I am almost certain that this is the reason why one of my patients recently syncopized.

Hair-grooming syncope in children. • 2009 Oct • Evans et al • Clin Pediatr (Phila) • PubMed

Hair-Grooming Syncope Seizures • 1993 Apr • Donald W. Lewis and L. Matthew Frank • Pediatrics • AAP Gateway

Syncope in Children Caused by Hair Grooming • 2014 May • Kelly R. Egan Huibregtse, MS, Brenna Van Frank, MD, Carl E. Stafstrom, MD, PhD • Clinical Pediatrics • SAGE journals