A simple saccadic reading test to assess ocular motor function in cerebellar ataxia

Area of Science:

• Neurology
• Ophthalmology
• Biomarker Discovery

Background:

• Cerebellar ataxia affects coordination, gait, and balance.
• Ocular motor deficits, including saccadic difficulties, are common in ataxia.
• Clinical assessment of reading-related ocular motor function is often limited.

Purpose of the Study:

• To assess visual performance during reading in cerebellar ataxia patients using simple clinical tests.
• To compare ocular motor abilities in ataxia patients and controls using video infrared oculography.
• To identify potential clinical biomarkers for ocular motor deficits in cerebellar ataxia.

Main Methods:

• Video infrared oculography was performed on 11 cerebellar ataxia patients and 11 age-matched controls.
• Participants completed simple reading tasks, including regularly and irregularly spaced number reading and a word reading task.
• Ocular motor parameters such as saccade count, fixation count, and scan path regularity were analyzed.

Main Results:

• Ataxia patients read number tasks significantly slower than controls (p = 0.02).
• The regularly spaced number reading task showed the largest difference (44%) between groups.
• Oculography revealed slower reading speeds in ataxia patients due to increased saccade/fixation counts and impaired saccade quality.

Conclusions:

• Infrared oculography is the gold standard for assessing ocular motor function during reading in ataxia.
• A simple, regularly spaced 120-digit number reading test can serve as a clinical biomarker for ocular motor abilities in reading.
• This test is quick to administer and can aid in the clinical evaluation of cerebellar ataxia patients.