How similar are whiplash and mild traumatic brain injury? A systematic review

Introduction Mild traumatic brain injury (mTBI) and whiplash are two pathologies which appear in the follow-up of a cranio-cervical trauma. The objective of this study is to review their definitions, to discuss each entity. Methods Whiplash and mTBI were defined. Then, a systematic literature review was carried out using the Pubmed database. Relevant studies after 1995 were selected, with 16 articles describing a link between whiplash and mTBI. 8 articles were analyzed after reading their abstracts. Results Whiplash and mTBI have many similarities (symptoms, biomechanics, cognitive disorders, presence of diffuse axonal lesions on functional imaging) and some differences (in posture, more vestibular and balance disorders in whiplash). mTBIs result from linear accelerations between 60- 160 g (gravity), studies on whiplash have shown that they can appear from 4.5 g, which could explain biomechanically the frequent concomitant appearance. Cervical joint dysfunction can appear in persistent concussive syndrome, with upper cervical pain, less endurance of the cervical flexor muscles, and an increase in cervical stiffness leading to tension headache. This could explain neck pain in mTBI and headache in whiplash. An explanation to vestibular and cochlear disorders is given, and the two pathologies concomitantly could increase the symptoms. Conclusion To our knowledge, no studies define distinct boundaries between these two pathologies, which overlap on many points. An explanation is their concomitant onset, due to the biomechanics of the trauma and anatomical reasons. Larger-scale studies of rigorous scientific quality are needed to answer the question of the difference between whiplash and mTBI.