How vestibular dysfunction transforms into symptoms of depersonalization and derealization?

Area of Science:

• Neuroscience
• Otolaryngology
• Psychiatry

Background:

• Psychiatric Depersonalization/Derealization (DPDR) symptoms have been observed in patients with peripheral vestibular disorders.
• Previous research primarily focused on semicircular canals (SCCs) dysfunction, leaving the otoliths' role and DPDR in central vestibular dysfunction unexplored.
• The interplay between DPDR, spatial disorientation, and anxiety in vestibular dysfunction requires further clarification.

Purpose of the Study:

• To investigate the contribution of otoliths (specifically sacculi) to DPDR symptoms.
• To examine DPDR in patients with central vestibular dysfunction.
• To clarify the relationship between vestibular dysfunction, spatial disorientation, anxiety, and DPDR.

Main Methods:

• Compared patients with peripheral Bilateral Vestibular Hypofunction (pBVH) and Machado Joseph Disease (MJD) (central vestibular hypofunction) to healthy controls.
• Assessed SCCs and sacculi function using vHIT and cVEMPt, respectively.
• Evaluated DPDR symptoms, spatial disorientation, and panic anxiety using standardized questionnaires and tests.

Main Results:

• pBVH patients exhibited SCCs and sacculi dysfunction, spatial disorientation, heightened panic anxiety, and DPDR symptoms.
• MJD patients showed SCCs hypofunction, spatial disorientation, but normal sacculi function, panic anxiety, and DPDR.
• A positive correlation between DPDR severity, spatial disorientation, and panic anxiety was found exclusively in pBVH patients.

Conclusions:

• DPDR development is associated with sacculi dysfunction, with or without SCCs involvement.
• Spatial disorientation and anxiety appear to be key mediators in the progression from vestibular dysfunction to DPDR.
• DPDR did not manifest in MJD patients with central vestibular hypofunction but preserved saccular response, suggesting a specific role for saccular function.