REM Behavior Disorder is another sleep disorder seen more frequently in MS. In this disorder, the individual has the paradoxical ability to act out their dreams. Normally, with the exception of the diaphragmatic and extraocular muscles, we become paralyzed during REM sleep (dream). We believe this results from damage to nerves in the brainstem that are involved in MS.
These areas of the brainstem normally send inhibitory signals to the spinal cord during REM sleep, causing paralysis. In the case of REM Behavior Disorder, this inhibition is lost. In many cases the dreams are of a violent nature and can result in harm to the individual or bed partner. Both the benzodiazepine Clonazepam as well as melatonin has been found to be effective in treating this condition.
Narcolepsy is also seen more commonly in MS. In fact, MS is listed as the fourth most common cause of narcolepsy that is associated with other disorders. In narcolepsy, the individual develops overwhelming sleepiness. This is accompanied by severe paroxysms with loss of muscle tone which are brought on by emotions such as laughing, anger, or being startled. This can affect the legs, arms, or facial muscles, and last from seconds to several minutes. This is called cataplexy. Both MS and narcolepsy share some common genetic links. This is one theory as to why narcolepsy occurs with increased frequency in MS.
Insomnia is another sleep disorder seen more commonly in MS. In some studies, as many as 50% of people with MS had insomnia. The most common causes for an inability to fall asleep were pain and spasm (27%) and anxiety (22%). The most common cause of an inability to remain asleep was nocturia–night time urination (40%). This is due to the fact that the bladder function, referred to as neurogenic bladder, is present in 80% of patients with M.S.
As in the general population, insomnia in MS is treatable. A multifaceted approach is indicated. The healthcare provider must appreciate and treat the associated conditions that are responsible while working on proper sleep hygiene, cognitive behavioral therapy, and medications if necessary.
There is evidence that sleep and the immune system interact in MS. Inflammatory mediators called cytokines are found in high concentrations in MS. These cytokines cause fatigue and sleepiness, two common symptoms in MS. However, sleep disorders such as sleep apnea and insomnia can also result in an increase in their production, thus potentially exacerbating MS and worsening symptoms. That is why it is so important to diagnose and treat sleep disorders in people with MS.
Finally, researchers at the University of Wisconsin have found in studying mice, sleep intensifies the production of cells that make myelin. This is the substance that protects the circuitry of the central nervous system and assures its proper functioning. It was found that the cells that produce myelin, called oligodendrocytes, double during sleep. Additionally, genes resulting in cell death were turned on when the animals were forced to stay awake. The researchers feel this study may suggest that sleep loss may worsen MS.
The take home message here is that if you or a loved one has MS, don’t assume that all of the symptoms are due to the MS. An underlying and treatable sleep disorder may be present. Its diagnosis and treatment can result in both a tangible improvement in quality of life and decreased frequency of attacks.