Rigby, Heather

Background: Low-contrast vision is thought to be reduced in Parkinson's disease (PD). This may have a direct impact on quality of life such as driving, using tools, finding objects, and mobility in low-light condition. Low-contrast letter acuity testing has been successful in assessing low-contrast vision in multiple sclerosis. We report the use of a new iPad application to measure low-contrast acuity in patients with PD. Objective: To evaluate low- and high-contrast letter acuity in PD patients and controls using a variable contrast acuity eye chart developed for the Apple iPad. Methods: Thirty-two PD and 71 control subjects were studied. Subjects viewed the Variable Contrast Acuity Chart on an iPad with both eyes open at two distances (40 cm and 2 m) and at high contrast (black and white visual acuity) and 2.5% low contrast. Acuity scores for the two groups were compared. Results: PD patients had significantly lower scores (indicating worse vision) for 2.5% low contrast at both distances and for high contrast at 2 m (p < 0.003) compared to controls. No significant difference was found between the two groups for high contrast at 40 cm (p = 0.12). Conclusions: Parkinson's disease patients have reduced low and high contrast acuity compared to controls. An iPad app, as used in this study, could serve as a quick screening tool to complement more formal testing of patients with PD and other neurologic disorders.

Abstract The pathologic changes of Parkinson's disease ( PD ) and Progressive Supranuclear Palsy (PSP) have been reported to coexist, but whether PSP pathology modifies the clinical course of those individuals is unknown. The aim of this study was to determine whether clinical features of pathologically confirmed PD subjects with concomitant PSP pathology differ from those with PD alone. Subjects enrolled in the Arizona Study of Aging and Neurodegenerative Disorders had annual movement and cognitive evaluations from enrollment until death/autopsy. All cases between 1997 and 2014 with a final clinicopathological diagnosis of PD with or without PSP at autopsy were analyzed. Overall, 12 of the 125 cases with pathologically confirmed PD had coexisting PSP pathology (9.6%). Those with PD ‐ PSP had more‐prominent postural instability, body bradykinesia, difficulty arising from a chair, and falls; asymmetric onset was less common in this group. Downgaze palsy and square wave jerks were infrequent in both groups. Gender, age at death, disease duration, rate of dementia, and presence of rest tremor did not differ between groups. Only 58% of subjects in the PD ‐ PSP group were correctly given a final diagnosis in life of PD, compared to 91% of those with PD alone. The combination of PD and PSP pathology yields a heterogeneous clinical syndrome that often resembles PD, but may be more symmetric at onset and have more‐prominent postural instability and falls. Our observations suggest that coexisting PSP pathology may be an important factor contributing to the clinical heterogeneity in PD and a potential confounder in diagnosis.