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Biomedical subjects

D J Clauw

Publications and source records attributed to D J Clauw.

At least 19 recordsLinked to original sources
PubMed2006

[Central pain processing in chronic low back pain. Evidence for reduced pain inhibition].

INTRODUCTION: A study of patients with low back pain (LBP) had revealed altered central pain processing. At an equal pain level LBP patients had considerably more neuronal activation in the somatosensory cortices than controls. In a new analysis of this dataset, we further investigated the differences in central pain processing between LBP patients and controls, looking for possible pathogenic mechanisms. METHODS: Central pain processing was studied by functional magnetic resonance imaging (fMRI), using equally painful pressure stimuli in a block paradigm. In this study, we reanalyzed the fMRI data to statistically compare pain-elicited neuronal activation of both groups. RESULTS: Equally painful pressure stimulation resulted in a significantly lower increase of regional cerebral blood flow (rCBF) in the periaqueductal gray (PAG) of the LBP patients. The analysis further revealed a significantly higher increase of rCBF in LBP than in HC in the primary and secondary somatosensory cortex and the lateral orbitofrontal cortex (LOFK), elicited by these same stimuli. CONCLUSIONS: These findings support a dysfunction of the inhibitory systems controlled by the PAG as a possible pathogenic mechanism in chronic low back pain.

Adult↗
PubMed2004

Pain catastrophizing and neural responses to pain among persons with fibromyalgia.

Pain catastrophizing, or characterizations of pain as awful, horrible and unbearable, is increasingly being recognized as an important factor in the experience of pain. The purpose of this investigation was to examine the association between catastrophizing, as measured by the Coping Strategies Questionnaire Catastrophizing Subscale, and brain responses to blunt pressure assessed by functional MRI among 29 subjects with fibromyalgia. Since catastrophizing has been suggested to augment pain perception through enhanced attention to painful stimuli, and heightened emotional responses to pain, we hypothesized that catastrophizing would be positively associated with activation in structures believed to be involved in these aspects of pain processing. As catastrophizing is also strongly associated with depression, the influence of depressive symptomatology was statistically removed. Residual scores of catastrophizing controlling for depressive symptomatology were significantly associated with increased activity in the ipsilateral claustrum (r = 0.51, P < 0.05), cerebellum (r = 0.43, P < 0.05), dorsolateral prefrontal cortex (r = 0.47, P < 0.05), and parietal cortex (r = 0.41, P < 0.05), and in the contralateral dorsal anterior cingulate gyrus (ACC; r = 0.43, P < 0.05), dorsolateral prefrontal cortex (r = 0.41, P < 0.05), medial frontal cortex (r = 0.40, P < 0.05) and lentiform nuclei (r = 0.40, P < 0.05). Analysis of subjects classified as high or low catastrophizers, based on a median split of residual catastrophizing scores, showed that both groups displayed significant increases in ipsilateral secondary somatosensory cortex (SII), although the magnitude of activation was twice as large among high catastrophizers. Both groups also had significant activations in contralateral insula, SII, primary somatosensory cortex (SI), inferior parietal lobule and thalamus. High catastrophizers displayed unique activation in the contralateral anterior ACC, and the contralateral and ipsilateral lentiform. Both groups also displayed significant ipsilateral activation in SI, anterior and posterior cerebellum, posterior cingulate gyrus, and superior and inferior frontal gyrus. These findings suggest that pain catastrophizing, independent of the influence of depression, is significantly associated with increased activity in brain areas related to anticipation of pain (medial frontal cortex, cerebellum), attention to pain (dorsal ACC, dorsolateral prefrontal cortex), emotional aspects of pain (claustrum, closely connected to amygdala) and motor control. These results support the hypothesis that catastrophizing influences pain perception through altering attention and anticipation, and heightening emotional responses to pain. Activation associated with catastrophizing in motor areas of the brain may reflect expressive responses to pain that are associated with greater pain catastrophizing.

Adaptation, Psychological↗
PubMed2002

The use of complementary medical therapies in the management of myofascial pain disorders.

Complementary medical therapies are commonly used for the treatment and management of myofascial pain. No universally accepted therapy for this condition exists; consequently, patients often seek alternative and complementary therapies. Many complementary treatments are available.This article focuses on acupuncture, biofeedback, ultrasound, lasers, and massage. Although anecdotally claimed as effective, most of these modalities have not been rigorously investigated because of poor research quality. Appropriate controls, sample sizes, and blinding measures are often lacking. Despite these issues, the trend toward efficacy exists and further examination is warranted.

Complementary Therapies↗
PubMed2001

Rigorous new approach to constructing a gold standard for validating new diagnostic criteria, as exemplified by the eosinophilia-myalgia syndrome.

BACKGROUND: Constructing diagnostic criteria, a common problem in clinical medicine, is particularly difficult for diseases that lack a pathognomonic "gold standard." To develop an improved strategy for constructing such criteria, we used the eosinophilia-myalgia syndrome as an example. The goal, for research classifications, was to construct validated clinically sensible criteria and to develop improved methods that can be used for other disorders. METHODS: Using a "pattern-based" approach with data from several separate sources, a committee of investigators first prepared and informally tested criteria for the diagnosis of eosinophilia-myalgia syndrome. A gold standard challenge set of reports of cases and noncases was independently generated and separately validated by an external panel of clinical experts. The criteria were then tested using the gold standard set, and interobserver variability and diagnostic accuracy were determined. RESULTS: Interobserver variability showed the following mean proportionate agreements: 98.7% for the presence of specific criteria elements, 99% to 100% for diagnosis, and 97% to 98% for diagnostic pattern. kappa Values were correspondingly high. Diagnostic accuracy showed sensitivity at 88%, specificity at 97%, and overall accuracy at 92%. CONCLUSIONS: The proposed criteria are accurate and reproducible, and can be used in future clinical investigations of the eosinophilia-myalgia syndrome. The new strategy and methods developed for this challenge can be valuable for solving analogous problems in constructing criteria for other clinical disorders.

Diagnostic Techniques and Procedures↗
PubMed2001

A multicenter two by two factorial trial of cognitive behavioral therapy and aerobic exercise for Gulf War veterans' illnesses: design of a veterans affairs cooperative study (CSP #470).

The Department of Veterans Affairs (VA) Cooperative Studies Program (CSP) Study #470 is a 2 x 2 factorial trial designed to evaluate the hypothesis that both cognitive behavioral therapy (CBT) and aerobic exercise will significantly improve physical function in participants with Gulf War veterans' illnesses (GWVI), and that adding CBT to aerobic exercise will provide further incremental benefit. One thousand three hundred fifty-six veterans will be randomized to one of four treatment arms: CBT plus aerobic exercise plus usual and customary care, aerobic exercise plus usual and customary care, CBT plus usual and customary care, or usual and customary care alone. The study duration is 2.5 years with 1.5 years of intake and 1 year of follow-up. The primary outcome measure is the proportion of veterans improved more than seven units on the physical component summary (PCS) scale of the Short Form Health Survey for Veterans (SF-36V) measured 12 months after randomization. This generic quality-of-life measure was chosen because there is no disease-specific measure for GWVI and the symptoms of GWVI span a wide range of physical manifestations that are related to the domains covered by the PCS scale. Sample size was determined to detect all six pairwise comparisons between the four treatment arms with 90% power and a Bonferroni adjustment for an overall type I error of 0.05 or 0.05/6 = 0.0083. CSP #470 was initiated in May 1999 in 18 VA and two Department of Defense medical centers. To date this represents the largest randomized trial designed to evaluate treatments for individuals with unexplained physical symptoms. This paper will focus on the rationale and unique features of the study design. Control Clin Trials 2001;22:310-332

Cognitive Behavioral Therapy↗
PubMed2001

Potential mechanisms in chemical intolerance and related conditions.

The symptom of chemical intolerance may occur in isolation, but often occurs in conjunction with other chronic symptoms such as pain, fatigue, memory disturbances, etc. This frequent clustering of symptoms in individuals has led to the definition of several chronic multisymptom syndromes, such as multiple chemical sensitivity, fibromyalgia, chronic fatigue syndrome, and Gulf War illnesses. The aggregate research into these syndromes has suggested some unifying mechanisms that contribute to symptomatology. Multiple lines of evidence suggest that there is aberrant function of numerous efferent neural pathways, such as the autonomic nervous system and hypothalamic-pituitary axes, in subsets of individuals with these conditions. There is perhaps the greatest evidence for abnormal sensory processing in these syndromes, with a low "unpleasantness threshold" for multiple types of sensory stimuli. Psychological and behavioral factors are known to play a significant role in initiating or perpetuating symptoms in some persons with these illnesses. In the field of pain research, the interrelationship between physiologic and psychologic factors in symptom expression has been well studied. Using both established and novel methodologies, studies have suggested that psychologic factors such as hypervigilance and expectancy are playing a relatively minor role in most individuals with fibromyalgia and that clear evidence exists of physiologic amplification of sensory stimuli. These studies need to be extended to more sensory tasks and to larger numbers of subjects with related conditions. It is of note, though, that existing data on this spectrum of illnesses would suggest that there may be greater psychologic contributions to symptomatology if an illness is defined in part by behavior (e.g., avoidance of chemical exposures) rather than on the basis of symptoms alone.

Afferent Pathways↗
PubMed2001

Elusive syndromes: treating the biologic basis of fibromyalgia and related syndromes.

Newer theories suggest that patients with fibromyalgia have a biologic predisposition to perceiving pain with more sensitivity than people without fibromyalgia. Several biologic triggers are implicated as possibly initiating or worsening the symptoms of fibromyalgia. Treatments to manage pain, help with sleep, and, when needed, treat cognitive disturbances show some success.

Fibromyalgia↗
PubMed2000

Sympathetic nervous system function in fibromyalgia.

This review focuses on studies of the sympathetic nervous system in fibromyalgia (FM). First, a brief review of the sympathetic system, and its relationship to the human stress response, is outlined. Then various studies of functional assessment of sympathetic function in FM are highlighted. Certain methods of assessment (eg, heart rate variability, biochemical, and psychophysical responses to various stressors) that we believe to be of specific importance for future research are discussed in greater detail. Finally, findings on autonomic function in related disorders--specifically, chronic fatigue syndrome, irritable bowel syndrome, and migraine--will be briefly presented.

Female↗
PubMed1999

Pain sensitivity as a correlate of clinical status in individuals with chronic low back pain.

STUDY DESIGN: A cross-sectional study of baseline correlates of clinical pain and functional status in consecutive patients being treated for chronic low back pain. OBJECTIVES: To determine if an individual's global pain sensitivity, measured by experimental pain threshold to pressure at various regions of the body, is associated with baseline measures of clinical pain and physical functioning. SUMMARY OF BACKGROUND DATA: Previous studies have demonstrated that in individuals with chronic low back pain, clinical pain and functional status are significantly associated with demographic, structural, and psychosocial factors. However, a large portion of variance remains unexplained. Because pain sensitivity (tenderness) has been shown to occur as a continuum in the population, the authors sought to determine if such sensitivity might be associated with clinical status in chronic low back pain, beyond what is known regarding demographic, structural, and psychosocial factors. METHODS: Forty-five patients with chronic low back pain were assessed for a variety of demographic, structural, and psychosocial factors, which previously have been shown to contribute to clinical status. In addition, all patients underwent testing for pain tolerance and threshold at various areas of the body. RESULTS: Age, degree of structural abnormality observed on magnetic resonance imaging, and depressive symptoms were all significantly correlated with either clinical pain or functional status. Pain sensitivity, the target of this investigation, accounted for significant proportions of variance in functional status and pain, even after controlling for demographic, structural, and psychosocial variables. CONCLUSIONS: These pilot data suggest that an individual's experimental pain threshold (a measure of tenderness) is associated with baseline functional status and pain in cases of chronic low back pain and may represent an important domain warranting further investigation.

Chronic Disease↗
PubMed1998

Rhinitis symptoms in chronic fatigue syndrome.

BACKGROUND: Atopy and allergic rhinitis are thought to be increased in prevalence in chronic fatigue syndrome (CFS). METHODS: To investigate this hypothesis, 51 CFS (CFS), 34 normal (N), 27 allergic rhinitis (AR), and 17 patients with other rheumatologic diseases filled out an Airway Symptom Severity self-report questionnaire to determine the frequencies of nasal, sinus, and chest symptoms, and a Systemic Complaints self-report questionnaire to determine the frequencies of complaints referable to neurologic, rheumatologic, gastrointestinal, and other systems. All subjects received a standard set of allergy skin tests, and were subdivided into those with positive and negative results. RESULTS: Allergy skin tests were positive in 35% of CFS and 44% of N subjects (difference not significant by Chi2). Significant rhinitis complaints were present in 83% of skin test positive CFS, 76% of skin test negative CFS, 74% of AR, and 23% of N subjects. Systemic Complaints scores were significantly elevated in skin test positive (94%) and negative (94%) CFS groups compared with AR (35%) and N (6%) groups. This score could significantly discriminate between CFS and N subjects. CONCLUSIONS: These data indicate that in this CFS population, 24% had no significant rhinitis complaints, 30% had positive skin tests suggesting the potential for allergic rhinitis complaints, and 46% had nonallergic rhinitis. The mechanism of the nonallergic component may offer insights into the pathogenesis of CFS.

Adult↗
PubMed1997

The relationship between fibromyalgia and the multiple chemical sensitivity syndrome.

Fibromyalgia (FM) patients often report a high frequency of non-musculoskeletal symptoms, including those suggestive of multiple chemical sensitivity (MCS) syndrome. The objective of this pilot study was to determine the prevalence of MCS in FM patients from a university-based rheumatology practice. Self-report questionnaires were administered to determine the presence of MCS, utilizing the criteria from a recent study of the immunologic profile of patients with this disorder. Patients also responded "yes" or "no" to the presence of 48 FM-related symptoms. Thirty-three of 60 patients with FM met the criteria for MCS. Eleven of these patients also fulfilled more restrictive criteria, requiring a "higher degree" of chemical sensitivity. The symptoms and substances most frequently cited were similar to those reported in other studies of MCS. FM patients with and without MCS did not differ in other symptomatology. MCS may represent an additional symptom complex within the spectrum of FM.

Adult↗
PubMed1996

Phosphorus nuclear magnetic resonance spectroscopy: in vivo magnesium measurements in the skeletal muscle of normal subjects.

31P nuclear magnetic resonance spectroscopy was used to study the skeletal muscle of 33 normal males and 32 females. Free intracellular magnesium levels and the ratios of the phosphorus metabolites were determined. Males had significantly lower free magnesium levels (499.8 microM +/- 26.3 microM vs. 530.7 microM +/- 36.0 microM, P = 0.001, d.f. = 63, analysis of variance). The free magnesium level (rs = -0.5431, P = 0.001) and the phosphocreatin/Inorganic phosphate ratio in males (rs = -0.4102, P = 0.018), and the phosphocreatine/Inorganic phosphate ratio in females (rn = -0.4759, P = 0.009) fell with the increasing Minnesota Heart Health Program Questionnaire score.

Adult↗
PubMed1996

Clinical features of eosinophilia myalgia syndrome and related disorders.

EMS, EF, and TOS are all relatively rare disorders. There are considerable data to suggest that most (if not all) of these cases may be due to toxin exposure, although the precise etiologic agent(s) has yet to be identified. It is likely that the pathogenic mechanisms responsible for disease are similar in these entities, and thus the distinctions between these illnesses may be largely semantic. Rational therapy includes the removal of an inciting agent if identified, and the application of symptom-based treatment based on the organ or tissue involved, and whether there is evidence of active inflammation is present.

Brassica↗