Chronic Post-Traumatic Neck and Head Pain

Seymour Solomon, MD

Disclosures

Headache. 2005;45(1):53-67. 

In This Article

Expectation

Just as expectation of a favorable outcome may evoke a placebo effect, expectation of a poor prognosis may result in a self-fulfilling nocebo response.[112] Both verbal and nonverbal communications of expectations play roles in etiology and prognosis.

Expectation as a major etiologic factor in the postconcussion syndrome was studied in 100 consecutive patients referred for neuropsychological examination because of chronic postconcussion complaints.[129] The symptoms of patients were compared to 223 volunteers who had not experienced head injury. Both groups were given a list of 30 symptoms including affective, somatic, and memory items. The volunteers were to note the symptoms they presently experienced and then imagine the symptoms that would be present 6 months after an MVA that caused transient loss of consciousness. The patients referred for examination were asked to check off the symptoms they experienced before the accident, soon after the accident and at the time of the present evaluation (an average of 1.7 years after injury). Of the 30 symptoms, 22 were anticipated by the volunteer control group. Their responses did not significantly differ from those of patients following an MVA. There was a common expectation of the following symptoms listed in order of decreasing frequency: headache, anxiety, depression, difficulty concentrating, dizziness, visual impairment, trouble thinking, irritability, fatigue, sensitivity to light, and memory impairment. Headache and visual symptoms were expected more often in volunteers than their occurrence in patients.

Expectation as a major factor in chronic post-traumatic pain was studied by comparing the responses to queries in different countries.[130] One hundred and seventy-nine Canadians and 171 Lithuanians who had not been involved in MVAs were given a 56 symptom check list and asked to imagine symptoms that might occur after an MVA with brief loss of consciousness. The acute symptoms anticipated by the Canadians and Lithuanians were similar. Canadians anticipated chronic symptoms much more often then Lithuanians. Forty-five percent of Canadians expected headache for months or years after MVA while only 23% of Lithuanians had this expectation. Similarly, 44% of Canadians thought they would have neck pain months or years after such an MVA, but only 1% of Lithuanians anticipated this symptom. The differences were similar when subjects were asked to imagine the effects of MVA causing neck sprain.[131] Headache months or years later was anticipated in 32% Canadians and 1% Lithuanians; neck pain in 50% Canadians and 20% Lithuanians. A similar study compared the expectations of Greeks (n = 200) and Canadians (n = 179) following minor head injury.[132] Again, both groups anticipated similar acute symptoms commonly reported by accident victims but, in contrast to Canadians, very few Greeks selected symptoms likely to present a chronic problem. Five percent of Greeks and 45% of Canadians expected headache or neck or shoulder pain lasting months or years.[132] Most recently, the same methodologic study was carried out in Germany.[133] Again, anticipation of acute head injury symptoms were similar in Germans and Canadians but strikingly different in expectation of chronic symptoms. Thirty-two percent of Canadians expected headache, and 50% anticipated neck pain as chronic symptoms, while the expectations of these symptoms in Germans was 5% and 6%, respectively. (The expectation of chronic disability due to rheumatoid arthritis was similar in Canadians and Germans.)[133] In a smaller study, patients who were symptomatic 2 years after whiplash injury had shown more concern for long-term suffering and disability at the time of injury than those who did not have chronic pain.[50]

Children, athletes, drivers in demolition derby, human volunteers rarely develop chronic pain at least in part because they don't expect to.[134–137] Other factors may also be operative. Children are more malleable, athletes have stronger musculature, people anticipating trauma can brace themselves. Conversely, acute whiplash symptoms may be evoked by exposure to a placebo rear-end collision.[138]

Lack of attention (distraction) may suppress pain (eg, the soldier wounded in battle), focusing attention on pain reinforces and amplifies pain.[139] Attention to pain is a primary factor in its intensity and duration.[111] This is in part innate but it also derives from experience and culture.[140] Attention to the pain experience may evoke fear of pain and catastrophizing beliefs.[110] Attention to chronic pain is dependent on pain-related fear and creates a state of hypervigilance to pain.[141] Chronic post-traumatic headache is unrelated or inversely related to the severity of trauma perhaps because people with obvious structural lesions are paying attention to their defects (eg, paresis, visual loss) rather than to headache. In volunteers, nociceptive-evoked potentials were modulated by attention to the pain stimuli applied to one hand in contrast to unattended stimuli applied to the other hand.[142]

These phenomena have practical implications. Labeling a condition may focus attention to and increase concern of pain. The labels of "cervicalgia" and "cephalalgia" are more threatening and imply a more serious condition than "neck pain" and "headache." Others have noted that applying the diagnosis of "whiplash" may be more disabling than the injury.[143] There are important therapeutic implications. Treatment by medication, physical therapy, or chiropracty may re-enforce pain behavior.[144] Of 200 patients who experienced whiplash neck injuries, those who were encouraged to engage in normal activities had less symptoms after 2 years than the patients who were given time off from work and prescribed a cervical collar.[24] (Moreover prolonged use of a cervical collar impedes the early mobilization that is an effective method of management.)[145] People with chronic back pain who were working had lower pain scores than a matched group who were not working.[146]

Amplification of pain may be associated with central pain sensitization which accounts for hypersensitivity beyond the area of primary pain.[147] Generalized muscular hyperalgesia has been demonstrated in people with the chronic whiplash syndrome.[148]

In summary, the trauma and initial pain activate symptom expectancies. The more attention paid to the symptoms (prompted by the therapeutic and legal communities) the more they are augmented in intensity and duration. Anxiety is generated about their significance reinforcing or amplifying expectations of chronic pain attributed to trauma, completing the cycle.[149]

It is natural to attribute pain to a past injury. Conversely, symptoms in the past are often forgotten.[150] Symptoms attributed to trauma occur frequently in the population as a whole and at an incidence similar to that following injury.[66,151–153] People who have had a history of headache before an MVA are more likely than others to experience headache after the accident.[50] If patients overestimate chronic symptoms attributed to injury, they would be expected to underestimate these symptoms prior to injury. In one study, a control group was asked to imagine being involved in an MVA with brief loss of consciousness and to note the symptoms they had prior to the imagined trauma.[129] Patients with chronic post-traumatic symptoms reported fewer premorbid symptoms than the controls. For example, prior to the injury 7% of patients reported headache while this symptom was noted in 12.5% of controls. In another study, only 16% of subjects admitted neck symptoms prior to neck injury while 34% of their noninjured peers experienced these symptoms.[154] However these results were modified in another study.[155]

Claimants of personal injury of all types, when compared to controls, report higher rates of neuropsychological symptoms.[65] In one study, 170 patients filed personal injury claims for industrial stress, for example, back pain or emotional distress, for example, harassment.[65] Excluded from this group were claimants who had a history of neuropsychological impairment or head injury. The following symptoms were recorded by patients on average of 2 years after injury or event and compared to controls (in parenthesis) somatic: headache 88% (62%), dizziness 44% (26%); psychological: anxiety 93% (54%), depression 89% (32%); cognitive: impaired memory 53% (20%), impaired concentration 78% (26%). Other features of the postconcussion syndrome were also affirmed.

"If you have to prove you are ill, you can't get well" and claimants are not "cured by a verdict."[156,157] After attributing chronic pain to a past injury, settlement of litigation or compensation may not alter the pain syndrome.[32,158–161] Indeed some believe that financial settlement confirms the diagnosis and may reinforce illness behavior.[162] Litigants with chronic back pain had higher pain scores than a comparable group who were not litigating.[146] Poor outcomes after low back surgery were associated with worker's compensation coverage and consultation with an attorney before surgery.[163] In Saskatchewan, delay in recovery was strongly associated with retention of a lawyer and the type of insurance or compensation system.[22] In one study in the United Kingdom of the patients with the postconcussion syndrome who were admitted to a hospital, the duration of work absence was very much longer in those who claimed compensation than those who did not.[52] This fact was not influenced by the age or gender of the patient or the severity of the head injury. But in another study in the United Kingdom, persistence of whiplash symptoms was not associated with compensation proceedings.[26] Work-related litigation for chronic pain was associated with the highest levels of disability even after accounting for other factors associated with poor outcomes.[164] In any case, litigation is only one of many pain reinforcing components. Removing or diminishing litigation from the start is associated with a marked decrease in claims for whiplash injury and may be one of the factors associated with the low prevalence of chronic symptoms in Lithuania and other countries.[33,41]

Most patients complaining of chronic post-traumatic head and neck pain are not malingering. But in one study of people with late postwhiplash symptoms there was a high prevalence of cognitive underperformance as a manifestation of malingering in a short-term memory malingering test.[165] The results were highest in those involved in litigation. The insurance industry estimates that post-traumatic symptoms are fabricated from 20% to 47% of claimants, especially in big cities.[166]

The great disparities in the prevalence of chronic post-traumatic head and neck pain cannot be explained by organic disease. Social, cultural, and ethnic factors may influence ones appraisal of pain and the emotional and behavioral response to pain.[167] The small prevalence of post-traumatic pain in Kaumas, Lithuania, and Patras, Greece was attributed to the facts that the population had little or no preconceived notion or expectation of chronic whiplash pain and no fear of long-term disability.[33,41] Those injured in Lithuania and Greece return to work in a few days after the MVA and have little or no involvement in ongoing therapy, insurance companies, or litigation. Cultural and social expectations and other concepts of chronic post-traumatic symptoms appear to account for the striking differences in the prevalence of these symptoms from one country and one society to another. This concept was supported by a recent extensive review of WADs.[168] The best prognosis was associated with societies that have little litigation, no compensation for pain and suffering, and least disability payments. Accident victims who initially consulted physicians, physical therapists, chiropractors, or lawyers took longer to recover and these factors were unrelated to the severity of injury.

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