Subjective visual vertical in patients with Usher syndrome

Area of Science:

• Neuroscience
• Ophthalmology
• Vestibular System

Background:

• Perception of verticality relies on integrating visual, vestibular, and somesthetic information.
• Usher syndrome involves both visual and vestibular impairments.

Purpose of the Study:

• To compare subjective visual vertical (SVV) perception in Usher syndrome patients (types I and II) versus healthy controls.
• To investigate the role of visual and vestibular functions in verticality perception.

Main Methods:

• SVV was assessed using a laser-projected line under clockwise and counter-clockwise head tilt conditions.
• Participants responded to the orientation of the projected line.
• SVV accuracy was quantified by the mean absolute error.

Main Results:

• Usher syndrome patients demonstrated significantly less accurate SVV responses compared to healthy participants.
• SVV accuracy was comparable between Usher type I and type II patients.

Conclusions:

• Visual input plays a critical role in the perception of verticality.
• Bilateral vestibular deficits in Usher type I do not significantly impact verticality perception, highlighting visual dominance.