We report on a test to assess the dynamic brain function at high temporal resolution using magnetoencephalography (MEG) for 45-60 s. After fitting an autoregressive integrative moving average (ARIMA) model and taking the stationary residuals, all pairwise, zero-lag, partial cross-correlations P CC 0 ij and their z-transforms z 0 ij between i and j sensors were calculated, providing estimates of the strength and sign (positive, negative) of direct synchronous coupling at 1 ms temporal resolution. We found that subsets of z 0 ij successfully classified individual subjects to their respective groups (multiple sclerosis, Alzheimer's disease, schizophrenia, Sjögren's syndrome, chronic alcoholism, facial pain, healthy controls) and gave excellent external cross-validation results..

Traditional classification and prognostic approaches for chronic pain conditions focus primarily on anatomically based clinical characteristics not based on underlying biopsychosocial factors contributing to perception of clinical pain and future pain trajectories. Using a supervised clustering approach in a cohort of temporomandibular disorder cases and controls from the Orofacial Pain: Prospective Evaluation and Risk Assessment study, we recently developed and validated a rapid algorithm (ROPA) to pragmatically classify chronic pain patients into 3 groups that differed in clinical pain report, biopsychosocial profiles, functional limitations, and comorbid conditions. The present aim was to examine the generalizability of this clustering procedure in 2 additional cohorts: a cohort of patients with chronic overlapping pain conditions (Complex Persistent Pain Conditions study) and a real-world clinical population of patients seeking treatment at duke innovative pain therapies. In each cohort, we applied a ROPA for cluster prediction, which requires only 4 input variables: pressure pain threshold and anxiety, depression, and somatization scales. In both complex persistent pain condition and duke innovative pain therapies, we distinguished 3 clusters, including one with more severe clinical characteristics and psychological distress. We observed strong concordance with observed cluster solutions, indicating the ROPA method allows for reliable subtyping of clinical populations with minimal patient burden. The ROPA clustering algorithm represents a rapid and valid stratification tool independent of anatomic diagnosis. ROPA holds promise in classifying patients based on pathophysiological mechanisms rather than structural or anatomical diagnoses. As such, this method of classifying patients will facilitate personalized pain medicine for patients with chronic pain.

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We used magnetoencephalography (MEG) to investigate the cortical processing of an innocuous facial tactile stimulus in healthy subjects and in a group of subjects suVering from chronic temporomandibular disorder (TMD). Equivalent current dipoles (ECDs) were extracted for a time period of 1 s following stimulus application, and their location, duration and onset time determined. The counts of ECDs extracted did not diVer signiWcantly between the two groups. In contrast, we found statistically signiWcant diVerences in ECD duration and onset time. SpeciWcally, ECD duration was longer in the TMD group in the precentral gyrus, and ECD onset time was earlier in the parietal operculum. In addition, we found diVerences in the internal organization and clustering of the brain areas involved indicating a less tight association and a less coordinated stimulus information processing in the TMD group. Altogether, these results show that an innocuous facial tactile stimulus is diVerently processed in the brain of TMD subjects, when compared to controls, reXecting altered brain mechanisms due to chronic pain.

Orofacial pain (OFP) is a group of symptoms affecting a signiicant portion of the population; inadequate diagnosis and management of these symptoms present a potential detrimental effect on the public's health. It has been suggested that dental schools must prepare their graduates to deal with these problems rather than relying on their participation in continuing education courses after graduation. The aim of this study was to determine how third-and fourth-year students at one dental school perceived their level of competence related to OFP. Out of 140 students who were sent the survey, seventy-four (53 percent response rate) completed it in its entirety. The cross-sectional survey included questions regarding the students' familiarity with the categories of OFP. Questions asked how they perceived their knowledge in each of these areas, how comfortable they felt providing diagnosis and treatment, and if more knowledge was needed. The results showed that the fourth-year students were more comfortable than the third-year students in diagnosing and managing intraoral pain. Multiple comparisons also showed statistically signiicant differences between OFP categories for questions related to perceived knowledge, comfort in diagnosing and treating, and perceived need for more information. Overall, the students' perceived knowledge of and conidence in treating OFP varied with respect to certain categories, being lowest for psychogenic pain.

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SynopsisEpidemiological studies have shown that migraine headaches are a common finding in the general population, often associated with a high degree of disability. Additionally, migraine has a reported co-morbidity with other medical conditions, most notably with chronic pains such as temporomandibular disorders (TMD). The pathophysiological mechanisms involved with migraine are suggestive of an increased and prolonged hyperexcitability to stimuli, especially within the trigeminal distribution. Since migraine is mediated via branches of the trigeminal nerve it has the potential to mimic other types of pains, such as toothache or sinusitis. Therefore, it is recommended that oral and maxillofacial surgeons be familiar with the diagnostic criteria for migraine headaches in order to identify and appropriately treat such individuals who present to their clinics. KeywordsMigraine Headache; Diagnosis; Epidemiology; Pathophysiology; Oral Surgery; Pain IntroductionNeurovascular pains, otherwise known as headaches, are a group of pain disorders that are felt as cephalalgias, or pains in the head. Likely they are a heterogeneous group of disorders that share a common anatomic region of presentation, the head, but have somewhat separate pathophysiological mechanisms. For the most part, neurovascular pains are currently viewed Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. as arising from neuronal firing of nociceptors associated with intracranial blood vessels and dura. For this reason these pain disorders were historically referred to as 'vascular pains' [1], but further research has identified both peripheral and central aspects of the nervous system are playing crucial roles in the initiation and perpetuation of these pains [2,3]. This brought about a change in nomenclature regarding headache, which are now referred to as 'neurovascular pains disorders', stressing the neuropathic aspect of migraine. (Table 1) Research has continued to more closely associate headache disorders with neuropathic mechanisms, which is starting to result in a shift in how headaches are viewed -from both clinical and research perspectives. In the midst of this paradigm shift this article seeks to provide an overview of the epidemiologic data and pathophysiologic mechanisms of one type of neurovascular pain, that being migraine headaches. The reason for focusing on migraine headache is because they are known to be common in the population [4,5] and have been reported to have the most disability associated with them [6,7], making migraine headache the prototypic neurovascular pain disorder. Migraine hea...