Sleep-Related Movement Disorders

Sleep Movements - Nighttime Twitch Party

• Simple, stereotyped movements during sleep or wakefulness, disrupting sleep.
• Restless Legs Syndrome (RLS):
  • Irresistible urge to move legs, worse with rest/evening, relieved by movement.
  • Associations: Iron deficiency (check ferritin), uremia, pregnancy, neuropathy.
  • Tx: Dopamine agonists (pramipexole, ropinirole), gabapentinoids.
• Periodic Limb Movement Disorder (PLMD):
  • Repetitive, brief limb jerks during sleep (0.5-10s duration, 5-90s intervals).
  • Patient often unaware; bed partner complains; daytime sleepiness.
  • PSG: PLMS index > 15/hour (adults); > 5/hour (children).
  • Tx: Similar to RLS if symptomatic or causing arousals.

⭐ In RLS, always check serum ferritin; aim for > 50-75 ng/mL with iron supplementation if low.

Itchy Legs Club - RLS & PLMD Unpacked

Restless Legs Syndrome (RLS) / Willis-Ekbom Disease:

• Diagnostic Criteria (📌 URGE):
  • Urge to move legs, often with dysesthesias.
  • Rest or inactivity precipitates/worsens.
  • Getting up or movement provides relief.
  • Evening or night-time predominance.
• Key Associations: Iron deficiency (ferritin!), uremia, pregnancy, neuropathy, meds (SSRIs, antihistamines, dopamine blockers).
• Management:
  • Non-pharma: Good sleep hygiene, avoid triggers (caffeine).
  • Iron supplementation if serum ferritin < 75 ng/mL.
  • Rx: Dopamine agonists (pramipexole, ropinirole), Alpha-2-delta ligands (gabapentin, pregabalin).
  • ⚠️ Augmentation risk with dopamine agonists.

Periodic Limb Movement Disorder (PLMD):

• Repetitive, stereotyped limb movements (PLMS) during sleep.
• Dx: PSG: PLMS index > 15/hr (adults) or > 5/hr (children) with associated symptoms (e.g., insomnia, daytime fatigue). Not otherwise explained.
• Often co-occurs with RLS, narcolepsy, OSA.
• Rx if symptomatic: Treat RLS if present. Options similar to RLS; clonazepam.

⭐ Serum ferritin < 75 ng/mL is a key treatable RLS factor. Aim > 75 ng/mL with iron if low.

Grinds & Bumps - Bruxism & RMDs

• Bruxism (Sleep Bruxism - SB)
  • Definition: Repetitive jaw-muscle activity; teeth grinding/clenching during sleep.
  • Triggers: Stress, anxiety, Obstructive Sleep Apnea (OSA), certain medications (e.g., SSRIs).
  • Symptoms: Tooth wear, jaw pain/hypertrophy (masseter), morning headaches.
  • Diagnosis: Clinical history, dental examination; Polysomnography (PSG) shows masseter EMG bursts.
  • Management: Dental splints/mouthguards, stress reduction. Botulinum toxin for refractory cases.
• Rhythmic Movement Disorder (RMD)
  • Definition: Repetitive, stereotyped movements (e.g., head banging, body rocking, head rolling) near sleep onset or during sleep. 📌 Mnemonic: "Rock, Bang, Roll".
  • Prevalence: Common in infants/toddlers (up to 59%), usually benign and self-limiting.
  • Diagnosis: Clinical history; video-PSG if atypical, persistent, or injurious.
  • Management: Reassurance, safety measures (e.g., padding crib). Clonazepam if severe/injurious.

  ⭐ RMD movements typically cease immediately upon arousal from sleep or if the child is called by name or touched gently.

Acting Out Dreams - RBD Alert

• REM Sleep Behavior Disorder (RBD): Parasomnia characterized by dream-enacting behaviors (e.g., punching, kicking, vocalizing) due to loss of normal muscle atonia during REM sleep.
• Pathophysiology: Dysfunction of brainstem nuclei (e.g., pontine tegmentum) responsible for REM atonia.
• Strong Association: Often a prodromal sign of α-synucleinopathies:
  • Parkinson’s Disease (PD)
  • Lewy Body Dementia (LBD)
  • Multiple System Atrophy (MSA)
  • May precede motor symptoms by years to decades.
• Clinical Features: Vivid, often violent dreams; patient unaware but bed partner may report. Risk of injury to self or partner.
• Diagnosis: Polysomnography (PSG) showing REM sleep without atonia (RSWA) + characteristic history.
• Management:
  • Safety: Padded bed, remove sharp objects.
  • Pharmacological: Clonazepam (first-line), Melatonin.

⭐ RBD is a highly specific predictor of future neurodegenerative disease, particularly α-synucleinopathies, with a conversion rate of over 80% within 10-15 years after diagnosis of idiopathic RBD.

High‑Yield Points - ⚡ Biggest Takeaways

• Restless Legs Syndrome (RLS): Irresistible urge to move legs, worse at rest/evening, relieved by activity. Key association: iron deficiency. Treat: dopamine agonists, gabapentin.
• Periodic Limb Movement Disorder (PLMD): Repetitive limb jerks during sleep, confirmed by PSG. Often with RLS.
• REM Sleep Behavior Disorder (RBD): Acting out dreams (loss of REM atonia). High risk for α-synucleinopathies (e.g., Parkinson's). Treat: clonazepam.
• Sleep Bruxism: Involuntary teeth grinding/clenching during sleep; causes dental wear, jaw pain.
• Rhythmic Movement Disorder (RMD): Stereotyped movements (e.g., head banging) near sleep onset; common in children, often benign.