Thus, the potential for pain to influence the assessment of brain injury, especially in mild brain injury, is always a concern. However, research studies have demonstrated the robustness of many neuropsychological tests and documented their ability to differentiate brain dysfunction from non-brain injury conditions such as pain, as well as from depression or anxiety. A comprehensive examination must consider pain and discomfort factors as well as brain injury factors in the overall functional consequences of injury and the potential for recovery. Medical records are just as important as the neuropsychological tests themselves in order to achieve a thorough assessment. Records provide the background for understanding the biomechanism of an injury and the evolution of injury characteristics, the quality and outcome of medical and other interventions, pre-existing health characteristics, and other data and independent observations to support or refute interpretations from neuropsychological test results.
Educational records can also help establish level of pre-injury mental functioning.
Case law in many jurisdictions across the United States has deemed clinical neuropsychologists, by virtue of their specialized training and experience, qualified as the professional expert of choice to determine the cause or etiology of brain damage and its resulting behavioral and psychological problems. In fact, it is the set of results from objective neuropsychological tests that provides the best foundation for rating functional impairment. Neuropsychological status, as well as medical condition, forms the basis for prognosis following a brain injury. The comprehensive neuropsychological examination evaluates these areas to help determine the injured person's potential to achieve functional improvement and to identify treatment that will help achieve that improvement. Maximum improvement from mild traumatic brain injury is usually achieved in six to nine months, but can take longer.