**5. Treatment**

*Updates in Sleep Neurology and Obstructive Sleep Apnea*

Disorders, Third Edition include [10]:

medication, or substance abuse.

during REM sleep

**(synucleinopathies)**

18 channel EEG montage during routine diagnostic PSG can help rule out NFLE,

Diagnostic criteria as established by the International Classification of Sleep

• Repeated episodes of sleep related vocalization and/or complex motor behaviors

• Disturbance is not better explained by another sleep disorder, mental disorder,

Once diagnosed, RBD can be classified as primary (idiopathic) or secondary. *Idiopathic RBD* can be considered an early symptom of alpha synucleinopathies which include: Parkinson's disease, Lewy Body Dementia and Multiple System Atrophy. The diagnosis of RBD can be made years before any other neurologic symptoms are identified. In 80% of cases RBD preceded the diagnosis of neurodegenerative disease (more easily recognized motor features), by a mean of 14 years [11]. There is evidence to suggest that patients with RBD and mild cognitive impairment will develop dementia in an interval of 5 years or less [9]. Other subtle potentially predictive biomarkers of RBD (see **Table 4**) include: olfactory loss/anosmia, autonomic dysfunction (ranging from sexual dysfunction to cardiovascular symptoms), color vision deficit, cognitive impairment, excessive daytime sleepiness, psychiatric disorders (such as anxiety, depression, psychosis, impulse control disorders), personality changes, dopamine dysfunction, and excessive EMG activity [11]. The pathophysiology and temporal relation between these symptoms and motor symptom onset is highly variable. Subsequent neurological examination may show subtle signs of Parkinsonism such as mild bradykinesia, while neurocognitive testing can show evidence of memory and executive dysfunction. Neuroimaging is useful if dopamine transporter scan shows evidence of decreased dopamine uptake in the putamen. Electroencephalogram can show cortical slowing as well [9]. Biopsy of the colon and submandibular gland in patients with idiopathic RBD has shown evidence of phosphorylated alpha synuclein deposits.

• Behaviors are documented by polysomnogram to occur during REM sleep or based on clinical history of dream enacting behavior, are presumed to occur

especially if a complex behavior is captured on the PSG study night.

• Polysomnogram demonstrates REM sleep without atonia

**3. Primary rapid eye movement sleep behavior disorder** 

**80**

**Table 4.**

Anosmia

Autonomic dysfunction Color vision deficit Cognitive impairment Excessive daytime sleepiness Psychiatric disorders Personality changes Dopamine dysfunction Excessive EMG activity

*Potential biomarkers of RBD.*

Symptomatic management of RBD should be approached from multiple angles. First, maintaining a safe sleep environment for the patient by removing objects that can inflict harm or lowering the bed closer to the floor. Bed partners may also opt for sleeping in separate bed for their own safety. Co-sleeping is an important part of intimacy, however, and this can continue by advising the patient to sleep in a sleeping bag on top of the bed shared with their loved one. Bed alarms to warn loved ones about the patient exiting the bed can also be helpful in reducing night time injuries associated with RBD.

Medical management with melatonin or low dose benzodiazepines such as clonazepam has been shown to reduce the dream enacting behaviors. Benzodiazepines are thought to work by suppressing REM sleep. Theoretically, other REM suppressant medications (including SSRIs, TCAs, selective SNRIs) may also help, given their mechanism of action. However there are no trials supporting or refuting their efficacy and some may precipitate RBD as previously mentioned. These medications do, however, have lower tolerance and abuse potential than benzodiazepines. These treatments do not modify the risk of progression to PD, MSA, or LBD. Dopaminergic agents have not been shown to reduce dream enactment behaviors but may help comorbid periodic limb movements if present. In RBD cases refractory to conventional treatment, cholinesterase inhibitors such as rivastigmine (studied in one trial) and donepezil (several cases) have been noted to reduce the number of dream enactment episodes as reported by bed partners.
