Effect of canalith repositioning on resting-state brain functional connectivity in patients with benign paroxysmal positional vertigo.

In people with benign paroxysmal positional vertigo (BPPV), resting-state functional connectivity (FC) between brain regions involved in vestibular, motor, and sensory processing is abnormally elevated compared to healthy controls. After a canalith repositioning maneuver, whole-brain average FC strength decreased significantly, and connectivity between specific region pairs—including prefrontal cortex, occipital cortex, middle temporal gyrus, motor cortex, and somatosensory cortex—returned to normal levels. Clinical symptoms also improved: the Dizziness Handicap Inventory score dropped by 23.4% and the Visual Analogue Scale score showed a significant reduction. The findings suggest BPPV involves compensatory enhancement of the vestibulo-sensorimotor network, and that repositioning therapy restores pathologically enhanced FC to normal, supporting functional near-infrared spectroscopy as a potential objective biomarker for evaluating BPPV neural mechanisms and treatment efficacy.

Study at a glance

Abstract

To compare the characteristics of resting-state functional connectivity (FC) before and after repositioning therapy in patients with benign paroxysmal positional vertigo (BPPV) using functional near-infrared spectroscopy (fNIRS). Fifty BPPV patients and fifty healthy controls were enrolled. Oxygenated hemoglobin (HbO) concentration changes during resting-state were recorded using fNIRS. The experimental group underwent Dizziness Handicap Inventory (DHI), Visual Analogue Scale (VAS) assessments, and 10-min resting-state fNIRS scans before and after repositioning therapy; the control group received baseline scans only. FC strength of the whole brain and specific regions of interest (ROIs) was analyzed using correlation coefficients. fNIRS analysis revealed significantly elevated FC strength between the middle temporal gyrus (MTG) and both the motor cortex (MC) and somatosensory cortex (SC) in BPPV patients at baseline compared to healthy controls (p < 0.05); after canalith repositioning, the whole-brain average FC strength in patients significantly decreased. Connectivity strength decreased synchronously in the following ROI pairs: prefrontal cortex (PFC)-occipital cortex (OC), PFC-MTG, PFC-MC, OC-MC, OC-SC, MTG-MC, and MTG-SC, and brain network parameters returned to normal levels post-repositioning. Clinical indicators improved simultaneously: the total DHI score decreased by 23.4% (p < 0.05), and the VAS score showed a significant reduction. BPPV involves compensatory enhancement of the vestibulo-sensorimotor network. Canalith repositioning eliminates abnormal vestibular input and restores pathologically enhanced FC to normal levels. This supports fNIRS as a potential objective neuroimaging biomarker for evaluating BPPV neural mechanisms and treatment efficacy.