Intensität von Gliederschmerzen und Erschöpfung bei Fibromyalgiesyndrom, depressiven Störungen und chronischen Rückenschmerzen

Not a general, symptom-unspecific, transdiagnostic marker for functional symptoms: sensorimotor processing of head control is intact in chronic pain

Introduction

Functional disorders are prevalent in all medical fields and pose a tremendous public health problem, with pain being one of the most common functional symptoms. Understanding the underlying, potentially unifying mechanism in functional (pain) disorders is instrumental in facilitating timely diagnosis, stigma reduction, and adequate treatment options. Neuroscientific models of perception suggest that functional symptoms arise due to dysregulated sensorimotor processing in the central nervous system, with brain-based predictions dominating the eventual percept. Experimental evidence for this transdiagnostic mechanism has been established in various functional symptoms. The goal of the current study was to investigate whether erroneous sensorimotor processing is an underlying transdiagnostic mechanism in chronic (functional) pain.

Method

A total of 13 patients with chronic (functional) pain [three patients with chronic (functional) pain disorder, F45.40, ICD-10; 10 patients with chronic pain disorder with somatic and psychological factors, F45.41, ICD-10]; and 15 healthy controls performed large combined eye-head gaze shifts toward visual targets, naturally and with increased head moment of inertia. We simultaneously measured participants' eye and head movements to assess head oscillations at the end of the gaze shift, which are an established indicator of (transdiagnostic) sensorimotor processing deficits of head control.

Results

Using a Bayesian analysis protocol, we found that patients with chronic (functional) pain and control participants stabilized their heads equally well (Bayes Factor 01 = 3.7, Bayes Factor exclusion = 5.23; corresponding to substantial evidence) during all sessions of the experiment.

Conclusion

Our results suggest that patients with chronic (functional) pain do not show measurable symptom-unspecific sensorimotor processing deficits. We discuss outcome parameter choice, organ system specificity, and selection of patient diagnoses as possible reasons for this result and recommend future avenues for research.

Diagnosis of fibromyalgia syndrome-a comparison of Association of the Medical Scientific Societies in Germany, survey, and American College of Rheumatology criteria

OBJECTIVES

The survey and the Association of the Medical Scientific Societies in Germany (AWMF) criteria had been developed to overcome problems associated with tender point criterion of the American College of Rheumatology (ACR) (lacking validation for clinical diagnosis, inconsistent use by rheumatologists, and nonrheumatologists) for the clinical diagnosis of fibromyalgia syndrome (FMS). We compared the concordance between these 3 criteria.

METHODS

Consecutive patients of different clinical settings referred for the evaluation of chronic widespread pain or management of established FMS diagnosis were assessed by medical history, a complete physical examination including tender points, and questionnaires [self-constructed symptoms questionnaire, regional pain scale (RPS), Patient Health Questionnaire (PHQ 9 and 15)]. FMS according to AWMF-criteria was diagnosed by the history of widespread pain (axial and all 4 extremities), the symptoms sleep disturbances, fatigue, and feeling of swelling or stiffness of the hands or feet or face (Numeric rating scale >or=1/10 each symptom) and the exclusion of somatic diseases sufficiently explaining the symptoms. FMS according to survey criteria was diagnosed by regional pain scale score >or=8 and fatigue score >or=6/10 on a visual analogue scale.

RESULTS

Out of 310 patients, 292 could be analysed. AWMF and ACR were concordant in 86.6%, AWMF and survey criteria were concordant in 78.8% and survey and ACR-criteria were concordant in 79.5% of the cases.

DISCUSSION

AWMF, survey, and ACR criteria were moderately concordant. As AWMF and survey criteria do not require tender point examination, these criteria can be used by nonrheumatologists for the clinical diagnosis of FMS.