The psychometric characteristics of an assessment instrument for perceived harmfulness in adolescents with musculoskeletal pain (PHODA-youth).

BACKGROUND: Cognitive-behavioural models of chronic pain predict that dysfunctional assumptions about harmfulness of activities may maintain pain-related fear and disability. To assess perceived harmfulness in adolescents, the Photograph Series of Daily Activities for youth (PHODA-youth) was developed. Information concerning its methodological quality is currently lacking. OBJECTIVE: To investigate psychometric characteristics (factor structure, test-retest reliability, construct validity) and feasibility of the PHODA-youth in adolescents with chronic musculoskeletal pain. STUDY DESIGN: Test-retest design. STUDY POPULATION: Adolescents aged 13-21 years with chronic nonspecific musculoskeletal pain. METHODS: Participants filled in an electronic version of the PHODA-youth including 89 items twice with a 4-week interval. The instrument's factor structure was determined by a factor analysis. Construct validity was studied with criterion variables: catastrophizing (Pain Catastrophizing Scale for Children), pain intensity (visual analogue scale), depression (Children's Depression Inventory) and pain-related disability (Functional Disability Inventory) using regression analysis. Test-retest reliability was evaluated based on the Pearson correlation coefficient. Feasibility was studied with self-constructed questions. RESULTS: Seventy-one adolescents participated. Results show a three-factor structure for the PHODA-youth including 51 items with subscales labelled as: 'activities of daily life', 'intensive physical activities' and 'social activities'. Total and subscale scores showed a high internal consistency. Its test-retest reliability was good (r = 0.94) and its construct validity is supported by the finding that both catastrophizing (ß = 0.25; p = 0.02) and disability (ß = 0.71; p < 0.001) were uniquely related to the PHODA-youth. In addition, feasibility appeared adequate. CONCLUSION: The findings support the PHODA-youth as a valid and reliable measure of the perceived harmfulness of activities in adolescents with musculoskeletal pain.

Guidance for robustness/ruggedness tests in method validation.

This paper is intended to give guidance in setting-up and interpreting a robustness test. The different steps in a robustness test are discussed and illustrated with examples. The recommendations given for the different steps are based on approaches found in the literature, several case studies performed by the authors and discussions of the authors within a commission of the French SFSTP (Société Française des Sciences et Techniques Pharmaceutiques). In the end of the paper a worked-out example is given of a robustness test case study set up and interpreted according to the guidelines.

ECG changes in dogs with hypothyroidism.

The results of electrocardiogram (ECG) recordings in 19 dogs with primary hypothyroidism are presented. Low voltage and inverted T waves were the most frequently observed abnormalities. In a number of dogs the ECG changes contributed to the diagnosis of hypothyroidism. A few dogs had even been referred to the cardiopulmonary service because of decreased exercise tolerance and the ECG pointed to the need for thyroid function studies.