A 55-year-old woman describes vivid, frightening dreams during which her husband reports she shouts and physically acts out the dreams without waking. Her REM sleep shows absence of the normal atonia. This REM sleep behavior disorder is associated with future development of which condition?
- A Alzheimer's disease due to amyloid-related hippocampal degeneration
- B Huntington's disease due to striatal degeneration affecting sleep circuitry
- C Alpha-synuclein neurodegenerative diseases such as Parkinson's disease, DLB, or MSA ✓
- D Frontotemporal dementia due to orbitofrontal disinhibition of REM motor circuits
Correct answer: C. Alpha-synuclein neurodegenerative diseases such as Parkinson's disease, DLB, or MSA
Explanation
REM sleep behavior disorder (RBD) results from failure of the normal brainstem mechanisms (sublaterodorsal nucleus/subcoeruleus area) that generate REM atonia, likely due to early alpha-synuclein deposition. Up to 80–90% of idiopathic RBD patients eventually develop an alpha-synuclein synucleinopathy — Parkinson's disease, dementia with Lewy bodies (DLB), or multiple system atrophy (MSA). It is considered a prodromal marker of synucleinopathy. Alzheimer's, Huntington's, and FTD are not specifically associated with idiopathic RBD.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.