Stereopsis in drug naïve Parkinson's disease patients

Motor deficits associated with Parkinson's disease (PD) have been well described, yet little attention has been paid to non-motor symptoms, especially cortical visual dysfunction. We investigated stereopsis, as well as the relationship between stereopsis and other cognitive function, in a sample of PD patients.

We used Titmus stereotest plates for assessing stereopsis. Fifty-nine subjects (29 PD patients and 30 normal controls) were included in this study. The included patients underwent a neurological examination, clinical rating scale and neuropsychological tests.

Drug naïve PD patients showed decreased stereopsis on the Titmus fly stereopsis test (Pearson χ2=23.80, p<0.001) compared to PD patients with normal stereopsis. The Hoehn-Yahr stages and Unified Parkinson's Disease Rating Scale motor scores were significantly higher in patients with PD with abnormal stereopsis than in patients with PD with normal stereopsis (p=0.026; p=0.046). The frequency of abnormal visual perception/constructive function was greater in patients with PD with abnormal stereopsis compared to patients with PD with normal stereopsis (Pearson χ2=5.11, p=0.024).

These findings suggest that stereopsis deficits and visual perception/constructive dysfunction are common in de novo PD patients.