Objective. In hypertensive primary care patients below 65 years of age, (i) to describe the occurrence of undiagnosed obstructive sleep apnoea (OSA), and (ii) to identify the determinants of moderate/severe OSA. Design. Cross-sectional. Setting. Four primary care health centres in Sweden. Patients. 411 consecutive patients (52% women), mean age 57.9 years (SD 5.9 years), with diagnosed and treated hypertension (BP andgt; 140/90). Main outcome measures. Occurrence of OSA as measured by the apnoea hypopnoea index (AHI). Results. Mild (AHI 5-14.9/h) and moderate/severe (AHI andgt; 15/h) OSA were seen among 29% and 30% of the patients, respectively. Comparing those without OSA with those with mild or moderate/severe OSA, no differences were found in blood pressure, pharmacological treatment (anti-hypertensive, anti-depressive, and hypnotics), sleep, insomnia symptoms, daytime sleepiness, or depressive symptoms. Obesity (BMI andgt; 30 kg/m(2)) was seen in 30% and 68% of the patients with mild and moderate/severe OSA, respectively. Male gender, BMI andgt; 30 kg/m(2), snoring, witnessed apnoeas, and sleep duration andgt; 8 hours were determinants of obstructive sleep apnoea. Conclusion. Previously undiagnosed OSA is common among patients with hypertension in primary care. Obesity, snoring, witnessed apnoeas, long sleep duration, and male gender were the best predictors of OSA, even in the absence of daytime sleepiness and depressive symptoms.

Purpose: The apnea–hypopnea index (AHI) is used to grade obstructive sleep apnea (OSA) into mild, moderate, and severe forms. Obstructive events are most common in the supine position. The amount of supine sleep thus influences total AHI. Our aim was to determine the prevalence of position-dependent OSA (POSA) and its relation to OSA severity classification as recommended by the American Academy of Sleep Medicine (AASM).

Methods: Two hundred sixty-five subjects were recruited from primary care hypertension clinics. Whole-night respiratory recordings were performed to determine the AHI in the supine and non-supine positions, respectively. POSA was defined as supine AHI twice the non-supine AHI with supine AHI ≥5.

Results: Fifty-three percent had POSA, 22% had non-position-dependent OSA, and 25% had normal respiration. By AASM classification, 81 subjects did not have OSA, but 42% of them had some degree of obstruction when supine, and 5 subjects would have been classified as moderate–severe if they had only slept supine. Conversely, of the 53 classified as mild OSA, 30% would have changed to a more severe classification if they had exclusively slept supine.

Conclusions: POSA was common both in subjects that by AASM classification had OSA as well as those without. The severity of OSA, as defined by AASM, could be dependent on supine time in a substantial amount of subjects

Objective: Several studies indicate an upper airway peripheral neuropathy in obstructive sleep apnea syndrome (OSAS). The sensation of cold, as measured by cold detection thresholds (CDT), in the oropharynx has been shown to be compromised in patients with sleep apnea and, to a lesser extent, habitual snoring. To reveal whether this neuropathy is part of the pathogenetic process of OSAS, longitudinal studies of snorers are needed. The objective of the present study was to establish the test-retest repeatability for the two most commonly used thermal testing methods: the reaction time exclusive method of levels (MLE) and the method of limits (MLI). Methods: Forty non-snoring subjects were tested at the soft palate and the lip at two separate occasions (mean interval 45 days) using a Medoc TSA - 2001 equipment with an intra-oral thermode. Results: With MLE mean CDTs were lower for both the lip and soft palate than with MLI. However, MLI showed a better test-retest repeatability (r = 2.2 vs. 2.6) for the soft palate. Conclusions: MLI should be used in longitudinal studies. The performance of this method is also faster. Significance: We have established a quick, safe and reliable method suitable for longitudinal studies of peripheral neuropathy in sleep apnea pathogenesis.

Objectives/Hypothesis: In general, obstructive sleep apnea (USA) seems to be a progressive disorder whose pathogenesis is not fully understood. One hypothesis is that long-standing snoring vibrations cause a local neuropathy in the upper airway, which predisposes to obstructive events during sleep. The aim of this study was to investigate sensory function in the upper airway in a cohort of subjects comprising nonsnorers, snorers, and untreated subjects with USA, and to correlate data to apnea-hypopnea index (AHI) and duration of snoring. Study Design: Cross-sectional cohort study. Methods: Subjects were recruited from primary care hypertension clinics. Whole-night respiratory recordings were performed to determine presence and degree of USA. Three groups were formed based on AHI and snoring history: 1) nonsnorers (n = 25); 2) snorers, AHI andlt; 10 (n = 32); 3) USA subjects, AHI andgt;= 10 (n = 33). Quantitative cold sensory testing of the soft palate and lip was used to assess neuropathy. Results: There were no significant differences concerning lip sensory function between groups. Nonsnorers showed significantly lower thresholds for cold (i.e., better sensitivity) in the soft palate compared to both other groups (P andlt; .01). Snorers had lower thresholds than USA subjects (P andlt; .05). There were significant correlations (P andlt; .01) between decreased sensory function and AHI (r(s) = .41) and to duration of snoring (r(s) = .47). Conclusions: The degree of sensory neuropathy in the upper airway correlates with degree of obstructive sleep disorder. Our results strengthen the hypothesis that snoring vibrations may cause a neuropathy in the upper airway, which contributes to the progression and development of USA.