A new systematic review suggests that a gentle cranial osteopathic technique seems to give functional benefit for some patients. One study they cited investigated its influence on sleep, another showed reduced pain levels in patients with tension type headaches and other studies suggested it may help relax patients.
A Żurowska, R Malak, et al “Compression of the Fourth Ventricle Using a Craniosacral Osteopathic Technique: A Systematic Review of the Clinical Evidence,” Evidence-Based Complementary and Alternative Medicine, vol. 2017, Article ID 2974962, 8 pages, 2017. https://onlinelibrary.wiley.com/doi/10.1155/2017/2974962.