Fig. (8) Overlap in chronic symptomology between atlanto-axial instability, whiplash associated disorder, post-concussion syndrome, vertebrobasilar insufficiency, and Barré-Liéou syndrome. There is considerable overlap in symptoms amongst these conditions, possibly because they all appear to be due to cervical instability. 1. Meadows J, Armijo-Olivo S, Magee D. Cervical Spine. Orthopedic Physical Assessment. 5 ed: Saunders Elsevier; 2008: 17-44. 2. Leddy J, Sandhu H, Sodhi V, Baker J, Wilier B. Rehabilitation of concussion and post-concussion syndrome. Sports Health. 2012; 4(2): 147-154. 3. Boake C, McCauley SR, Levin HS, et al. Diagnostic criteria for postconcussional syndrome after mild to moderate traumatic brain injury. J Neuropsychiatry Clin Neurosci. 2005; 17: 350-356. 4. Swinkels RA, Oostendorp RA. Upper cervical instability: fact or fiction. J Manip Physiol Ther. 1996; 19(3): 185-194. 5. Tamura T. Cranial symptoms after cervical injury. Aetiology and treatment of the BarrÉ-LiÉou Syndrome. J Bone Joint Surg Br. 1989; 71 B: 282-287. 6. Chen HB, Yang KH, Wang ZG. Biomechanics of whiplash injury. Chin J Traumata/. 2009; 12(5): 305-314. 7. Endo K, lchimaru K, Komagata M, Yamamoto K. Cervical vertigo and dizziness after whiplash injury. fur Spine J. 2006; 15: 886-890. 8. Pearce J. BarrÉ-LiÉou "syndrome". J Neural Neurosurg Psychol 2004; 75(2).•Also based on the evaluation and treatment of thousands of patients at Caring Medical and Rehabilitation Services in Oak Park, IL over a 20 year period.