Validity and reliability of the perceived deficit questionnaire to assess cognitive symptoms in people with chronic whiplash-associated disorders.
OBJECTIVE
To investigate the validity and reliability of the Perceived Deficit Questionnaire (PDQ) for use in people with chronic whiplash-associated disorders.


METHODS
Cross-sectional.


METHODS
Tertiary institution.


METHODS
Patients (N=105) with chronic whiplash-associated disorders and asymptomatic controls (n=50).


METHODS
Not applicable.


METHODS
The 20-item PDQ inclusive of 4 sections (attention/concentration, retrospective memory, prospective memory, and organization/planning) rated on a 5-point scale.


RESULTS
Internal construct validity of the PDQ was examined by Rasch analysis, confirming the appropriateness of its 5-point scale and the unidimensionality of each section after modification by eliminating 1 item each from the attention/concentration and retrospective memory sections. Preliminary evidence was also gained for external construct validity (convergent validity) of the modified PDQ by demonstrating significant (P<.05) correlations of all sections with a global measure of disability due to neck pain (the Neck Disability Index). The whiplash group demonstrated significantly (P<.05) higher scores in each section of the modified PDQ than did the control group, indicating evidence for discriminant validity. In addition, the modified PDQ demonstrated good internal consistency (Rasch-generated reliability >.8) and acceptable test-retest reliability with 1-month interval (intraclass correlation coefficients >.8).


CONCLUSIONS
The modified PDQ appears to be a valid and reliable questionnaire and could be used quickly in clinical practice to gain a basic understanding of perceived cognitive symptoms in people with chronic whiplash-associated disorders.
National Health and Medical Research Council Centre of Clinical Research Excellence - Spinal Pain, Injury and Health, Division of Physiotherapy, School of Health and Rehabilitation Science, The University of Queensland, Brisbane, Queensland, Australia. h.takasaki@uq.edu.au
Hiroshi
H
Takasaki
Chi-Wen
CW
Chien
Venerina
V
Johnston
Julia
J
Treleaven
Gwendolen
G
Jull
D000328:Adult; D000704:Analysis of Variance; D002908:Chronic Disease; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D011594:Psychometrics; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D014911:Whiplash Injuries / Q000150:complications* / Q000534:rehabilitation