phases and the pulse wave amplitude (PWA) after airway obstruction in patients with obstructive sleep apnoea demonstrates a significant correlation between respiratory events combined with A-phases and respiratory events combined with PWA drops [25]. In summary, these findings indicate significant sympathetic activity alterations underpinning the microstructure of sleep.…”