Eye Movement Abnormalities in Amyotrophic Lateral Sclerosis.

Area of Science:

• Neurology
• Ophthalmology
• Neuroscience

Background:

• Amyotrophic lateral sclerosis (ALS) is often thought to spare eye movements, but recent findings suggest abnormalities.
• Previous studies on eye movement abnormalities in ALS are controversial, with bulbar involvement being a key consideration.

Purpose of the Study:

• To investigate the presence and characteristics of eye movement abnormalities in ALS patients.
• To determine the association between these abnormalities and bulbar disability in ALS.

Main Methods:

• Standardized oculomotor system evaluations using videonystagmography were performed on 60 ALS patients and 30 controls.
• Subgroup analyses were conducted based on the presence or absence of bulbar involvement and disease onset pattern.

Main Results:

• Square-wave jerks and abnormal cogwheeling during smooth pursuit were significantly more frequent in ALS patients than controls.
• These abnormalities were more prevalent in ALS patients with bulbar involvement compared to those without.
• No significant differences in eye movement parameters were found between bulbar-onset and spinal-onset ALS patients.

Conclusions:

• ALS patients exhibit eye movement abnormalities, primarily affecting ocular fixation and smooth pursuit.
• The region of neurological involvement, particularly bulbar function, is a better indicator of these abnormalities than the onset pattern.
• Eye movement abnormalities may serve as potential clinical markers for assessing neurodegeneration in the upper brainstem or supratentorial cerebrum in ALS.