Utility of a brief assessment tool developed from the Dizziness Handicap Inventory to screen for Cervicogenic dizziness : A case control study

Background
Cervicogenic dizziness (CGD) is hard to diagnose as there is no objective test.
Objective
Can a brief assessment tool be derived from the Dizziness Handicap Inventory (DHI) to assist in screening for CGD?
Design
Case-control study with split-sample analysis.
Method
86 people with CGD and 86 people with general dizziness completed the DHI as part of the assessment of their dizziness. Descriptive statistics were used to assess how frequently each question on the DHI was answered ‘yes’ or ‘sometimes’ by participants with CGD and by participants with general dizziness. The questions that best discriminated between GCD and general dizziness were compiled into a brief assessment tool for CGD. Data from 80 participants (40 from each group) were used to generate a receiver operating characteristic (ROC) curve to establish a cut-off score for that brief assessment tool. Then, data from the remaining 92 participants were used to try to validate the diagnostic ability of the brief assessment tool using that cut-off score.
Results
Questions 1, 9 and 11 were the most discriminatory and were combined to form the brief assessment tool. The ROC curve indicated an optimal threshold of 9. The diagnostic ability of the brief assessment tool among the remaining 46 participants from each group was: sensitivity 77% (95% CI: 67 to 84), specificity 66% (56–75), positive likelihood ratio 2.28 (1.66–3.13), and negative likelihood ratio 0.35 (0.23–0.53).
Conclusion
A brief assessment tool of three questions appears to be helpful in screening for CGD.