# Effects of external diaphragm pacing combined with repetitive peripheral magnetic stimulation of the phrenic nerve on respiratory function in stroke patients

## TL;DR

This study finds that combining diaphragm pacing and magnetic nerve stimulation improves breathing function more than either treatment alone in stroke patients.

## Contribution

The novel finding is that combined external diaphragm pacing and repetitive peripheral magnetic stimulation yields greater respiratory improvements than monotherapies in stroke patients.

## Key findings

- Combined treatment group showed significantly greater improvements in FVC, FEV1, and MIP compared to monotherapy groups.
- Combined treatment led to more pronounced increases in diaphragmatic thickness and excursion than either EDP or rPMS alone.
- Combined treatment resulted in a more significant reduction in phrenic nerve conduction time compared to monotherapies.

## Abstract

To investigate the effects of external diaphragmatic pacing (EDP) and repetitive peripheral magnetic stimulation (rPMS) of the phrenic nerve on respiratory function in stroke patients.

Fifty-four stroke patients were randomly assigned to three groups: an EDP group (n = 18), an rPMS group (n = 18), and a combined treatment group (n = 18). All groups received routine breathing training. Additionally, the EDP group underwent EDP, the rPMS group received repeated peripheral magnetic stimulation of the phrenic nerve, and the combined treatment group received a combination of both interventions. The treatment regimen lasted for 4 weeks. Pulmonary function parameters, including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC%, peak expiratory flow (PEF), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP), were assessed using a pulmonary function tester. Diaphragmatic thickness (DT) and diaphragmatic excursion (DE) were evaluated via ultrasound imaging, whereas compound muscle action potential (CMAP) amplitude and phrenic nerve conduction time (PNCT) were measured using transcranial magnetic stimulation technology.

Following 4 weeks of treatment, significant improvements were observed in FVC, FEV1, PEF, MIP, and MEP across all three groups (all p < 0.05). Moreover, the combined treatment group demonstrated significantly greater improvements in FVC, FEV1, and MIP compared with either the EDP or rPMS group (p < 0.05). DT and DE were also significantly increased in all groups (p < 0.05), with more pronounced improvements in the combined treatment group than in the other groups (p < 0.05). In all three groups, CMAP amplitude increased significantly, whereas PNCT decreased significantly (p < 0.05). Furthermore, the reduction in PNCT was more obvious in the combined treatment group than in either the EDP or rPMS group (p < 0.05).

Compared with monotherapy using either EDP or rPMS, combined treatment demonstrates significantly greater efficacy in promoting respiratory function rehabilitation in stroke patients. Additionally, it shows potential advantages in improving phrenic nerve motor conduction.