In general, post-concussion syndrome follows the occurrence of an injury or trauma to the head and/or neck. Not all people who suffer mild traumatic head injury experience post-concussion syndrome. This syndrome may be worse in people who have had previous concussions or head trauma. It may also be more severe in those who have early symptoms of headache after injury, or who have mental changes such as amnesia, fogginess, or fatigue. Other risk factors include younger age and prior history of headaches. Atlas misalignment places measurable stress on the brain stem and the pain-sensitive surrounding tissue. Also, blood supply to the brain is often compromised. Another primary issue that directly causes seizure disorders is disruption in cerebrospinal fluid, which is crucial for proper brain function.