Pattern of snoring in obstructive sleep apnea patients and in heavy snorers.

We measured respiratory mechanical characteristics during sleep in five heavy, nonapneic snorers (HS) and in five obstructive sleep apnea (OSA) patients. In two HS and in two OSA patients we obtained lateral pharyngeal cineradiographic images during sleep while snoring. Flow limitation preceded all snores in both HS and OSA. Pattern of snoring, hysteresis and temporal relationship between supraglottic pressure (Psg) and flow rate were different in HS and OSA. Maximal flow during snoring was less (p less than 0.05) in OSA (0.18 +/- 0.07 liter/second) than in HS (0.36 +/- 0.06 liter/second). Linear supraglottic resistance during inspiratory snoring was higher, though not significantly, in OSA patients (7.11 +/- 3.01 cm H2O/liter/second) than in HS (4.80 +/- 2.83 cm H2O/liter/second). We conclude that: 1) Snoring is characterized by high frequency oscillations of the soft palate, pharyngeal walls, epiglottis and tongue. 2) Flow limitation appears to be a sine qua non for snoring during sleep. 3) The pattern of snoring is different in OSA and HS. 4) Pharyngeal size during snoring is probably larger in HS than in OSA patients.     

MMPI correlates of sleep and respiratory disturbance in obstructive sleep apnea.

STUDY OBJECTIVE: To evaluate associations between polysomnographic variables in obstructive sleep apnea (OSA) and a variety of psychological responses (including depressive symptoms) as assessed by the Minnesota Multiphasic Personality Inventory (MMPI). DESIGN: Cross-sectional. SETTING: University sleep disorders center. PATIENTS: One-hundred seventy eight consecutive clinical OSA patients. INTERVENTIONS: Not applicable. MEASUREMENTS AND RESULTS: Patients completed the MPI prior to overnight diagnostic polysomnography. Fifty-eight percent demonstrated at least one MMPI elevation (mean = 1.8 elevations), with Depression (D) elevated for 32%, Hypochondriasis (Hs) for 30%, and Hysteria (Hy) for 21%. Thirty-eight percent demonstrated two or more elevations, with several variations of Hs-D and Hs-D-Hy configurations evident. "Conversion V" profiles were fairly rare, and a large number of miscellaneous configurations occurred once. Significant correlations were detected between several MMPI scale scores and total sleep time, the apnea-hypopnea index (AHI) during REM, and particularly arterial oxygen saturation, even when partialling out variance related to body mass index (BMI). In contract, D scores were not correlated with any polysomnographic parameters. Based upon MMPI configuration, the sample was subdivided into the following seven profile groups: Nonelevated (n = 74); Single D (n = 11); Single non-D (n = 25); Combined D plus (a) HS or HY (n = 7), (b) Hs and Hy (n = 10), or (c) other (n = 29); and Multiple non-D (n = 22). Multivariate analysis controlling for age and gender indicated higher AHI in the Single non-D, Combined D plus other, and Multiple non-D groups, compared to the Single D group. Also, there was lower average oxygen saturation in the Multiple non-D group, compared to Single D, Single non-D, and Nonelevated groups. The Combined D plus HS and/or Hy groups did not differ from each other or from other groups, even when merged. The Multiple non-D findings were unattributable to any specific scale or overall number of elevations. CONCLUSIONS: OSA patients who have core depressive symptoms (as measured by MMPI scale D) without significant psychological symptoms in other areas tend to have less severe OSA, whereas those with a diverse set of other psychological symptoms overshadowing depressive symptoms (e.g., somatic focus, emotional reactivity, family/marital problems, cognitive problems, etc.) tend to have greater AHI and lower oxygen saturation. Although it seems probable that these MMPI differences primarily reflect OSA effects, prospective research is needed to confirm this hypothesis.     

Autonomic stress tests in obstructive sleep apnea syndrome and snoring.

Apneic events in the obstructive sleep apnea syndrome (OSAS) are associated with cardiovascular responses mediated through the autonomic nervous system. We examined autonomic cardiovascular responses in 33 patients (median age = 50 years, range = 20-72 years) undergoing polysomnography for suspected OSAS. We examined these responses in the evening and at arousal in the morning. Tests consisted of heart rate responses to Valsalva maneuver, deep breathing and change from lying down to standing. In addition, systolic blood pressure (BP) response to standing and diastolic BP response to handgrip were studied. Each abnormal test scored +1 and each marginal result +0.5. Autonomic nervous system (ANS) test results were scored as abnormal if a subject had a score > 1 which included at least one abnormal test. The total scores for evening and morning tests combined showed 11/24 sets of scores > 1 in 12 severe OSAS patients [median RDI (apnea+hypopnea per hour slept) = 44 (range = 31-74)] compared to 3/22 in non-OSAS (p = 0.04). The response to deep breathing, expressed as an expiratory to inspiratory ratio (E/I), was the test most often found abnormal. A significant difference between normal abnormal autonomic stress test (AST) groups was observed in the evening and the morning as regards cumulative time spent under 90% SaO2 and minimal SaO2. We conclude that abnormal autonomic stress responses are common in OSAS and are probably a secondary defect.     

Oral appliances for snoring and obstructive sleep apnea: a review

We conducted an evidence-based review of literature regarding use of oral appliances (OAs) in the treatment of snoring and obstructive sleep apnea syndrome (OSA) from 1995 until the present. Our structured search revealed 141 articles for systematic scrutiny, of which 87 were suitable for inclusion in the evidence base, including 15 Level I to II randomized controlled trials and 5 of these trials with placebo-controlled treatment. The efficacy of OAs was established for controlling OSA in some but not all patients with success (defined as no more than 10 apneas or hypopneas per hour of sleep) achieved in an average of 52% of treated patients. Effects on sleepiness and quality of life were also demonstrated, but improvements in other neurocognitive outcomes were not consistent. The mechanism of OA therapy is related to opening of the upper airway as demonstrated by imaging and physiologic monitoring. Treatment adherence is variable with patients reporting using the appliance a median of 77% of nights at 1 year. Minor adverse effects were frequent whereas major adverse effects were uncommon. Minor tooth movement and small changes in the occlusion developed in some patients after prolonged use, but the long-term dental significance of this is uncertain. In comparison to continuous positive airway pressure (CPAP), OAs are less efficacious in reducing the apnea hypopnea index (AHI), but OAs appear to be used more (at least by self report), and in many studies were preferred over CPAP when the treatments were compared. OAs have also been compared favorably to surgical modification of the upper airway (uvulopalatopharyngoplasty, UPPP). Comparisons between OAs of different designs have produced variable findings. The literature of OA therapy for OSA now provides better evidence for the efficacy of this treatment modality and considerable guidance regarding the frequency of adverse effects and the indications for use in comparison to CPAP and UPPP.     

Vigilance in patients with obstructive sleep apnea and surgical patients

Aim

The Marburg vigilance test (VigiMar) is a vigilance task implemented as a four-choice reaction time task with long duration and low stimulus rate. It tests readiness for reaction under monotonous conditions characterized by sensory deprivation. This study was conducted to compare test results of subjects without sleep disorders to those of patients with untreated obstructive sleep apnea (OSA). In addition, whether patients treated for OSA by continuous positive airway pressure (CPAP) exhibited improvements in vigilance testing and whether subjects without sleep disorders have stable test results in a retest after 2 days were investigated. As test results are given for test thirds separately, these were used to determine whether there was a time-on-task effect for patients with untreated OSA and to check for internal consistency of the VigiMar test.

Patients and methods

A total of 20 patients with OSA and 20 surgical patients (knee arthroscopy) between 25 and 65 years of age were included. All patients were male. Vigilance testing was performed on the day before CPAP treatment was started or on the day before arthroscopy and 2 days later after the second CPAP night or on the first day after the surgical procedure, respectively.

Results

In the baseline vigilance test, reaction times of OSA patients were longer than those of surgical patients, especially during the last third of the test. After 2 nights CPAP, reaction times of OSA patients improved to the same level as those of surgical patients who exhibited homogenous results in baseline and postintervention testing.

Conclusion

The VigiMar test is suitable for the assessment of impaired vigilance. Its internal consistency is high, retest reliability is satisfactory, and it is sensitive for changes in vigilance after only 2 nights CPAP treatment.     

CSF hypocretin measures in patients with obstructive sleep apnea

The majority of patients with narcolepsy-cataplexy were reported to have very low cerebrospinal fluid (CSF) hypocretin-1 (orexin-A) levels. The hypocretin-1 levels of secondary excessive daytime sleepiness (EDS) disorders are not known. In this study, we found that CSF hypocretin levels in the patients with obstructive sleep apnea syndrome were within the control range. The low hypocretin levels seem to reflect only the presence of cataplexy and DR2 positive in narcoleptics but not EDS itself.     

Plasma insulin and lipid levels in untreated obstructive sleep apnoea and snoring; their comparison with matched controls and response to treatment

SUMMARY  Obstructive sleep apnoea (OSA), and snoring are associated with coronary heart disease. To assess whether OSA or snoring may contribute to this by raising fasting lipid or insulin levels, venous fasting total cholesterol, triglyceride, very-low-density lipoprotein, low-density lipoprotein, high-density lipoprotein, and insulin were measured in 15 untreated OSA patients and 18 snorers. Each of these subjects was individually matched to a control of the same sex, age ± 10%, body index ± 15%, smoking and drinking habits. This produced study groups which did not differ significantly by any of these criteria. Fasting venous blood samples were collected at 06.30 hours following polysomnography, and analysed blind of the subjects respiratory status. The OSA patients were then treated with nasal continuous positive airway pressure. In 10 of these subjects lipid and insulin levels were repeated after more than three months treatment. Lipid and insulin levels were also remeasured in the controls matched to these 10 subjects. The end points were compared with paired t -tests.
There was no difference in any of the end points when the untreated OSA patients and the snorers were compared to their matched controls ( P >0.25 for all comparisons), and none of the indices changed when OSA was corrected with nasal continuous positive airway pressure ( P > 0.25 for all comparisons).
Patients with obstructive sleep apnoea or snoring do not have significant fasting hyperlipidaemia or hyperinsulinaemia when compared to carefully matched controls. These factors are therefore unlikely to be the cause of the excess cardiovascular mortality experienced by this patient group.     

A comparison of two screening tools for paediatric obstructive sleep apnea

Untreated obstructive sleep apnea in children is associated with significant medical and psychological morbidities. Polysomnographic testing is the gold‐standard method for diagnosis of obstructive sleep apnea. However, laboratory‐based polysomnography is expensive and associated with a substantial healthcare burden. Thus, a simple valid tool to accurately identify those at high risk of obstructive sleep apnea is essential. We performed a retrospective cross‐sectional study of children referred to the Youthdale Child and Adolescent Sleep Clinic. Data were collected from questionnaires and sleep studies reports of 395 children. A comparison between two screening tools for paediatric obstructive sleep apnea – a six‐item (parent‐response) and an eight‐item IF‐SLEEPY/IM‐SLEEPY scales – was performed. The results showed that 42% of the children (n = 164) were diagnosed with obstructive sleep apnea. The six‐item scale (score ≥3) exhibited a sensitivity of 17% and a specificity of 95% for diagnosing obstructive sleep apnea. The eight‐item IF‐SLEEPY scale displayed 82% sensitivity and 28% specificity. The IM‐SLEEPY scale exhibited 79% sensitivity and 32% specificity. In children ≥7 years old, the IF‐SLEEPY (parent‐response) had a sensitivity of 82% and specificity of 28% compared with the child‐response (66% and 37%, respectively). Logistic regression analysis revealed that age (odds ratio = 0.78), IF‐SLEEPY/IM‐SLEEPY score ≥3 (odds ratio = 1.78) and a score ≥2.72 on the six‐item scale (odds ratio = 4.54) were predictors of obstructive sleep apnea. This study suggests that the eight‐item scale is a better screening tool for paediatric obstructive sleep apnea, with a higher sensitivity and simple yes/no responses that are easy to complete and to score.     

Advanced glycation endproducts in nondiabetic patients with obstructive sleep apnea

SUBJECT OBJECTIVE: The formation and accumulation of advanced glycation endproducts (AGEs) has been implicated in the progression of age-related diseases such as diabetes mellitus and atherosclerosis. We hypothesize that AGE concentrations may be increased in subjects with obstructive sleep apnea (OSA), a condition associated with increased oxidative stress. METHODS: One hundred nineteen nondiabetic patients with OSA and 234 age-matched healthy controls and 134 patients with type 2 diabetes were recruited for participation in the study. Serum AGEs were assayed by competitive enzyme-linked immunosorbent assay using a polyclonal rabbit antisera raised against AGE-RNase. RESULTS: Serum AGEs were increased in OSA subjects, as compared with controls, but were less increased than the AGEs of patients with type 2 diabetes (control: 3.22 +/- 0.54 unit per mL; OSA: 3.68 +/- 0.39; diabetes mellitus: 4.11 +/- 0.99; analysis of variance p < .01). In the subjects with OSA, serum AGEs correlated with the duration of nocturnal desaturation (r = 0.21, p = .025) and plasma total 8-isoprostane concentration, a biochemical marker of oxidative stress (r = 0.22, p = .015), but not with fasting glucose level. On general linear model univariate analysis, the association between serum AGEs and 8-isoprostane was independent of age, sex, body mass index, smoking status, and glucose. CONCLUSION: Serum levels of AGEs were increased in nondiabetic subjects with OSA and were associated with the severity of OSA. Whether increased AGE formation contributes significantly to the high cardiovascular risk associated with OSA remains to be determined.     

Comprehensive coronary plaque assessment in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) is associated with an increased risk of cardiovascular disease. Previous studies have assessed the relationship between OSA and coronary artery disease (CAD) using coronary artery calcium score (CAC) measurements. However, limited data are available regarding the association of OSA with non‐calcified plaque burden. We therefore aimed to assess the relationship between CAD severity as assessed by coronary computed tomography angiography (CTA) and OSA. Forty‐one adult subjects (59 ± 9 years, 15 men) underwent a 256‐slice coronary CTA, which was followed by a diagnostic attended cardiorespiratory polygraphy (n = 13) or polysomnography (n = 28). Segment involvement score (SIS), segment stenosis score (SSS) and CAC were used to quantify total CAD burden. Correlation analysis was used to assess potential associations between CAD and OSA. Twenty‐two patients were diagnosed with OSA. SIS and SSS were elevated in OSA (2.90 ± 2.78 versus 1.79 ± 2.39 and 4.91 ± 5.94 versus 1.79 ± 4.54, OSA versus controls, SIS and SSS respectively, both p < 0.01) and correlated with OSA severity as measured by the apnea‐hypopnea index (AHI, r = 0.41 and 0.43, p < 0.01) and oxygen desaturation index (ODI, r = 0.45 and 0.46, p < 0.01). However, no significant correlation was observed between CAC and OSA. Compared to CAC, SIS and SSS provide additional information on coronary plaque burden in OSA, which shows a significant association with OSA.     

Reduced mammillary body volume in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) patients show compromised emotional and cognitive functions, including anterograde memory deficits. While some memory inadequacies in OSA may result from earlier-described structural deficits in the hippocampus, mammillary body injury also could contribute, since these structures receive projections from the hippocampus via the fornix, project heavily to the anterior thalamus, and have been implicated in other conditions with memory deficiencies, such as Korsakoff's syndrome. However, volume loss in mammillary bodies has not been reported in OSA, likely a consequence of logistic difficulties in size assessment. We evaluated mammillary body volumes in 43 OSA (mean age+/-S.D., 46.9+/-9.2 years; mean apnea-hypopnea-index+/-S.D., 31.2+/-19.9 events/h) and 66 control subjects (age, 47.3+/-8.9 years). Two high-resolution T1-weighted image volumes were collected on a 3.0 T magnetic resonance scanner, averaged to improve signal-to-noise, and reoriented (without warping) into a common space. Brain sections containing both mammillary bodies were oversampled, and the bodies were manually traced and volumes calculated. OSA patients showed significantly reduced left, right, and combined mammillary body volumes compared with control subjects, after partitioning for age, gender, and head size (multivariate linear model, p<0.05). Left-side mammillary bodies showed greater volume reduction than the right side. Diminished mammillary body volume in OSA patients may be associated with memory and spatial orientation deficits found in the syndrome. The mechanisms contributing to the volume loss are unclear, but may relate to hypoxic/ischemic processes, possibly assisted by nutritional deficiencies in the syndrome.     

MESAM: a heart rate and snoring recorder for detection of obstructive sleep apnea

The high prevalence of sleep-related breathing disorders demands the development of ambulatory recording devices that can handle data with a high degree of selectivity and are easy to use and to interpret. A digital device based on the recording of heart rate and breathing sounds was developed. Patients with sleep-related breathing disorders can be preselected before they undergo sleep laboratory investigations. Treatment control can be achieved ambulatory, having an initial recording.     

Dental side effects of an oral device to treat snoring and obstructive sleep apnea

STUDY OBJECTIVES: Snoring and obstructive sleep apnea (OSA) are common and related conditions--with major social and health implications--which can be treated successfully with dental devices that reposition the mandible. Despite wide use, side effects of these devices have not yet been systematically evaluated. The purpose of the study was to evaluate side effects of a mandibular advancement splint (MAS) previously described by the authors. DESIGN: Questionnaire survey and dental examination of a consecutive case series of patients treated with the MAS SETTING: Dental outpatient clinic PATIENTS: Attempts were made to contact all 191 patients treated over a 5-year period. All had snored loudly and habitually with or without OSA prior to treatment. MEASUREMENTS AND RESULTS: Of 191 patients treated, 132 agreed to complete the questionnaire. All were scheduled to attend for dental examination and 106 underwent examination. Of the 132 interviewed, patient and partner report indicated that the device was well tolerated and controlled snoring satisfactorily in 100 after 31 +/- 18 (mean +/- SD) months of use. Dental side effects were reported in 107 patients, although these were mostly minor, and only 10 patients ceased using the device because of them. Side effects included excess salivation (in 40), xerostomia (in 30), temporomandibular joint pain (in 35), dental discomfort (in 35), myofacial discomfort (in 33) and bite changes (in 16). Of 106 patients examined, 30 had increased maximal opening and 76 had no change compared with pretreatment records. Temporomandibular joint noises were found in 9 patients, and occlusal changes (12 m mylar strip and wax bite, relative to pretreatment) in 15. None of these effects could be related to degree of opening or protrusion produced by the MAS. CONCLUSION: Dental side effects occur in a significant proportion of patients using the MAS. In most cases these are minor and their importance must be balanced against the efficacy of the MAS in treating snoring and OSA.