Eastern Australian Farmers Managing and Thinking Differently: Innovative Adaptation Cycles.

The uncertainty of climate change is a significant challenge prompting Australian farmers to create different thinking and different management systems that ensure sustained farm business viability and continuity, particularly in extreme environments. The purpose of this study was to explore the conditions and adaptive processes for managing farm resilience and cyclic adaptation pathways, in response to climate change. A positive deviance sample of farmers was interviewed, and data was collected from a cohort of twenty-two climate change innovators across Eastern Australia. Grounded theory analysis of data identified three processes and two transactional maps of climate change adaptation, in this under studied farmer cohort. The development of the transactional maps found the resilience and preparedness processes as adaptive learning responses to the stressors of climate change. The processes of managing the business and resources were identified as markers of preparedness and resilience that ensured business viability and continuity. Farmers prepared for climate change through transforming make-over processes as an adaptive learning response to climate challenges. Mapping the cycle of adaptation identified the processes of socio-cognitive agency, learning from feedback and consequences, and contextual variables as critical elements of adaptation. The intervening socio-ecological processes of intelligence gathering and influencing, and socio-cognitive precursors, were found to regulate the adaptation cycle. The cycle was found to have both incremental and transformative transmission processes, and intervening processes of climate and contextual variables. The changing patterns and extremes of climate change were found to impact the growing season, and its potential, as unique variables that demand farm adaptation. Ultimately, this study identified potential points of influence for leveraging preparedness behaviours.

Bubble-positive expiratory pressure device and sputum clearance in bronchiectasis: A randomised cross-over study.

OBJECTIVES: The bubble-positive expiratory pressure (PEP) device may be used for sputum clearance in people with daily sputum production. However, this device has never been studied in people with bronchiectasis. Hence, the objective of this study was to compare the effect of bubble-PEP device, the active cycle of breathing technique (ACBT) and no intervention (control) on sputum clearance in people with bronchiectasis. METHODS: This was a prospective, randomised cross-over trial with concealed allocation, assessor blinding and intention-to-treat analysis. Adult participants with stable bronchiectasis and productive of sputum daily were recruited. Participants performed 30-min of bubble-PEP, ACBT or control in random order whilst sitting, followed by 60-min of quiet sitting, on three separate days at the same time within a 10-day period. Primary outcome measure was wet weight of expectorated sputum during 30-min intervention, 60-min post intervention and total wet weight (30 min plus 60 min). RESULTS: Thirty-five-participants (11 males, mean [standard deviation] age 75 [8] years, forced expiratory volume in 1 s 72 [20] % predicted) were recruited and 34 completed the study. There was no significant difference in sputum wet weight between bubble-PEP and ACBT during 30-min intervention (mean difference [95% confidence interval]) -0.59 g [-1.37, 0.19] and total wet weight (0.74 g [-0.54, 2.02]). Sputum wet weight was significantly greater in bubble-PEP than ACBT at 60-min post intervention (1.33 g [0.19, 2.47]). CONCLUSION: Sputum wet weight was significantly greater with bubble-PEP than control at all time periods, and greater than ACBT at 60-min-post. Bubble-PEP could be considered an alternative sputum clearance technique to ACBT.

Impact of respiratory muscle training on respiratory muscle strength, respiratory function and quality of life in individuals with tetraplegia: a randomised clinical trial.

BACKGROUND: Respiratory complications remain a leading cause of morbidity and mortality in people with acute and chronic tetraplegia. Respiratory muscle weakness following spinal cord injury-induced tetraplegia impairs lung function and the ability to cough. In particular, inspiratory muscle strength has been identified as the best predictor of the likelihood of developing pneumonia in individuals with tetraplegia. We hypothesised that 6 weeks of progressive respiratory muscle training (RMT) increases respiratory muscle strength with improvements in lung function, quality of life and respiratory health. METHODS: Sixty-two adults with tetraplegia participated in a double-blind randomised controlled trial. Active or sham RMT was performed twice daily for 6 weeks. Inspiratory muscle strength, measured as maximal inspiratory pressure (PImax) was the primary outcome. Secondary outcomes included lung function, quality of life and respiratory health. Between-group comparisons were obtained with linear models adjusting for baseline values of the outcomes. RESULTS: After 6 weeks, there was a greater improvement in PImax in the active group than in the sham group (mean difference 11.5 cmH2O (95% CI 5.6 to 17.4), p<0.001) and respiratory symptoms were reduced (St George Respiratory Questionnaire mean difference 10.3 points (0.01-20.65), p=0.046). Significant improvements were observed in quality of life (EuroQol-Five Dimensional Visual Analogue Scale 14.9 points (1.9-27.9), p=0.023) and perceived breathlessness (Borg score 0.64 (0.11-1.17), p=0.021). There were no significant improvements in other measures of respiratory function (p=0.126-0.979). CONCLUSIONS: Progressive RMT increases inspiratory muscle strength in people with tetraplegia, by a magnitude which is likely to be clinically significant. Measurement of baseline PImax and provision of RMT to at-risk individuals may reduce respiratory complications after tetraplegia. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN 12612000929808).

Effect of 1†month of zopiclone on obstructive sleep apnoea severity and symptoms: a randomised controlled trial.

Hypnotic use in obstructive sleep apnoea (OSA) is contraindicated due to safety concerns. Recent studies indicate that single-night hypnotic use worsens hypoxaemia in some and reduces OSA severity in others depending on differences in pathophysiology. However, longer clinical trial data are lacking. This study aimed to determine the effects of 1 month of zopiclone on OSA severity, sleepiness and alertness in patients with low-moderate respiratory arousal thresholds without major overnight hypoxaemia.69 participants completed a physiology screening night with an epiglottic catheter to quantify arousal threshold. 30 eligible patients (apnoea-hypopnoea index (AHI) 22±11 events·h-1) then completed standard in-laboratory polysomnography (baseline) and returned for two additional overnight sleep studies (nights 1 and 30) after receiving either nightly zopiclone (7.5 mg) or placebo during a 1-month, double-blind, randomised, parallel trial (ANZCTR identifier ANZCTRN12613001106729).The change in AHI from baseline to night 30 was not different between zopiclone versus placebo groups (-5.9±10.2 versus -2.4±5.5 events·h-1; p=0.24). Similarly, hypoxaemia, next-day sleepiness and driving simulator performance were not different.1 month of zopiclone does not worsen OSA severity, sleepiness or alertness in selected patients without major overnight hypoxaemia. As the first study to assess the effect of a hypnotic on OSA severity and sleepiness beyond single-night studies, these findings provide important safety data and insight into OSA pathophysiology.

Advances in Remote Respiratory Assessments for People with Chronic Obstructive Pulmonary Disease: A Systematic Review.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality. Advances in remote technologies and telemedicine provide new ways to monitor respiratory function and improve chronic disease management. However, telemedicine does not always include remote respiratory assessments, and the current state of knowledge for people with COPD has not been evaluated. OBJECTIVE: Systematically review the use of remote respiratory assessments in people with COPD, including the following questions: What devices have been used? Can acute exacerbations of chronic obstructive pulmonary disease (AECOPD) be predicted by using remote devices? Do remote respiratory assessments improve health-related outcomes? MATERIALS AND METHODS: The review protocol was registered (PROSPERO 2016:CRD42016049333). MEDLINE, EMBASE, and COMPENDEX databases were searched for studies that included remote respiratory assessments in people with COPD. A narrative synthesis was then conducted by two reviewers according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: Fifteen studies met the inclusion criteria. Forced expiratory volume assessed daily by using a spirometer was the most common modality. Other measurements included resting respiratory rate, respiratory sounds, and end-tidal carbon dioxide level. Remote assessments had high user satisfaction. Benefits included early detection of AECOPD, improved health-related outcomes, and the ability to replace hospital care with a virtual ward. CONCLUSION: Remote respiratory assessments are feasible and when combined with sufficient organizational backup can improve health-related outcomes in some but not all cohorts. Future research should focus on the early detection, intervention, and rehabilitation for AECOPD in high-risk people who have limited access to best care and investigate continuous as well as intermittent monitoring.

Role of common hypnotics on the phenotypic causes of obstructive sleep apnoea: paradoxical effects of zolpidem.

Hypnotics are contraindicated in obstructive sleep apnoea (OSA) because of concerns of pharyngeal muscle relaxation and delayed arousal worsening hypoxaemia. However, human data are lacking. This study aimed to determine the effects of three common hypnotics on the respiratory arousal threshold, genioglossus muscle responsiveness and upper airway collapsibility during sleep.21 individuals with and without OSA (18-65 years) completed 84 detailed sleep studies after receiving temazepam (10 mg), zolpidem (10 mg), zopiclone (7.5 mg) and placebo on four occasions in a randomised, double-blind, placebo-controlled, crossover trial (ACTRN12612001004853).The arousal threshold increased with zolpidem and zopiclone versus placebo (mean±sd -18.3±10 and -19.1±9 versus -14.6±7 cmH2O; p=0.02 and p<0.001) but not with temazepam (-16.8±9 cmH2O; p=0.17). Genioglossus muscle activity during stable non-REM sleep and responsiveness during airway narrowing was not different with temazepam and zopiclone versus placebo but, paradoxically, zolpidem increased median muscle responsiveness three-fold during airway narrowing (median -0.15 (interquartile range -1.01 to -0.04) versus -0.05 (-0.29 to -0.03)% maximum EMG per cmH2O epiglottic pressure; p=0.03). The upper airway critical closing pressure did not change with any of the hypnotics.These doses of common hypnotics have differential effects on the respiratory arousal threshold but do not reduce upper airway muscle activity or alter airway collapsibility during sleep. Rather, muscle activity increases during airway narrowing with zolpidem.

Home-based telerehabilitation via real-time videoconferencing improves endurance exercise capacity in patients with COPD: The randomized controlled TeleR Study.

BACKGROUND AND OBJECTIVE: Telerehabilitation has the potential to increase access to pulmonary rehabilitation (PR) for patients with COPD who have difficulty accessing centre-based PR due to poor mobility, lack of transport and cost of travel. We aimed to determine the effect of supervised, home-based, real-time videoconferencing telerehabilitation on exercise capacity, self-efficacy, health-related quality of life (HRQoL) and physical activity in patients with COPD compared with usual care without exercise training. METHODS: Patients with COPD were randomized to either a supervised home-based telerehabilitation group (TG) that received exercise training three times a week for 8 weeks or a control group (CG) that received usual care without exercise training. Outcomes were measured at baseline and following the intervention. RESULTS: Thirty-six out of 37 participants (mean ± SD age = 74 ± 8 years, forced expiratory volume in 1 s (FEV1 ) = 64 ± 21% predicted) completed the study. Compared with the CG, the TG showed a statistically significant increase in endurance shuttle walk test time (mean difference = 340 s (95% CI: 153-526, P < 0.001)), an increase in self-efficacy (mean difference = 8 points (95% CI: 2-14, P < 0.007)), a trend towards a statistically significant increase in the Chronic Respiratory Disease Questionnaire total score (mean difference = 8 points (95% CI: -1 to 16, P = 0.07)) and no difference in physical activity (mean difference = 475 steps per day (95% CI: -200 to 1151, P = 0.16)). CONCLUSION: This study showed that telerehabilitation improved endurance exercise capacity and self-efficacy in patients with COPD when compared with usual care.

Obstructive Sleep Apnea without Obesity Is Common and Difficult to Treat: Evidence for a Distinct Pathophysiological Phenotype.

STUDY OBJECTIVES: To determine the proportion and physiological characteristics of nonobese patients with obstructive sleep apnea (OSA) and their response to prescribed therapy. METHODS: Data from 163 consecutive in-laboratory diagnostic sleep studies for participants referred to an academic teaching-hospital sleep clinic for suspected OSA were assessed. Sleep and anthropometric parameters at baseline and follow-up (up to 22 mo) were examined and compared between obese and nonobese patients with a diagnosis of OSA (apnea-hypopnea index > 5 events/h sleep). A key nonanatomical contributor to OSA pathogenesis, the respiratory arousal threshold, was compared between groups. RESULTS: Twenty-five percent of the participants with a diagnosis of OSA had a body mass index (BMI) within the normal range (BMI < 25 kg/m2) and 54% had a BMI < 30 kg/m2 (nonobese). Of the patients prescribed continuous positive airway pressure (CPAP), more nonobese patients reported not using their CPAP machine at all at follow-up (36% vs. 13%, p = 0.03). Objective CPAP compliance was also lower in the nonobese patients with OSA (5.1 ± 0.4 vs. 6.4 ± 0.4 h/night, p < 0.03). A higher proportion of the nonobese patients had a low respiratory arousal threshold compared to obese OSA patients (86% vs. 60%, p < 0.001). CONCLUSIONS: A substantial proportion of patients with OSA are not obese. These patients are challenging to treat with existing therapies as they are less adherent and compliant with CPAP therapy. Nonanatomical contributors to OSA, such a low threshold for arousal, are likely to be particularly important in OSA pathogenesis in nonobese patients with OSA. These findings have important implications for the pathogenesis of OSA in nonobese patients and potential therapeutic targets for this group of patients.

Continuous positive airway pressure treatment does not normalize the prolonged reflex inhibition to inspiratory loading in obstructive sleep apnea.

In obstructive sleep apnea (OSA), the short-latency inhibitory reflex (IR) of inspiratory muscles to airway occlusion is prolonged in proportion to the severity of the OSA. The mechanism underlying the prolongation may relate to chronic inspiratory muscle loading due to upper airway obstruction or sensory changes due to chronic OSA-mediated inflammation. Continuous positive airway pressure (CPAP) therapy prevents upper airway obstruction and reverses inflammation. We therefore tested whether CPAP therapy normalized the IR abnormality in OSA. The IR responses of scalene muscles to brief airway occlusion were measured in 37 adult participants with untreated, mostly severe, OSA, of whom 13 were restudied after the initiation of CPAP therapy (usage >4 h/night). Participants received CPAP treatment as standard clinical care, and the mean CPAP usage between initial and subsequent studies was 6.5 h/night (range 4.1-8.8 h/night) for a mean of 19 mo (range 4-41 mo). The duration of the IR in scalene muscles in response to brief (250 ms) inspiratory loading was confirmed to be prolonged in the participants with OSA. The IR was assessed before and after CPAP therapy. CPAP treatment did not normalize the prolonged duration of the IR to airway occlusion (60 ± 21 ms pretreatment vs. 59 ± 18 ms posttreatment, means ± SD) observed in participants with severe OSA. This suggests that the prolongation of IR reflects alterations in the reflex pathway that may be irreversible, or a specific disease trait.

Effects of 12 Months Continuous Positive Airway Pressure on Sympathetic Activity Related Brainstem Function and Structure in Obstructive Sleep Apnea.

Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnea (OSA) during normoxic daytime wakefulness. Increased MSNA is a precursor to hypertension and elevated cardiovascular morbidity and mortality. However, the mechanisms underlying the high MSNA in OSA are not well understood. In this study we used concurrent microneurography and magnetic resonance imaging to explore MSNA-related brainstem activity changes and anatomical changes in 15 control and 15 OSA subjects before and after 6 and 12 months of continuous positive airway pressure (CPAP) treatment. We found that following 6 and 12 months of CPAP treatment, resting MSNA levels were significantly reduced in individuals with OSA. Furthermore, this MSNA reduction was associated with restoration of MSNA-related brainstem activity and structural changes in the medullary raphe, rostral ventrolateral medulla, dorsolateral pons, and ventral midbrain. This restoration occurred after 6 months of CPAP treatment and was maintained following 12 months CPAP. These findings show that continual CPAP treatment is an effective long-term treatment for elevated MSNA likely due to its effects on restoring brainstem structure and function.

Zopiclone Increases the Arousal Threshold without Impairing Genioglossus Activity in Obstructive Sleep Apnea.

STUDY OBJECTIVES: To determine the effects of the nonbenzodiazepine sedative zopiclone on the threshold to arousal with increasing respiratory effort and genioglossus muscle activity and to examine potential physiological factors mediating disparate effects of zopiclone on obstructive sleep apnea (OSA) severity between patients. METHODS: Twelve patients with OSA (apnea-hypopnea index = 41 ± 8 events/h) were studied during 2 single night sleep studies conducted approximately 1 w apart after receiving 7.5 mg of zopiclone or placebo according to a double-blind, placebo-controlled, randomized, crossover design. The respiratory arousal threshold (epiglottic pressure immediately prior to arousal during naturally occurring respiratory events), genioglossus activity and its responsiveness to pharyngeal pressure during respiratory events, and markers of OSA severity were compared between conditions. Genioglossus movement patterns and upper airway anatomy were also assessed via magnetic resonance imaging in a subset of participants (n = 7) during wakefulness. RESULTS: Zopiclone increased the respiratory arousal threshold versus placebo (-31.8 ± 5.6 versus -26.4 ± 4.6 cmH2O, P = 0.02) without impairing genioglossus muscle activity or its responsiveness to negative pharyngeal pressure during respiratory events (-0.56 ± 0.2 versus -0.44 ± 0.1 %max/-cmH2O, P = 0.48). There was substantial interindividual variability in the changes in OSA severity with zopiclone explained, at least in part, by differences in pathophysiological characteristics including body mass index, arousal threshold, and genioglossus movement patterns. CONCLUSIONS: In a group of patients with predominantly severe OSA, zopiclone increased the arousal threshold without reducing genioglossus muscle activity or its responsiveness to negative pharyngeal pressure. These properties may be beneficial in some patients with OSA with certain pathophysiological characteristics but may worsen hypoxemia in others. CLINICAL TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, http://www.anzctr.org.au, trial ID: ACTRN12614000364673.

Satisfaction and Experience With a Supervised Home-Based Real-Time Videoconferencing Telerehabilitation Exercise Program in People with Chronic Obstructive Pulmonary Disease (COPD).

Telerehabilitation, consisting of supervised home-based exercise training via real-time videoconferencing, is an alternative method to deliver pulmonary rehabilitation with potential to improve access. The aims were to determine the level of satisfaction and experience of an eight-week supervised home-based telerehabilitation exercise program using real-time videoconferencing in people with COPD. Quantitative measures were the Client Satisfaction Questionnaire-8 (CSQ-8) and a purpose-designed satisfaction survey. A qualitative component was conducted using semi-structured interviews. Nineteen participants (mean (SD) age 73 (8) years, forced expiratory volume in 1 second (FEV1) 60 (23) % predicted) showed a high level of satisfaction in the CSQ-8 score and 100% of participants reported a high level of satisfaction with the quality of exercise sessions delivered using real-time videoconferencing in participant satisfaction survey. Eleven participants undertook semi-structured interviews. Key themes in four areas relating to the telerehabilitation service emerged: positive virtual interaction through technology; health benefits; and satisfaction with the convenience and use of equipment. Participants were highly satisfied with the telerehabilitation exercise program delivered via videoconferencing.

Physical activity levels improve following discharge in people admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease.

This study aimed to determine the physical activity level of people admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and whether physical activity changed immediately after discharge and 6 weeks post hospital admission. In this prospective observational study, people admitted to hospital with an AECOPD had physical activity levels monitored using the SenseWear(®) Armband (model MF-SW) for 3 days in hospital (T1), during the first week at home following discharge (T2), and at home during the sixth week after admission (T3). Fifty participants (mean age (SD) 71 (10) years) completed the study. There was a linear increase in average steps per day over the three time periods (T1, mean (SD) 1385 (1972) steps/day; T2, 2040 (2680); T3, 2328 (2745); analysis of variance (ANOVA) p = 0.001) and time spent in moderate activity (3.0-6.0 metabolic equivalents; minutes/day) (T1, mean (SD) 16 (27) minutes/day; T2, 32 (46) minutes/day; T3, 35 (58) minutes/day; ANOVA p = 0.008). For both outcomes, post hoc t-tests showed significant improvements from T1 to T2 and from T1 to T3, but not between T2 and T3. Physical activity was low in hospital and significantly improved in the week after discharge but showed no further significant improvement at 6 weeks following a hospitalized AECOPD.

Reversal of functional changes in the brain associated with obstructive sleep apnoea following 6 months of CPAP.

Obstructive sleep apnoea (OSA) is associated with an increase in the number of bursts of muscle sympathetic nerve activity (MSNA), leading to neurogenic hypertension. Continuous positive airway pressure (CPAP) is the most effective and widely used treatment for preventing collapse of the upper airway in OSA. In addition to improving sleep, CPAP decreases daytime MSNA towards control levels. It remains unknown how this restoration of MSNA occurs, in particular whether CPAP treatment results in a simple readjustment in activity of those brain regions responsible for the initial increase in MSNA or whether other brain regions are recruited to over-ride aberrant brain activity. By recording MSNA concurrently with functional Magnetic Resonance Imaging (fMRI), we aimed to assess brain activity associated with each individual subject's patterns of MSNA prior to and following 6 months of CPAP treatment. Spontaneous fluctuations in MSNA were recorded via tungsten microelectrodes inserted into the common peroneal nerve in 13 newly diagnosed patients with OSA before and after 6 months of treatment with CPAP and in 15 healthy control subjects while lying in a 3 T MRI scanner. Blood Oxygen Level Dependent (BOLD) contrast gradient echo, echo-planar images were continuously collected in a 4 s ON, 4 s OFF (200 volumes) sampling protocol. MSNA was significantly elevated in newly diagnosed OSA patients compared to control subjects (55 ± 4 vs 26 ± 2 bursts/min). Fluctuations in BOLD signal intensity in multiple regions covaried with the intensity of the concurrently recorded bursts of MSNA. There was a significant fall in MSNA after 6 months of CPAP (39 ± 2 bursts/min). The reduction in resting MSNA was coupled with significant falls in signal intensity in precuneus bilaterally, the left and right insula, right medial prefrontal cortex, right anterior cingulate cortex, right parahippocampus and the left and right retrosplenial cortices. These data support our contention that functional changes in these suprabulbar sites are, via projections to the brainstem, driving the augmented sympathetic outflow to the muscle vascular bed in untreated OSA.

Cognitive behaviour therapy reduces dyspnoea ratings in patients with chronic obstructive pulmonary disease (COPD).

There is evidence that psychological factors contribute to the perception of increased difficulty of breathing in patients with chronic obstructive pulmonary disease (COPD), and increase morbidity. We tested the hypothesis that cognitive behaviour therapy (CBT) decreases ratings of perceived dyspnoea in response to resistive loading in patients with COPD. From 31 patients with COPD, 18 were randomised to four sessions of specifically targeted CBT and 13 to routine care. Prior to randomisation, participants were tested with an inspiratory external resistive load protocol (loads between 5 and 45cmH2O/L/s). Six months later, we re-measured perceived dyspnoea in response to the same inspiratory resistive loads and compared results to measurements prior to randomisation. There was a significant 17% reduction in dyspnoea ratings across the loads for the CBT group, and no reduction for the routine care group. The decrease in ratings of dyspnoea suggests that CBT to alleviate breathing discomfort may have a role in the routine treatment of people with COPD.

Brain stem activity changes associated with restored sympathetic drive following CPAP treatment in OSA subjects: a longitudinal investigation.

Obstructive sleep apnea (OSA) is associated with significantly elevated muscle sympathetic nerve activity (MSNA), leading to hypertension and increased cardiovascular morbidity. Although little is known about the mechanisms responsible for the sympathoexcitation, we have recently shown that the elevated MSNA in OSA is associated with altered neural processing in various brain stem sites, including the dorsolateral pons, rostral ventrolateral medulla, medullary raphe, and midbrain. Given the risk associated with elevated MSNA, we aimed to determine if treatment of OSA with continuous positive airway pressure (CPAP) would reduce the elevated MSNA and reverse the brain stem functional changes associated with the elevated MSNA. We performed concurrent recordings of MSNA and blood oxygen level-dependent (BOLD) signal intensity of the brain stem, using high-resolution functional magnetic resonance imaging, in 15 controls and 13 subjects with OSA, before and after 6 mo CPAP treatment. As expected, 6 mo of CPAP treatment significantly reduced MSNA in subjects with OSA, from 54 ± 4 to 23 ± 3 bursts/min and from 77 ± 7 to 36 ± 3 bursts/100 heart beats. Importantly, we found that MSNA-coupled changes in BOLD signal intensity within the dorsolateral pons, medullary raphe, and rostral ventrolateral medulla returned to control levels. That is, CPAP treatment completely reversed brain stem functional changes associated with elevated MSNA in untreated OSA subjects. These data highlight the effectiveness of CPAP treatment in reducing one of the most significant health issues associated with OSA, that is, elevated MSNA and its associated elevated morbidity.

Tongue stiffness is lower in patients with obstructive sleep apnea during wakefulness compared with matched control subjects.

STUDY OBJECTIVES: This study aimed to determine whether tongue stiffness (shear modulus) in patients with obstructive sleep apnea (OSA) is different for controls matched for age, sex, and body mass index (BMI), and to investigate the effect of continuous positive airway pressure (CPAP) on stiffness. DESIGN: Controlled experimental study. SETTING: Medical research institute. PARTICIPANTS: Patients with OSA and age-, sex-, and BMI-matched healthy controls. MEASUREMENTS: Magnetic resonance elastography was performed in nine patients with OSA (apnea-hypopnea index (AHI) > 15 events/h) and seven controls (AHI < 10 events/h) matched for age, sex, and BMI. Six of these OSA subjects were also scanned while 10 cmH2O CPAP was applied. Mean isotropic shear modulus and anisotropic shear moduli parallel and perpendicular to the muscle fascicles in the tongue were calculated. RESULTS: Tongue shear modulus in patients with OSA was lower than that in matched controls (2.68 ± 0.35 (mean ± standard deviation) kPa versus 2.98 ± 0.44 kPa, P < 0.001). Shear modulus decreased with increasing AHI (R = -0.496, P = 0.043), but not age, BMI, or percentage tongue fat. Anisotropic analysis revealed that reduction in stiffness was greatest parallel to the muscle fibers. CPAP had no significant effect on tongue shear modulus. CONCLUSIONS: In awake subjects with obstructive sleep apnea, the tongue is less stiff than in similar healthy subjects and this difference occurs in the muscle fiber direction. CPAP did not significantly reduce tongue stiffness. Thus, any change in neural drive to genioglossus during wakefulness is insufficient to restore normal tongue stiffness.

Acceptability of the aquatic environment for exercise training by people with chronic obstructive pulmonary disease with physical comorbidities: Additional results from a randomised controlled trial.

OBJECTIVES: Water-based exercise training is a relatively new concept in the management of people with COPD. This study aimed to examine the acceptability of the aquatic environment as a medium for exercise training in people with COPD with physical comorbidities. DESIGN: Following a supervised eight week, three times a week, water-based exercise training programme conducted in a hospital hydrotherapy pool as part of a randomised controlled trial, participants completed a questionnaire about their experience with exercise training in the pool including adverse events, barriers and factors enabling exercise programme completion, satisfaction with the aquatic environment and their preference for an exercise training environment. RESULTS: All 18 participants (mean (SD) age 72 (10) years; FEV1% predicted 60 (10) %) who commenced the water-based exercise training programme completed the questionnaire. Three participants withdrew from training. High acceptability of the water and air temperature, shower and change-room facilities, staff assistance and modes of pool entry was reported (94% to 100%). Six factors were highly rated as enabling exercise programme adherence and completion: staff support (chosen by 93% of participants), enjoyment (80%), sense of achievement (80%), noticeable improvements (73%), personal motivation (73%) and participant support (53%). Eighty-nine percent of the participants indicated they would continue with water-based exercise. CONCLUSIONS: This study provides the first insight into the acceptability of the aquatic environment for exercise training in people with COPD and indicates water-based exercise and the aquatic environment is well accepted.

Functional and structural changes in the brain associated with the increase in muscle sympathetic nerve activity in obstructive sleep apnoea.

Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnoea (OSA) during daytime wakefulness, leading to hypertension, but the underlying mechanisms are poorly understood. By recording MSNA concurrently with functional Magnetic Resonance Imaging (fMRI) of the brain we aimed to identify the central processes responsible for the sympathoexcitation. Spontaneous fluctuations in MSNA were recorded via tungsten microelectrodes inserted percutaneously into the common peroneal nerve in 17 OSA patients and 15 healthy controls lying in a 3 T MRI scanner. Blood Oxygen Level Dependent (BOLD) contrast gradient echo, echo-planar images were continuously collected in a 4 s ON, 4 s OFF (200 volumes) sampling protocol. Fluctuations in BOLD signal intensity covaried with the intensity of the concurrently recorded bursts of MSNA. In both groups there was a positive correlation between MSNA and signal intensity in the left and right insulae, dorsolateral prefrontal cortex (dlPFC), dorsal precuneus, sensorimotor cortex and posterior temporal cortex, and the right mid-cingulate cortex and hypothalamus. In OSA the left and right dlPFC, medial PFC (mPFC), dorsal precuneus, anterior cingulate cortex, retrosplenial cortex and caudate nucleus showed augmented signal changes compared with controls, while the right hippocampus/parahippocampus signal intensity decreased in controls but did not change in the OSA subjects. In addition, there were significant increases in grey matter volume in the left mid-insula, the right insula, left and right primary motor cortices, left premotor cortex, left hippocampus and within the brainstem and cerebellum, and significant decreases in the mPFC, occipital lobe, right posterior cingulate cortex, left cerebellar cortex and the left and right amygdala in OSA, but there was no overlap between these structural changes and the functional changes in OSA. These data suggest that the elevated muscle vasoconstrictor drive in OSA may result from functional changes within these brain regions, which are known to be directly or indirectly involved in the modulation of sympathetic outflow via the brainstem. That there was no overlap in the structural and functional changes suggests that asphyxic damage due to repeated episodes of nocturnal obstructive apnoea is not the main cause of the sympathoexcitation.

Brainstem changes associated with increased muscle sympathetic drive in obstructive sleep apnoea.

Obstructive sleep apnoea (OSA) is associated with significantly increased bursts of muscle sympathetic nerve activity (MSNA), leading to hypertension and increased cardiovascular morbidity. The underlying mechanism responsible for this sympathoexcitation is unknown. The aim of this investigation was to determine brainstem sites that contribute to this increased on-going muscle vasoconstrictor drive. We measured regional grey matter volume using voxel-based morphometry of T1-weighted anatomical images in 20 subjects with OSA and 19 healthy age-matched controls. We also performed concurrent recordings of MSNA and Blood Oxygen Level Dependent (BOLD) signal intensity of the brainstem, using high-resolution functional magnetic resonance imaging, in 15 subjects with OSA and 15 controls. OSA subjects had significantly elevated MSNA, which was correlated to altered BOLD signal intensity changes in the dorsolateral pons, rostral ventrolateral medulla, medullary raphe and midbrain. The medullary raphe, rostroventrolateral medulla and dorsolateral pons also had significantly increased grey matter volumes in subjects with obstructive sleep apnoea compared with controls. Furthermore, we also found that obstructive sleep apnoea was associated with increases in grey matter volume in the region of the hypoglossal nucleus. These data suggest that the elevated muscle vasoconstrictor drive in obstructive sleep apnoea may result from functional and anatomical changes within the dorsolateral pons, rostroventrolateral medulla and medullary raphe. These brainstem regions are known to modulate sympathetic output either directly or indirectly via sympathetic preganglionic neurons within the spinal cord. In addition, the known increase in genioglossus muscle activity in OSA may reflect the increase in grey matter volume of the hypoglossal nucleus.