Pierre Mayer

Experimental pain perception remains equally active over all sleep stages

&NA; The literature on sensory perception during sleep suggests that light sleep (Stage 2) is more responsive to external sensory stimulation (e.g. sound, electrical shock) than deep sleep (Stages 3 and 4) and REM sleep. The main objective of this study was to characterize the specificity of nociceptive stimulation to trigger sleep arousal–awakening over all sleep stages. Thirteen healthy adults (e.g. without pain or sleep problems; six female and seven male of a mean age of 24.2±1.3 years) were included in the study. The responses to noxious intramuscular 5% hypertonic infusion were compared to innocuous vibrotactile and to respective control stimulations: isotonic infusion and auditory stimulations. These stimulations were applied during wakefulness and were repeated during sleep. Polygraphic signals (e.g. brain activity, heart rate) signals were recorded to score sleep arousal over all sleep stages. A subjective assessment of sleep quality was made on next morning. No overnight sensitization or habituation occurred with any of the experimental stimulations. The vibratory–auditory stimulations and the noxious hypertonic infusions triggered significantly (P<0.05) more awakenings in sleep Stage 2 and in REM than their respective control stimulations. In sleep Stage 2, both vibratory+auditory stimulations and the noxious hypertonic infusions has the same awakening response frequency (≈30%), however, with the noxious infusions the response frequency were similar in sleep Stages 3 and 4 (P<0.05) and in REM (trend). Compared to the baseline night, sleep quality was lower following the night with noxious stimulation (90.1±2.7 and 73.3±7.4 mm, respectively; P<0.03). These data suggest that pain during sleep could trigger a sleep awaking response over all sleep stages and not only in light sleep.

A Significant Increase in Breathing Amplitude Precedes Sleep Bruxism

BACKGROUND Sleep bruxism (SB) is a stereotyped movement disorder that is characterized by rhythmic masticatory muscle activity (RMMA) and tooth grinding. Evidence has suggested that SB is associated with sleep arousals and that most RMMA episodes are preceded by physiologic changes occurring in sequence, namely, a rise in autonomic sympathetic-cardiac activity followed by a rise in the frequency of EEG and suprahyoid muscle activity. In the present study, we hypothesize that an increase in respiration also characterizes the onset of SB within the arousal sequence. METHODS Polygraphic sleep recordings of 20 SB subjects without any sleep-related breathing disorders were analyzed for changes in respiration (ie, root mean square, area under the curve, peak, peak-to-peak, and length) extracted from a nasal cannula signal. Variables were analyzed and compared using analysis of variance and correlation tests. RESULTS Measurements of respiration showed significant changes over time. Four seconds before RMMA muscle activity, the amplitude of respiration is already increased (8 to 23%); the rise is higher at the onset of the suprahyoid activity (60 to 82% 1 s before RMMA); the rise is maximal during RMMA (108 to 206%) followed by a rapid return to levels preceding RMMA. A positive and significant correlation was found between the frequencies of RMMA episodes and the amplitude of breath (R(2) = 0.26; p = 0.02). The amplitude of respiratory changes was 11 times higher when arousal was associated with RMMA in comparison to arousal alone. CONCLUSIONS To our knowledge, this is the first report showing that RMMA-SB muscle activity is associated with a rise in respiration within arousal.

The Epworth Sleepiness Scale: self-administration versus administration by the physician, and validation of a French version.

BACKGROUND/OBJECTIVES The Epworth Sleepiness Scale (ESS) measures sleepiness and is used for, among others, patients with obstructive sleep apnea (OSA). The questionnaire is usually self-administered, but may be physician administered. The aim was to compare the two methods of administration and to validate a French version. METHODS Consecutive patients presenting to the sleep clinic at a tertiary care centre completed a self-administered questionnaire containing the ESS. During the medical interview the same day, one of three pulmonologists who specialized in sleep medicine administered the ESS. Correlations with the apnea-hypopnea index and mean sleep latencies were used to assess construct validity, while results of previous self-administered ESS questionnnaires in untreated and recently treated OSA patients were used to test reproducibility and longitudinal construct validity, respectively. RESULTS In OSA patients, the ESS weakly correlated with the apnea-hypopnea index (r=0.224; P=0.05; n=120) and negatively with mean sleep latency. For untreated patients (test-retest), the mean (+/- SD) average score was unchanged (10.3+/-6.0 to 10.8+/-6.5; P=0.35; n=56) after a median of seven months. With continuous positive airway pressure use, the mean score decreased from 12.4+/-6.8 to 7.6+/-5.0 after 40.2 months (P<0.0001; n=68). For all subjects, the ESS score obtained by the physician was less than that of the self-administered result (9.4+/-5.9 versus 8.5+/-5.8; P<0.0001 [paired t test]; n=188). CONCLUSIONS In a sleep clinic population, the French version of the ESS performed similarly to the English version. However, the systematic underscoring during physician administration may be important to consider in the research setting if questionnaire administration methods are not consistent.

Design of the effect of adaptive servo-ventilation on survival and cardiovascular hospital admissions in patients with heart failure and sleep apnoea: the ADVENT-HF trial

Both types of sleep‐disordered breathing (SDB), obstructive and central sleep apnoea (OSA and CSA, respectively), are common in patients with heart failure and reduced ejection fraction (HFrEF). In such patients, SDB is associated with increased cardiovascular morbidity and mortality but it remains uncertain whether treating SDB by adaptive servo‐ventilation (ASV) in such patients reduces morbidity and mortality.

Predictive value of automated oxygen saturation analysis for the diagnosis and treatment of obstructive sleep apnoea in a home-based setting

Background: A portable monitor for the automated analysis of episodic nocturnal oxygen saturation or Spo2 (the Remmers Sleep Recorder, RSR) has been proposed for the diagnosis of obstructive sleep apnoea-hypopnoea (OSAH). A study was undertaken to compare the diagnostic performance of automated analysis with the manual scoring of polygraphic data by a more comprehensive respiratory monitor (the Suzanne recorder) used simultaneously in their intended home environment. Methods: The respiratory disturbance indexes of the two monitors were compared in 94 consecutive adult patients suspected of having OSAH and who were deemed eligible for home-based investigation. Results: The RSR overestimated the number of respiratory events associated with a ⩾4% fall in Spo2 by 13% (p<0.005) but underestimated the number of apnoeas and hypopnoeas defined on the basis of respiratory variables alone or their association with a ⩾4% fall in Spo2 or autonomic arousals by 38–48% (p<0.0001). In addition to these significant biases, the limits of agreement in all instances were wide, indicating a poor concurrence between the two monitors. Conclusion: The automated analysis of Spo2 with the RSR cannot be substituted for the manual scoring of polygraphic data with the more comprehensive respiratory monitor in the diagnosis of OSAH in an ambulatory home-based setting.

Sleep, chronic pain, and opioid risk for apnea

&NA; Pain is an unwelcome sleep partner. Pain tends to erode sleep quality and alter the sleep restorative process in vulnerable patients. It can contribute to next‐day sleepiness and fatigue, affecting cognitive function. Chronic pain and the use of opioid medications can also complicate the management of sleep disorders such as insomnia (difficulty falling and/or staying asleep) and sleep‐disordered breathing (sleep apnea). Sleep problems can be related to various types of pain, including sleep headache (hypnic headache, cluster headache, migraine) and morning headache (transient tension type secondary to sleep apnea or to sleep bruxism or tooth grinding) as well as periodic limb movements (leg and arm dysesthesia with pain). Pain and sleep management strategies should be personalized to reflect the patients history and ongoing complaints. Understanding the pain–sleep interaction requires assessments of: i) sleep quality, ii) potential contributions to fatigue, mood, and/or wake time functioning; iii) potential concomitant sleep‐disordered breathing (SDB); and more importantly; iv) opioid use, as central apnea may occur in at‐risk patients. Treatments include sleep hygiene advice, cognitive behavioral therapy, physical therapy, breathing devices (continuous positive airway pressure – CPAP, or oral appliance) and medications (sleep facilitators, e.g., zolpidem; or antidepressants, e.g., trazodone, duloxetine, or neuroleptics, e.g., pregabalin). In the presence of opioid‐exacerbated SDB, if the dose cannot be reduced and normal breathing restored, servo‐ventilation is a promising avenue that nevertheless requires close medical supervision. HighlightsPain can exacerbate complaints of poor sleep, and poor sleep quality alters pain perception and reduces coping skills.A comprehensive assessment of the role of mood in sleep disorders is essential to decipher the role of pain in sleep.A comprehensive assessment of poor sleep with insomnia and sleep apnea is essential for defining the role of pain in sleep.The effects of opioid use must be balanced with the risk of worsened SDB, especially for central sleep apnea and addiction.Pain care plans include sleep hygiene, cognitive behavioral therapy, medication, CPAP, oral devices and servo‐ventilation.

Distinct Patterns of Hyperpnea During Cheyne-Stokes Respiration: Implication for Cardiac Function in Patients With Heart Failure

STUDY OBJECTIVES In heart failure (HF), we observed two patterns of hyperpnea during Cheyne-Stokes respiration with central sleep apnea (CSR-CSA): a positive pattern where end-expiratory lung volume remains at or above functional residual capacity, and a negative pattern where it falls below functional residual capacity. We hypothesized the negative pattern is associated with worse HF. METHODS Patients with HF underwent polysomnography. During CSR-CSA, hyperpnea, apnea-hyperpnea cycle, and lung to finger circulation times (LFCT) were measured. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentration and left ventricular ejection fraction (LVEF) were assessed. RESULTS Of 33 patients with CSR-CSA (31 men, mean age 68 years), 9 had a negative hyperpnea pattern. There was no difference in age, body mass index, and apnea-hypopnea index between groups. Patients with a negative pattern had longer hyperpnea time (39.5 ± 6.4 versus 25.8 ± 5.9 seconds, P < .01), longer cycle time (67.8 ± 15.9 versus 51.7 ± 9.9 seconds, P < .01), higher NT-proBNP concentrations (2740 [6769] versus 570 [864] pg/ml, P = .01), and worse New York Heart Association class (P = .02) than those with a positive pattern. LFCT and LVEF did not differ between groups. CONCLUSIONS Patients with HF and a negative CSR-CSA pattern have evidence of worse cardiac function than those with a positive pattern. Greater positive expiratory pressure during hyperpnea is likely generated during the negative pattern and might support stroke volume in patients with worse cardiac function. COMMENTARY A commentary on this article appears in this issue on page 1227. CLINICAL TRIAL REGISTRATION The trial is registered with Current Controlled Trials (www.controlled-trials.com; ISRCTN67500535) and Clinical Trials (www.clinicaltrials.gov; NCT01128816).

Accuracy of the Oxford Sleep Resistance Test versus SimultaneousElectroencephalography to Detect Sleep Onset

Background: The Oxford Sleep Resistance test (OSLER) is a useful tool to assess daytime vigilance. However, it has not been validated against simultaneous electroencephalography (EEG) recordings in large populations. The main objective of the study was to compare the OSLER values versus EEG-determined Sleep Onset latency (EEGSOL). Methods: Patients referred for assessment of daytime vigilance were recruited from a tertiary sleep clinic. Patients underwent the OSLER (4 x 40 minutes trials; if 7 consecutive stimuli are missed, the trial is terminated and sleep onset is concluded to have occurred) with simultaneous EEG recordings. Determination of EEG-SOL using American Academy of sleep Medicine (AASM) criteria to score sleep during daytime testing was compared to OSLER values. Results: 65 OSLER were performed in 65 subjects for a total of 260 trials (65X4 trials/OSLER). In 136 out of the 260 trials (52.3%), subjects remained awake according to the OSLER, while EEG-SOL was scored in 5 of the 136 trials (3.7%). Of the 124 trials (47.7%) with sleep onset, (i.e. 7 consecutive missed stimuli) the mean sleep onset value was 14.5 ± 10.9 min and EEG-SOL was recorded before the end of the trial in 37 trials (29.8%) (Mean difference EEG-SOL vs. OSLER 4.1 ± 5.8 min). Conclusion: Using current AASM criteria for daytime testing, EEG-determined sleep onset latency is unlikely to occur in subjects with no sleep onset in the OSLER. However, the presence of sleep onset in the OSLER cannot be used as a precise surrogate to detect EEG sleep onset.

T-I-074 SLEEP ILLNESS REPRESENTATION AS A POTENTIAL BARRIER TO TREATMENT ADHERENCE IN OBSTRUCTIVE SLEEP APNEA: A PILOT STUDY

Introduction and Objectives: Sleep apnea is a chronic disease with severe comorbidities and CPAP adherence is often suboptimal. Behavioral strategies have been shown to help patients accept their disease and encourage them to seek medical attention. Patient perceptions (e.g. cognition, emotion) are viewed as psychological correlates amenable to intervention. The impacts of these perceptions in sleep apnea remain unexplored. The aim of our study was to assess the patient’s sleep illness perceptions and to correlate them to the level of sleepiness, a determinant of disease severity and of CPAP adherence, in patients investigated for sleep apnea. Materials and Methods: Eleven patients (56±14 years; seven men) participated in our study. Sleepiness was measured by the ESS and illness representation by the Brief Illness Perceptions Questionnaire (BIPQ). Questionnaires were filled after the sleep studies. Elevated scores suggest a negative impact in the patient’s life. Results: In terms of cognition, our results suggest that patients believe they will live with the disease all their lives (8/10) and had a low perception of future treatment efficacy (4/10). In terms of emotion, they feel negatively affected by their illness (6.5/10) and their understanding for the latter is rather low (4.5/10). The results of the BIPQ (mean of 6/10±1) and the ESS (11/24±6) correlated positively (r=0.5, p=0.1). We also observed that patients without pathological sleepiness (6 patients, ESS 7/24±3) had better results on the BIPQ (4.6±7.6) compared to those with pathological sleepiness (ESS 16/24±5; BIPQ 5.5±9) (T-test p=0.01). Conclusion: Our study suggests that sleep illness perceptions are interesting avenues to understanding the coping behaviour of our patients and possibly treatment adherence. Further studies are needed to confirm these findings in patients with diagnosed and treated sleep apnea. Acknowledgements: Biron Soins du Sommeil for their constant support