Cross-cultural adaptation of an outcome questionnaire.
The aim of the study was to cross-culturally adapt the Neck Bournemouth Questionnaire (NBQ) for the Dutch language in a population of people with subacute and chronic whiplash associated disorders (WAD), and to assess its psychometric qualities.
The NBQ covers the salient dimensions of the biopsychosocial model of pain, and has been shown to be reliable, valid, and responsive to clinically significant change in patients with non specific neck pain. However, no Dutch validated version was available for patients with WAD at the time our study was initiated.
The English version of the NBQ was translated into Dutch (NBQ-NL) and back-translated according to established guidelines. The internal consistency (with help of Cronbach's α), construct validity, and convergent validity were estimated in a different group of 92 patients. Agreement and correlation between the NBQ-NL scores and counterpart questionnaires (SF-36, Neck Disability Index, Hospital Anxiety and Depression Scale, the General Perceived Self-Efficacy and a numerical rating scale for perceived pain) were investigated, using Bland and Altman method and Spearman rank correlation coefficient. Subsequently, 34 patients with subacute WAD completed the questionnaire twice over 1 to 3 weeks, to assess its test-retest reliability.
Ninety-two patients, with subacute and chronic WAD, completed the study. Their mean age was 41 years (SD = 11). There were relative high mean scores on the Neck Disability Index (25.5; SD = 8.2), and the NBQ (43.9; SD = 14.8). The NBQ-NL was granted face-validity. Spearman rank correlation coefficient was 0.51 to 0.82 (except for General Perceived Self-Efficacy (0.21). The limits of agreement of normalized scores were relative variable, from small to wide. Cronbach's α (internal consistency) for the NBQ-NL whole scale was 0.87. The Intraclass correlation coefficient for the test-retest reliability was excellent (0.92) and the SEM was relatively low (3.7).
Overall, the rank correlation level in general was good, whereas the agreement between questionnaires outcome was variable, most of which seems to be attributable to absolute scale differences. The NBQ-NL is a useable patient-orientated tool for assessing disability in clinical studies and clinical diagnosis in Dutch speaking patients with WAD.
The objective of this study was to validate the Dutch version of the Neck Bournemouth Questionnaire in a population of people with subacute and chronic whiplash associated disorders. Satisfactory values for the internal validity (Cronbach's α, 0.87), external construct validity, and test-retest reliability were found.
From the *Institute for Master Education in Manual Therapy, SOMT, Amersfoort, The Netherlands; †University Medical Center Utrecht, Utrecht, The Netherlands; ‡Department of Oral Function and Prosthetic Dentistry, College of Dental Science, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; §Department of Pediatric Physical Therapy and Clinical Exercise Physiology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands; ¶Department of Epidemiology and Health Care, Division Julius Centre for Health Sciences and Primary Care Research, University Medical Centre Utrecht, Utrecht, The Netherlands; and ∥Department of Health Promotion, TNO Quality of Life, Leiden, The Netherlands.
Acknowledgment date: October 31, 2007. First revision date: March 17, 2009. Second revision date: April 5, 2009. Acceptance date: April 7, 2009.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Maarten Schmitt, MPT, Institute for Master Education in Manual Therapy, SOMT, Softwareweg 5, 3821 BN Amersfoort, The Netherlands; E-mail: firstname.lastname@example.org.