Central crosstalk for somatic tinnitus: abnormal vergence eye movements

Area of Science:

• Neuroscience
• Ophthalmology
• Audiology

Background:

• Oulomotricity problems are frequently reported in tinnitus patients during orthoptic testing.
• Somatic tinnitus patients can modulate their tinnitus through movements, suggesting a link between somatosensation and auditory perception.

Purpose of the Study:

• To objectively assess vergence eye movements in patients with somatic tinnitus.
• To investigate the relationship between somatic tinnitus and oculomotor control.

Main Methods:

• Vergence eye movements were recorded using the Eyelink II video system.
• 19 subjects with somatic tinnitus and 15 control adults participated.

Main Results:

• Somatic tinnitus subjects showed lower divergence accuracy, longer vergence duration, and lower peak velocity compared to controls.
• Increased embedded saccades and saccade amplitude were observed in tinnitus subjects, but saccades did not enhance vergence peak velocity.
• No significant differences in vergence latency were found between groups.

Conclusions:

• Findings suggest dysfunction in vergence control involving cortical-brainstem-cerebellar circuits.
• Hypothesized that central auditory dysfunction in tinnitus may trigger cerebellar-brainstem issues, or that both are linked to a syndrome of abnormal cross-modality interactions.