Parasomnias

Parasomnias 101 - Sleep's Strange Acts

• Abnormal behaviors/experiences during sleep or sleep-wake transitions.
• Key Types:
  • NREM-Related (Disorders of Arousal):
    • Sleepwalking, Sleep Terrors, Confusional Arousals.
    • Features: First 1/3 of night (N3 sleep), amnesia, hard to arouse.
  • REM-Related:
    • REM Sleep Behavior Disorder (RBD), Nightmare Disorder, Sleep Paralysis.
    • Features: Latter half of night, dream recall.

⭐ REM Sleep Behavior Disorder (RBD) often predates synucleinopathies (e.g., Parkinson's disease, Lewy body dementia).

NREM Parasomnias - Night's Unconscious Antics

• Arousal disorders from NREM stage N3 sleep (slow-wave); occur in the first ⅓ of the night.
• Key Features: Incomplete awakening, significant confusion, reduced responsiveness to stimuli, and subsequent amnesia for the event.
• Common Types:
  • Confusional Arousals: Disorientation, slow speech, and impaired mentation upon partial awakening.
  • Sleepwalking (Somnambulism): Complex motor behaviors (e.g., walking, eating) performed while asleep; risk of injury.
  • Sleep Terrors (Pavor Nocturnus): Sudden arousal with intense fear, screaming, and autonomic hyperactivity (tachycardia, tachypnea, sweating); individual is typically inconsolable.

⭐ Adult-onset or persistent sleepwalking warrants investigation for underlying conditions like Obstructive Sleep Apnea (OSA) or psychiatric disorders.

• Common Triggers: Sleep deprivation, stress, fever, alcohol, certain medications (e.g., zolpidem, SSRIs, antipsychotics).
• Management: Primarily reassurance, ensuring a safe environment (e.g., removing hazards), and managing identifiable triggers. Clonazepam may be considered for severe, frequent, or dangerous episodes. )

REM Parasomnias - Dreamtime Disturbances

• REM Sleep Behavior Disorder (RBD)
  • Complex motor behaviors during REM, enacting dreams (often violent).
  • Due to loss of normal REM sleep atonia.
  • Polysomnography (PSG) confirms: REM sleep without atonia (RSWA).
  • Strong prodromal marker for α-synucleinopathies (Parkinson's, Lewy Body Dementia, MSA).
  • Rx: Clonazepam (low dose), Melatonin.
• Nightmare Disorder
  • Recurrent, extended, extremely dysphoric, well-recalled dreams.
  • Usually occur during the second half of the sleep period.
  • Rapidly alert and oriented upon awakening; causes significant distress/impairment.
• Recurrent Isolated Sleep Paralysis
  • Inability to perform voluntary movements at sleep onset (hypnagogic) or upon awakening (hypnopompic).
  • Consciousness and recall intact; often associated with vivid hallucinations (hypnagogic/hypnopompic).

⭐ RBD has a high conversion rate (over 80% in 10-15 years) to a defined neurodegenerative disease, primarily α-synucleinopathies.

Other Parasomnias & Approach - Oddities & Order

• Uncommon Parasomnias:

  • Exploding Head Syndrome: Abrupt, loud imagined noise/flash on sleep-wake transitions; benign.
  • Sleep Groaning (Catathrenia): Monotonous groaning during expiration, mainly in REM; partner reports.
  • Sleep Paralysis: Transient atonia at sleep onset/offset; often with vivid hallucinations.

• Nightmare Disorder: Recurrent, highly dysphoric, well-recalled dreams, typically in late REM. Tx: Imagery Rehearsal Therapy (IRT), Prazosin.

• Diagnostic & Management Flow:

• Core Management: Education, reassurance, robust sleep hygiene, ensuring environmental safety. Address comorbid conditions.

• Pharmacotherapy (if severe/frequent):

  • NREM Parasomnias/RBD: Clonazepam (0.5-2 mg hs).
  • RBD: Melatonin.

⭐ Video-Polysomnography (V-PSG) is crucial for differentiating parasomnias from nocturnal seizures and confirming REM Sleep Behavior Disorder, especially with injury risk.

High‑Yield Points - ⚡ Biggest Takeaways

• NREM Parasomnias (Sleepwalking, Sleep Terrors): Occur in N3 sleep (first third of night), amnesia for event.
• REM Sleep Behavior Disorder (RBD): Dream-enacting behaviors during REM sleep (latter half), linked to α-synucleinopathies (e.g., Parkinson's).
• Nightmare Disorder: Frightening dreams during REM sleep (latter half), full recall on awakening.
• Key distinction: NREM disorders = amnesia; REM disorders (RBD, Nightmares) = dream recall.
• Clonazepam is effective for RBD; NREM disorders often require only safety measures and reassurance_._