Fifty percent of MS patients report that the quality of their sleep is inadequate. : "A common symptom of MS is general fatigue and this report discusses the relevance of underlying sleep disorders. Sleep disorders, as opposed to general tiredness, should be correctly diagnosed since the two complaints require different treatment strategies. For example, clinical studies have shown that the drug Modafinil used for excessive sleepiness has no effect on fatigue.

In order to determine a correct diagnosis it is important to recognise that a patient may use the term “fatigue” to describe sleepiness. A patient is initially required to fill out a sleep diary and give a symptom history to decide if there is a primary sleep disorder. It is possible that medications the patient is taking may affect sleep patterns.

Electrophysiological tests looking at electrical activity of the brain can be used to determine the quality of night time sleep and various day time tests are used to look at sleep drive though out the day. Similarities between the sleep disorder narcolepsy and MS have been reported, indicating that these patients have a predisposition to excessive sleepiness. Napping and sleeping throughout the day can affect the quality of night time sleep and these features need to be determined.

Patients with MS can also suffer sleeping disorders to the same extent as the general population, such as insomnia or sleep apnoea where breathing temporarily stops for example. Given that over 30% of the general population suffer from primary insomnia which is not related to any psychiatric, medical or identifiable reason, it is probable that some MS patients have the same issues. However, MS patients may have additional sleep disruption problems such as leg-jerking movements which affect their ability to sleep as seen in 36% of patients.

Fatigue issues can be reduced by avoiding excessive heat, modifying time management of daily activities, and identifying whether depression is an underlying factor. Certain drug strategies such as Amantadine can be used. However, it is important to obtain a correct diagnosis whether it is a sleep or fatigue problem.