HUMAN ECHOLOCATION AND SENSORY SUBSTITUTION IN REAL AND VIRTUAL ENVIRONMENTS (KOLARIKA_U23PSY)

Recent fMRI studies show that cortical reorganisation occurs following visual loss, where visual brain areas are recruited to process sound. Behaviourally, research shows that hearing becomes important for providing information about spatial layout and identity when vision is impaired. Bats echolocate to detect nearby objects, by producing soundbursts and listening to returning echoes. Some severely visually impaired people use echolocation or sensory substitution devices (SSDs, electronic travel aids that use sound echoes) for navigation.

While echolocation can be trained, movements guided by this require precise motor responses for safe navigation and to avoid collisions when walking around obstacles. To date very little is known about how the central nervous system (CNS) uses the available information holistically in the absence of vision to use sound echoes to guide human movement, and indeed what factors influence its correct and efficient employment. Previous studies show that severe visual loss enhances hearing abilities. How this translates to behavioural benefits is unknown.

The PhD will assess whether the CNS can use sound echoes for navigating, determine whether enhanced hearing following visual loss leads to measurable behavioural benefits, and how effective echolocation and SSDs are for safe navigation and obtaining the position, orientation, shape and material of obstacles. A virtual environment will be used to train visually impaired children and adults to use echolocation and SSDs. The overarching aim is to improve independence and quality of life for individuals with severe visual loss through an evidence-based rehabilitation program.