The disappearing hand: vestibular stimulation does not improve hand localisation

Area of Science:

• Neuroscience
• Sensory Integration
• Bodily Self-Consciousness

Background:

• Bodily self-consciousness relies on integrating sensory inputs, including visual, somatosensory, and vestibular information.
• Vestibular input is crucial for self-location, but its precise role is challenging to ascertain.
• Investigating vestibular contributions enhances our understanding of spatial awareness and body perception.

Purpose of the Study:

• To investigate if cold caloric vestibular stimulation (CVS) augments self-location shifts.
• To determine the impact of vestibular stimulation on the integration of visual and proprioceptive hand position information.
• To explore the role of the vestibular system in multisensory integration for body awareness.

Main Methods:

• A randomized controlled experiment utilized the MIRAGE multisensory illusion box.
• Participants experienced a conflict between visual and proprioceptive hand position cues.
• Left cold caloric vestibular stimulation (CVS) was applied to assess its effect on perceived hand location shifts.

Main Results:

• Contrary to the hypothesis, CVS did not significantly alter the shift in perceived hand location.
• Participants undergoing CVS were more likely to report their hand as "no longer there".
• Neither objective measurements nor subjective reports supported the hypothesis of vestibular-enhanced self-location.

Conclusions:

• The study found no evidence that CVS enhances self-location perception.
• Vestibular stimulation did not augment the integration of visual and proprioceptive information regarding hand position.
• The findings suggest that vestibular input may not play a significant role in enhancing self-location within this specific multisensory context.