Functional Brain Connectivity Changes Following Vestibular Rehabilitation in Persistent Postural–Perceptual Dizziness: A Single-Case Resting-State fMRI Study

Background: Persistent postural–perceptual dizziness (PPPD) is a chronic functional vestibular disorder characterized by persistent dizziness and unsteadiness. Resting-state functional magnetic resonance imaging (rs-fMRI) has identified dysfunction in vestibular, visual, somatosensory, spatial cognitive, and emotional networks in PPPD. Although vestibular rehabilitation has demonstrated efficacy in PPPD, its effects on these dysfunctional neural networks remain unclear. Case: A 37-year-old woman with PPPD had experienced recurrent rotational vertigo approximately every 6 months followed by persistent non-spinning dizziness. Assessment: Baseline assessment showed severe dizziness-related disability (Dizziness Handicap Inventory (DHI) score: 66) and depressive symptoms (Self-Rating Depression Scale (SDS): 40). Posturography demonstrated increased sway with eyes closed, whereas video head impulse testing revealed no significant abnormalities. Rs-fMRI was also performed, and functional connectivity was analyzed using SPM12 and the CONN toolbox with a region-of-interest-to-region-of-interest approach. Outcome: During the 8-week period of vestibular rehabilitation, including continued pharmacotherapy, the DHI score decreased from 66 to 16 and the SDS score from 40 to 27. Among the nine prespecified ROI-to-ROI connections, the largest longitudinal connectivity difference was observed between the right hippocampus and left frontal pole, decreasing from z = 0.110 at baseline to z = −0.277 at follow-up (Δz = −0.387). At the uncorrected exploratory level, connectivity decreased between the right anterior parahippocampal cortex and right angular gyrus but increased between the right parieto-insular vestibular cortex and right lingual gyrus. Conclusion: Clinical improvement following vestibular rehabilitation coincided with changes in PPPD-related functional connectivity, particularly reduced connectivity between the right hippocampus and left frontal pole. Although this single-patient case report had no control condition, included only one rs-fMRI scan at each time point, and involved concurrent pharmacotherapy, this finding may reflect anxiety-related mood changes in spatial cognitive processing.