Vagally mediated heart rate variability in headache patients–a systematic review and meta-analysis.
https://www.ncbi.nlm.nih.gov/pubmed Cephalalgia. 2016 Mar;36(3):265-78. doi: 10.1177/0333102415583989. Epub 2015 May 11. Vagally mediated heart rate variability in headache patients–a systematic review and meta-analysis. Koenig J1, Williams DP1, Kemp AH2, Thayer JF3. Author information 1 Department of Psychology, The Ohio State University,
