Correlations Between Oculometric Measures and Traditional Clinical Assessments in Multiple Sclerosis.

BACKGROUND

Oculomotor abnormalities are common in multiple sclerosis (MS) but are not quantitatively evaluated in clinical practice. Oculometric measures (OMs) are characteristics of eye movements captured while performing a visual task, e.g., the latency of saccadic and anti-saccadic metrics. Physical and cognitive deficits are prevalent among persons with MS, including disease-related oculomotor dysfunction. Recently, we have implemented a novel software-based platform enabling the extraction of OMs using a PC and a webcam.

OBJECTIVE

The objective of this study is to investigate the relationships between OMs and traditional outcome measures of physical and cognitive dysfunction in MS.

METHODS

Oculometric evaluation using a novel software-based platform (NeuraLight, Israel) was performed in patients with relapsing-remitting MS (n = 57; 36 females, age 41.4 ± 8.6). Physical disability was assessed by an MS-specific neurologic exam (Expanded Disability Status Scale; EDSS) and quantitative measures of cognitive and sensorimotor function (Symbol Digit Modalities Test; SDMT and Nine Hole Peg Test; NHPT). Various OMs were calculated out of multiple measures: Saccadic latency, gain and gaze during fixation, as well as error rate of saccades. Spearman's rank correlation was computed for each OM to assess the relationship with clinical scores.

RESULTS

Various OMs were correlated with EDSS scores, as pro- and anti-saccadic latency (OM1 r = 0.36, OM2 r = 0.50, OM3 r = 0.39, OM4 r = 0.49; P-values<0.0001), initial gain during saccades (OM6 r = 0.47, OM7 r = 0.30, OM8 r = 0.59; p < 0.0001), stability of gaze during fixation (OM9 r = 0.48, OM10 r = 0.41; p < 0.0001) and error rate of anti-saccades (OM11 r = 0.59; p < 0.0001). Similar correlations were found between these OMs and NHPT scores (OM1 r = 0.41, OM2 r = 0.46, OM3 r = 0.31, OM4 r = 0.50; P-values<0.0001), initial gain (OM6 r = 0.40, OM7 r = 0.39, OM8 r = 0.58; Ps<0.0001) and error rate (OM11 r = 0.36; p < 0.0001). Finally, OMs were correlated with SDMT scores: OM1 and OM2 r=-0.31, OM3 r=-0.26, SD r=-0.38; p < 0.05), OM7 r=-0.36, OM8 r=-0.45; Ps<0.0001) and fixation stability (OM9 r=-0.36, Om10 r=-0.45; p < 0.05).

CONCLUSIONS

OMs captured using a novel software-based platform were found to be associated with physical and cognitive function, suggesting that they can be used as a relevant tool in MS clinical assessment. Further studies will include larger cohorts and assess participants longitudinally to determine the potential value of OMs as predictors of future MS-related disability.