Objective: To investigate the relationship of eye movement characteristics during natural, self-paced reading and basic visually-guided saccades (VGS) and antisaccades (AS) tasks in PD.

Background: In PD patients, saccades are hypometric and saccadic latency tends to be prolonged. Furthermore, AS performance is related to executive functions in healthy individuals and PD. Compared to basic saccade paradigms used in research, reading is a rather sophisticated cognitive task. PD patients may read slower than healthy individuals due to longer fixations and increased numbers of regressive saccades.(1) However, it is unclear whether alterations of eye movements during reading may be accounted to primary oculomotor deficits or to impaired higher cognitive control in PD.

Method: Eye movements of 60 PD patients (mean age 63.9, disease duration 8.2, Hoehn&Yahr 2.4, MoCA 24.9) were recorded during mute reading of a text as well as while performing horizontal and vertical VGS and horizontal AS (10°, gap 200 ms).

Results: Slower reading speed and higher numbers of progressive and regressive saccades during reading correlated with a higher AS error rate. Longer fixation duration during reading was associated with increased latency of vertical VGS and AS. The amplitude of saccades during reading tended to correlate with AS gain, but not VGS gain. No correlations of reading parameters with horizontal VGS were found.

Conclusion: The observed correlation of reading speed and reading pattern with AS, but not VGS performance further supports the hypothesis that rather higher top-down cognitive control, than primary oculomotor processes, is the more powerful driver of eye movements during natural reading. Further research is needed to determine whether therapeutic interventions, e.g. medication, DBS or neuropsychological training, may improve the reading experience in PD.

References: Waldthaler J, Tsitsi P, Seimyr GÖ, Benfatto MN, Svenningsson P. Eye movements during reading in parkinson’s disease: A pilot study. Mov Disord [Internet]. 2018;50(14):1–2. Available from: http://doi.wiley.com/10.1002/mds.105

« Back to 2019 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/relationship-between-eye-movements-during-natural-reading-and-basic-oculomotor-tasks-in-pd/