Contrast Sensitivity Visual Acuity is Degraded in REM Sleep Behavior Disorder

REM Sleep Behavior Disorder (RBD) is a sleep disorder that produces motor enactment during REM sleep. Although pathophysiology is uncertain, studies demonstrate nigrostriatal dopamine deficiencies in RBD patients,1 a condition frequently linked to alpha-synuclein-associated disorders i.e. Parkinson's disease (PD), characterized by cellular alpha-synuclein aggregation and death in dopamine producing cells. We previously reported contrast sensitivity visual acuity (CSVA) deficits in early-stage Parkinsonism.2 A recent study identified that misfolded alpha-synuclein, a regulator of dopamine synthesis, is present in the inner retina of PD patients.3 We therefore speculated that CSVA might be impaired in individuals with RBD.