An Analysis of Caloric Eye Speeds in Vestibular Migraine

Anthony A Mikulec, MD, Michael D Darley Department of Otolaryngology, Saint Louis University Saint Louis, Missouri ABSTRACT Objective: Investigate the utility of caloric testing and videonystagmography in the dizzy patient as it may relate to vestibular migraine. Study design: Retrospective cohort. Setting: Tertiary referral center in an ambulatory setting. Patients: 28 adult patients with a complaint of dizziness presented to a combined dizzy clinic and completed a migraine questionnaire in addition to caloric testing. Intervention: Migraine questionnaire administered in addition to caloric testing already indicated for dizzy patients. Main outcome measures: Responses to migraine questionnaire and nystagmus sum frequency (eye speeds) from caloric testing. Results: After exclusion criteria, 28 patients were included in the analysis. 13 Dizzy patients who answered ‘yes’ to two or more questions on the migraine questionnaire (migraine group) were compared with 15 patients that answered ‘yes’ to less than two questions (non-migraine group). Affirmative response to ≥2/3 of the first three questions was previously demonstrated to have good sensitivity and specificity for migraine headache1. The nystagmus sum beat frequency including right and left ears with warm and cold water caloric testing was measured. Patients in the migraine group vs. patients in the non-migraine group had a mean nystagmus frequency of 97 and 99 beats respectively. A trend was observed in which migraine patients were four times less likely to have a sum nystagmus frequency less than 50 than those in the non-migraine population 7.7% (1/13) vs. 26.6% (4/15) respectively (p=0.33). Conclusions: Nystagmus sum frequency observed between the migraine and non-migraine group was remarkably similar. The migraine group was observed to have a trend sum frequency less than 50 four times less than the non-migraine group. Further investigation is necessary to determine the utility and reproducibility of these findings. INTRODUCTION Migraine is the underlying pathology of a significant number of patients seen for dizziness by Otolaryngologists2. Unfortunately, clear diagnostic criteria for vestibular migraine, also known as migraine associated vertigo, are lacking, and the disorder is not recognized as a variant of migraine by the International Headache Society. Neuhauser and others have attempted to apply diagnostic criteria to vestibular migraine3, but a clear consensus is lacking and no objective test for vestibular migraine exists. Clinically, many vestibular migraine patients seem to have a sensitivity to complex and difficult visual surroundings and to motion in their environment, such as walking down grocery store aisles, scrolling on a computer screen, or riding in the back seat of a car. This study sought to determine if such symptoms, suggestive of a global sensitivity to motion, would also translate to sensitivity to caloric testing resulting in higher total eye speeds in patients with dizziness and migraine. METHODS After IRB approval, retrospective chart review was performed for patients presenting to a combined dizzy clinic for evaluation. All patients were included in the study for whom complete information was available including: survey results, caloric testing results, audiogram, and patient notes documenting hearing status or evidence of Meniere’s disease. Mean age was 54 (range 27-79). Patients were given a survey asking questions regarding migraine symptoms (see figure 1). These questions have been previously shown to have a sensitivity of 0.81 (95% CI, 0.77 to 0.85), and a specificity of 0.75 (95% CI, 0.64 to 0.84) when ≥ 2 of the first 3 questions on the survey were answered to the affirmative1. The patients’ responses were reviewed in person and confirmed or clarified. All patients subsequently underwent caloric testing with videonystagmography (VNG). Patients were later separated into groups based on their questionnaire responses i.e. ≥ 2 questions to the affirmative of the first three survey questions were placed in the migraine group, others were placed in the non-migraine group. The caloric testing results were then compared between the two groups. The sum nystagmus frequency was calculated by adding all nystagmus frequencies for warm and cold water calorics for each ear (4 nystagmus frequencies total) in each patient. Patient age sex q1 q2 q3 q4 q7 Yes ≥ 2/3 RC RW LC LW Sum 1 27 f yes no yes yes no + 15 21 36 13 85 2 49 f yes yes yes yes n/a + 6 7 32 53 98 3 45 f yes yes yes yes yes + 7 12 17 19 55 4 44 f yes yes yes yes no + 20 43 18 43 124 5 55 m yes yes yes no n/a + 32 40 29 33 134 6 43 f yes yes yes yes no + 21 25 25 28 99 7 59 m no yes yes no n/a + 39 26 34 30 129 8 64 f yes yes no yes no + 50 42 35 50 177 9 55 f yes yes yes no no + 22 32 17 36 107 10 57 m no no no no n/a + 0 14 2 3 19 11 41 m yes no yes yes n/a + 43 49 36 36 164 12 34 f yes yes yes no no + 17 24 23 27 91 13 69 f yes yes no yes no + 27 17 5 5 54 14 68 f no yes no no no 14 21 7 5 47 15 50 m no yes no yes n/a 27 45 29 51 152 16 39 m no no no no n/a 46 44 29 41 160 17 51 m no no no no n/a 26 27 73 71 197 18 65 m no no no no n/a 24 25 23 20 92 19 52 m no no no no n/a 9 34 6 5 54 20 51 m no no no no n/a 21 33 14 22 90 21 62 m no no no no n/a 10 16 6 13 45 22 60 m no no no no n/a 31 50 29 35 145 23 45 f no no yes no no 10 13 10 9 42 24 79 f no no yes yes no 15 15 17 13 60 25 50 f no yes no yes no 14 18 32 37 101 26 86 m no no no no n/a 8 9 8 11 36 27 60 m no no no no n/a 27 31 24 23 105 28 58 f no no yes yes no 30 60 32 43 165