**5. Conclusions**

In our work, no significant differences were found in the vestibular contribution to the perception of verticality between healthy subjects or those suffering from migraines or TTHs. The variables usually related to headaches could not explain either the presence of a poor perception of verticality or the MAE during the SVV test.

For future research, it would be interesting to observe whether there are alterations in the perception of verticality during attacks as well as to observe the contribution of somatosensory and visual inputs to the perception of verticality in this and other populations. For this, it would be relevant to measure the differences in the perception of verticality between healthy and headache subjects using tests other than static SVV.

Given the versatility of new mobile devices for measuring verticality, different tests must be implemented to be able to use them both in clinical practice and in research. This could contribute to a better understanding of the pathophysiological mechanisms that are present in patients with headaches and migraines.

**Author Contributions:** Conceptualization, R.L.-V. and A.A.-O.; methodology, R.L.-V., D.R.-A., and A.A.-O.; software, R.L.-V. and D.R.-A.; validation, D.R.-A. and A.A.-O.; formal analysis, R.L.-V., E.O.-G., and D.R.-A.; investigation, A.A.-O., M.C.O.-P., and N.Z.-A.; resources, A.A.-O., M.C.O.-P., and N.Z.-A.; data curation, D.R.-A., M.C.O.-P., and N.Z.-A.; writing—original draft preparation, N.Z.-A. and D.R.-A.; writing—review and editing, E.O.-G. and A.A.-O.; visualization, R.L.-V. and E.O.-G.; supervision, R.L.-V. and A.A.-O.; project administration, R.L.-V. and A.A.-O.; funding acquisition, R.L.-V. and M.C.O.-P. All authors read and agreed to the published version of the manuscript.

**Funding:** E.O.-G. received external funding by gran<sup>t</sup> number FPU17/01619 of the Ministry of Science, Innovation, and Universities, Government of Spain.

**Acknowledgments:** The authors thank Fidel Hita for his contribution to the diagnosis and classification of the participants in this study.

**Conflicts of Interest:** The authors declare that Daniel Rodríguez-Almagro and Rafael Lomas-Vega each own 14% of the intellectual property rights of the software developed for the operation of this mobile device. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
