The effect of transcutaneous auricular vagus nerve stimulation on nerve conduction velocity, grip strength, pain and upper extremity functionality in individuals diagnosed with carpal tunnel syndrome

Carpal tunnel syndrome (KTS) has a high frequency of appearance in society. The absence of a gold standard treatment protocol that can be applied to CTS enables the efficacy of new treatments to be investigated in CTS. It is aimed to investigate the effect of transcutaneous auricular vagus stimulation (taVNS) on parameters such as nerve conduction velocity, grip strength, pain, and upper extremity functionality in CTS. 51 patients (90 hands) aged between 18-58 were included in the study. The individuals participating in the study were divided into three groups as experimental, sham, and control groups. To measure the transmission rate of the sensory branch of the median boundary before and after treatment, the electromyography (EMG) evaluation was implemented with a digital dynamometer to measure the hand grip force, the visual analogue scale (VAS) and pain interrogation and the functionality of the upper extremity functional index (UEFI) scale. A conventional rehabilitation program was applied to all participants in the treatment, and vagus nerve stimulation was also performed with the help of the Vagustim device in the experimental group. Headphones belonging to the device were attached to the Sham group, but no current was supplied. In the evaluations made for the study, the degree of significance was calculated as p<0.05. In the study, no significant differences were found between the groups in terms of parameters such as BMI, age, gender, education level, and smoking status(p>0.05). In the evaluations made within the group, a significant difference was found compared to the baseline in terms of nerve conduction velocity, pain, and upper extremity functionality, except for grip strength(p<0.05). In the analysis made to compare the groups, there was a significant difference in favor of the experimental group in all parameters except the grip strength parameter (p<0.05), but no significant difference was found between the sham and control groups (p>0.05). As a result of the study, it was found that taVNS applied in addition to the conventional rehabilitation program in individuals diagnosed with CTS increased the sensory nerve conduction velocity and upper extremity functionality level and decreased pain, but did not have any effect on grip strength.