Oculomotor dysfunction in amyotrophic lateral sclerosis: a comprehensive review.

Area of Science:

• Neuroscience
• Ophthalmology
• Neurology

Background:

• Amyotrophic lateral sclerosis (ALS) traditionally spares oculomotor control, but emerging evidence shows various dysfunctions like ophthalmoparesis, pursuit, nystagmus, and saccadic impairments.
• The relative preservation of oculomotor pathways in ALS compared to other motor systems makes them valuable for studying motor neuronal vulnerability.
• Oculomotor assessment, enhanced by portable eye-tracking, reveals subtle ALS impairments linked to phenotype and cerebral networks.

Purpose of the Study:

• To investigate oculomotor dysfunction in amyotrophic lateral sclerosis (ALS).
• To understand the relationship between oculomotor function, ALS phenotype, and underlying cerebral abnormalities.
• To explore the potential of oculomotor tests as biomarkers for ALS prognosis and monitoring.

Main Methods:

• Review of existing literature on oculomotor dysfunction in ALS.
• Utilizing advanced eye-tracking technology for detailed assessment of eye movements.
• Correlating oculomotor findings with clinical phenotypes and neuroimaging data.

Main Results:

• Oculomotor impairments, particularly ophthalmoparesis, are more frequent in ALS than previously thought, especially in longer-surviving patients.
• Subtle eye movement abnormalities are detectable with modern tools and correlate with specific ALS phenotypes.
• Oculomotor function assessment offers a non-verbal method to study cognitive changes in advanced ALS.

Conclusions:

• Oculomotor dysfunction is a significant feature of amyotrophic lateral sclerosis (ALS), not just an incidental finding.
• The study of eye movements in ALS provides insights into disease mechanisms and extramotor cerebral involvement, including frontotemporal dementia overlap.
• Oculomotor biomarkers hold promise for monitoring ALS progression, predicting outcomes, and understanding disease mechanisms.