Development of the body-relatedness observation scale: A feasibility study

Aim One characteristic of somatoform disorder (DSM-IV) and somatic symptom disorder (dsm-5) is the troubled relation of patients to their body. To assess body-relatedness in its full range, observation by a physical therapist may add valuable information to self-report questionnaires. This study examines the feasibility of the Body-Relatedness Observation Scale (BROS), an instrument for the standardized observation of patients with somatic symptom disorder by a physical therapist. Methods In cross-sectional analyses the factorial validity and inter-rater reliability of observer scores were studied. Physical therapists observed 191 patients performing two short exercises lying face up. Fourteen potential indicators of body-relatedness were selected for observation, covering four domains: execution of instructions, perception of the body, muscle tension, and behavioural adaptation to somatic symptoms. Results Inter-rater reliabilities were excellent for four observation scores (ICC > 0.75 or Kappa>0.80), substantial for two (0.60 < ICC < 0.75 or 0.60 < Kappa<0.80), fair for two (0.40 < ICC < 0.60 or 0.20 < Kappa<0.40) and poor for six. Items in particular relating to patients' ability to perceive the body had low inter-rater reliabilities. Categorical principal components analysis with the eight reliable scores indicated a 1-factor structure including seven items with Cronbach's alpha 0.69. Conclusion This initial analysis of a structured physical therapeutic observation for people with somatic symptom disorder indicated modestly sound psychometric quality of observations of execution of instructions, muscle tension and behavioural adaptation, but not of patient's ability to perceive the body adequately. This shows that these observations are feasible when restricted to observable behaviour and it indicates the viability of further validation of the BROS.