Subjective visual vertical/horizontal and video head impulse test in dyslexic children

Area of Science:

• Neuroscience
• Pediatrics
• Ophthalmology

Background:

• Dyslexia is a common learning disorder with potential links to sensory processing.
• The vestibular system, crucial for balance and spatial orientation, has been implicated in previous studies on dyslexia.
• Subjective Visual Vertical/Horizontal (SVV/SVH) and Video Head Impulse Test (VHIT) are valuable tools for assessing vestibular function, particularly in pediatric populations.

Purpose of the Study:

• To investigate vestibular system function in children with dyslexia.
• To evaluate the utility of SVV/SVH and VHIT in identifying potential vestibular alterations in dyslexic children.

Main Methods:

• The study included 18 dyslexic children and 18 age-matched typically developing controls.
• All participants underwent VHIT to assess vestibulo-ocular reflex (VOR) gain and symmetry.
• SVV and SVH tests were performed to measure perceived verticality and horizontality.

Main Results:

• Vestibulo-ocular reflex (VOR) gain and symmetry were normal in both dyslexic and control groups via VHIT.
• A significant difference in SVV and SVH was observed between dyslexic children and controls.
• 83.3% of dyslexic children exhibited at least one abnormality in SVV or SVH measurements.

Conclusions:

• The findings confirm a relationship between dyslexia and alterations in Subjective Visual Vertical/Horizontal (SVV/SVH) perception.
• These vestibular differences may stem from visual processing impairments, potentially involving the magnocellular pathway or broader multimodal cortical network deficits.