The efficacy of a modified Dix-Hallpike test with a pillow under shoulders

BACKGROUND: Dix-Hallpike (DH) test is sometimes done in a modified or reduced manner in a clinical setting. However, there has been no study that evaluated the reliability of this modified test. OBJECTIVES: The purposes of this study were to determine whether the efficacy of a modified DH test, named the 'pillow under shoulders' test, was equivalent to the standard DH test and to assess the difference in patient discomfort between the two methods. METHODS: Randomized controlled study at three academic referral hospitals, conducted in compliance with the CONSORT statement. Patients suspected for BPPV based on symptoms were randomly assigned to Group A or Group B. Patients in Group A received a standard DH test initially, followed by a modified DH test with a pillow under shoulders. Patients in Group B also received the two tests, but in the reverse order. The diagnostic results of both tests and patients' subjective scoring for uneasiness (discomfort, pain, anxiety) were statistically analyzed. RESULTS: McNemar's test and Kappa statistics showed a statistically equivalent diagnostic value between standard and modified DH tests (Cohen's kappa = 0.823 and McNemar P = 0.18). The modified DH test had high sensitivity (95.5%) and fairly good specificity (87.9%). There was no statistical significance in the patients' subjective scoring for uneasiness between the two methods, although most patients reported less inconvenience after the modified DH test compared to the standard DH test. CONCLUSIONS: The modified version of the standard DH test, the 'pillow under shoulders' method, may be a reliable, comfortable option to diagnose vertical canal BPPV. We suggest that this method can be used when head hanging is not feasible or sufficient for the standard DH test.