Etienne Masquelier

Development and validation of the neuropathic pain symptom inventory

&NA; This study describes the development and validation of the Neuropathic Pain Symptom Inventory (NPSI), a new self‐questionnaire specifically designed to evaluate the different symptoms of neuropathic pain. Following a development phase and a pilot study, we generated a list of descriptors reflecting spontaneous ongoing or paroxysmal pain, evoked pain (i.e. mechanical and thermal allodynia/hyperalgesia) and dysesthesia/paresthesia. Each of these items was quantified on a (0–10) numerical scale. The validation procedure was performed in 176 consecutive patients with neuropathic pain of peripheral (n=120) or central (n=56) origin, recruited in five pain centers in France and Belgium. It included: (i) assessment of the test–retest reliability of each item, (ii) determination of the factorial structure of the questionnaire and analysis of convergent and divergent validities (i.e. construct validity), and (iii) evaluation of the ability of the NPSI to detect the effects of treatment (i.e. sensitivity to change). The final version of the NPSI includes 10 descriptors (plus two temporal items) that allow discrimination and quantification of five distinct clinically relevant dimensions of neuropathic pain syndromes and that are sensitive to treatment. The psychometric properties of the NPSI suggest that it might be used to characterize subgroups of neuropathic pain patients and verify whether they respond differentially to various pharmacological agents or other therapeutic interventions.

Determination of nerve conduction velocity of C-fibres in humans from thermal thresholds to contact heat (thermode) and from evoked brain potentials to radiant heat (CO2 laser).

This study was designed to estimate and compare nerve conduction velocity (NCV) of cutaneous heat-sensitive C-fibres obtained using two methods. The first is a method based on reaction times to different rates of temperature change produced by a large contact thermode (Thermotest). The second is a novel method based on ultra-late-evoked brain potentials to CO2 laser stimuli with tiny beam sections (< 0.25 mm2), allowing selective and direct activation of very slow conducting afferents. Both methods were applied on three sites of the right leg (foot, knee and thigh) of ten healthy subjects. When based on the reaction times to contact heat, NCV estimations were 0.4 +/- 0.22 m/s for the proximal segment (knee-thigh) and 0.6 +/- 0.23 m/s for the distal segment (foot-knee). When based on the difference in latency of the ultra-late positivity of laser-evoked brain potentials, NCV estimations were respectively 1.4 +/- 0.77 m/s and 1.2 +/- 0.55 m/s. For both methods, the difference in NCV between proximal and distal limb segments was not significant. Although both methods give NCV estimations within the range of C-fibres, the systematic difference between NCV obtained from each method may result from the activation of subpopulations of C-fibres with different NCV depending on the method of stimulation (low-threshold thermal receptors by the thermode and thermal nociceptors by the CO2 laser). Considering the difficulty of investigating peripheral fibres with slow conduction velocities (C-fibres) in humans, the methods used in the present study may be useful tools in both experimental and clinical situations.

Fitness and perceived exertion in patients with fibromyalgia syndrome

OBJECTIVE The aim of this study was to evaluate the cardiorespiratory fitness and perceived exertion of female patients with fibromyalgia syndrome (FMS) compared with that of healthy female subjects. DESIGN AND SUBJECTS This was designed as a cross-sectional case-control study, with a consecutive sample of 30 female patients with FMS and an age-matched control group of 67 healthy female subjects. SETTING This study was conducted at the multidisciplinary pain center of a university hospital in a city of more than 1 million inhabitants. OUTCOME MEASURES A cardiorespiratory fitness index (PWC65%/kg) and an original perceived exertion index (B65%) were obtained from the heart rates and perceived exertions scored on a 10-point Borg scale during a submaximal cycle ergometer test. Average indexes for the FMS patients and control subjects were compared. RESULTS The mean cardiorespiratory fitness index of the FMS patients was not significantly different from that of the controls. The mean perceived exertion index in the FMS patients was significantly greater than that of the controls, meaning that the FMS patients systematically reported higher ratings of perceived exertion during exercise. CONCLUSIONS Cardiorespiratory fitness, as expressed by a submaximal work capacity index, seems normal in female patients with FMS compared with age- and sex-matched healthy individuals. The fact that FMS patients overscore their perception of exertion may be due to a greater overlap of peripheral pain and perceived exertion perceptions during exercise. This observation should be noted when using perceived exertion scores to prescribe and monitor exercise in FMS patients.

Cognitive deficits in patients with chronic fatigue syndrome compared to those with major depressive disorder and healthy controls

OBJECT Chronic fatigue syndrome (CFS) patients report usually cognitive complaints. They also have frequently comorbid depression that can be considered a possible explanation for their cognitive dysfunction. We evaluated the cognitive performance of patients with CFS in comparison with a control group of healthy volunteers and a group of patients with MDD. PATIENTS AND METHODS Twenty-five patients with CFS, 25 patients with major depressive disorder (MDD), and 25 healthy control subjects were given standardized tests of attention, working memory, and verbal and visual episodic memory, and were also tested for effects related to lack of effort/simulation, suggestibility, and fatigue. RESULTS Patients with CFS had slower phasic alertness, and also had impaired working, visual and verbal episodic memory compared to controls. They were, however, no more sensitive than the other groups to suggestibility or to fatigue induced during the cognitive session. Cognitive impairments in MDD patients were strongly associated with depression and subjective fatigue; in patients with CFS, there was a weaker correlation between cognition and depression (and no correlation with fatigue). CONCLUSIONS This study confirms the presence of an objective impairment in attention and memory in patients with CFS but with good mobilization of effort and without exaggerated suggestibility.

Behavioral and Representational Components of “Hyperactivity” in Fibromyalgia Syndrome Patients

ABSTRACT Hyperactive premorbid lifestyle is frequently reported by fibromyalgia patients. The present study investigates the original assumption that hyperactive lifestyle could be viewed as a two-sided concept, with a representational side (ones own attitude toward activities) and a behavioural one (effective engagement in many activities). Twenty-four patients diagnosed with fibromyalgia were recruited together with their significant others [SOs]. A group of 24 healthy control participants was matched with the fibromyalgia group for gender, age, educational level, and type of profession. The aims of the study were to (1) compare ratings of fibromyalgia patients and SOs, and (2) compare ratings of patients and controls on past and present behavioral and representational components of hyperactivity. No differences were observed between patients and SOs. For the comparison between patients and controls, patients scored significantly higher on representational components of past hyperactivity, but lower on representational components of current hyperactivity. For past behavioral hyperactivity, patients and controls did not differ, except that patients had less time devoted to resting activities and sleep. The discussion emphasises the need for a systematic assessment of both representational and behavioral components of hyperactivity and argues for a better identification of related pathogenic mechanisms.

Adaptation et validation en français d’un questionnaire d’attitudes vis-à-vis de la douleur chronique: étude préliminaire

RésuméLes représentations que le patient a de sa douleur, de ses répercussions fonctionnelles, des traitements et de sa capacité à gérer sa situation sont devenus des éléments centraux dans l’évaluation psychologique du patient douloureux chronique. Peu d’outils validés et spécifiques à l’évaluation des aspects psychologiques de la douleur chronique existent actuellement en français. Cet article rapporte la procédure utilisée pour l’adaptation en français du «Survey of Pain Attitudes» (SOPA) et la première étape de validation (analyse factorielle et consistance interne) du questionnaire en français.SummaryThe beliefs of the chronic pain patients about their pain, the functional limitations, their coping skills and treatment’s expectations are central in the psychological assessment of chronic pain. Few reliable tools designed for a specific assessment of the psychological aspects of chronic pain are available for french-speaking practitioners. This article reports the procedure used for the adaptation into french of the «Survey of Pain Attitudes» (SOPA) and the first stage of the validation (factorial analysis and internal consistency) of the french version of the SOPA.

L’école du dos chez le lombalgique chronique Revue critique de la littérature

RésuméSuite à l’importance croissante sur le plan social et économique de patients souffrant de lombalgies, une nouvelle approche appelée «Ecole du Dos» s’est développée dans les années 1970 en Suède puis progressivement aux U.S.A. et au Canada. L’enseignement des notions de base d’anatomie et de physiologie du rachis ainsi que la responsabilité du patient face à son handicap constituent les dénominateurs communs de ces écoles du dos. Leurs approches dans la gestion de la douleur divergent avec un programme suédois orienté sur des concepts biomécaniques, une école californienne privilégiant un processus de type opérant par son parcours d’obstacles et les C.B.E.U. offrant une approche plus globale. Chez les lombalgiques chroniques, la majorité des études contrôlées, malgré leurs difficultés méthodologiques, soulignent les effets thérapeutiques positifs plus dans le changement d’autonomie du patient que sur l’élément douloureux subjectif. La satisfaction au travail, le degré de motivation et les capacités cognitives et intellectuelles des sujets sont les facteurs prédictifs les plus importants de bonne évalution.SummaryAs a result of the growing of people afflicted with low back pain, the low Back School was developed in Sweden at the beginning of the seventies and progressively in the United States and Canada. Teaching material concerning the anatomy and physiology of the spine and increasing «self care» behaviors constitutes the common denominator of these back schools. The approach on how to cope with pain diverges, with a Swedish programme teaches ergonomic principles, a Californian School applying a manager type of behavior therapy with its obstacle course and the C.B.E.U. giving more importance to a global approach. The majority of these controlled studies carried out in the chronic low back pain, in spite of methodological difficulties, have stressed the positive therapeutic effects more with regard to changes in the autonomy of the patient rather than the subjective feeling of pain. The work satisfaction, the degree of motivation and the cognitive and intellectual abilities are the best predictor of the outcome of treatment.

Determinants of representational and behavioral hyperactivity in patients with fibromyalgia syndrome

Fibromyalgia is associated with a premorbid hyperactivity. This study examines how contextual and personality factors contribute to premorbid hyperactivity. A total of 45 patients completed questionnaires. The results show that the number of children and the basic bodily needs neglect (and their interaction) explain nearly 50 percent of the variance of hyperactivity. The neglect toward bodily needs completely mediates the relation between self-oriented perfectionism and hyperactivity. This study suggests that hyperactivity itself would not have a pathological value, but that the neglect of basic bodily needs would represent a vulnerability factor in a hyperactive premorbid lifestyle in fibromyalgia patients.

Spinal cord stimulation for complex regional pain syndrome type 1 with dystonia: a case report and discussion of the literature.

Background: Complex Regional Pain Syndrome type 1 (CRPS-1) is a debilitating chronic pain disorder, the physiopathology of which can lead to dystonia associated with changes in the autonomic, central and peripheral nervous system. An interdisciplinary approach (pharmacological, interventional and psychological therapies in conjunction with a rehabilitation pathway) is central to progress towards pain reduction and restoration of function. Aim: This case report aims to stimulate reflection and development of mechanism-based therapeutic strategies concerning CRPS associated with dystonia. Case description: A 31 year old female CRPS-1 patient presented with dystonia of the right foot following ligamentoplasty for chronic ankle instability. She did not have a satisfactory response to the usual therapies. Multiple anesthetic blocks (popliteal, epidural and intrathecal) were not associated with significant anesthesia and analgesia. Mobilization of the foot by a physiotherapist was not possible. A multidisciplinary approach with psychological support, physiotherapy and spinal cord stimulation (SCS) brought pain relief, rehabilitation and improvement in the quality of life. Conclusion: The present case report demonstrates the occurrence of multilevel (peripheral and central) pathological modifications in the nervous system of a CRPS-1 patient with dystonia. This conclusion is based on the patient’s pain being resistant to anesthetic blocks at different levels and the favourable, at least initially, response to SCS. The importance of the bio-psycho-social model is also suggested, permitting behavioural change.