Delayed emergence of a parkinsonian disorder or dementia in 81% of older men initially diagnosed with idiopathic rapid eye movement sleep behavior disorder: a 16-year update on a previously reported series.
Level 4 - case-series / case-control
Longitudinal follow-up of a single-arm case series without a comparison group
PubMed 23347909 · doi:10.1016/j.sleep.2012.10.009
What was done
A 16-year follow-up update was conducted on a previously described 1996 cohort of 29 men aged 50 years or older with video-polysomnography-confirmed idiopathic rapid eye movement sleep behavior disorder (iRBD). The authors tracked the rate and timing of phenoconversion to parkinsonian disorders or dementia.
What was found
Of the 26 patients with available follow-up (3 lost to follow-up), 80.8% (21/26) developed a parkinsonian disorder or dementia. Converted diagnoses included Parkinson's disease (n=13), dementia with Lewy bodies (n=3), multiple system atrophy (n=2), clinically diagnosed Alzheimer's disease with autopsy-confirmed combined Alzheimer's and Lewy body disease pathology (n=2), and unspecified profound dementia (n=1). For the 21 converters, mean (±SD) age of iRBD onset was 57.7 ± 7.7 years, mean age of parkinsonism/dementia onset was 71.9 ± 6.6 years, and mean interval from iRBD onset to conversion was 14.2 ± 6.2 years (range: 5–29 years).
Why it matters
The findings demonstrate that idiopathic RBD is strongly linked to long-term development of neurodegenerative synucleinopathies, with latency periods extending up to nearly three decades. This establishes iRBD as a key prodromal marker and target cohort for trials testing neuroprotective agents.
Limits
The study is limited by a small sample size (n=26 analyzed) comprised entirely of older men, limiting generalizability to women. It is an uncontrolled case series, 3 patients were lost to follow-up, and most diagnoses were made clinically without systematic autopsy confirmation across the entire cohort.
Cited by
- partial Sleep disorders can precede and lead to the development of neurodegenerative diseases like Alzheimer's or Parkinson's disease 20 years later.