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THE ROLE OF CHRONIC PAIN IN EVERY DAY FUNCTIONING

In recent NLBC Forensic Updates, I reviewed a number of studies suggesting that multiple factors impact cognitive efficiency and general functioning beyond the limitations created by physical conditions. The role of chronic pain, particularly impacting psychological test performance, has continued to be explored and discussed. This Update will provide further overview and opinion concerning this issue.

Very clearly pain is a multi-dimensional, subjective experience. It is impacted by emotion, attitude and other perceptual influences. Variability in pain response is common and likely reflects a complex biopsychosocial interaction of genetics, development, culture, environment and psychological factors. Neuropsychologists during the course of their assessment confront two types of patient pain. Acute pain occurs shortly after an injury, is often characterized by relatively discrete body locations, a time limited course and the relative absence of marked psychosocial or behavioral changes. Chronic pain typically persists beyond six months, is relatively ambiguous in neuroanatomic pathways, often occurs with a protracted course of treatment with minimal positive impact as well as being accompanied by marked behavioral and emotional changes. Both may exert a direct impact on neuropsychological test performance. However, the former may be accompanied as well by difficulty sitting during the course of the assessment while the latter is often accompanied by a variety of beliefs, attitudes and self-perceptions the patient brings along during the course of what is often a stressful assessment. In this regard, multiple studies suggest associations between neuropsychological impairment based upon test performance and other features often associated with chronic pain such as mood and emotional distress, sleep disturbance, fatigue and perceived interference with daily activity. Emotional distress frequently accompanies chronic pain. This combination often leads to a sense of helplessness and for many, clinical depression. Clinical depression then may further negatively impact effort and attitude during testing but may also lead to higher cortisol levels and chemical changes in the brain which may directly affect actual test performance.

A review of current research reflects a lack of salient data concerning the interrelationships among variables such as pain intensity, location, sleep disturbance, fatigue, tendency towards somatization and emotional state. It is thus unclear to what extent these different factors mediate the influence of pain on neuropsychological performance or may uniquely contribute to subjective complaints or objective signs of impairment in chronic pain populations. Further, some of the conditions and symptoms associated with chronic pain, such as depression and sleep disturbance are known to produce neuropsychological test deficits.

The most significant challenge facing neuropsychologists is assessing the etiology of problems for patients with histories of chronic pain and documented traumatic brain injury. Here too, the literature has yet to be fully developed. The positive findings in individuals with chronic pain syndrome does not imply that there is necessarily the same relationship between pain symptoms and neuropsychological performance in patients whose central nervous system disorders or injuries are sufficient to produce persistent neurological and physical abnormalities. Associations between pain and cognitive dysfunction may be attenuated by the overriding impact of structural brain damage. Several investigators have reported considerable overlap in the symptoms of chronic pain and mild traumatic brain injury. It is likely that chronic pain complicates the symptom picture in traumatic brain injury but that resolution of the post concussive syndrome and a successful adaptation to any residual problems may frequently be dependent on the patient’s success in coping with post traumatic pain such as headache.

Numerous studies demonstrate neuropsychological impairment in patients with chronic pain, particularly on measures assessing attentional capacity, processing and psychomotor speed. These deficits may lead to a general decline in cognitive efficiency during daily activities and routine. In some studies this level of impairment has been related to greater pain intensity and to the involvement of the head and neck. It is also safe to conclude a cause and effect association between impairment and other symptoms often associated with pain, such as mood change, increased somatic awareness, sleep disturbance and fatigue. Attorneys should be aware, however, that research to date has not yet explored in a comprehensive manner, specific relationship among these variables, nor addressed the multi-dimensional aspects of the pain experience. Neuropsychologists evaluating individuals with chronic pain, particularly those recovering from post-concussive syndrome or frank traumatic brain injury must consider the role chronic pain may play in symptom complaints and to some extent even neuropsychological test performance.