How to manage a patient with a movement disorder, such as Parkinson's disease (PD) or essential tremor (ET), that persists during sleep?

Movement Disorders Persisting During Sleep

The primary movement disorder that persists during sleep is REM Sleep Behavior Disorder (RBD), which requires environmental safety measures as first-line intervention, followed by pharmacotherapy with clonazepam (0.25-1.0 mg at bedtime) or immediate-release melatonin (3-15 mg at bedtime) as conditional first-line treatments. 1

Understanding Movement Disorders in Sleep

Most movement disorders associated with Parkinson's disease (PD) and essential tremor (ET) actually decrease or disappear during sleep due to normal muscle atonia. 2, 3 The critical exception is RBD, where the normal paralysis of REM sleep is lost, allowing patients to physically act out their dreams. 1

Key Distinction: RBD vs. Typical PD Movements

• RBD movements occur specifically during REM sleep (typically latter half of night), involve loss of normal muscle atonia on polysomnography, and consist of dream enactment behaviors ranging from subtle limb twitches to complex violent actions. 1
• Typical PD tremor and rigidity are generally suppressed during sleep, though some motor activity may persist during wakefulness periods at night. 2
• RBD is extremely common in PD, affecting up to 80% of patients, and may precede motor symptoms by years. 4, 2

Mandatory First Step: Environmental Safety

Before any pharmacological intervention, implement comprehensive bedroom safety measures to prevent injury—this is a critical good practice statement. 1

Specific Safety Interventions Required:

• Remove all weapons from the bedroom, particularly loaded firearms, as they can be discharged during episodes. 4
• Remove or pad sharp furniture (nightstands, headboards, dresser corners). 1, 4
• Place soft carpet, rug, or mat next to the bed to cushion falls. 1
• Consider lowering the mattress to floor level for severe cases. 1, 4
• Install window protection if episodes involve getting out of bed. 4
• Separate sleeping arrangements for severe uncontrolled RBD, or at minimum place a pillow barrier between patient and bed partner. 1

Pharmacological Management Algorithm

For RBD Secondary to Parkinson's Disease:

First-Line Options (choose based on patient factors):

1. Clonazepam 0.25-1.0 mg at bedtime 1

   • Most commonly prescribed and effective in 90% of cases. 1
   • Reduces dream enactment with minimal effect on REM muscle tone. 1
   • Avoid in patients with: dementia/cognitive impairment, sleep apnea, high fall risk, or respiratory disease. 1, 4
   • Listed on Beers Criteria as potentially inappropriate in older adults. 1
   • May cause morning drowsiness—can be taken 1-2 hours before bedtime if this occurs. 1
   • Discontinuation typically results in symptom recurrence. 1

2. Immediate-release melatonin 3 mg at bedtime, titrate up to 15 mg in 3 mg increments 1

   • Preferred in patients with: dementia, cognitive impairment, sleep apnea, or high fall risk. 4
   • Suppresses REM motor tone and normalizes circadian REM features. 1
   • Effects persist several days after discontinuation but gradually reemerge. 1
   • Available over-the-counter in US/Canada but quality varies—look for USP Verification Mark. 1

3. Transdermal rivastigmine (for PD patients specifically) 1

   • Conditional recommendation for RBD secondary to Parkinson's disease. 1
   • Consider particularly if cognitive impairment is present. 1

Second-Line Option:

Pramipexole 0.125 mg at bedtime, slowly titrate up to 2.0 mg 1

• Dopamine agonist that may reduce dream enactment, possibly by treating underlying periodic limb movements. 1
• Mechanism in RBD is uncertain as RBD is not caused by dopaminergic dysfunction. 1
• Caution: Can cause nausea, orthostasis, and impulse control disorders. 1, 5

Combination Therapy:

• If monotherapy with clonazepam or melatonin is inadequate, combination therapy is commonly used in clinical practice, though evidence is limited. 1

Drug-Induced RBD:

If RBD is medication-induced (SSRIs, TCAs, MAOIs most common), discontinue the offending agent when possible. 1

Critical Pitfalls to Avoid

Do Not Confuse RBD with Other Nocturnal Movements:

• Periodic limb movements are rhythmic, stereotyped toe/ankle movements every 20-40 seconds during NREM sleep, not violent dream enactment. 6
• Nocturnal leg cramps are painful muscle contractions relieved by stretching, without urge to move. 6
• Restless legs syndrome involves uncomfortable urge to move while awake/resting, relieved by movement. 6, 7

Avoid Deep Brain Stimulation for RBD:

The AASM conditionally recommends against using DBS for treatment of RBD secondary to medical conditions. 1

Diagnostic Confirmation Required

Polysomnography with video-audio monitoring is mandatory to confirm RBD diagnosis before initiating treatment, documenting either: 4

• Sustained muscle activity (>50% of REM epoch with elevated chin EMG), OR
• Excessive transient muscle activity (phasic bursts in >50% of mini-epochs). 4

Prognostic Counseling

Patients with idiopathic RBD have a 70% risk of developing neurodegenerative α-synucleinopathy (PD, dementia with Lewy bodies, multiple system atrophy) within 12 years of diagnosis. 4 This counseling is important for long-term monitoring and care planning. 1

Monitoring and Follow-Up

• Reassess treatment efficacy and side effects regularly. 4
• Monitor for development of neurodegenerative symptoms in isolated RBD. 4
• Screen for melanoma regularly, as PD patients have 2-6 fold increased risk. 5
• Assess for impulse control disorders (gambling, hypersexuality) if using dopaminergic agents. 5