Psychometric properties of a Norwegian adaption of the Barratt Impulsiveness Scale‐11 in a sample of Parkinson patients, headache patients, and controls

OBJECTIVE: To assess the psychometric properties of a Norwegian translation of the Barratt Impulsiveness Scale (BIS‐11) for use in populations of headache, Parkinson's disease (PD), and healthy controls. MATERIALS AND METHODS: The BIS‐11 was forward and backward translated by native speakers of both Norwegian and English to give Norwegian BIS‐11 (Nor‐BIS‐11). A convenience sample (110 subjects) of healthy controls (47), PD patients (43), and chronic headache patients (20) (the latter two recruited from a Neurology outpatient clinic), were asked to complete the scale (a subset twice for test–retest). Exploratory and confirmatory factor analyses were done for a single‐factor model, the original three‐factor model and a two‐factor model. Test–retest results were analyzed using the Bland–Altman approach. RESULTS: The Nor‐BIS‐11 scale showed good utility and acceptability as well as good test–retest reliability in this sample. Cronbach's α was .68, test–retest bias was −0.73, Cohen's δ = −.134, and limits of agreement were −11.48 to 10.01. The factor structure was found to fit better with a two‐factor model than with the original model with three factors. The model fit indices indicated a moderate fit. CONCLUSIONS: The Nor‐BIS‐11 scale is acceptable and reliable to use in Parkinson's disease patients, chronic headache patients, and healthy controls. The results should be interpreted in a two‐factor model but with caution due to low construct validity. External validity needs to be further tested.