Increasing evidence suggests that vestibular migraine (VM) is a common cause of episodic vertigo, with an estimated 2.7% of US adults having been diagnosed with the condition. “Despite being common, there is limited data available to guide clinical decision making in caring for patients with VM,” explains Jeffrey D. Sharon, MD. In an effort to provide more data in this area by quantifying VM, Dr. Sharon and colleagues sought to develop a patient-reported outcome measure.
Developing a Questionnaire
For a study published in Otology & Neurotology, the researchers developed the Vestibular Migraine Patient Assessment Tool and Handicap Inventory (VM-PATHI). They first conducted a literature review to better understand the symptoms of patients with VM. From the literature review and input from care experts, the team developed a scaled list of symptoms and a preliminary questionnaire designed to gauge VM symptom severity. The questionnaire was provided to patients with VM who then offered feedback on the questions and ease of understanding. Finally, a refined version was administered to patients with VM and controls (Table). Patients completed the questionnaire at baseline, 1 week, and 3 months. Scores could then be used by patients’ physicians to indicate areas of treatment on which to focus, as well as to track treatment progress. Treatments were determined by patients and their physicians and not standardized.
The VM-PATHI results indicated that it has promising test-retest ability. “Internal reliability was assessed with Cronbach’s alpha, which was valid at 0.92,” highlights Dr. Sharon. The correlation between the initial test and the retest a week later was 0.90. The mean score for all patients with VM at baseline was 42.5 out of a total of 100 points, and the mean score for patients with VM who completed the questionnaire 3 months later was 39.4. Conversely, control patients scored significantly lower, with a mean score of 9.6. To highlight the significance, the team created a box and whiskers plot to demonstrate the difference in scores between patients with and without VM (Figure).
“Our study design does have limitations,” notes Dr. Sharon. “Although we did actively engage patients in open-ended questions to help ensure face and content validity, we were not able to convene focus groups of patients during the item-generation phase of the study. However, we now have a tool, which didn’t exist before, to be able to quantify disease-related suffering for VM. This can be used for research, but it can also be used by both patients and healthcare professionals to monitor response to treatment. For example, a patient with VM could complete the questionnaire—free at ohns.ucsf.edu/balance-falls/node/5516—to obtain a baseline score. With each treatment, they could then retake the test to determine if they are improving or not, as well as which treatments seem to work for them.”
Dr. Sharon believes there are more studies to be done in VM. “Our team viewed this study as a foundation for future studies to evaluate the effectiveness of different treatments for VM,” he says. “VM-PATHI is a validated tool that can be used to study patients with VM. However, we still need more data, especially from randomized trials, to understand which treatments work for VM and which don’t.”
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