Fatigue is not due to sleep apnoea

Fatigue and sleep disorders. #MSBlog #MSResearch

"I have previously stressed the importance of sleep hygiene in MSers to improve daytime fatigue levels and the possibility of sleep disorders occurring in MSers due to their disease. This study albeit it very small suggests that sleep disorders are rare in MSers and not a major cause of daytime tiredness and fatigue. Although uncommon sleep apnoea and other sleep disorders need to be excluded when addressing daytime fatigue. Other causes of a poor nights sleep need to be treated as well; i.e. restless legs, limb jerks and spasms, pain, urinary frequency. stimulants (caffeine and drugs), excessive alcohol intake,  and anxiety and depression. Anxiety and depression are a frequent cause of early morning wakening; don't ignore them."  


Wunderlin et al. Fatigue in multiple sclerosis is not due to sleep apnoea. Eur J Neurol. 1997 Jan;4(1):72-78.

Background: Fatigue is a frequent and disabling phenomenon among MSers. Daytime sleepiness is a typical symptom of the sleep apnoea/hypopnoea syndrome due to nocturnal hypoxia (lack of oxygen at night) and recurrent arousals causing sleep fragmentation. 

Hypothesis: Since MS plaques are often found in the midbrain, brain stem and upper cervical cord on magnetic resonance imaging (MRI) we hypothesized that fatigue in MS patients might be caused by a central respiratory dysfunction. 

Methods: We investigated 10 MSers by oligography, two questionnaires assessing fatigue (Fatigue Severity Scale, FSS) and daytime sleepiness (Epworth Sleepiness Scale, ESS), MRI and pulmonary function tests. 

Results: A total of 6 MSers had either an elevated FSS and/or an elevated ESS. None of the 6 MSers with an elevated FSS and/or ESS has an apnoea index > 5/hour. CT90 was normal in 9 MSers. 

Conclusion: We conclude that fatigue and daytime sleepiness in MS cannot be explained by nocturnal apnoeas or oxygen desaturations. The Fatigue Severity Scale should be integrated to the extended Barthel index, which is a new instrument for disability assessment in MSers.

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