Validation of the Norwegian version ofHannover Functional Ability Questionnaire

Area of Science:

• Rehabilitation medicine
• Clinical assessment
• Psychometrics

Background:

• Low back pain is prevalent, necessitating reliable functional assessment tools.
• Existing instruments vary in scope; the FFbH-R uniquely measures perceived daily activity capability.
• The FFbH-R's utility in Norwegian populations with chronic back pain requires validation.

Purpose of the Study:

• Translate the Hannover Functional Ability Questionnaire (FFbH-R) into Norwegian.
• Evaluate the psychometric properties of the Norwegian FFbH-R in patients with long-lasting back pain.
• Assess factor structure, internal consistency, reproducibility, construct validity, and responsiveness.

Main Methods:

• Prospective cohort study employing cross-sectional and longitudinal designs.
• Translation followed recommended guidelines; validation adhered to quality criteria.
• 111 patients (aged 18-65) with long-lasting back pain were recruited; 224 total for factor analysis.
• Predefined hypotheses for construct and longitudinal validity were tested.

Main Results:

• Factor analysis supported a 3-factor solution (flexibility, dynamic strength, posture endurance) after removing 2 items.
• The Norwegian FFbH-R showed satisfactory internal consistency and reproducibility.
• Construct and longitudinal validity were largely confirmed, with demonstrated discriminant ability.
• Minor floor and ceiling effects were observed.

Conclusions:

• The Norwegian FFbH-R is a psychometrically sound instrument for patients with long-lasting back pain.
• The dynamic strength and posture endurance subscales may benefit from additional items for enhanced measurement.
• The validated questionnaire aids in assessing functional status in this patient group.