Cardiovascular autonomic function in normotensive awake patients with obstructive sleep apnoea syndrome was studied in 21 normotensive (mean age 48 +/- 14 years), drug-free men with obstructive sleep apnoea syndrome. Cardiovascular reflex tests with continuous blood pressure monitoring and biochemical indices were performed the morning after a standard polygraphic sleep recording. A group of 20 age-matched (mean age 49 +/- 19 years) normal subjects was used as controls. The obstructive sleep apnoea syndrome patients showed higher heart rate and noradrenaline plasma levels (p < 0.05) at rest and a higher blood pressure response to head-up tilt (p < 0.01), suggesting sympathetic overactivity. Respiratory arrhythmia, baroreflex sensitivity index and Valsalva ratio were significantly lower in the obstructive sleep apnoea syndrome group (p < 0.01) whereas the decrease in heart rate induced by the cold face test was significantly higher (p < 0.05) showing a blunting of reflexes dependent on baroreceptor or pulmonary afferents with normal or increased cardiac vagal efferent activity. These abnormalities in autonomic regulation may predispose obstructive sleep apnoea syndrome patients to cardiovascular complications like hypertension and cardiac arrhythmias.

Determinants of altered quality of life in patients with sleep-related breathing disorders. E. Sforza, J.P. Janssens, T. Rochat, V. Ibanez. #ERS Journals Ltd 2003. ABSTRACT: Recent reports have suggested that altered quality of life and well-being are reported by patients with sleep-related breathing disorders (SRBD). There seems to be no data available in the literature on factors underlying these behavioural consequences. In this study, health-related quality of life (HRQL) scores were examined in SRBD patients in order to establish which factors are implicated in these disturbances.The study group consisted of 130 patients: 49 snorers and 81 patients with obstructive sleep apnoea. The Medical Outcome Survey Short Form-36 questionnaire was administered the morning after the sleep study and scores for the eight dimension scores were obtained. Patient9s data were compared to normative sex-and age-matched data.In comparison with normal values, scores for all HRQL dimensions were decreased in SRBD patients, with a greater impact on subscores for "vitality", "physical role", "social functioning", "mental health" and "role emotional" dimensions. While impairment in physical function was mostly influenced by sleep stage and obesity, subjective daytime sleepiness mainly affected the other dimensions.The authors conclude that the altered health-related quality of life of sleep-related breathing disorder patients is a multifactorial phenomenon depending on the interaction of sleep stages, daytime sleepiness and obesity, with no significant contribution of sleep fragmentation, hypoxaemia and apnoea recurrence. Sleep-related breathing disorders (SRBD) are common disorders, which affect o2-4% of the general population and are characterised by repetitive pharyngeal collapse during sleep, inducing sleep fragmentation and nocturnal hypoxaemia. These two factors have been suggested as causal factors of the excessive daytime sleepiness and neuropsychological and cognitive disturbances affecting the daytime functioning of these patients. Several studies have demonstrated that a large number of patients with SRBD may also have altered health-related quality of life (HRQL) scores, using either generic questionnaires, such as the Nottingham Health Profile [1,2] or the Medical Outcome Survey Short Form (SF)-36 [3], or disease-specific questionnaires, such as the Calgary Sleep Apnea Quality of Life [4,5]. These all showed impairment more frequently in vitality and social functioning [6]. Despite the frequent association between SRBD and altered daily functioning and well-being [7,8], and the importance of altered quality of life in SRBD [6], no data are available in the literature concerning the mechanisms underlying these psychological disturbances. This could be due, at least in part, to the fact that quality of life scores are not routinely used by clinicians to detect the impact of the sleep disorder on the well-being of their patients [9] and also to the difficulty in defining which parameters better reflect a clinically meaning...

Altered vigilance performance has been documented in patients with sleep-related breathing disorders (SRBDs). Sleep fragmentation, sleepiness, respiratory disturbances and nocturnal hypoxaemia have been suggested as the pathogenesis of these deficits, yet it remains difficult to find a good correlation between performance deficits and the above factors. In the present study, which performance measure better characterised SRBD patients and the main factors implicated in these disturbances were examined.The study group consisted of 152 patients and 45 controls, all examined using a performance vigilance task and subjective sleepiness assessment. Speed and accuracy in the psychomotor vigilance task (PVT) were measured in patients and controls. Objective daytime sleepiness was assessed in the patient group using the maintenance of wakefulness test.In comparison with controls, PVT accuracy rather than speed seems to be affected in SRBD patients, with lapses and false responses significantly greater in patients with more severe objective sleepiness and higher apnoea/hypopnoea index. Although slowing and increased variability in reaction time were associated with shorter sleep latency in the maintenance of wakefulness test, subjective sleepiness, sleep fragmentation, nocturnal hypoxaemia and apnoea/hypopnoea index influenced mainly PVT accuracy.It is concluded that vigilance impairment, sleep fragmentation and severity of disease may partially and differentially contribute to the diurnal performance consequences found in sleep-related breathing disorders. Since the psychomotor vigilance task worsening is more marked in accuracy that in speed, measurement of lapses and false responses would better characterise the degree of diurnal impairment in these patients. It is well known that the main consequence of sleep-related breathing disorders (SRBDs) is excessive daytime sleepiness associated with several adverse effects, including impaired daytime performance [1], neuropsychological dysfunction [2,3] and increased risk of road traffic accidents [4][5][6]. Since the meaning of daytime dysfunction varies between patients and includes not only sleepiness but also reduced capacity to sustain attention and concentration [7], impaired short-term memory [8], and altered verbal learning and fluency [9], more objective measures of vigilance and attention have been developed in SRBD patients, such as the performance vigilance test [10,11] and the Oxford Sleep Resistance (OSLER) test [12]. Using these tests, several studies have shown that patients diagnosed with obstructive sleep apnoea (OSA) syndrome frequently exhibit some degree of performance impairment [7,13,14] that improves after treatment [15,16]. The problem in interpreting these results stems from whether the observed deficit is present in all patients with SRBD, mildto-moderately affected patients being frequently unaware of their alertness deficit and the decrement in their performance. Moreover, from a clinical perspective, unanswered questions remain as to t...

No abstract