Are migraine and tension-type headache diagnostic types or points on a severity continuum? An exploration of the latent taxometric structure of headache.

The objective of this study was to assess whether migraine and tension-type headache (TTH) are best viewed as discrete entities or points on a severity continuum using taxometric analysis. Historically, classification systems have conceptualized the primary headache disorders of migraine and TTH as fundamentally different disorders that are differentiated by their characteristic symptom profiles and, as such, imply differing pathophysiologies and required treatments. Despite this categorical nosology, findings continue to emerge suggesting that migraine and TTH instead reflect dimensions of severity within the same headache construct. However, few studies have assessed this issue using taxometric statistical analyses or investigated how this taxonomic structure varies as a function of age and headache frequency. We conducted a latent-mode factor analysis of headache symptomatology obtained from 3449 individuals with headache from 2 previous, large-scale cross-sectional studies of primary headache sufferers (Martin et al., 2005, and Smitherman and Kolivas, 2013). Stratified taxometric analyses suggest that the validity of a categorical vs dimensional classification varies as a function of sample characteristics. Specifically, graphical results revealed that high headache frequency (>15 d/mo) and younger age (<24 years old) were associated with unimodal distributions suggestive of a dimensional construct of primary headache, whereas lower headache frequency and older age were associated with bimodal distributions characteristic of discrete diagnostic entities. Conceptualizing primary headache as a severity continuum was supported for young adults and those with frequent headaches. The distinctions of a categorical classification system were supported for adults (>24 years old) and those with infrequent headache.

Attentional strategy moderates effects of pain catastrophizing on symptom-specific physiological responses in chronic low back pain patients.

In the present study, we examined whether experimentally-manipulated attentional strategies moderated relations between pain catastrophizing and symptom-specific physiological responses to a cold-pressor task among sixty-eight chronic low back patients. Patients completed measures of pain catastrophizing and depression, and were randomly assigned to sensory focus, distraction or suppression conditions during a cold pressor. Lumbar paraspinal and trapezius EMG, and cardiovascular responses to the cold pressor were assessed. Attentional strategies moderated the relation between pain catastrophizing and lumbar paraspinal muscle, but not trapezius muscle or cardiovascular responses. Only for participants in the suppression condition was catastrophizing related significantly to lumbar paraspinal muscle responses. Depressed affect did not account for this relation. These findings indicate that 'symptom-specific' responses among pain catastrophizers with chronic low back depend on how they attend to pain-related information. Specifically, it appears that efforts to suppress awareness of pain exaggerate muscular responses near the site of injury.

The predictive value of abbreviated migraine diagnostic criteria.

OBJECTIVE: To determine the operating characteristics and predictive value of abbreviated criteria for the diagnosis of migraine headache. BACKGROUND: The International Headache Society (IHS) diagnostic criteria for migraine have been adopted in limited fashion in clinical practice. Primary care physicians in particular deal with innumerable conditions and diagnostic algorithms. Unless the IHS criteria are simplified the recognition of migraine headache in primary care settings will not be apt to improve. METHODS: This study was a retrospective analysis of four discrete research databases: headache clinic patients (N = 390), private practice neurology patients (N = 290), college students (N = 99), and community-based patients (N = 784). Physicians and psychologists expert in the diagnostic criteria for migraine headache syndromes conducted a standardized diagnostic interview in all patients (N = 1524). Each was later assigned an IHS headache diagnosis by a previously validated computer-based algorithm. The sensitivity, specificity, positive and negative predictive values, and accuracy were calculated for single- and multiple-variable models of migraine predictors. Optimal models were defined as those with positive likelihood ratios (+LRs) of >4.5 and negative likelihood ratios (-LRs) of <0.25 for the combined population. RESULTS: The only optimal single-variable model was nausea, which had an overall +LR of 4.8 and -LR of 0.23. None of the two-variable models met criteria for an optimal model. The best of the optimal three-variable models were nausea/photophobia/pulsating (+LR 6.7, -LR 0.23) and nausea/photophobia/worsening with physical activity (+LR 5.9, -LR 0.21). These three models maintained positive predictive values >0.80 in all 4 patient populations and negative predictive values >0.70 in the majority of populations. CONCLUSION: The single-variable model of nausea and the three-variable models of nausea/photophobia/worse with exertion and nausea/phonophobia/pulsating can effectively predict migraine in diverse clinical settings. These models however, should only be applied after a careful exclusion of secondary headache disorders.

Patterns of pain descriptor usage in African Americans and European Americans with chronic pain.

This study examined ethnic differences in the use of pain descriptors, comparing standardized pain assessment data from African American and European American patients with heterogeneous chronic pain syndromes. The measure was the Short-Form McGill Pain Questionnaire (SF-MPQ) including the embedded Visual Analog Scale (VAS). Exploratory factor analyses of SF-MPQ data identified differences in factor structure with the VAS loading on a different factor for each group. A 5-factor solution was obtained from the African American group and a 4-factor solution was obtained from the European American group. There was little overlap in the pattern matrices for African American and European American groups. Results suggest that the VAS is as sensitive to ethnic differences as other traditional pain measures.