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

## TL;DR

This study shows that canalith repositioning therapy in BPPV patients reduces abnormal brain connectivity and improves symptoms, as measured by fNIRS.

## Contribution

The study demonstrates that canalith repositioning normalizes resting-state brain connectivity in BPPV patients, suggesting a neural mechanism for treatment efficacy.

## Key findings

- BPPV patients showed elevated FC between MTG and motor/somatosensory cortex at baseline compared to controls.
- Canalith repositioning significantly reduced whole-brain FC strength and restored ROI connectivity to normal levels.
- Clinical scores improved after therapy, with DHI decreasing by 23.4% and VAS scores significantly reduced.

## 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.