Slow wave sleep rebound and REM rebound following the first night of treatment with CPAP for sleep apnea: correlation with subjective improvement in sleep quality

Objective: The purpose of this study was to correlate changes in PSG parameters between the diagnostic polysomnogram (dPSG) and the first night of treatment with continuous positive airway pressure (CPAP) (cpapPSG) to subjective improvement in sleep quality.Background: In patients with obstructive sleep apnea syndrome (OSAS), therapy with CPAP results in reduction of sleep latency, stage 1 sleep, arousal index (Al) and respiratory disturbance index (RDI), and increase in stage 2 sleep, REM sleep and REM density. No data exists on the differences in polysomnographic (PSG) parameters in patients who have subjective improvement in sleep quality and those who do not.Methods: We retrospectively reviewed PSG studies of 44 patients with OSAS who presented to the Sleep Disorders Center at Duke University Medical Center. Patient's qualitative assessment of sleep was noted using a Likert-type scale administered the morning after the dPSG and cpapPSG. PSG indices of patients noting subjective improvement were compared to those with no improvement.Results: Patients noting a subjective improvement in sleep quality showed a decrease in the percentages of stage 1 sleep (P<0.001) and an increase in percentages of stages 3 and 4 sleep (slow wave sleep rebound; P<0.007) and stage REM sleep (REM rebound; P<0.008).     

Suppression of REM rebound by Pergolide

Summary A 71 year old retired printer developed idiopathic Parkinson's disease over a period of 3 years. On account of his worsening condition he was admitted to hospital. Following the interruption of his medication the patient developed an akinetic crisis. A 48 hour polysomnogram recording, repeated five times during hospitalization, showed severe sleep deprivation. Treatment with Pergolide alone was then started; and sleep monitoring showed suppression of REM rebound, REM only appearing when the dose of the drug was reduced. It is suggested that REM rebound phenomena produced by sleep deprivation in a Parkinson's disease patient are suppressed by the effect of the dopaminergic agent Pergolide.     

Determinants of nasal CPAP compliance

BACKGROUND: Obstructive sleep apnea is a prevalent condition with potentially serious medical and psychosocial consequences. Nasal continuous positive airway pressure (CPAP) is the treatment-of-choice and has been shown to reduce the frequency of nocturnal respiratory events, improve sleep architecture and decrease daytime sleepiness. Patient compliance with CPAP is disappointingly low. Previous studies examining determinants of CPAP compliance have limited the variables studied to patient (sociodemographic), disease status, and treatment variables, with few reliable determinants found. METHODS: The purpose of the current study was to investigate the relationship between objectively measured CPAP compliance and variables from social cognitive theory (SCT) and the transtheoretical model (TM). Scales that measure variables from each model were developed and reliability evaluated. The relationship between the SCT and TM variables and compliance at 1-month post-CPAP-fitting was prospectively evaluated on 51 first-time CPAP users. SCT and TM variables were measured on the day of CPAP-fitting, at 1-week post-CPAP-fitting, and at 1-month post-CPAP-fitting. RESULTS: SCT variables measured 1-week post-CPAP-fitting (R(2)=0.261, P=0.001) and TM variables measured 1-week post-CPAP-fitting (R(2)=0.17, P=0.002) accounted for a statistically significant amount of variance in objective CPAP compliance measured at 1 month. The decisional balance index (from TM) individually accounted for a significant amount of variance in objective CPAP compliance in the above analyses. CONCLUSIONS: The ability of these new behavior change scales to predict CPAP compliance provides us with a new direction of research to better understand factors associated with compliance. The principal advantage of these theory-driven and empirically validated scales are that they measure modifiable factors that can provide the basis for sound interventions to improve CPAP compliance.     

Quipazine has a biphasic effect on slow wave sleep and reduces REM sleep rebound in REM sleep deprived rats

Rats implanted with electrodes for polygraphic recording were deprived of REM sleep for 24 hr. Following REM sleep deprivation animals were injected with quipazine maleate (7.5 mg/kg IP) and were polygraphically recorded for 48 hr. The results show that quipazine reduces REM sleep rebound and that it has a biphasic effect on slow-wave sleep: initial 6 hr suppression is followed by a delayed increase in the second 24 hr recording period. The initial suppression of slow-wave sleep we attribute to the stimulation of central serotonergic receptors while the effect on REM sleep rebound may result from quipazine's action on central catecholamines.     

Dose-response relationship between CPAP compliance and measures of sleep apnea severity

BACKGROUND: Obstructive sleep apnea is a prevalent condition with serious medical and psychosocial consequences. Nasal continuous positive airway pressure (CPAP) is the treatment of choice and has been shown to reduce the frequency of nocturnal respiratory events, improve sleep architecture, and decrease daytime sleepiness. However, little is known about the dose-response relationship between CPAP compliance and measures of sleep apnea severity. This study examined the relationship between level of CPAP compliance and change in polysomnographic measures of sleep apnea severity. METHODS: Twenty-three CPAP-naive OSA patients were studied. None had other major medical illnesses or were receiving antihypertensive medication. Sleep apnea variables were measured at baseline and after 1 week of treatment. Objective CPAP compliance was measured nightly and was defined as the average number of hours of use per night. RESULTS: Higher rates of CPAP compliance were linearly associated with significant reductions in the respiratory disturbance index (R=0.49, P=0.017), the oxygen desaturation index (R=0.48, P=0.029), and the arousal index (R=0.51, P=0.016). CONCLUSIONS: These data suggest that increased CPAP compliance is linearly associated with reductions in sleep apnea severity such that greater reductions in apnea were seen with increased CPAP use. It should be noted that all patients were reasonably compliant (i.e. >4h CPAP use/night) and that even within this range of reasonable compliance, there was a significant benefit with more as opposed to less compliance. These findings offer support to the current recommendation that CPAP be used during the total time in bed to optimize treatment of polysomnographic measures of sleep apnea.     

REM sleep deprivation during 5 hours leads to an immediate REM sleep rebound and to suppression of non-REM sleep intensity.

Nine healthy male subjects were deprived of REM sleep during the first 5 h after sleep onset. Afterwards recovery sleep was undisturbed. During the deprivation period the non-REM EEG power spectrum was reduced when compared to baseline for the frequencies up to 7 Hz, despite the fact that non-REM sleep was not experimentally disturbed. During the recovery interval a significant rebound of REM sleep was observed, which was only accompanied by a very slight increase of power in the lower non-REM EEG frequencies. In order to control for intermittent wakefulness, the same subjects were subjected to non-REM sleep interruption during the first 5 h after sleep onset 2 weeks later. Again subsequent recovery sleep was undisturbed. The interventions resulted in a similar amount of wakefulness in both conditions. During the intervention period, the non-REM EEG power spectrum was only marginally reduced in the delta frequency range. REM sleep duration was only slightly reduced. During the recovery interval, however, a substantial increase in EEG power in the delta frequency range was noted, without notable changes in REM time. It is concluded that an increased pressure for REM sleep results in longer REM episodes and a reduced intensity of non-REM sleep.     

Amphetamine abolishes REM sleep rebound in rats: effect of a single injection

Rats implanted with electrodes for polygraphic recording were deprived of REM sleep for 24 h. Following REM deprivation animals were injected with d-amphetamine (3 mg/kg, i.p.) and were polygraphically recorded for 48 h. The results show that administration of amphetamine abolished the initial 12 h of REM sleep rebound and that this loss of REM sleep was not regained during the entire 0–48 post-REM deprivation period.     

Geranylgeranylacetone, an inducer of HSP 70, attenuates REM sleep rebound after sleep deprivation

The effect of pretreatment of geranylgeranylacetone (GGA), an inducer of heat shock protein (HSP) 70, on responses in sleep and core body temperature (Tcore) against sleep deprivation (SD) was examined in rats. After 3 days of GGA or vehicle injection, a 6-h period of SD was performed. During the recovery period, both rapid-eye movement (REM) and non-REM (NREM) sleep were increased in both GGA- and vehicle-injected rats. However, in GGA-injected rats, REM-sleep rebound was significantly suppressed, while NREM-sleep rebound remained unaffected. In addition, the increase of Tcore caused by SD was also attenuated in GGA-injected rats. In the hippocampus, both SD and the GGA pretreatment induced an increase in the expression of HSP70 mRNA, indicating that the SD functions as a stress for hippocampal neurons and that the GGA induces HSP70 expression. The findings suggest that pretreatment with GGA suppresses REM sleep rebound and the response of Tcore against SD.     

Insomnia symptoms and CPAP compliance in OSAS patients: A descriptive study using Data Mining methods

BackgroundObstructive Sleep Apnoea Syndrome (OSAS) and insomnia are common pathologies sharing a high comorbidity. CPAP is a cumbersome treatment. Yet, CPAP compliance must remain optimal in order to reverse excessive daytime sleepiness and prevent the cardiovascular consequences of OSAS. But chronic insomnia could negatively affect CPAP compliance.ObjectiveTo assess the consequences of insomnia symptoms on long-term CPAP use.MethodsA prospective study was conducted on 148 OSAS patients (RDI = 39.0 ± 21.3/h), age = 54.8 ± 11.8 years, BMI = 29.1 ± 6.3 kg/m², Epworth Score = 12.2 ± 5.4, on CPAP. Using the Insomnia Severity Index (ISI) as an indicator of insomnia (ISI ? 14 = moderate to severe insomnia) and baseline data (anthropometric data, sleeping medication intakes, CPAP compliance, Epworth, Pittsburgh Sleep Quality and ISI scores, polygraphic recording data), Data Mining analysis identified the major rules explaining the features “High” or “Low ISI” and “High” or “Low Use” in the groups defined, according to the median values of the ISI and the 6th month-compliance, respectively.ResultsMedian ISI was 15 and median 6th month-compliance was 4.38 h/night. Moderate to severe insomnia complaint was found in 50% of patients. In the “High” and “Low ISI,” the 6th month-compliance was not significantly different (3.7 ± 2.3 vs 4.2 ± 2.3 h/night). In the classification models of compliance, the ISI was not a predictor of CPAP rejection or of long-term use, the predictor for explaining CPAP abandonment being the RDI, and the predictor of the 6th month-compliance being the one month-compliance.ConclusionInsomnia symptoms were highly prevalent in OSAS patients, but had no impact on CPAP rejection or on long-term compliance.     

Nasal CPAP treatment for obstructive sleep apnea: developing a new perspective on dosing strategies and compliance

Nasal continuous positive airway pressure (CPAP) is presently considered as the “treatment of choice” for obstructive sleep apnea (OSA). Though some OSA patients adhere to treatment recommendations and ultimately respond quite well to CPAP therapy, there is a substantial subgroup for which compliance is a particularly difficult issue. Despite receiving recommendations to the contrary and for reasons that are incompletely understood, the majority of OSA patients settle for a partial compliance pattern. Whether a partial compliance schedule is beneficial or harmful is virtually unexamined: Unlike other medical treatments, there are few data concerning the “dose–response relationship” of CPAP to its desired effects. We argue that CPAP “dose” is a function not only of CPAP pressure but of time-on-CPAP as well. Critical questions that remain unanswered are what “dose” of CPAP is needed to effect an appropriate treatment outcome and which treatment outcomes should form the basis of our recommendations. Recent placebo-controlled studies comparing CPAP to suboptimal CPAP pressures may be informative in this regard. Directions for future research are suggested.     

Individual differences in compensatory rebound of REM sleep, with particular reference to their relationship to personality and behavioral characteristics.

In subjecting 14 healthy university students to partial differential rapid eye movement (REM) sleep deprivation (PDRD), the compensatory rebound of REM sleep during the next night was determined, and showed fairly substantial individual differences in the increased percentage of REM sleep time. This rate was approximately the same for the same individual for two sleep recordings. These individual differences had no positive correlation with the decreased rate of REM time in the PDRD nights or with the percentage of REM time in the baseline night. Therefore, the individual differences in the increased percentage of REM time can be presumed to reflect individual differences in need for deprived REM sleep. Next, we looked into the relationship between the individual subject's personality and behavior characteristics, and his increased percentage of REM time. This revealed that the individuals who were extrovertive, active, optimistic, showy, and who had many friends had significantly higher increases in the percentage of REM time than the individuals who were introvertive, neurotic, inactive, nervous, modest, and who had few friends. Also discussed was the neurophysiological and biochemical basis of the central nervous system as the background for the relationship between the personality and behavioral characteristics and the increased percentage of REM sleep time.