Purpose
Research during the past 10–20 years shows that positional therapy (PT) has a significant influence on the apnea–hypopnea index. These studies are predominantly performed as case series on a ...comparably small number of patients. Still, results have not found their way into the daily diagnostic and treatment routine. An average of 56 % of patients with obstructive sleep apnea (OSA) have position-dependent OSA (POSA), commonly defined as a
difference of 50 % or more in apnea index between supine and non-supine positions
. A great deal could be gained in treating patients with POSA with PT. The aim of this paper was to perform a thorough review of the literature on positional sleep apnea and its therapy.
Methods
A broad search strategy was run electronically in the MEDLINE and EMBASE databases using synonyms for position and sleep apnea.
Results
Sixteen studies were found which examined the effect of PT on OSA. In this literature review, we discuss the various techniques, results, and compliance rates.
Conclusion
Long-term compliance for PT remains an issue, and although remarkable results have been shown using innovative treatment concepts for PT, there is room for both technical improvement of the devices and for further research.
This Letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV/c bunched and polarized deuteron beam in the Cooler Synchrotron ...(COSY) storage ring in order to control both the precession rate (≈121 kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a 1 standard deviation range of σ=0.21 rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles.
Background
In 1984, Cartwright suggested that physicians should differentiate between patients with either positional obstructive sleep apnoea (POSA) or non-positional OSA. Treatment of POSA has ...advanced dramatically recently with the introduction of a new generation of positional therapy (PT), a small device attached to either the neck or chest which corrects the patient from adopting the supine position through a vibrating stimulus. Encouraging data have been published suggesting that this simple therapy successfully prevents patients with POSA from adopting the supine position without negatively influencing sleep efficiency, as well as allowing for good adherence. Unfortunately, evaluating the efficacy of PT and comparing results are hindered by the fact that there are no universally used POSA criteria. In 1984, Cartwright introduced the arbitrary cut-off point of a difference of 50 % or more in apnoea index between supine and non-supine positions.
Introduction
The aim of this project was to introduce a new classification system, which ideally should identify suitable candidates for PT: patients that will benefit from a clinically significant improvement of their OSA with PT. The shared use of this classification can facilitate collection of data across multiple centres and comparison of results across studies. We report on the development and process that resulted in the Amsterdam Positional OSA Classification (APOC).
Method
A panel of three field experts were instructed to independently assign the diagnosis POSA to 100 randomly selected patients they considered likely to benefit from a clinically significant improvement of their OSA with PT. In a group setting, the completed lists were compared. Discrepancies were discussed until consensus was met. This resulted in the consensus standard used to calibrate the new classification. Using the nominal group technique, the APOC was developed.
Results
The APOC criteria evolve around the percentage of total sleep time spent in either the worst sleeping position (WSP) or the best sleeping position (BSP) and the apnoea–hypopnoea index (AHI) in BSP. On applying APOC, one discriminates between the true positional patient, the non-positional patient and the multifactorial patient, whose OSA severity is influenced in part by sleep position. APOC has an increased sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) compared to previously applied POSA criteria in identifying patients that will benefit from positional therapy.
Purpose
To analyze the presence of a floppy epiglottis (FE) during drug-induced sleep endoscopy in non-apneic snoring patients, non-positional obstructive sleep apnea (OSA) patients (NPP), and ...position-dependent OSA patients (PP) and to evaluate the impact of maneuvers and body position during drug-induced sleep endoscopy, including jaw thrust and supine and lateral head (and trunk) position.
Methods
Retrospective cohort study.
Results
In total, 324 patients were included. In 60 patients (18.5%), a FE was found in supine position: seven non-apneic snoring patients and 53 OSA patients. When performing lateral head rotation only, a FE was present in four patients (NPP,
N
= 0; PP,
N
= 4). When patients were tilted to both lateral head and trunk position, a FE was found in only one subject. After applying jaw thrust, a FE was still present in 10 patients. The prevalence of a FE did not differ between NPP and PP. When comparing baseline characteristics between patients with and without a FE in supine position, no significant differences were found.
Conclusion
A FE appears almost exclusively in supine position. In patients with a FE, positional therapy can be a promising alternative as a standalone treatment, but also as part of combination therapy with for example mandibular advancement devices or less invasive forms of upper airway surgery.
Purpose
The aims of this study are to evaluate the effect of palatal surgery (uvulopalatopharyngoplasty (UPPP) or Z-palatoplasty (ZPP)) with or without (+/−) concomitant radiofrequent ablation of the ...base of the tongue (RFTB) on body position-specific apnea–hypopnea index (AHI) values in patients with obstructive sleep apnea (OSA) and to compare this treatment outcome to the theoretical effect of (addition of) positional therapy (PT).
Methods
Retrospective analysis of pre- and posttreatment polysomnographies in 139 patients who had undergone UPPP/ZPP +/− RFTB was performed. Hypothetical evaluation of the effects of (addition of) ideal PT on AHI in positional OSA (POSA) patients was carried out.
Results
Median AHI significantly decreased from 18.0 to 11.2 (
p
< 0.001). Median AHI in all separate positions decreased significantly as well. Sixty-eight patients suffered from POSA and showed a significant decrease in median AHI from 15.5 to 11.5 (
p
= 0.002). In the 71 non-positional OSA (NPOSA) patients, the significant AHI decrease was more outspoken, from 23.0 to 11.0 (
p
< 0.001). Our hypothetical model to treat POSA patients with an ideal PT (as monotherapy or in addition to surgery) resulted in a significant median AHI decrease from 18.0 to 4.5 (
p
< 0.0001).
Conclusions
UPPP/ZPP +/− RFTB significantly reduces AHI and all body position-specific AHI values. This reduction is significantly higher in NPOSA than in POSA patients. When considering UPPP/ZPP +/− RFTB, the effect of body position needs to be taken into account. PT, either as monotherapy or in addition to surgery, theoretically has shown to improve treatment results dramatically in POSA patients. Prospective, controlled trials focusing on the effects of this combination of treatments should further evaluate this hypothetical conclusion.
Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ...ultimate aim is to measure the electric dipole moments with a sensitivity up to 15 orders in magnitude better than the magnetic dipole moment of the stored particles. This formidable task requires an understanding of the background to the signal of the electric dipole from rotations of the spins in the spurious magnetic fields of a storage ring. One of the observables, especially sensitive to the imperfection magnetic fields in the ring is the angular orientation of stable spin axis. Up to now, the stable spin axis has never been determined experimentally, and in addition, the JEDI collaboration for the first time succeeded to quantify the background signals that stem from false rotations of the magnetic dipole moments in the horizontal and longitudinal imperfection magnetic fields of the storage ring. To this end, we developed a new method based on the spin tune response of a machine to artificially applied longitudinal magnetic fields. This novel technique, called spin tune mapping, emerges as a very powerful tool to probe the spin dynamics in storage rings. The technique was experimentally tested in 2014 using polarized deuterons stored in the cooler synchrotron COSY, and for the first time, the angular orientation of the stable spin axis at two different locations in the ring has been determined to an unprecedented accuracy of better than 2.8μrad .
Purpose/background
A considerable portion of patients has residual positional obstructive sleep apnea (POSA) after upper airway surgery. Those patients could benefit from additional treatment with ...positional therapy (PT). The objective of this prospective study was to assess the additional effect of PT in patients with residual POSA after upper airway surgery for sleep apnea.
Methods
A polysomnography (PSG) was used to diagnose a patient with residual POSA after surgery. After informed consent, patients were treated with PT for 3 months and underwent a follow-up PSG while using the sleep position trainer (SPT). Changes in apnea-hypopnea index (AHI) and sleep position parameters were analyzed. Compliance rates and mean disease alleviation (MDA) were determined.
Results
Thirty-three patients with a median postoperative AHI of 18.3/h sleep were included. With the SPT median AHI dropped to 12.5/h sleep and the Epworth Sleepiness Scale (ESS) improved from 10.0 to 7.0. After 3 months, 37.5 % patients were considered responders of whom 31.3 % had treatment success. The compliance rate with SPT was 89.0 %. MDA was 44.7 % for SPT alone. With the combination of both surgery and SPT, MDA was 65.6 %.
Conclusions
The results of this study indicate that additional PT in a complex OSA patient population with residual POSA after surgery can increase overall therapeutic effectiveness by improving the median MDA from 39.5 % (effect of surgery alone) to 65.6 % (effect of combining surgery and PT).
The aim of this study was to evaluate prevalence of obstructive sleep apnea among patients undergoing bariatric surgery and the predictive value of various clinical parameters: body mass index (BMI), ...neck circumference (NC) and the Epworth Sleepiness Scale (ESS). We performed a prospective, multidisciplinary, single-center observational study including all patients on the waiting list for bariatric surgery between June 2009 and June 2010, irrespective of history or clinical findings. Patients visited our ENT outpatient clinic for patient history, ENT and general examination and underwent a full night polysomnography, unless performed previously. As much as 69.9% of the patients fulfilled the criteria for OSA (mean BMI 44.2 ± SD 6.4 kg/m
2
); 40.4% of the patients met the criteria for severe OSA. The regression models found BMI to be the best clinical predictor, while the ROC curve found the NC to be the most accurate predictor of the presence of OSA. The discrepancy of the results and the poor statistical power suggest that all three clinical parameters are inadequate predictors of OSA. In conclusion, in this large patient series, 69.9% of patients undergoing BS meet the criteria for OSA. More than 40% of these patients have severe OSA. A mere 13.3% of the patients were diagnosed with OSA before being placed on the waiting list for BS. On statistical analysis, increased neck circumference, BMI and the ESS were found to be insufficient predictors of the presence of OSA. Polysomnography is an essential component of the preoperative workup of patients undergoing BS. When OSA is found, specific perioperative measures are indicated.
In this paper, we demonstrate the connection between a magnetic storage ring with additional sextupole fields set so that thexandychromaticities vanish and the maximizing of the lifetime of in-plane ...polarization (IPP) for a0.97−GeV/cdeuteron beam. The IPP magnitude was measured by continuously monitoring the down-up scattering asymmetry (sensitive to sideways polarization) in an in-beam, carbon-target polarimeter and unfolding the precession of the IPP due to the magnetic anomaly of the deuteron. The optimum operating conditions for a long IPP lifetime were made by scanning the field of the storage ring sextupole magnet families while observing the rate of IPP loss during storage of the beam. The beam was bunched and electron cooled. The IPP losses appear to arise from the change of the orbit circumference, and consequently the particle speed and spin tune, due to the transverse betatron oscillations of individual particles in the beam. The effects of these changes are canceled by an appropriate sextupole field setting.
This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. ...The experiments were performed at the Cooler Synchrotron COSY in Jülich using a vector polarized, bunched0.97GeV/cdeuteron beam. Using the new spin feedback system, we set the initial phase difference between the solenoid field and the precession of the polarization vector to a predefined value. The feedback system was then switched off, allowing the phase difference to change over time, and the solenoid was switched on to rotate the polarization vector. We observed an oscillation of the vertical polarization component and the phase difference. The oscillations can be described using an analytical model. The results of this experiment also apply to other rf devices with horizontal magnetic fields, such as Wien filters. The precise manipulation of particle spins in storage rings is a prerequisite for measuring the electric dipole moment (EDM) of charged particles.
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