Lesion network mapping of eye-opening apraxia

Area of Science:

• Neuroscience
• Neurology
• Clinical Neuroimaging

Background:

• Apraxia of eyelid opening (eye-opening apraxia) is a condition of impaired supranuclear control, preventing voluntary eye opening.
• Understanding the neural basis of eye-opening apraxia is crucial for diagnosing and treating this condition.

Purpose of the Study:

• To investigate the neural substrates underlying eye-opening apraxia using lesion network mapping.
• To compare the lesion locations and functional connectivity patterns of eye-opening apraxia patients with those of aphasia and hemiballismus patients.

Main Methods:

• Analysis of brain lesions in 27 stroke patients with eye-opening apraxia.
• Comparison with lesions from 20 aphasia and 45 hemiballismus control patients.
• Lesion mapping onto a standard brain atlas using resting-state functional MRI data from 966 healthy adults.

Main Results:

• Eye-opening apraxia lesions were predominantly in the right hemisphere, involving subcortical or mixed cortical/subcortical areas.
• These lesions functionally converged on the bilateral dorsal anterior and posterior insula.
• Functional connectivity maps for eye-opening apraxia differed from those for aphasia (frontal operculum) and hemiballismus (putamen).

Conclusions:

• Disruptions in the dorsal anterior and posterior insula are implicated in eye-opening apraxia.
• These insular disruptions may impair the initiation of eyelid-opening responses due to compromised salience detection and motor execution.
• The findings highlight the insula's role in voluntary eye movements and response initiation.