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.10
REM Behavior Disorder
REM behavior disorder (RBD) is a prodromal symptom of PD — statistically, 50% of people who have RBD will develop PD within 10 years.11 The first stage of managing RBD is to modify the sleeping environment to ensure the safety of the patient and their sleeping partner. Medicinal options include melatonin or clonazepam, neither of which have been clinically shown to worsen PD symptoms or interfere with the any of the pharmaceuticals used to treat PD.8,11
Unrelated Sleep Disorders
Other sleep disorders that are not associated with PD, such as obstructive sleep apnea (OSA), although not more common in patients with PD still occur at the same rates as in the general population.12 Therefore, there will be some select individuals who suffer from both PD and unrelated sleep disorders. There is limited clinical evaluation of traditional treatments for these sleep disorders in PD, so clinicians should use their discretion when adopting methods such as continuous positive airway pressure and be mindful of how PD symptoms may interfere with the treatment of the sleep disorder.
Choosing a Treatment Method
Finding a suitable treatment for sleep disorders in patients with movement disorders can be difficult. In cases in which the movement disorder is directly responsible for affecting the patient’s sleep, effective treatment of the underlying condition usually leads to full sleep performance being restored. However, in the case of more complicated conditions that have an indirect relationship with sleep quality, treatment methods can be much more difficult to determine because physicians need to bear in mind the effect that any treatment will have on the symptoms associated with the movement disorder. Dr Mari advised, “Only a full sleep consultation by a sleep neurologist may be able to help properly diagnose a sleep disorder in complex, neurodegenerative movement disorders and provide the right direction for therapy.”
More clinical research is needed in this area, but until then clinicians and sleep neurologists must work together closely to help formulate a specific treatment plan that has the potential to improve the quality of life of each patient.
- Florida Hospital. Statistics of restless leg syndrome, Florid Hospital. www.floridahospital.com/restless-legs-syndrome-rls/statistics-restless-leg-syndrome-rls. 2018. Accessed September 19, 2018.
- Hoque R, Chesson A. Pharmacologically induced/exacerbated restless leg syndrome, periodic limb movements of sleep, and REM behaviour disorder/REM sleep without atonia: literature review, qualitative scoring and comparative analysis. J Clin Sleep Med. 2018;6(1):79-83.
- Rangarajan S, d’Souza GA. Restless legs syndrome in Indian patients having iron deficiency anemia in a tertiary care hospital. Sleep Med.2018;8(3):247-251.
- Trenkwalder C, Paulus W. Restless leg syndrome: pathophysiology, clinical presentation and management. Nature Rev Neurol. 2018;6:337-346.
- Silver N, Allen R, Senerth J, Earley C. Sleep Medicine. 2011;12(5):440-444.
- Pigeon W, Yurcheshen M. Behavioural sleep medicine interventions for restless leg syndrome and periodic limb movement disorder. Sleep Med Clin. 2009;4(4):487-494.
- Florida Hospital. Statistics of Parkinson’s disease, Florid Hospital. www.floridahospital.com/parkinsons-disease-pd/statistics-parkinsons-disease-pd. 2018. Accessed September 19, 2018.
- Gulyani S, Salas R, Mari Z, Choi S, Mahajan A, Gamaldo C. Evaluating and managing sleep disorders in the Parkinson’s disease clinic. Basal Ganglia. 2016;6(3):165-172.
- Morgenthaler T, Kapur V, Brown T, et al. Practice parameters for the treatment of narcolepsy and other hyposomnias of central origin: an American Academy of Sleep Medicine report. Sleep. 2007;30(12):1705-1711.
- Srinivasan V, Cardinali D, Srinivasan U, et al. Therapeutic potential of melatonin and its analogues in Parkinson’s disease: focus on sleep and neuroprotection. Ther Advan Neurolog. Dis. 2011;4(5):297-317.
- Howell MJ, Schneck CH. Rapid eye movement sleep behaviour disorder and -neurodegenerative disease. JAMA Neurol. 2015;72(6):707-712.
- Diederich NJ, Vaillant M, Leischen M, et al. Sleep apnea syndrome in Parkinson’s disease. A case-control study in 49 patients. Mov Dis. 2005;20(11):1413-1418.