Pathogenesis of posttraumatic headache and migraine: a common headache pathway?

In recent years, research implicating biochemical abnormalities in various pathological conditions has spiralled. Headache is an area in which numerous research studies have been conducted examining biochemical alterations. We have noticed several similarities in biochemical changes reported to occur in migraine and in experimental traumatic brain injury. The most common symptom in mild head injury or mild traumatic brain injury is headache which, in many instances, resembles migraine but has a poorly understood pathophysiology. Biochemical mechanisms believed to be similar in both conditions include: increased extracellular potassium and intracellular sodium, calcium, and chloride; excessive release of excitatory amino acids; alterations in serotonin; abnormalities in catecholamines and endogenous opioids; decline in magnesium levels and increase in intracellular calcium; impaired glucose utilization; abnormalities in nitric oxide formation and function; and alterations in neuropeptides. In this paper, these proposed biochemical alterations will be reviewed and compared. Very similar alterations suggest posttraumatic headache associated with mild head injury and migraine may share a common headache pathway.

A retrospective, follow-up study of biofeedback-assisted relaxation therapy in patients with posttraumatic headache.

Although biofeedback in the treatment of migraine and tension-type headache has been widely researched, there is little research examining biofeedback therapy in posttraumatic headache (PTH). In this retrospective study, 40 subjects with PTH who had received biofeedback-assisted relaxation at our headache clinic were questioned at least 3 months following the completion of therapy. Subjects were queried about improvements in headache, increases in ability to relax and cope with pain, and overall benefits, lasting effectiveness, and continued use of biofeedback in daily life. Results indicate 53% reported at least moderate improvement in headaches; 80% reported at least moderate improvement in ability to relax and cope with pain; 93% found biofeedback helpful to some degree; 85% felt headache relief achieved through biofeedback had continued at least somewhat; and 95% stated they were continuing to use biofeedback skills in daily life. A correlation analysis revealed a negative relationship between response to biofeedback and increased chronicity of the disorder. In other words, the more chronic the disorder, the poorer the response to treatment. A stepwise regression analysis found that chronicity of the disorder and number of treatment sessions significantly affected response to treatment. Data suggest that biofeedback-assisted relaxation should at least be considered when planning treatment strategies for posttraumatic headache.

Psychopathology in individuals with post-traumatic headaches and other pain types.

In this study, the psychological functioning of patients with chronic post-traumatic headache (PTH), chronic combination headache and chronic low back pain without headache, whose time of onset was similar, and a matched group of controls was investigated. The Symptom Checklist 90-Revised (SCL-90-R), State-Trait Anger Expression Inventory (STAXI), State-Trait Anxiety Inventory, Form Y (STAI-Y), and Beck Depression Inventory (BDI) were used to assess the degree of psychopathology. A MANOVA test indicated highly significant differences between groups. In general, the pain groups fell along a continuum with PTH subjects demonstrating the highest elevations, back pain subjects demonstrating the next highest elevations, and combination subjects demonstrating fewer elevations. A cluster analysis indicated that findings were best classified into four clusters, but no one pain diagnosis predominated in any cluster. Eighty-nine percent of controls were assigned to clusters 1 or 2, which revealed essentially normal scores on all tests. It is suggested that while chronic pain patients demonstrate more psychopathology than non-pain controls, a variety of coping styles exists within each pain group independent of diagnostic categorization.

Posttraumatic headache.

The authors review posttraumatic headache (PTH). The most common symptom following head injury, PTH is paradoxically most severe after mild head injury. Although most cases resolve within 6 to 12 months, many patients have protracted or even permanent headache. Because PTH generally has no objective findings, it is often controversial whether the symptom is "real," "psychogenic," or "fabricated." Despite persisting beliefs by physicians, attorneys, and insurers that PTH resolves upon legal settlement, recent studies have shown that "permanent" PTH is usually still present several years after a legal settlement. Often PTH affects family life, recreation, and employment. Patients require education and support as well as appropriate evaluation and treatment.

Impairment ratings for posttraumatic headache.

No standardized criteria are available for establishing impairment ratings for pain or posttraumatic headache. The AMA Guides to the Evaluation of Permanent Impairment, 3rd Edition, 1988, defines impairment as "the loss of use of, or derangement of any body part, system or function." Headaches may be classified under episodic neurological disorders and impairment based loosely on frequency, severity and duration of attacks and how activities of daily living are affected. Other systems base ratings by physical findings or diagnosis. Criteria for posttraumatic headache are proposed in the form of a mnemonic: IMPAIRMENT. Intensity, Medication use, Physical signs/symptoms, Adjustment, Incapacitation, Recreation, Miscellaneous activity of daily living, Employment, Number (frequency), Time (duration of attacks). Each are scored from 0 to 2 points. There are three physician modifiers, scored from 0 to -4 points: Motivation for treatment, Overexaggeration or overconcern, Degree of legal interest. Case examples will illustrate how impairment ratings are determined, along with further details on scoring. Proposed criteria for posttraumatic headache impairment are understandable, easy to utilize and reproducible.

Cognitive symptoms in patients with posttraumatic headache.

A variety of symptoms (postconcussion symptoms) have been consistently reported following mild head or neck injury. One symptom which may have been under reported is cognitive impairment. We conducted a retrospective study of 100 patients presenting for evaluation and treatment of posttraumatic headache at our headache clinic. Sixty-five percent reported difficulties with either memory, concentration, and/or thinking. The most common cognitive symptoms reported were concentration+memory problems, concentration + memory + thinking difficulties, concentration disturbances, and difficulty remembering, respectively. Subjects in both groups (with cognitive symptoms and without cognitive symptoms) were similar in age, but females seemed more predisposed than males to cognitive impairment following mild head injury. It is suggested that clinicians thoroughly evaluate patients for cognitive symptoms, particularly when patients have a permanent condition and are subsequently involved in litigation.

Posttraumatic headache: determining chronicity.

In the headache literature, there exists a great deal of discrepancy regarding when posttraumatic headache (PTH) may be classified as chronic. Although chronic pain is usually described as pain persisting for longer than six months, many view chronic posttraumatic headache as persisting for more than two months, including the International Headache Society criteria. Observations made by Brenner and Friedman in 1944 have been repeatedly cited for this determination. Surprisingly, a review of this original source revealed that the term "chronic" was never used when discussing posttraumatic headache over two months duration. The authors, in fact, suggested two months as an "arbitrary" dividing line. Recent studies suggest that many patients with PTH continue to improve or change over the first six months but start to plateau after that time. We feel six months serves as a better time indicator for defining chronicity in cases of posttraumatic headache. This would be more consistent with the current literature concerning chronic pain and the international Headache Society criteria for chronic tension headache.