REM sleep, characterized by rapid eye movements and active brainwaves, occurs in five to seven cycles each night and makes up 20–25% of total sleep. Individuals awakened during this stage often recall vivid dreams. Unlike deep sleep, REM sleep supports memory consolidation and emotional processing. Disruptions in REM sleep have been linked to memory issues, anxiety, and depression. Physiologically, REM sleep features muscle atonia (temporary muscle paralysis), irregular breathing, fluctuating heart rates, and rapid eye movements.
REM sleep behavior disorder occurs when muscle atonia fails during REM sleep, allowing individuals to physically act out vivid and often violent dreams. This condition is more common in older adults, particularly men. Typical behaviors include shouting, kicking, punching, or falling out of bed—sometimes resulting in bruises, fractures, or even brain injuries. In severe cases, patients may unintentionally harm their bed partner. While sometimes mistakenly dismissed as age-related sleep-talking, RBD is rooted in brainstem dysfunction and requires clinical attention.
A 12-year longitudinal study conducted by McGill University in Canada found that nearly 50% of individuals diagnosed with RBD later developed Parkinson’s disease or dementia. This strong association positions RBD as an early clinical marker of neurodegenerative disorders, reflecting deterioration in brain pathways responsible for movement and cognition.
Dr. Kim adds, “RBD frequently signals progressive neurodegeneration, with many patients ultimately diagnosed with Parkinson’s disease or dementia. A reduced sense of smell, or olfactory dysfunction, is another early warning sign. When RBD is accompanied by this symptom, prompt evaluation with a sleep study is essential.”
Lim Hye Jung, HEALTH IN NEWS TEAM
press@hinews.co.kr
