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.

Illusory touch temporarily improves sensation in areas of chronic numbness: a brief communication.

BACKGROUND: Creating the visual illusion of touch can improve tactile perception in healthy subjects. OBJECTIVE: We were interested in seeing if creating the illusion of touch in an insensate area could improve sensation in that area. METHODS: Fourteen people with chronic numbness participated in a randomized crossover experiment. The 4 conditions were the following: (a) stimulation over the unaffected limb with mirror visual feedback (experimental condition), (b) stimulation over the affected limb with mirror visual feedback, (c) stimulation over the unaffected limb without mirror visual feedback, and (d) stimulation over the affected limb without mirror visual feedback. Participants were assessed before and after each condition using the Ten-Test and mechanical detection thresholds. Data were analyzed using linear mixed models. RESULT: Only the experimental condition produced a change in the Ten-Test (mean difference = -1.1; 95% confidence interval = -1.8 to -0.4; P = .003), corresponding to a 24% improvement in sensation. No differences were observed for any condition in mechanical detection thresholds. CONCLUSION: Creating the illusion of touch may improve sensory function in areas of chronic numbness. This preliminary finding adds to the growing body of evidence supporting the use of techniques that directly target cortical function in people with peripheral nerve injury.