Vestibular-Visual Reweighting in Persistent Postural-Perceptual Dizziness: A Multilevel Resting-State fMRI Study

Area of Science:

• Neuroscience
• Functional Neuroimaging
• Vestibular Disorders

Background:

• Persistent postural-perceptual dizziness (PPPD) is a common yet poorly understood functional vestibular disorder.
• It causes chronic dizziness and unsteadiness, significantly impacting daily life.
• Currently, PPPD lacks objective neurobiological markers for diagnosis.

Purpose of the Study:

• To identify objective neurobiological markers for PPPD using multimodal neuroimaging.
• To investigate functional brain network alterations in patients with PPPD compared to healthy controls.
• To correlate brain network findings with clinical symptoms and psychological factors in PPPD.

Main Methods:

• Resting-state functional MRI (rs-fMRI) was performed on 52 PPPD patients and 50 healthy controls.
• Data analyzed using independent component analysis (ICA-FNC), amplitude of low-frequency fluctuations (ALFF/fALFF), and seed-based connectivity.
• Regions of interest included vestibular, subcortical, and visual network areas.

Main Results:

• Observed increased connectivity in cerebellar (CB) and visual (VIS) networks.
• Found reduced connectivity between brainstem-cerebellar (BSC) and vestibular/oculomotor/default-mode networks.
• Decreased ALFF in vestibular integration areas contrasted with increased fALFF in other cortical regions.
• Strengthened thalamo-VIS, striato-limbic, and nodulus-hippocampal connectivity noted.
• Increased BSC-VIS coupling correlated with depression, anxiety, and reduced balance confidence.

Conclusions:

• PPPD exhibits a multiscale neurobiological signature characterized by vestibular cortical disengagement.
• Maladaptive visual-cerebellar network reinforcement is implicated in PPPD pathophysiology.
• Network-level markers show potential as adjuncts for diagnosing PPPD and understanding its biopsychosocial phenotype.