Item Level Psychometrics of the Dizziness Handicap Inventory in Vestibular Migraine and Meniere's Disease.

OBJECTIVES: Evaluate the measurement properties of the Dizziness Handicap Inventory (DHI) using item response theory in patients diagnosed with vestibular migraine (VM) and Meniere's disease (MD). DESIGN: One hundred twenty-five patients diagnosed with VM and 169 patients diagnosed with MD by a vestibular neurotologist according to the Bárány Society criteria in two tertiary multidisciplinary vestibular clinics and who completed the DHI at their initial visit, were included in the study. The DHI (total score and individual items) was analyzed using the Rasch Rating Scale model for patients in each subgroup, VM and MD, and as a whole group. The following categories were assessed: rating-scale structure, unidimensionality, item and person fit, item difficulty hierarchy, person-item match, and separation index, standard error of measurement, and minimal detectable change (MDC). RESULTS: Patients were predominantly female (80% of the VM subgroup and 68% of the MD subgroup) with a mean age of 49.9 ± 16.5 years and 54.1 ± 14.2 years, respectively. The mean total DHI score for the VM group was 51.9 ± 22.3 and for the MD group was 48.5 ± 26.6 ( p > 0.05). While neither all items nor the separate constructs met all criteria for unidimensionality (i.e., items measuring a single construct), post hoc analysis showed that the all-item analysis supported a single construct. All analyses met the criterion for showing a sound rating scale and acceptable Cronbach's alpha (≥0.69). The all-item analysis showed the most precision, separating the samples into three to four significant strata. The separate-construct analyses (physical, emotional, and functional) showed the least precision, separated the samples into less than three significant strata. Regarding MDC, the MDC remained consistent across the analyses of the different samples; approximately 18 points for the full analyses and approximately 10 points for the separate construct (physical, emotional, and functional). CONCLUSIONS: Our evaluation of the DHI using item response theory shows that the instrument is psychometrically sound and reliable. The all-item instrument fulfills criteria for essential unidimensionality but does seem to measure multiple latent constructs in patients with VM and MD, which has been reported in other balance and mobility instruments. The current subscales did not show acceptable psychometrics, which is in line with multiple recent studies favoring the use of the total score. The study also shows that the DHI is adaptable to episodic recurrent vestibulopathies. The total score shows better precision and separation of subjects in up to four strata compared to the separate construct that separate subjects into less than three strata. The measurement error smallest detectable change was found in our analysis to be 18 points, which means any change in the DHI of less than 18 points is not likely to be clinically significant. The minimal clinically important difference remains indeterminate.

Does Catastrophizing Predict Response to Treatment in Patients With Vestibular Disorders? A Prospective Cohort Study.

OBJECTIVE: Determine levels of catastrophizing in patients with vestibular disorders and prospectively evaluate their relationship with patient-reported outcome measures. STUDY DESIGN: Prospective cohort study. SETTING: Tertiary care neurotology vestibular disorders clinic. PATIENTS: Adult patients with various vestibular disorders. INTERVENTIONS: Patients were given the Dizziness Handicap Inventory (DHI) and the Dizziness Catastrophizing Scale (DCS) at a baseline visit and follow-up visit after treatment. MAIN OUTCOME MEASURES: Correlation studies were used to determine the relationships between DHI and DCS. Multivariable linear regression was performed to determine the relationship between DCS and DHI change with treatment, accounting for demographic variables. RESULTS: Forty-six subjects completed both the DHI and the DCS before and after treatment. Patients with higher baseline DCS scores had higher baseline DHI scores ( p < 0.001). There was a significant improvement in both DHI score ( p < 0.001) and DCS ( p < 0.001) at follow-up. Patients who had reduction in DCS scores during were more likely to show reduction in DHI scores ( p < 0.001). A subset of patients had a mindfulness-based stress reduction program included in their treatment. These patients had a greater reduction in both DCS and DHI scores at follow-up compared with those who received other treatments. CONCLUSIONS: Catastrophizing is associated with higher pretreatment DHI scores and worse treatment outcomes. Addressing dizziness catastrophizing may help improve vestibular outcomes.

Correlating Vestibular Migraine Patient Assessment Tool and Handicap Inventory to Daily Dizziness Symptoms.

OBJECTIVE: Investigate the relationship between Vestibular Migraine Patient Assessment Tool and Handicap Inventory (VM-PATHI) scores and daily dizziness symptoms. STUDY DESIGN: Prospective cohort analysis of 52 patients with vestibular migraine (VM). SETTING: Tertiary referral center. PATIENTS: Fifty-two patients diagnosed with VM or probable VM according to Barany Society criteria. INTERVENTIONS: Subjects reported their dizzy symptoms (on a scale of 0 [no symptoms], 1 [mild], 2 [moderate], and 3 [severe]) every day for 1 month via automated text messaging linked to a cloud-based research database. Subjects completed VM-PATHI and Dizziness Handicap Inventory (DHI) scores at the end of the month. We examined the correlation between a composite of daily dizziness scores with VM-PATHI and DHI scores through linear regression and correlation analysis. MAIN OUTCOME MEASURES: Pearson correlation coefficient, R2 value. RESULTS: VM-PATHI showed a moderate correlation with daily dizziness symptoms (correlation coefficient, 0.51). DHI showed a lower correlation with daily dizziness (correlation coefficient, 0.38). VM-PATHI score was a strong predictor of daily dizziness with univariate linear regression ( R2 = 0.26, p = 0.001). In a multiple linear regression model with age, history of anxiety and/or depression, and VM-PATHI, the VM-PATHI score was the only statistically significant predictor of daily dizziness ( p < 0.001). CONCLUSIONS: Daily dizziness symptoms are better correlated with VM-PATHI score than the DHI, providing further validation of VM-PATHI as a disease-specific outcome measure for patients with VM.

VM-PATHI Correlates With Cognitive Function Improvement After Successful Treatment in Patients With Vestibular Migraine.

OBJECTIVE: To assess changes in cognitive function in vestibular migraine patients undergoing treatment. STUDY DESIGN: Prospective cohort. SETTING: Single-institution tertiary-care center. PATIENTS: Thirty-four patients with vestibular migraine were included in the study. Average age at diagnosis was 47.9 years. A majority of patients (91.2%) were female. INTERVENTIONS: Vestibular therapies included pharmacologic treatment (67.6%), mindfulness-based stress reduction (58.8%), vestibular physical therapy (20.6%), and lifestyle changes only (2.9%). MAIN OUTCOME MEASURES: Pretreatment and posttreatment questionnaires were collected including the Cognitive Failures Questionnaire (CFQ), Vestibular Migraine Patient Assessment Tool and Handicap Inventory (VM-PATHI), and Dizziness Handicap Inventory. RESULTS: Median time between pretreatment and posttreatment questionnaire was 4.4 months (range, 2.8-15.6. mo). CFQ scores decreased in subjects who responded to treatment, as defined by those with a positive change in VM-PATHI score (average decrease, 6.5; p = 0.03). CFQ scores did not improve in subjects who had no improvement in their vestibular condition, as defined by no change or an increase in VM-PATHI score (average increase, 2.0; p = 0.53). Univariate linear regression showed that VM-PATHI score change was highly predictive of CFQ change ( p < 0.01, r2 = 0.36). Multivariate regression demonstrated that the VM-PATHI ( p = 0.03) and not the Dizziness Handicap Inventory ( p = 0.10) predicted changes in CFQ score. CONCLUSIONS: Self-reported cognitive dysfunction improves with successful treatment of vestibular migraine.