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Aberrant regeneration of the third nerve
1Department of Neurology, National Neuroscience Institute, 11, Jalan Tan Tock Seng, Singapore 308433. hoe_chin_chua@notes.ttsh.gov.sg
Singapore Medical Journal
|February 24, 2001
Summary
Aberrant regeneration of the third cranial nerve after traumatic brain injury can cause complex eye movement disorders. This study details a specific syndrome of miswiring, observed in 15% of patients.
Area of Science:
- Neuroscience
- Ophthalmology
- Neurology
Background:
- Traumatic brain injury (TBI) can lead to complex neurological deficits.
- Aberrant regeneration of cranial nerves, particularly the third nerve (oculomotor nerve), is a known but incompletely understood complication of TBI.
Purpose of the Study:
- To describe a specific syndrome of aberrant third nerve regeneration following TBI.
- To detail the characteristic clinical features and estimate the incidence of this 'miswiring' phenomenon.
Main Methods:
- Case series describing three patients with TBI and subsequent third nerve dysfunction.
- Detailed clinical examination focusing on ocular motility, eyelid function, and pupillary responses.
Main Results:
- Patients presented with a constellation of symptoms including horizontal gaze-eyelid synkinesis, pseudo-Graefe sign, and abnormal eye movements (limitation of elevation/depression, globe retraction, adduction).
- Pseudo-Argyll Robertson pupil and absent vertical optokinetic response were also noted.
- The incidence of this specific 'misdirection' syndrome was estimated at 15% in the observed patient group.
Conclusions:
- Aberrant regeneration of the third nerve following TBI can manifest as a distinct clinical syndrome with characteristic features.
- This 'miswiring' phenomenon, involving aberrant innervation, represents a significant cause of complex ocular motor dysfunction after head trauma.