Minimal Clinically Important Difference of Vestibular Migraine Patient Assessment Tool and Handicap Inventory (VM-PATHI).

Abstract

To calculate the minimal clinically important difference (MCID) for the Vestibular Migraine Patient Assessment Tool and Handicap Inventory (VM-PATHI). Prospective cohort study. A single tertiary care balance and falls center. Fifty-three subjects meeting Barany Society criteria for vestibular migraine (VM) or probable VM were included and divided into 3 treatment groups. Treatment was not standardized, instead, management was decided individually between each patient and their provider. All subjects completed VM-PATHI before and after intervention. A Global Rating of Change (GRoC) questionnaire was also completed following intervention. Anchor-based methods, using a GRoC questionnaire, were utilized to estimate the MCID that produced the highest sensitivity and specificity on a receiver operating characteristic (ROC) curve. Forty-three subjects were classified as responders and 10 were classified as nonresponders. The mean VM-PATHI pretreatment score minus the posttreatment score between the responders (mean = 14, SD 13) and nonresponders (mean = 4 SD = 12) was statistically significant (mean difference = 10, 95% confidence interval, CI [1, 20], P = .03). The VM-PATHI score change cutoff that best differentiated between responders and nonresponders was a VM-PATHI change of 6. Thus, the MCID was defined as a change of 6 points (sensitivity = 72%, specificity = 70%). The area under the ROC curve was 0.89, 95% CI [0.80, 0.98], which demonstrates an excellent ability for the VM-PATHI score change to discriminate between responders and nonresponders. The average change in VM-PATHI scores was 9 points (SD 11) for those with "a little better" rating on the GRoC, 14 points (SD 14) for those with a "moderately better" rating, and 20 points (SD 13) for those with a "very much better" rating. Patients with VM are likely to demonstrate clinical improvement if their VM-PATHI score decreases by 6 or more.