Corneal reflex and blink reflex changes in thalamic hemorrhage

Area of Science:

• Neuroscience
• Ophthalmology
• Neurology

Background:

• The corneal reflex (CR) is a crucial protective mechanism involving trigeminal and facial nerve pathways.
• Thalamic hemorrhage (TH) can disrupt neurological functions, including sensory reflexes.

Purpose of the Study:

• To investigate the effects of thalamic hemorrhage on the corneal reflex (CR) and blink reflex (BR).
• To compare the efficacy of air-puff and direct touch methods in eliciting CR in TH patients.

Main Methods:

• Standardized assessment of corneal reflex (CR) using air-puff and direct corneal touch.
• Evaluation of blink reflex (BR) responses, including R1 and R2 components.
• Comparison of CR and BR in 15 patients with thalamic hemorrhage and 21 healthy controls.

Main Results:

• Stimulation of the non-affected cornea in TH patients elicited bilateral CR with delayed latency on the affected side.
• Stimulation of the affected cornea in TH patients resulted in abnormal or absent CR responses bilaterally.
• Abnormal ipsilateral R1 and R2 BR responses were observed on the affected side in TH patients, while contralateral R2 remained normal.
• No significant difference was found between air-puff and direct touch for CR elicitation (p > 0.05).
• CR responses were significantly different from the R2 response of the BR (p < 0.005).

Conclusions:

• Thalamic hemorrhage significantly disrupts the corneal reflex pathways, particularly on the affected side.
• The corneal reflex is a sensitive indicator of neurological damage following thalamic hemorrhage.
• Both air-puff and direct touch are reliable methods for assessing CR, and CR differs from the blink reflex.