Faculty Bibliography

Introduction: Sleep scoring performed using the 10-20 system is usually performed in the laboratory with a trained technician applying electrodes. Home monitoring of sleep is made easier by self-application of limited number of electrodes positioned only on the face. We evaluated moving the F4 lead to the forehead and scoring sleep using this and a bipolar chin EMG only. This study examines agreement for sleep scoring using full polysomnography compared to scoring using these modiied leads. Methods: 21 subjects (11M/10F) who were undergoing full in-laboratory polysomnography for evaluation of obstructive sleep apnea had one frontal lead moved to the forehead. Conventional sleep scoring from the unmodiied F4, C4, EOG and EMG was performed by an experienced sleep technologist using AASM rules. Limited monitoring (LM) sleep scoring was done independently by 2 scorers while viewing only the modiied F4 and chin EMG. For each study, epoch-by-epoch agreement was tabulated (i) between each scorer's LM scoring and full PSG AASM scoring and (ii) between scorers LM scoring. Results: 17,786 epochs were scored (669-990 epochs/subject). The mean agreement between LM and full PSG was 78% (range 59-88%/ subject) for scorer 1 and 80% (range 66-92%/subject) for scorer 2. For both scorers agreement between LM and full PSG for epochs scored as sleep or wake scoring only was 93% (range 75-98%) and for REM vs NREM was 93% (83-99%). For LM alone, inter-scorer agreement was 78% (range 63-88%), 91% for sleep-wake (range 76-97%) and 88% for REM vs NREM (range 78-90%). Conclusion: Repositioning of F4 EEG to the forehead and scoring from this and chin EMG resulted in excellent discrimination of sleep from wake and REM from NREM sleep. Inter-scorer LM epoch-by-epoch agreement across all stages is similar to that seen between scorers using full polysomnograpy and suggests its utility in the home

Introduction: In obstructive sleep apnea (OSA) treated with a mandibular advancement device Remmers et al recently showed that therapeutic outcome was predicted by a titration study in the laboratory using a remotely controlled mandibular positioner (RCMP, SomnoMed MATRxTM, Zephyr Sleep Technologies Inc., Canada). Furthermore this study showed that optimal titration could be established in a single night. We report on use of the RCMP in a clinical sleep practice. Methods: 30 patients (22M/8F, BMI 26 + 3 kg/m2) with pre-treatment AHI (AHIDx) < 30/hr (n = 18), or AHIDx > 30/hr who refused CPAP (n = 12) were studied with RCMP during a full night polysomnography (PSG). Baseline and maximum jaw advancement (ADVmax) was determined prior to study by a dentist. During PSG, RCMP was progressively advanced past baseline to ADVmax until all obstructive events were eliminated (ADVopt), or until the patient expressed discomfort. AHIRCMP was calculated as the sum of apneas and hypopneas (30% reduction in low with 3% O2 desaturation or arousal) divided by the sleep time limited to the section of the RCMP study with optimal/maximal advancement. Successful titration was deined as AHIRCMP < 15. If pre-treatment AHIDx was < 20, a 50% reduction was also required. Results: Titration was successful in 20 subjects. (AHIDx = 34 + 9/hr vs AHIRCMP = 9 + 7/hr). ADVopt was within 2 mm of ADVmax in 15/20 patients. In the remaining 5 patients the ADVopt was 2-5 mm lower than ADVmax. Titration resulted in no beneit in 10 subjects (AHIDx = 27 + 26/hr vs AHIRCMP = 24 + 11/hr). Conclusions: The RCMP system was used to advance the dental device over a range of jaw advancements and was tolerated by all subjects. In 20/30 subjects successful titration was obtained during the one night titration, with 25% of these subjects requiring less than maximal advancement. Lack of beneit was predicted in 10/30 subjects. The long-term utility of suboptimal advancement, prediction of futility and sustained eficacy need to be addressed separate!

Introduction: Obstructive sleep apnea (OSA) is generally deined as the conluence of sleep disordered breathing (S

STUDY OBJECTIVES: Inspiratory flow limitation (IFL) during sleep occurs when airflow remains constant despite an increase in respiratory effort. This respiratory event has been recognized as an important parameter for identifying sleep breathing disorders. The purpose of this study was to investigate how much IFL normal individuals can present during sleep. DESIGN: Cross-sectional study derived from a general population sample. SETTING: A "normal" asymptomatic sample derived from the epidemiological cohort of Sao Paulo. PATIENTS AND PARTICIPANTS: This study was derived from a general population study involving questionnaires and nocturnal polysomnography of 1,042 individuals. A subgroup defined as a nonsymptomatic healthy group was used as the normal group. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: All participants answered several questionnaires and underwent full nocturnal polysomnography. IFL was manually scored, and the percentage of IFL of total sleep time was considered for final analysis. The distribution of the percentage of IFL was analyzed, and associated factors (age, sex, and body mass index) were calculated. There were 95% of normal individuals who exhibited IFL during less than 30% of the total sleep time. Body mass index was positively associated with IFL. CONCLUSIONS: Inspiratory flow limitation can be observed in the polysomnography of normal individuals, with an influence of body weight on percentage of inspiratory flow limitation. However, only 5% of asymptomatic individuals will have more than 30% of total sleep time with inspiratory flow limitation. This suggests that only levels of inspiratory flow limitation > 30% be considered in the process of diagnosing obstructive sleep apnea in the absence of an apnea-hypopnea index > 5 and that < 30% of inspiratory flow limitation may be a normal finding in many patients. CITATION: Palombini LO; Tufik S; Rapoport DM; Ayappa IA; Guilleminault C; de Godoy LBM; Castro LS; Bittencourt L. Inspiratory flow limitation in a normal population of adults in Sao Paulo, Brazil. SLEEP 2013;36(11):1663-1668.

Effects of exercise on dynamic aspects of sleep have not been studied. We hypothesized exercise altered dynamic sleep morphology differently for healthy controls relative to chronic fatigue syndrome (CFS) patients. Sixteen controls (38 +/- 9 years) and 17 CFS patients (41 +/- 8 years) underwent polysomnography on baseline nights and nights after maximal exercise testing. We calculated transition probabilities and rates (as a measure of relative and temporal transition frequency, respectively) between sleep stages and cumulative duration distributions (as a measure of continuity) of each sleep stage and sleep as a whole. After exercise, controls showed a significantly greater probability of transition from N1 to N2 and a lower rate of transition from N1 to wake than at baseline; CFS showed a significantly greater probability of transition from N2 to N3 and a lower rate of transition from N2 to N1. These findings suggest improved quality of sleep after exercise. After exercise, controls had improved sleep continuity, whereas CFS had less continuous N1 and more continuous rapid eye movement (REM) sleep. However, CFS had a significantly greater probability and rate of transition from REM to wake than controls. Probability of transition from REM to wake correlated significantly with increases in subjective fatigue, pain, and sleepiness overnight in C

OBJECTIVES: Electroencephalography (EEG) assessment in research and clinical studies is limited by the patient burden of multiple electrodes and the time needed to manually score records. The objective of our study was to investigate the accuracy of an automated sleep-staging algorithm which is based on a single bipolar EEG signal. METHODS: Three raters each manually scored the polysomnographic (PSG) records from 44 patients referred for sleep evaluation. Twenty-one PSG records were scored by Rechtschaffen and Kales (R&K) criteria (group 1) and 23 PSGs were scored by American Academy of Sleep Medicine (AASM) 2007 criteria (group 2). Majority agreement was present in 98.4% of epochs and was used for comparison to automated scoring from a single EEG lead derived from the left and right electrooculogram. RESULTS: The kappa coefficients for interrater manual scoring ranged from 0.46 to 0.89. The kappa coefficient for the auto algorithm vs manual scoring by rater ranged from 0.42 to 0.63 and was 0.61 (group 1, kappa=0.61 and group 2, kappa=0.62) for majority agreement for all studies. The mean positive percent agreement across subjects and stages was 72.6%, approximately 80% for stages wake (78.3%), stage 2 sleep (N2) (80.9%), and stage 3 sleep (N3) (78.1%); the percentage slightly decreased to 73.2% for rapid eye movement (REM) sleep and dropped to 31.9% for stage 1 sleep (N1). Differences in agreement were observed based on raters, obstructive sleep apnea (OSA) severity, medications, and signal quality. CONCLUSIONS: Our study demonstrated that automated scoring of sleep obtained from a single-channel of forehead EEG results in agreement to majority manual scoring are similar to results obtained from studies of manual interrater agreement. The benefit in assessing auto-staging accuracy with consensus agreement across multiple raters is most apparent in patients with OSA; additionally, assessing auto-staging accuracy limited disagreements in patients on medications and in those with compromised signal quality.

A major hypothesis regarding the cause of chronic fatigue syndrome (CFS) is immune dysregulation, thought to be reflected in upregulated proinflammatory cytokines leading to the symptoms that are characteristic of this illness. Because the symptoms worsen with physical exertion or sleep loss, we hypothesized that we could use these stressors to magnify the underlying potential pathogenic abnormalities in the cytokine systems of people with CFS. We conducted repeat blood sampling for cytokine levels from healthy subjects and CFS patients during both postexercise and total sleep deprivation nights and assayed for protein levels in the blood samples, mRNA activity in peripheral blood lymphocytes (PBLs), and function in resting and stimulated PBLs. We found that these environmental manipulations did not produce clinically significant upregulation of proinflammatory cytokines. These data do not support an important role of immune dysregulation in the genesis of stress-induced worsening of CFS.

Background: Glucose hypometabolism measured with FDG-PET in the medial temporal lobe (MTL) has been associated with longitudinal cognitive decline in normal elderly. Other studies find the temporal lobe may be relevant in the regulation of normal breathing, such that apneas and dyspnea are elicited with lesions and electrical stimulation in this region. Our recent work has shown that sleep-disordered breathing (S

OBJECTIVES: The authors examined magnitude/variability of residual sleep disordered breathing (SDB) at pressures around the therapeutic continuous positive airway pressure (CPAP), and described a multinight approach to CPAP titration/retitration consisting of recording airflow and summarizing SDB over multiple nights at multiple pressures and choosing an optimal pressure from these summarized data. DESIGN: Prospective, single-center nonblinded study. PATIENTS: Ten female/18 male patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) (respiratory disturbance index [RDI] 67/h), 17 newly-initiated, 11 chronic CPAP users. INTERVENTIONS: A custom CPAP device (Fisher & Paykel Healthcare) recording airflow and pre-programmed to vary CPAP between 2-3 cm H2O below and 1-2 cm H2O above prescription pressure as determined by a full laboratory titration. RESULTS: Airflow and pressure continuously recorded for multiple nights (15.9 +/- 5.1 nights) at four to seven different pressures in each patient. SDB events manually scored from the airflow as apnea (airflow reduction > 90%), hypopnea (airflow reduction > 30% lasting 10 to 120 sec with inspira-tory flow limitation [IFL]) and runs of sustained IFL > 2 min identified. RDI = (apnea + hypopnea)/total sleep time calculated for each night and an obstruction index, including sustained IFL, also was calculated. PressureMultinight was obtained for each patient from multiple nights of data using two mathematical techniques. Night-to-night variability of SDB indices was low in some patients and significant in others. PressureMultinight could be determined in 17 of 28 patients and was similar to the in-laboratory pressure. CONCLUSIONS: This study showed that recording multiple nights of CPAP airflow in the home and analyzing these data for residual SDB provided useful information, including the possibility of determining a therapeutic prescription for fixed CPAP in most patients and identification of others with significant physiologic variability of SDB. CITATION: Callahan CY; Norman RG; Taxin Z; Mooney AM; Rapoport DM; Ayappa I. Multinight recording and analysis of continuous positive airway pressure airflow in the home for titration and management of sleep disordered breathing. SLEEP 2013;36(4):535-545.