Minimal Clinically Important Difference of Vestibular Migraine Patient Assessment Tool and Handicap Inventory...

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.