Cognitive functions and stereopsis in patients with Parkinson's disease and Alzheimer's disease using 3-dimensional television: a case controlled trial.

Stereopsis or depth perception is an awareness of the distances of objects from the observer, and binocular disparity is a necessary component of recognizing objects through stereopsis. In the past studies, patients with neurodegenerative disease (Alzheimer dementia, AD; Parkinson's disease IPD) have problems of stereopsis but they did not have actual stimulation of stereopsis. Therefore in this study, we used a 3-dimensional (3D) movie on 3D television (TV) for actual stereopsis stimulation. We propose research through analyzing differences between the three groups (AD, IPD, and Controls), and identified relations between the results from the Titmus Stereo Fly Test, and the 3D TV test. The study also looked into factors that affect the 3D TV test. Before allowing the patients to watch TV, we examined Titmus stereo Fly Test and cognitive test. We used the 3D version of a movie, of 17 minutes 1 second duration, and carried out a questionnaire about stereopsis. The scores of the stereopsis questionnaire were decreased in AD patients, compared with in IPD and controls, although they did not have any difference of Titmus Stereo Fly Test scores. In IPD patients, cognitive function (Montreal cognitive assessment, MoCA) scores were correlated with the scores of the stereopsis questionnaire. We could conclude that Titmus fly test could not distinguish between the three groups and cognitive dysfunction contributes to actual stereopsis perception in IPD patients. Therefore the 3D TV test of AD and IPD patients was more effective than Titmus fly test