Assessing self-perception in patients with chronic low back pain: development of a back-specific body-perception questionnaire.

BACKGROUND There is considerable interest in the role that disturbance of body-perception may play in long standing pain problems such as chronic low back pain (CLBP), both as a contributor to the clinical condition and as a potential target for treatment. In some chronic pain conditions body-perception has been investigated using self-report questionnaires. There is currently no questionnaire for assessing body-perception in people with CLBP. OBJECTIVE To describe the development of a back-specific body-perception questionnaire and examine the psychometrics of this new scale. METHODS Based on available evidence a back-specific body-perception questionnaire was developed. Fifty-one people with CLBP and an equal number of healthy controls completed the questionnaire; a subset of the patient population completed the questionnaire again one-week later. Scale-consistency and test-retest reliability were investigated on the patient sample. Validity was investigated by comparing responses between patients and controls as well as exploring the relationship between the questionnaire and important clinical characteristics. RESULTS All but one of the patients endorsed items on the questionnaire, which suggests that distorted body-perception may exist in this population. The internal-consistency and test-retest reliability of the scale appear acceptable. The discriminative validity of the questionnaire is supported by the marked differences in the questionnaire responses between patients and healthy controls and the construct validity by the significant association between the questionnaire score and important clinical variables. CONCLUSION Symptoms of body-perception distortion were endorsed by most CLBP patients, while these symptoms are very infrequent amongst healthy controls. Our results suggest the questionnaire has reasonable psychometric properties.