Capturing saccades in multiple sclerosis with a digitized test of rapid number naming

Abstract

The King–Devick (K–D) test of rapid number naming is a visual performance measure that captures saccadic eye movements. Patients with multiple sclerosis (MS) have slowed K–D test times associated with neurologic disability and reduced quality of life. We assessed eye movements during the K–D test to identify characteristics associated with slowed times. Participants performed a computerized K–D test with video-oculography. The 25-Item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and its 10-Item Neuro-Ophthalmic Supplement measured vision-specific quality of life (VSQOL). Among 25 participants with MS (age 37 ± 10 years, range 20–59) and 42 controls (age 33 ± 9 years, range 19–54), MS was associated with significantly longer (worse) K–D times (58.2 ± 19.8 vs. 43.8 ± 8.6 s, P = 0.001, linear regression models, accounting for age). In MS, test times were slower among patients with higher (worse) Expanded Disability Status Scale scores (P = 0.01). Average inter-saccadic intervals (ISI) were significantly longer in MS participants compared to controls (362 ± 103 vs. 286 ± 50 ms, P = 0.001), and were highly associated with prolonged K–D times in MS (P = 0.006). MS participants generated greater numbers of saccades (P = 0.007). VSQOL scores were reduced in MS patients with longer (worse) K–D times (P = 0.04–0.001) and longer ISI (P = 0.002–0.001). Patients with MS have slowed K–D times that may be attributable to prolonged ISI and greater numbers of saccades. The K–D test and its requisite eye movements capture VSQOL and make rapid number naming a strong candidate efferent visual performance measure in MS.

Visual Pathway Measures are Associated with Neuropsychological Function in Multiple Sclerosis

“…These findings may be in accordance with prior studies, which suggest that not only may LCLA better capture visual dysfunction in MS than HCVA, but also that LCLA may be a more encompassing and reliable biomarker and outcome reflective of the MS disease process [28]. Additionally, our study findings support preliminary studies that found associations between LCLA and cognitive function in a small sample of RRMS and SPMS patients [11], and decreased visual-cognitive performance in MS measured by the King-Devick test [29]. Importantly, similar relationships within the visual-cognition axis have been implicated in other neurological disorders, including Alzheimer’s disease [30] and Parkinson’s disease [31].…”

Quantitative Analysis of Smooth Pursuit Eye Movement Using Video-Oculography

“…Professional equipment is usually necessary to perform quantitative analysis of SPEM. Though such devices can be purchased, and published studies have reported using them [12], they are expensive and impractical for routine use during medical treatment. Our investigation, however, used commercially available equipment and free software to construct a cheap, effective system: a commercially available infrared CCD camera and a PC.…”

A nonlinear generalization of the Savitzky-Golay filter and the quantitative analysis of saccades

“…For example, we make small intraline saccades and large interline saccades during reading. Recent studies showed that chronic concussion patients and multiple sclerosis patients made more saccades to complete a rapid number naming test, and these extra saccades appear to be small (Hainline et al, 2017 ; Rizzo et al, 2016 ). As shown in the Results section, the conventional SG filter tends to underestimate the peak velocity of saccades, especially small-amplitude saccades.…”