Differential pain response at local and remote muscle sites following aerobic cycling exercise at mild and moderate intensity

Physical exercise has been shown to inhibit experimental pain response in the post-exercise period. Modulation of the pain system may be differentiated between muscle sites engaging in contractile activity. The purpose of this study was to assess the pain response at remote and local muscle sites following aerobic exercise at different work intensities. Participants included 10 healthy and physically active males (mean age ± SD, 21.2 ± 3.4). Somatic pressure pain threshold (PPT) at the rectus femoris (local) and brachioradialis (remote) muscle site was measured at before (Pre), 5 min after (Post1), and 15 min after (Post2) aerobic cycling exercise at 70 and 30 % of peak oxygen uptake (VO(2peak)) performed on different occasions in a counterbalanced order, separated by minimum of 3 days interval. Repeated measures ANOVA for PPT reveals significant main effect for time (f = 3.581, p = 0.049, observed power = 0.588) and muscle site (f = 17.931, p = 0.002, observed power = 0.963). There was a significant interaction shown for exercise intensity by time (f = 11.390, p = 0.012, observed power = 0.790). PPT at rectus femoris following cycling exercise at 70 % of VO(2peak) reveals a significant increase between Pre-Post1 (p = 0.040). PPT for rectus femoris following cycling exercise at 30 % of VO(2peak) revealed a significant decrease between Pre-Post1 (p = 0.026) and Pre-Post2 (p = 0.008). The PPT for brachioradialis following cycling exercise at 30 % of VO(2peak) revealed a significant decrease between Pre-Post1 (p = 0.011) and Pre-Post2 (p = 0.005). These results show that aerobic exercise increases PPT locally at the exercise muscle site following exercise at 70 % of VO(2peak) but reduces PPT following exercise at 30 % of VO(2peak)

Measurement of the Association of Pain with Clinical Characteristics in Oral Cancer Patients at Diagnosis and Prior to Cancer Treatment

Caroline M Sawicki,1 Malvin N Janal,2 Sung Hye Gonzalez,3 Angie K Wu,3 Brian L Schmidt,3– 5,* Donna G Albertson3– 5,* 1Department of Pediatric Dentistry, New York University College of Dentistry, New York, NY, USA; 2Department of Epidemiology & Health Promotion New York University College of Dentistry, New York, NY, USA; 3NYU Dentistry Translational Research Center, New York University College of Dentistry, New York, NY, USA; 4Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, New York, NY, USA; 5NYU Pain Research Center, New York University College of Dentistry, New York, NY, USA*These authors contributed equally to this workCorrespondence: Donna G Albertson, NYU Dentistry Translational Research Center, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY, 10010, USA, Tel +1 212-998-9396, Fax +1 212-995-4843, Email [email protected]: Oral cancer patients suffer pain at the site of the cancer, which degrades quality of life (QoL). The University of California San Francisco Oral Cancer Pain Questionnaire (UCSFOCPQ), the only validated instrument specifically designed for measuring oral cancer pain, measures the intensity and nature of pain and the level of functional restriction due to pain.Purpose: The aim of this study was to compare pain reported by untreated oral cancer patients on the UCSFOCPQ with pain they reported on the Brief Pain Inventory (BPI), an instrument widely used to evaluate cancer and non-cancer pain.Patients and Methods: The correlation between pain measured by the two instruments and clinical characteristics were analyzed. Thirty newly diagnosed oral cancer patients completed the UCSFOCPQ and the BPI.Results: Pain severity measurements made by the UCSFOCPQ and BPI were concordant; however, the widely used BPI average pain over 24 hours score appeared less sensitive to detect association of oral cancer pain with clinical characteristics of patients prior to treatment (nodal status, depth of invasion, DOI). A BPI average score that includes responses to questions that measure both pain severity and interference with function performs similarly to the UCSFOCPQ in detection of associations with nodal status, pathologic T stage (pT stage), stage and depth of invasion (DOI).Conclusion: Pain assessment instruments that measure sensory and interference dimensions of oral cancer pain correlate with biologic features and clinical behavior.Keywords: pretreatment oral cancer pain, University of California San Francisco Oral Cancer Pain Questionnaire, Brief Pain Inventory, pain severity, pain interference with functionin

Thermal temporal summation and decay of after-sensations in temporomandibular myofascial pain patients with and without comorbid fibromyalgia

Malvin N Janal,1 Karen G Raphael,2 Dane B Cook,3 David A Sirois,2 Lena Nemelivsky,2 Roland Staud4 1Epidemiology and Health Promotion, 2Oral and Maxillofacial Pathology, Radiology, and Medicine, NYU College of Dentistry, New York, NY, 3Department of Kinesiology, University of Wisconsin, Madison, WI, 4Department of Medicine, University of Florida College of Medicine, Gainesville, FL, USA Introduction: Chronic myofascial temporomandibular disorders (TMD) may have multiple etiological and maintenance factors. One potential factor, central pain sensitization, was quantified here as the response to the temporal summation (TS) paradigm, and that response was compared between case and control groups. Objectives: As previous research has shown that fibromyalgia (FM) is diagnosed in ~20% of TMD patients, Aim 1 determined whether central sensitization is found preferentially in myofascial TMD cases that have orofacial pain as a regional manifestation of FM. Aim 2 determined if the report of after-sensations (AS) following TS varied depending on whether repeated stimuli were rated as increasingly painful. Methods: One hundred sixty-eight women, 43 controls, 100 myofascial TMD-only cases, and 25 myofascial TMD + FM cases, were compared on thermal warmth and pain thresholds, thermal TS, and decay of thermal AS. All cases met Research Diagnostic Criteria for TMD; comorbid cases also met the 1990 American College of Rheumatology criteria for FM. Results: Pain thresholds and TS were similar in all groups. When TS was achieved (~60%), significantly higher levels of AS were reported in the first poststimulus interval, and AS decayed more slowly over time, in myofascial TMD cases than controls. By contrast, groups showed similar AS decay patterns following steady state or decreasing responses to repetitive stimulation. Conclusion: In this case–control study, all myofascial TMD cases were characterized by a similar delay in the decay of AS. Thus, this indicator of central sensitization failed to suggest different pain maintenance factors in myofascial TMD cases with and without FM. Keywords: temporomandibular joint dysfunction syndrome, temporal summation of pain, women, central sensitization, QS

Association of polymorphism (Val66Met) of brain-derived neurotrophic factor with suicide attempts in depressed patients

Introduction: Recent post-mortem studies of suicide victims have implicated brain-derived neurotrophic factor (BDNF) in suicide. Therefore, it was decided to examine the possible role of a gene in the regulation of BDNF activity in relation to suicidal behaviour among depressed patients. Method: A series of 170 depressed patients were evaluated for their history of suicide attempts and genotyped for the BDNF Val66Met polymorphism (SNP ID: rs6265). Depressed patients who had (n = 97) or had not (n = 73) attempted suicide were compared. Results: Depressed patients who carried the BDNF Val66Met polymorphism variant (GA + AA) appeared to show a significantly increased risk of suicidal behaviour. The risk of a suicide attempt was also significantly higher among those reporting higher levels of childhood emotional, physical and sexual abuse. Secondary analyses suggested that depression severity was a significant risk factor only in the wild-type BDNF genotype, and that the risk of suicide attempts was more predictable within the wild-type group. Conclusion: These preliminary data suggest that BDNF may play a role in the suicidal behaviour of depressed patients

A system for inducing concurrent tactile and nociceptive sensations at the same site using electrocutaneous stimulation

Item does not contain fulltextStudies of the interaction between mechanoception and nociception would benefit from a method for stimulation of both modalities at the same location. For this purpose, we developed an electrical stimulation device. Using two different electrode geometries, discs and needles, the device is capable of inducing two distinct stimulus qualities, dull and sharp, at the same site on hairy skin. The perceived strength of the stimuli can be varied by applying stimulus pulse trains of different lengths. We assessed the perceived stimulus qualities and intensities of the two electrode geometries at two levels of physical stimulus intensity. In a first series of experiments, ten subjects participated in two experimental sessions. The subjects reported the perceived quality and intensity of four different stimulus classes on visual analogue scales (VASs). In a second series, we added a procedure in which subjects assigned descriptive labels to the stimuli. We assessed the reproducibility of the VAS scores by calculating intraclass correlation coefficients. The results showed that subjects perceived stimuli delivered through the disc electrodes as dull and those delivered through the needles as sharp. Increasing the pulse train length increased the perceived stimulus intensities without decreasing the difference in quality between the electrode types. The intraclass correlation coefficients for the VAS scores ranged from .75 to .95. The labels that were assigned for the two electrode geometries corresponded to the descriptors for nociception and touch reported by other researchers. We concluded that our device is capable of reliably inducing tactile and nociceptive sensations of controllable intensity at the same skin site