CONCLUSIONS
orthostatic intolerance, impairment of the autonomic regulation, TBI
Our findings suggest that patients in the early phase after TBI exhibit a blunted cardiac autonomic response to tilting according to several HRV metrics. We speculate that an increased sympathetic activity in the supine position in patients, which could not be further increased during head‐up tilt, may explain this blunted response. However, this hypothesis as well as the role of methodological limitations and sedation remains to be further investigated. This study extends earlier research by investigating the autonomic response to tilting in the acute phase, rather than later during rehabilitation. Patients may benefit from an increased focus on possible impairment of the autonomic regulation, including orthostatic intolerance, to improve early rehabilitation.