Poster Presentation at the North American Neuro-Ophthalmology Society North America 2017 Annual Meeting

Visual Disability and Reading Difficulties in Patients with Parkinson’s Disease

Authors: Yaping Liao1, Caroline Yu1, Mohammed Shariati1, Veronica Santini1, Kathleen Poston1 (1 Stanford University, Stanford, California, USA)
Publication: Poster Presentation at the North American Neuro-Ophthalmology Society North America 2017 Annual Meeting
Date: April 6, 2017
Tags: Parkinson’s Disease,Reading,

Introduction:

Parkinson’s Disease (PD) is the second most common neurodegenerative disease globally. While the majority of PD patients report difficulties with vision (1-3), few studies have examined reading in PD (4-5). The goal of this study is to better assess vision disability and reading difficulties in patients with PD.

Methods:

We recruited 112 subjects (59 PD, 53 age-matched controls) per approved protocol at a single academic institution. All subjects were assessed using National Eye Institute Visual Function Questionnaire (VFQ-25), 10-Item Neuro-Ophthalmic (NO-10) Supplement, and King-Devick test to assess reading speed. We performed 500-Hz infrared oculography (RED500, SMI) on some subjects (21 PD and 14 controls) during reading.

Results:

Per vision disability questionnaires, PD patients experienced greater visual dysfunction, with a significantly lower scores compared with that of controls (VFQ-25 P<0.00001; NO-10: P=0.00002; Mann-Whitney U test for all statistical analyses). Notably, the largest differences were observed in the near activities and mental health subscores (P<0.0001). On the King-Devick test, PD patients read significantly slower by 24% (P=0.00002), which correlated with VFQ-25 scores (P=0.0009) but not with Unified Parkinson’s Disease Rating Scale scores (P= 0.14). Infrared oculography revealed that PD patients exhibited significantly slower number (P=0.001) and word reading (P=0.024) and made a greater number of saccades (P=0.08) and fixations per line (P=0.025). They also made smaller saccades (P=0.035), longer fixations, and more errors (regressive saccades).

Conclusions

Our study is the largest so far to systematically assess vision disability and reading, which are significantly worse in PD, can occur early, is not necessarily correlated with Unified Parkinson's Disease Rating Scale, and likely directly impact quality of life and psychological health. Infrared oculography reveals that both fixation and saccade measurements are significantly affected during reading, and some PD patients also exhibited poor ocular motor planning and made more mistakes, likely related to issues impacting higher order processes.