High prevalence of severe sleep cycle disruption in de novo acromegaly and underdiagnosis by common clinical screening tools: A prospective, observational, cross-sectional study.

CONTEXT: Although sleep disordered breathing (SDB) is well-recognised in acromegaly, most studies have reported heterogeneous, often heavily treated, groups and few have performed detailed sleep phenotyping at presentation. OBJECTIVE: To study SDB using the gold standard of polysomnography, in the largest group of newly-diagnosed, treatment-naïve patients with acromegaly. SETTING AND PATIENTS: 40 patients [22 males, 18 females; mean age 54 years (range 23-78)], were studied to: (i) establish the prevalence and severity of SDB (ii) assess the reliability of commonly employed screening tools [Epworth Sleepiness Scale (ESS) and overnight oxygen desaturation index (DI)] to detect SDB (iii) determine the extent to which sleep architecture is disrupted. RESULTS: Obstructive sleep apnoea (OSA), defined by the apnoea-hypopnoea index (AHI), was present in 79% of subjects (mild, n = 12; moderate, n = 5; severe, n = 14). However, in these individuals with OSA by AHI criteria, ESS (positive in 35% [n = 11]) and DI (positive in 71%: mild, n = 11; moderate, n = 6; severe, n = 5) markedly underestimated its prevalence/extent. Seventy-eight percent of patients exhibited increased arousal, with marked disruption of the sleep cycle, despite most (82%) having normal total time asleep. Fourteen patients spent longer in stage 1 sleep. Deeper sleep stages were severely attenuated in many subjects (reduced stage 2, n = 18; reduced slow wave sleep, n = 24; reduced rapid eye movement sleep, n = 32). CONCLUSION: Our study provides strong support for clinical guidelines that recommend screening for sleep apnoea syndrome in patients with newly-diagnosed acromegaly. Importantly, however, it highlights shortcomings in commonly recommended screening tools (questionnaires, desaturation index) and demonstrates the added value of polysomnography to allow timely detection of obstructive sleep apnoea and associated sleep cycle disruption.

Sleep deficits but no metabolic deficits in premanifest Huntington's disease.

OBJECTIVE: Huntington disease (HD) is a fatal autosomal dominant, neurodegenerative condition characterized by progressively worsening motor and nonmotor problems including cognitive and neuropsychiatric disturbances, along with sleep abnormalities and weight loss. However, it is not known whether sleep disturbances and metabolic abnormalities underlying the weight loss are present at a premanifest stage. METHODS: We performed a comprehensive sleep and metabolic study in 38 premanifest gene carrier individuals and 36 age- and sex-matched controls. The study consisted of 2 weeks of actigraphy at home, 2 nights of polysomnography and multiple sleep latency tests in the laboratory, and body composition assessment using dual energy x-ray absorptiometry scanning with energy expenditure measured over 10 days at home by doubly labeled water and for 36 hours in the laboratory by indirect calorimetry along with detailed cognitive and clinical assessments. We performed a principal component analyses across all measures within each studied domain. RESULTS: Compared to controls, premanifest gene carriers had more disrupted sleep, which was best characterized by a fragmented sleep profile. These abnormalities, as well as a theta power (4-7Hz) decrease in rapid eye movement sleep, were associated with disease burden score. Objectively measured sleep problems coincided with the development of cognitive, affective, and subtle motor deficits and were not associated with any metabolic alterations. INTERPRETATION: The results show that among the earliest abnormalities in premanifest HD is sleep disturbances. This raises questions as to where the pathology in HD begins and also whether it could drive some of the early features and even possibly the pathology.

Pre-flight assessment in patients with obesity hypoventilation syndrome.

BACKGROUND AND OBJECTIVE: Reduced atmospheric pressure during air travel can cause significant hypoxaemia in some patients with respiratory disease. Our aims were to investigate the degree of hypoxaemia in patients with obesity hypoventilation syndrome (OHS) during hypoxic challenge test (HCT), and to identify any predictors of a positive HCT. METHODS: Thirteen patients underwent assessment, including HCT, lung function and incremental shuttle walk test. All had OHS well controlled with long-term nocturnal non-invasive ventilation (NIV). Patients with chronic obstructive pulmonary disease were excluded. A positive HCT was defined according to the British Thoracic Society (BTS) recommendation as arterial oxygen tension (PaO2) <6.6 kPa and/or oxygen saturation <85%. RESULTS: Mean age was 57 (± 11) years. Mean body mass index was 51.7 (± 12) kg/m(2) . Mean baseline PaO2 and arterial carbon dioxide tension (PaCO2) were 10.2 (9.5-11.3) kPa and 5.2 (3.7-6.8) kPa, respectively. Seven patients (54%) had a positive HCT. The correlation between baseline PaO2 and PaO2 at the end of the HCT was not statistically significant (r = 0.433, P = 0.184). A negative correlation was observed between baseline PaCO2 and PaO2 at the end of the HCT (r = -0.793, P = 0.004). A positive correlation was observed between the distance walked and the PaO2 at the end of the HCT (r = 0.608, P = 0.047). CONCLUSIONS: OHS is a risk factor for severe hypoxaemia during air travel even if the ventilatory failure is well controlled. An HCT before air travel is advisable in all OHS patients. Those with positive HCT may use NIV or have oxygen on-board as per BTS recommendation.

Premature ageing of the immune system underlies immunodeficiency in ataxia telangiectasia.

ATM kinase modulates pathways implicated in premature ageing and ATM genotype predicts survival, yet immunodeficiency in ataxia telangiectasia is regarded as mild and unrelated to age. We address this paradox in a molecularly characterised sequential adult cohort with classical and mild variant ataxia telangiectasia. Immunodeficiency has the characteristics of premature ageing across multiple cellular and molecular immune parameters. This immune ageing occurs without previous CMV infection. Age predicts immunodeficiency in genetically homogeneous ataxia telangiectasia, and in comparison with controls, calendar age is exceeded by immunological age defined by thymic naïve CD4+ T cell levels. Applying ataxia telangiectasia as a model of immune ageing, pneumococcal vaccine responses, characteristically deficient in physiological ageing, are predicted by thymic naïve CD4+ T cell levels. These data suggest inherited defects of DNA repair may provide valuable insight into physiological ageing. Thymic naïve CD4+ T cells may provide a biomarker for vaccine responsiveness in elderly cohorts.

Weaning from prolonged invasive ventilation in motor neuron disease: analysis of outcomes and survival.

INTRODUCTION: Non-invasive ventilation (NIV) improves prognosis in patients with motor neuron disease (MND) in the absence of major bulbar involvement. However, some experience a rapid and unexpected decline in respiratory function and may undergo emergency tracheal intubation. Weaning from invasive ventilation can be difficult, and reported independence from invasive ventilation is uncommon with poor prognosis. The outcomes of patients with MND referred to a specialist weaning service following emergency tracheal intubation were examined and compared with MND patients electively initiating NIV. METHODS: A case note review was performed on all patients with MND invasively ventilated and referred to a specialist weaning service between 1992 and 2007. Outcomes were compared with those electively commenced on NIV during the same period. RESULTS: Thirty patients were referred for weaning from invasive ventilation which was started in 17 before MND was diagnosed. Fourteen patients (47%) were weaned from invasive ventilation but still required NIV, 13 failed to wean, and three died. Seventeen were discharged home from hospital. The median survival from tracheal intubation was 13.7 months (95% CI 0 to 30.8) for those previously diagnosed and 7.2 months (95% CI 5.1 to 9.4) for those not previously known to have MND. Comparison with patients initiated electively on NIV demonstrated similar survival estimates to that from emergency intubation (median 9.4 (95% CI 6.9 to 12.0) vs 7.8 (95% CI 2.6 to 12.9) months respectively). CONCLUSION: The prognosis in MND following acute respiratory failure and intubation is not always complete ventilator dependence if patients are offered a comprehensive weaning programme.

Asymptomatic sleep abnormalities are a common early feature in patients with Huntington's disease.

Huntington's disease (HD) is a fatal neurodegenerative disease characterized by motor, cognitive, and psychiatric disturbance. In this article, we used polysomnography, actigraphy and a variety of validated questionnaires to ascertain the extent to which sleep changes are identifiable and measurable in mild stage HD, and importantly, to see whether patients are negatively impacted by the changes in their sleep. We found significant differences in sleep architecture and sleep efficiency in patients compared with controls using polysomnography. However, patient scores on the Functional Outcomes of Sleep Questionnaire, Medical Outcomes of Sleep Scale, and Epworth Sleepiness Scale were not significantly different to controls. These results suggest that although marked changes in sleep architecture are present in early HD and can be detected using polysomnography, patients do not necessarily recognize or report these abnormalities.

'Distant socializing,' not 'social distancing' as a public health strategy for COVID-19.

Social distancing, also referred to as physical distancing, means creating a safe distance of at least two meters (six feet) between yourself and others. This is a term popularized during the COVID-19 pandemic, as it is one of the most important measures to prevent the spread of this virus. However, the term 'social distancing' can be misleading, as it may imply that individuals should stop socializing. However, socializing in a safe context (i.e. over the phone, video-chat, etc.) is especially important during this time of crisis. Therefore, in this narrative review, we suggest the term 'distant socializing' as more apt expression, to promote physical distancing measures while also highlighting the importance of maintaining social bonds. Further, articles discussing the practice, implementation, measurement, and mental health effects of physical distancing are reviewed. Physical distancing is associated with psychiatric symptoms (such as anxiety and depression), suicidal ideation, and domestic violence. Further, unemployment and job insecurity have significantly increased during COVID-19, which may exacerbate these negative mental health effects. Governments, medical institutions, and public health bodies should therefore consider increasing mental health resources both during and after the pandemic, with a specific focus on frontline workers, COVID-19 survivors, and marginalized communities.

Long-term non-invasive ventilation to manage persistent ventilatory failure after COPD exacerbation.

BACKGROUND AND OBJECTIVE: Patients with ventilatory failure at discharge from hospital following an exacerbation of COPD (ECOPD) have increased work of breathing and reduced inspiratory muscle strength compared with those with a normal arterial carbon dioxide tension (PaCO(2)). They also have a significantly worse prognosis. Long-term non-invasive positive pressure ventilation (NIPPV) may offer a treatment strategy but benefits have not been established. METHODS: We examined the outcomes of 35 patients, with a PaCO(2) >7.5 kPa and normal pH, following hospital admission with an ECOPD. Patients were initiated on long-term NIPPV. Our aims were to establish if NIPPV was tolerated and to describe the effects on ventilatory parameters. RESULTS: Daytime arterial blood gases and nocturnal ventilatory parameters improved significantly on NIPPV. Diurnal PaO(2), self-ventilating, rose from (mean (SD)) 7.3 (1.8) to 8.1 (0.9) kPa (P = 0.005) and PaCO(2) fell from 8.8 (1.3) to 7.3 (0.8) kPa (P

Effect of treatment with continuous positive airway pressure or oxygen on sleep-disordered breathing in patients with heart failure: results of the Sleep Events, Arrhythmias, and Respiratory Analysis in Chronic Heart Failure (SEARCH) study.

The response to sleep-disordered breathing (SDB)-directed therapy was evaluated using the Clear Path home-based monitoring system. There were 26 patients with heart failure enrolled in the Sleep Events, Arrhythmias, and Respiratory Analysis in Chronic Heart Failure (SEARCH) study with SDB requiring treatment (apnea-hypopnea index [AHI] >or=15 events/h). Patients were monitored using both standard polysomnography and the Clear Path system to determine the change in SDB parameters before and after initiation of therapy. Accuracy of the Clear Path system compared with polysomnography was >or=87% to detect SDB events. A marked reduction in the mean number of sleep time respiratory disturbances was observed by both techniques after the initiation of SDB-directed therapy, and 21 patients (87.5%) experienced a 16.7-events/h mean reduction in AHI. Thus, the Clear Path system appears to be a useful device to monitor response to SDB-directed treatment for apnea in patients with heart failure.

REM sleep behaviour disorder treated with melatonin in a patient with Alzheimer's disease.

We report a case of a 68-year-old man with probable Alzheimer's disease who developed rapid eye movement (REM) sleep behaviour disorder. This was confirmed with polysomnography but the patient also had some sleep apnea, which prevented the use of clonazepam for treatment. Melatonin was successfully used as an alternative treatment.

Idiopathic hypersomnia: a study of 77 cases.

STUDY OBJECTIVES: To review the clinical and polysomnographic characteristics of idiopathic hypersomnia as well as the long-term response to treatment. SETTING: The Respiratory Support and Sleep Centre at Papworth Hospital, Cambridge, UK. PATIENTS AND DESIGN: A large database of more than 6000 patients with sleep disorders was reviewed. A retrospective study of the clinical and polysomnographic characteristics of 77 patients with idiopathic hypersomnia was performed. Comparison with a similar group of patients with narcolepsy was performed. The response to drug treatment was assessed in 61 patients over a mean follow-up of 3.8 years. MEASUREMENTS AND RESULTS: Idiopathic hypersomnia was 60% as prevalent as narcolepsy. Comparison with a similar group of patients with narcolepsy showed that those with idiopathic hypersomnia were more likely to have prolonged unrefreshing daytime naps, a positive family history, increased slow-wave sleep, and a longer sleep latency on the Multiple Sleep Latency Test. The results of the Multiple Sleep Latency Test were not helpful in predicting disease severity or treatment response. The clinical features were heterogeneous and of variable severity. The majority of patients with idiopathic hypersomnia had symptoms that remained stable over many years, but 11% had spontaneous remission, which was never seen in narcolepsy. Two thirds of patients with idiopathic hypersomnolence had a sustained improvement in daytime somnolence with medication, although a third needed high doses or combinations of drugs. CONCLUSIONS: Idiopathic hypersomnolence has characteristic clinical and polysomnographic features but the prolonged latency on the Multiple Sleep Latency Test raises doubt about the validity of this test within the current diagnostic criteria. The disease often responds well to treatment and a substantial minority of patients appear to spontaneously improve.

Screening the human prepro-orexin gene in a single-centre narcolepsy cohort.

BACKGROUND AND PURPOSE: Although the orexin system has an established role in narcolepsy, the mechanism of orexin deficiency in human cases is unknown. The strong association with human leukocyte antigen (HLA) DQB1*0602 suggests an autoimmune basis, but supporting evidence is lacking. Although data indicate that HLA status is not the sole genetic factor, only a single case of a functional orexin system mutation has been discovered, in a study with a selection bias designed to increase yield. In this study, we examined the prepro-orexin gene for mutations in a cohort of unrelated patients with narcolepsy from a national UK referral centre. PATIENTS AND METHODS: Subjects with a diagnosis of narcolepsy were recruited from a patient database. DNA samples were obtained using buccal smear kits. The prepro-orexin gene was amplified using polymerase chain reactions and screened for polymorphisms and mutations. RESULTS: Eighty-one patients were recruited, of whom 69 provided DNA samples. A previously described intronic single nucleotide polymorphism, of unlikely significance, was identified in one subject who had typical clinical and electrophysiological features of narcolepsy. It was located 16 base pairs downstream from exon 1. No other mutations were found. CONCLUSION: This result supports existing evidence which indicates that mutations of the prepro-orexin gene are rare and that the genetic contribution to the aetiology of human narcolepsy is likely to be complex.

Prolonged invasive ventilation following acute ventilatory failure in COPD: weaning results, survival, and the role of noninvasive ventilation.

BACKGROUND: Invasive ventilation for COPD has significant mortality, and weaning can be difficult. At Papworth Hospital, we provide a specialist weaning service using noninvasive ventilation (NIV) for patients requiring prolonged invasive ventilation after recovery from acute illness. We analyzed our results for patients with COPD to identify factors associated with weaning outcome and survival. METHODS: A retrospective analysis was conducted of COPD patients admitted for weaning from invasive ventilation, from 1992 to 2003. Weaning success and survival were assessed. Associations were sought between these outcomes and age, sex, spirometry, arterial blood gas levels, APACHE (acute physiology and chronic health evaluation) II score, length of stay (LOS), and the use of NIV and long-term oxygen therapy. RESULTS: Sixty-seven patients were identified, all of whom were receiving tracheostomy ventilation on transfer to the Respiratory Support and Sleep Centre (RSSC). Sixty-four patients (95.5%) were weaned, and 62 patients survived to hospital discharge. NIV was used in weaning 40 patients and in the long term in 25 patients. Median survival was 2.5 years (interquartile range, 0.7 to 4.6 years). One-year, 2-year, and 5-year survival rates were 68%, 54%, and 25%, respectively. Long-term survival was inversely associated with age and LOS in the ICU and the RSSC. The provision of maintenance NIV after weaning was associated with better long-term survival, independent of age and LOS (hazard rate, 0.48; p = 0.03). CONCLUSIONS: These results demonstrate that a specialist multidisciplinary approach, including the use of NIV, can be successful in weaning most COPD patients from prolonged invasive ventilation. The data also suggest that long-term NIV may improve survival in selected patients.

Validation and clinical utility of a simple in-home testing tool for sleep-disordered breathing and arrhythmias in heart failure: results of the Sleep Events, Arrhythmias, and Respiratory Analysis in Congestive Heart Failure (SEARCH) study.

Fifty patients with New York Heart Association class III systolic heart failure were enrolled in this prospective multicenter study that compared the diagnostic accuracy of a home-based cardiorespiratory testing system with standard attended polysomnography. Patients underwent at least 2 nights of evaluation and were scored by blinded observers. At diagnostic cutoff points of > or =5, > or =10, and > or =15 events per hour for respiratory disturbance severity, polysomnography demonstrated a sleep-disordered breathing prevalence of 69%, 59%, and 49%, respectively. Compared with polysomnography, the cardiorespiratory testing system demonstrated predictive accuracies of 73%, 73%, and 75%, which improved to 87%, 87%, and 83%, respectively, when analysis of covariance suggested reanalysis omitting one site's data. The system accurately identified both suspected and unsuspected arrhythmias. The device was judged by 80% of patients to be easy or very easy to use, and 74% of patients expressed a preference for the in-home system. Therefore, this system represents a reasonable home testing device in these patients.

Risk of Narcolepsy after AS03 Adjuvanted Pandemic A/H1N1 2009 Influenza Vaccine in Adults: A Case-Coverage Study in England.

STUDY OBJECTIVES: An increased risk of narcolepsy has been observed in children following ASO3-adjuvanted pandemic A/H1N1 2009 (Pandemrix) vaccine. We investigated whether this risk extends to adults in England. METHODS: Six adult sleep centers in England were visited between November 2012 and February 2014 and vaccination/clinical histories obtained from general practitioners. Suspected narcolepsy cases aged older than 17 y were selected. The risk of narcolepsy following Pandemrix was calculated using cases diagnosed by the time of the center visits and those with a diagnosis by November 30, 2011 after which there was increased awareness of the risk in children. The odds of vaccination in cases and in matched population data were compared using a case-coverage design. RESULTS: Of 1,446 possible cases identified, most had onset before 2009 or were clearly not narcolepsy. Of the 60 remaining cases, 20 were excluded after expert review, leaving 40 cases with narcolepsy; 5 had received Pandemrix between 3 and 18 mo before onset. All the vaccinated cases had cataplexy, two received a diagnosis by November 2011 and two were aged 40 y or older. The odds ratio for vaccination in cases compared to the population was 4.24 (95% confidence interval 1.45-12.38) using all cases and 9.06 (1.90-43.17) using cases with a diagnosis by November 2011, giving an attributable risk of 0.59 cases per 100,000 doses. CONCLUSIONS: We found a significantly increased risk of narcolepsy in adults following Pandemrix vaccination in England. The risk was lower than that seen in children using a similar study design.

The validation of a new actigraphy system for the measurement of periodic leg movements in sleep.

BACKGROUND AND PURPOSE: To determine the accuracy of a new actigraphy system for the measurement of periodic leg movements (PLMs). Continuous measurements of leg movements, made overnight, are essential to diagnose and monitor treatment for PLMs. We have developed the Actiwatch with Cambridge Neuro-Technology Ltd (Cambridge, UK) to detect leg movements consistent with PLMs, to record these movements from both feet over three consecutive nights and to report standard indices of PLMs. We describe three studies designed to validate this device. PATIENTS AND METHODS: The Actiwatch was assessed on a bench model across a range of movement amplitudes. The level of agreement on individual movements between the Actiwatch and bilateral anterior tibialis electromyography (BATEMG) measures was assessed in 199 epochs from five patients with known PLMs. The ability of the Actiwatch to correctly identify patients with PLMs was assessed in a comparison with polysomnography (PSG) in 50 consecutive patients investigated in the sleep laboratory. RESULTS: The Actiwatch detected all mechanically generated movements (100% sensitivity and 100% specificity) on the bench test. On individual movements BATEMG measurement and the Actiwatch agreed on 94% of epochs. The sensitivity and specificity of the Actiwatch to detect leg movements in severe PLMs as defined by BATEMG (PLMI>or=25) are high (100% sensitive and 97% specific). Our bilateral system gave better agreement with BATEMG than previous systems but the two measures are still not interchangeable. CONCLUSIONS: EMG is only a surrogate measure of limb movement and indices measured in this way correlate poorly with symptoms. We have demonstrated that the Actiwatch faithfully records movement, which offers the potential to reassess the relationships between limb movement indices and symptoms. This which offers a convenient and economical alternative to PSG in the study of large populations to increase our understanding of the epidemiology and clinical significance of PLMs.

Chronic treatment with modafinil may not be beneficial in patients with chronic fatigue syndrome.

Fourteen patients (7 male, 7 female, 22-63 years), classified as having chronic fatigue syndrome (CFS), but without concurrent major depression, significant sleepiness or use of psychoactive medication, completed a double-blind, placebo-controlled, crossover study of the effects of the selective wakefulness-promoting agent, modafinil (200 and 400mg/day). The treatment periods were each 20 days, with washout periods of 2 weeks. The primary aim was to determine effects on cognition and the secondary aim was to determine effects on self-ratings of fatigue, quality of life and mood. Modafinil had mixed effects in two cognitive tasks. In a test of sustained attention, treatment with 200mg reduced the latency to correctly detect sequences, but 400mg increased the number of missed targets. In a test of spatial planning, the 200mg dose resulted in a slower initial thinking time for the easiest part of the task, whereas 400mg reduced the initial thinking time for the hardest part of the test. Lastly, in a test of mental flexibility and one of motor speed, patients performed worse whilst on modafinil (400mg), compared with the placebo period. No effects were observed on the performance of other psychometric tests or on self-ratings of fatigue, quality of life or mood, but this may have been due to insufficient statistical power. It is discussed whether the limited and mixed cognitive effects that we observed could have occurred by chance, or whether a subgroup of CFS patients with daytime sleepiness would have shown greater benefits.

Cognitive effects of modafinil in student volunteers may depend on IQ.

The results of two previous studies on the effects of modafinil, a selective wakefulness-promoting agent, in healthy university students were combined in a retrospective analysis. This allowed determination of whether the effects of modafinil were dependent on IQ and whether the larger sample size (n=89) would reveal more cognitive benefits. A battery of cognitive tests was completed 2-3 h after dosing. In the whole sample, modafinil (200 mg) significantly reduced the number of missed targets in a test of sustained attention (RVIP). However, interestingly, several interactions between modafinil and IQ emerged. Modafinil (100 and 200 mg) significantly improved target sensitivity in the RVIP test, but only in the group of 'lower' IQ (mean+/-sem=106+/-0.6), not in the 'higher' IQ group (mean+/-sem=115.5+/-0.5). Furthermore, there were significant modafinil x IQ interactions in two further tests. Modafinil significantly reduced speed of responding in a colour naming of dots, and in clock drawing, but only in the 'lower' IQ group. Thus, the cognitive benefits of modafinil seem particularly marked in tests of vigilance and speed, in which sleepiness would be an important factor. Furthermore, the results indicate that high IQ may limit detection of modafinil's positive effects.

Domiciliary-assisted ventilation in patients with myotonic dystrophy.

STUDY OBJECTIVES: Respiratory failure is found in many neuromuscular diseases, even when the lungs may be healthy, because of an inadequacy of the ventilatory pump. Long-term domiciliary ventilation is a well-established treatment in conditions such as postpoliomyelitis; however, its use in patients with respiratory failure secondary to myotonic dystrophy has not been well described. The purpose of this study was to review the use of domiciliary-assisted ventilation in these patients and to assess their response to treatment. DESIGN: Descriptive analysis of retrospective and prospective clinical data. SETTING: Inpatient, noninvasive respiratory-care unit in a tertiary referral center. PATIENTS: Sixteen patients with myotonic dystrophy, 13 of whom required ventilatory support. INTERVENTIONS AND MEASUREMENTS: A retrospective study of all patients with myotonic dystrophy referred for assessment for assisted ventilation was performed, including results of arterial blood gas analysis, pulmonary function tests, and overnight oxygen saturation and transcutaneous carbon dioxide levels. A prospective reassessment of all patients established on domiciliary ventilation was performed, including measurements of quality of life. RESULTS: Results of arterial blood gas analysis showed a fall in mean PaCO(2) from 64.3 to 53.8 mm Hg (p < 0.05) on discharge after starting ventilation and a rise in mean PaO(2) from 53.0 to 65.3 mm Hg (p < 0.05). There were three deaths, at 5 months, 32 months, and 57 months, respectively. The survivors received assisted ventilation for a mean period of 27 months (range, 2 to 76 months). At reassessment, improvements in arterial blood gas levels were maintained, with mean PaCO(2) of 52.4 mm Hg and PaO(2) of 59.0 mm Hg. Mean overnight mean arterial oxygen saturation rose from 80.5 to 90.3% after the start of treatment (p < 0.001) and was maintained at 90.4% at reassessment. Mean transcutaneous PCO(2) during sleep fell from 59.3 to 41.4 mm Hg (p < 0.05), and to 43.7 mm Hg at reassessment. There were no significant changes in spirometry or maximum mouth pressures. Compliance with treatment for our test group was lower than compliance in a group of age- and sex-matched postpoliomyelitis patients. CONCLUSION: Use of domiciliary-assisted ventilation in patients with myotonic dystrophy is associated with prolonged survival and a sustained improvement in arterial blood gas tensions.