Treatment Considerations for Movement Disorder-Related Sleep Disorders
Movement disorders often interfere with sleep and can considerably reduce the quality of life of individuals who suffer from these kinds of disturbances. In most cases, involuntary movements make it difficult to fall asleep; however, in some movement disorders — such as Parkinson disease [PD] — the disorder may affect the neurologic condition of the patient and cause other sleep-related issues such as insomnia and rapid eye movement (REM) sleep behavior disorder.
Treatment of the underlying movement disorder may help, worsen, or interfere with the treatment of the related sleep disorder, proving to be a particularly complicated therapeutic area. “Most often, the sleep disorder in the context of a movement disorder will have to be fully assessed diagnostically and treated accordingly, as there is not a single formula or treatment and the nature of sleep disorders [in different movement disorders] can be diverse across patients,” said Zoltan Mari, MD, chair of movement disorders at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas, Nevada.
Restless Leg Syndrome
Restless leg syndrome (RLS) is one of the most common movement disorders, affecting as many as 1 in 10 people in the United States, with 5 million people suffering from moderate to severe RLS.1 It is considered a sleep-wake condition: the majority of these patients experience worse symptoms during the evening as they try to fall asleep, and so it has a detrimental effect on their sleep routines.2 RLS may be caused by iron deficiency,3 certain pharmaceutical drugs,2 conditions that cause low dopamine levels in the brain, or even genetics.4 By determining the cause of RLS, a suitable treatment plan can be found, which may include iron supplements, dopamine agonists,5 lifestyle changes, and/or physical therapy.
Addressing Sleep Disorders in Parkinson Disease
PD is a neurodegenerative disease that affects up to 1 million people in the United States.7 Its symptoms usually include difficulty with motor control, but PD can also be associated with non-motor symptoms, such as sleep disturbances, which affect approximately 64% of patients with PD.8 PD is associated with a wide range of sleep disturbances, including insomnia, hypersomnia, and REM sleep behavior disorder.
As with all common sleep disorders, teaching patients with PD about the importance of sleep hygiene is the first step. Ensuring that an individual avoids bright lights before bed, goes to bed at the same time every day, and other simple techniques can have positive effects on sleep quality and will have no effect on any form of PD treatment. In the case of hypersomnia, if good sleep hygiene does not resolve the issue of daytime sleepiness, mild stimulants may be prescribed. Modafinil is the most commonly prescribed drug for this purpose and has reportedly been well tolerated in PD.8,9 Adverse effects include depression, headaches, and insomnia; however, to this date, it has not been seen to have any specific adverse effects in PD.
Insomnia sufferers are usually prescribed benzodiazepines, a mild tranquilizer that induces relaxation. However, this treatment is not always suitable for patients with PD, as tranquilizers and hypnotics are associated with worsening of cognitive and memory functions. In patients with PD, melatonin or melatonergic agents are often prescribed for patients experiencing poor sleep quality or who have difficulty falling asleep at night.8 These medications have not been shown to have any adverse effects and can be a particularly effective treatment in PD because these patients often have lower levels of melatonin receptors in the brain compared with healthy individuals.