Rapid Picture Naming in Parkinson's Disease Using the Mobile Universal Lexicon Evaluation System (MULES) Test

The Mobile Universal Lexicon Evaluation System (MULES) is a test of rapid picture naming that captures an extensive visual network involving afferent/efferent visual and cognitive pathways. MULES performance is impaired in concussion and multiple sclerosis in which visual impairment is common. Similarly, visual deficits also occur in Parkinson's Disease (PD). These visual deficits influence overall motor function and are a risk factor for developing visual hallucinations. Since many of the visual factors captured by MULES may be abnormal in PD (e.g., visual acuity, color discrimination, object recognition, visual processing speed, and saccadic eye movements), MULES may serve as a useful screening tool for visual dysfunction in PD. The purpose of this study was to introduce MULES to visual assessment in PD.