From the Guidelines
Rapid Eye Movement Sleep Disorder (RMTD) is primarily associated with REM sleep, but it can also occur during Non-Rapid Eye Movement Sleep stage 2 (N2 sleep), although this is considered atypical and may represent a variant of the disorder or overlap with other parasomnias. The phenomenon of RMTD during N2 sleep occurs when the normal muscle paralysis (atonia) that accompanies REM sleep is incomplete or absent, allowing patients to physically act out their dreams 1. The underlying mechanism involves dysfunction in the brainstem pathways responsible for muscle atonia during sleep, particularly the sublaterodorsal nucleus and related structures. When these pathways are compromised, patients may exhibit movements ranging from simple twitches to complex behaviors during what should be periods of muscle paralysis.
Some key points to consider in the diagnosis and treatment of RMTD include:
- The use of polysomnography with video monitoring for proper identification of RMTD, especially in cases where the disorder presents atypically during N2 sleep 1.
- Treatment approaches that remain similar to classic RMTD, including medications like clonazepam or melatonin, and addressing any underlying conditions 1.
- The importance of considering the patient's quality of life and potential risks, such as injury to themselves or their bed partners, when developing a treatment plan for RMTD 1.
- The need for ongoing monitoring and adjustment of treatment as necessary, given the potential for RMTD to evolve over time or overlap with other sleep disorders 1.
In terms of specific treatment options, clonazepam and melatonin are commonly used medications for RMTD, with clonazepam promoting GABAergic inhibition and melatonin binding to the M1 and M2 receptors to suppress REM sleep motor tone 1. The choice of medication and dosage will depend on the individual patient's needs and response to treatment, and may involve a combination of therapies to achieve optimal results.
From the Research
Rapid Eye Movement Sleep Disorder (RMTD) and Non-Rapid Eye Movement Sleep stage 2 (N2 sleep)
- The provided studies do not directly address whether Rapid Eye Movement Sleep Disorder (RMTD) can occur during Non-Rapid Eye Movement Sleep stage 2 (N2 sleep) 2, 3, 4, 5, 6.
- However, the studies suggest that RMTD is characterized by the loss of muscle atonia during REM sleep, known as REM sleep without atonia (RSWA), and is typically associated with dream enactment behaviors that emerge during REM sleep 4, 5.
- The studies do not provide evidence that RMTD can occur during N2 sleep, which is a stage of non-REM sleep 2, 3, 4, 5, 6.
- It is worth noting that the proportion of N2 sleep was increased in patients treated with clonazepam for RBD, but this does not necessarily imply that RMTD can occur during N2 sleep 2.
REM Sleep Behavior Disorder (RBD) and Sleep Stages
- RBD is characterized by complex behavioral manifestations in response to dream content that may cause sleep disruption or injuries to the patient or the bed partner, and is typically associated with REM sleep 3, 4, 5, 6.
- The studies suggest that RBD can result in significant injuries, prompting patients to seek medical attention, and can also present as non-violent behaviors noted as an incidental finding during polysomnography (PSG) 4, 5.
- The discovery that isolated or idiopathic RBD (iRBD) represents a prodromal stage of incurable synucleinopathies has galvanized the research community into delineating the pathophysiology of RBD and defining biomarkers of neurodegeneration 4.
Treatment of RBD
- Clonazepam and melatonin are recommended as first-line treatments for isolated RBD, with clonazepam being efficacious and well tolerated by the majority of patients afflicted by RBD 2, 3.
- Melatonin may be a good alternative to clonazepam in patients at risk of falls who have cognitive impairment or who have obstructive sleep apneas 3.
- Anticholinesterase inhibitors and dopaminergic agents are not of clear benefit, and monoamine oxidase inhibitors, tricyclic antidepressants, serotonergic synaptic reuptake inhibitors, and noradrenergic antagonists can induce or aggravate RBD symptoms and should be avoided in patients with RBD 3.