Idiopathic REM sleep behavior disorder

1. Idiopathic REM sleep behavior disorder impairs visual acuity in both the iRBD and PD groups.

   “one study reported functional changes, including diminished contrast sensitivity and visual acuity in both the iRBD and PD groups.”

   Reviewin both the iRBD and PD groups

   Retinal Architecture in Parkinson's Disease with Rapid Eye Movement Sleep Behaviour Disorder: Insights from a Scoping Review

   Annals of neurosciences·Jun 3, 2026

1. Idiopathic REM sleep behavior disorder decreases retinal layer thickness in subjects with iRBD and PD with and without RBD.

   “Findings reported thinning of the retinal ganglion cell layer, nerve fibre layer (RNFL), outer and inner plexiform layers, inner and outer nuclear layers”

   Reviewin subjects with iRBD and PD with and without RBD

   Retinal Architecture in Parkinson's Disease with Rapid Eye Movement Sleep Behaviour Disorder: Insights from a Scoping Review

   Annals of neurosciences·Jun 3, 2026

More on Retinal layer thickness

1. Idiopathic REM sleep behavior disorder is associated with neurodegenerative disease in humans (idiopathic REM sleep behavior disorder) (8 (24%) developed neurodegenerative illness).

   “8 (24%) iRBD subjects developed neurodegenerative illness”

   Humansidiopathic REM sleep behavior disorder1 to 3 years9 women and 24 mensn = 33

   Neurologic and psychiatric features of impending neurodegeneration in iRBD

   Clinical parkinsonism & related disorders·Aug 25, 2023

2. Idiopathic REM sleep behavior disorder is associated with neurodegenerative disease in humans (Japanese patients with idiopathic REM sleep behavior disorder) (14 (24.6%) developed neurodegenerative disorders; estimated cumulative incidence 18.5% at 5 years and 68.1% at 10 years).

   “Among 57 consecutive patients diagnosed with iRBD, 14 (24.6%) were later diagnosed with neurodegenerative disorders.”

   HumansJapanese patients with idiopathic REM sleep behavior disorderFollow-up of ≥6 monthsn = 57

   Retrospective analysis of the incidence of neurodegenerative disorders in idiopathic rapid eye movement sleep behavior disorder: a preliminary study in Japanese patients

   Fujita medical journal·Jan 1, 2020

More on Neurodegenerative disease

1. Idiopathic REM sleep behavior disorder predicts alpha-synucleinopathy in humans (more than a 90% risk at 14 years follow-up).

   “People diagnosed with idiopathic rapid eye movement (REM) sleep behavior disorders have more than a 90% risk of developing an α-synucleinopathy at 14 years follow-up.”

   Review14 years follow-up

   Sleep and Neurodegeneration

   Continuum (Minneapolis, Minn.)·Aug 3, 2026

More on Alpha-synucleinopathy

1. Idiopathic REM sleep behavior disorder is associated with turning angular velocity in TUG at normal speed (p = 0.006, p < 0.001).

   “iRBD participants also showed a longer turn duration and lower mean (p = 0.006) and peak angular velocities (p < 0.001) compared to controls, but only in the TUG at normal speed.”

   Humansin TUG at normal speed

   Turning alterations detected by mobile health technology in idiopathic REM sleep behavior disorder

   NPJ Parkinson's disease·Mar 18, 2024