Development of the Body-Relatedness Observation Scale: A feasibility study

BACKGROUND: One characteristic of somatoform (DSM-IV) and somatic symptom disorder (DSM-5) is the troubled relation of patients to their body. To assess body-relatedness, standardized observation by a physical therapist may add valuable information to questionnaires. Purpose: This study examines the feasibility of a physiotherapeutic observation instrument: the Body-Relatedness Observation Scale (BROS). Methods: Factorial validity and inter-rater reliability of observer scores were studied in 191 patients performing two short exercises, lying face up. Fourteen indicators of body-relatedness were selected, covering execution of instructions, perception of the body, muscle tension, and behavioral adaptation to somatic symptoms. Results: Inter-rater reliability values (Kappa or Intraclass correlation [ICC] according to model 1,1) were excellent for four observation scores, substantial for two, fair for two, and poor for six. Four out of five items relating to patients' ability to perceive the body had low inter-rater reliability values (ICC < 0.40 or Kappa < 0.20). 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 behavioral adaptation, but not of patients' ability to perceive the body adequately. This shows that body-related observations are feasible and indicates the viability of further development of the BROS.