Changes Detected in the Electroencephalogram and Heart Rate Variability in Healthy Dogs After the Use of a Novel Device for Transcutaneous Vagus Nerve Stimulation
Transcutaneous vagus nerve stimulation (tcVNS) has been used to treat epilepsy in people and dogs. Objective electroencephalographic and heart rate variability data associated with tcVNS have been reported in people. The question remained to determine whether electroencephalography (EEG) and electrocardiography (ECG) would detect brain activity and changes in heart rate variability (HRV) changes after tcVNS in 6 client-owned healthy dogs. Simultaneous EEG and ECG recording were analyzed for differences pre and post tcVNS in the frequency band and power spectral analysis (EEG) and heart rate variability (HRV). The differences were then compared using a general linear mixed model. The feasibility and tolerance of the patients to the tcVNS were also noted. In the frequency band analysis, the average amplitude was found to be significantly different pre- and post-treatment in the theta (p=0.02) and alpha bands (p=0.04). The power spectral analysis detected a significant decrease in the alpha (p=<0.01), theta (p=0.01) and beta (p=0.035) frequencies post stimulation. There was a significant increase in the HRV measured by the standard deviation of the of NN intervals (SDNN) index (p=<0.01) and a decrease in mean heart rate (p=<0.01) after tcVNS. The tcVNS was found to be well tolerated. The results of this pilot study suggest that EEG and ECG can detect changes in brain activity and HRV associated with tcVNS in healthy dogs. Further studies are required to confirm the results of this study and to assess the tcVNS relevance as a potential therapeutic tool.