Abstract
Purpose :
Both eye movement disorders and cognitive deficits occur in the majority of patients with multiple sclerosis (MS), in this prospective study the relationship between saccadic eye movements and cognitive functioning in patients with MS is investigated.
Methods :
51 MS patients and 25 healthy controls were included, the patients underwent a thorough ophthalmological examination. A validated standardized infrared oculography protocol was developed for quantifying pro-saccades and anti-saccades, and we determined peak velocity, gain, latency and percentage of errors. Seven cognitive domains were evaluated using a validated neuropsychological test battery, and the results were converted into Z-scores, corrected for age, gender and education. The MS patients were stratified into equal subgroups based on median splits of saccadic parameters, and into cognitively preserved (CP), mildly cognitive impaired (MCI) and severely cognitive impaired (SCI). Logistic regression was used to test the relationship between saccadic parameters and cognitive function, taking age, gender and visual acuity into account as possible confounders.
Results :
Of all 51 patients, 17 were classified as MCI and 11 as SCI. Table 1 summarises the patient characteristics. The subgroup with a lower gain (hypometric saccades) and a lower peak velocity in the pro-saccade task, had significantly higher odds for being SCI and CI (mild or severe) respectively, compared to the patients with a higher gain (OR 6.77, p=0.032) and higher peak velocity (OR 7.39, p=0.015). The proportion of errors in the anti-saccade task was not related to cognitive function. For the anti-saccade task, patients with hypermetric fixation had higher odds, and patients with hypermetric saccades a tendency to higher odds, for being CI (mild or severe) compared to the patients with a more hypometric fixation (OR 5.95, p=0.013) and hypometric saccades (OR 2.95, p=0.145) respectively.
Conclusions :
Cognitive function in MS was related to peak velocity and gain in pro-saccade and anti-saccade tasks. This suggests that precise quantitative saccadic testing may be considered as a potential surrogate outcome for cognitive function in longitudinal studies and treatment trials.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.