Diagnosing and quantifying a common deficit in multiple sclerosis: Internuclear ophthalmoplegia

Area of Science:

• Ophthalmology
• Neurology
• Medical Diagnostics

Background:

• Internuclear ophthalmoplegia (INO) is a common ocular motor disorder in multiple sclerosis (MS).
• Accurate and objective diagnosis of INO in MS is crucial for patient management and research.
• Current diagnostic methods may lack quantitative precision.

Purpose of the Study:

• To develop and validate an objective, quantitative approach for diagnosing INO in MS patients.
• To establish a standardized infrared oculography protocol for INO assessment.
• To determine the prevalence of INO in MS and its impact on quality of life.

Main Methods:

• A validated infrared oculography protocol (DEMoNS) was employed to quantify prosaccades in MS patients and healthy controls (HCs).
• The versional dysconjugacy index (VDI) was calculated using parameters like peak velocity, acceleration, and area under the curve (AUC).
• Receiver operating characteristic (ROC) analysis assessed diagnostic accuracy; the National Eye Institute Visual Function Questionnaire-25 evaluated quality of life.

Main Results:

• The highest diagnostic accuracy for INO was achieved using the VDI AUC of 15° horizontal prosaccades.
• A combined VDI AUC and peak velocity/amplitude detection identified a 34% prevalence of INO in the MS cohort.
• MS patients with INO reported more double vision and had lower vision-related quality of life compared to those without INO.

Conclusions:

• This study establishes an accurate, quantitative, and clinically relevant definition for INO in MS using infrared oculography.
• The developed INO standard requires prospective validation but offers a reliable model for future MS treatment trials.
• The high prevalence of INO in MS underscores its significance and potential as a quantifiable outcome measure.