Assessment of sleep studies in myotonic dystrophy

Myotonic dystrophy (MD) is the commonest adult muscular dystrophy and is associated with respiratory muscle weakness. The role of screening sleep studies is unclear in MD. We prospectively evaluated polysomnography/overnight oximetry in a group of MD patients and related this to the daytime respiratory function in an attempt to evaluate the usefulness of screening sleep studies. Twenty-five patients with type I MD [15 males; mean age (SD) 40.0 (10.9) years] who had at least one symptom suggestive of nocturnal hypoventilation were included in the study. We performed spirometry, maximal inspiratory and expiratory mouth pressures, sniff nasal inspiratory pressure, arterial blood gases and polysomnography or overnight oximetry. Excessive tiredness and sleepiness were the most common presenting symptoms. Prevalence of sleep related breathing disorder (SRBD) was 36%. FVC was found to be normal in 33% of subjects with significant SRBD. Mouth pressures were reduced more than FVC, even in patients with normal overnight oxygen saturation. Of all the daytime measures, FVC correlated best with arterial carbon dioxide tension ( r = -0.7). Sleep studies were useful to identify a small group of myotonic dystrophy patients (12%, three out of 25 in our series) with SRBD that would have been missed with routine daytime assessments. Targeted sleep monitoring in patients who are older, with multiple symptoms suggestive of SRBD, especially if they are over-weight seems to be the best way to utilize the existing resources. Home unattended oximetry was well tolerated and offers a practical screening tool in this challenging patient group where excess daytime sleepiness is often due to causes other than SRBD.

Do wind and brass players snore less? A cross-sectional study of snoring and daytime fatigue in professional orchestral musicians

OBJECTIVES

To determine whether playing a wind or brass musical instrument is associated with reduced snoring or daytime fatigue.

DESIGN

Cross-sectional, controlled, anonymous, questionnaire-based observational study.

SETTING

Rehearsal and performance halls.

PARTICIPANTS

Three hundred and forty musicians from Scotland's five professional orchestras.

MAIN OUTCOME MEASURES

Snore Outcomes Survey questionnaire and the Epworth Sleepiness Score.

STATISTICAL METHOD

Hierarchical linear regression analysis.

RESULTS

No significant difference was found between the snoring severity (Snore Outcomes Survey score) or daytime sleepiness (Epworth score) of wind/brass and other professional musicians. A regression model with snoring severity (Snore Outcomes Survey score) as the dependent variable and the three covariates of gender, age and body mass index as independent variables was significant [F(3, 206) = 28.77, P < 0.01, adjusted r(2) = 0.285]. Increasing age, body mass index and male gender were all significantly associated with lower Snore Outcomes Survey scores (i.e. worse snoring).The addition of instrument type did not significantly increase the fit of the model, and the regression coefficient for instrument type was not significant. There were similar results when the Epworth Sleepiness Score was used as the dependent variable.

CONCLUSIONS

This study demonstrated no significant difference between the snoring severity or daytime sleepiness of brass/wind players and other professional orchestral musicians. This result may have been attributed to comparatively low levels of snoring/daytime sleepiness in the population studied. The findings contrast with previous studies examining the effects of singing and didgeridoo playing but concur with a recent similar study of orchestral musicians. A prospective interventional study would be required to determine whether playing a wind or brass instrument improves these variables in patients complaining of disruptive snoring.

Home based neuromuscular electrical stimulation as a new rehabilitative strategy for severely disabled patients with chronic obstructive pulmonary disease (COPD)

BACKGROUND

Passive training of specific locomotor muscle groups by means of neuromuscular electrical stimulation (NMES) might be better tolerated than whole body exercise in patients with severe chronic obstructive pulmonary disease (COPD). It was hypothesised that this novel strategy would be particularly effective in improving functional impairment and the consequent disability which characterises patients with end stage COPD.

METHODS

Fifteen patients with advanced COPD (nine men) were randomly assigned to either a home based 6 week quadriceps femoris NMES training programme (group 1, n=9, FEV(1)=38.0 (9.6)% of predicted) or a 6 week control period before receiving NMES (group 2, n=6, FEV(1)=39.5 (13.3)% of predicted). Knee extensor strength and endurance, whole body exercise capacity, and health related quality of life (Chronic Respiratory Disease Questionnaire, CRDQ) were assessed.

RESULTS

All patients were able to complete the NMES training programme successfully, even in the presence of exacerbations (n=4). Training was associated with significant improvements in muscle function, maximal and endurance exercise tolerance, and the dyspnoea domain of the CRDQ (p<0.05). Improvements in muscle performance and exercise capacity after NMES correlated well with a reduction in perception of leg effort corrected for exercise intensity (p<0.01).

CONCLUSIONS

For severely disabled COPD patients with incapacitating dyspnoea, short term electrical stimulation of selected lower limb muscles involved in ambulation can improve muscle strength and endurance, whole body exercise tolerance, and breathlessness during activities of daily living.