Table 1.
Symptoms characteristics and vestibular test results in VM patients.
| Characteristics of dizziness | Vestibular tests results | ||
|---|---|---|---|
| n (%) | vHIT | Mean (SEM) | |
| Moderate intensity | 6 (22.2) | Gain, left | 0.96 (0.02) |
| Severe intensity | 21 (77.8) | Gain, right | 1.00 (0.02) |
| Lasting minutes | 2 (7.4) | vHIT gain asymmetry | 0.04 (0.01) |
| Lasting hours | 25 (92.6) | ||
| Chair rotation velocity steps | Mean (SEM) | ||
| Characteristics of headaches | 60°/s gain, left | 0.64 (0.03) | |
| 60°/s gain, right | 0.69 (0.04) | ||
| Mean (SEM) | 240°/s gain, left | 0.57 (0.04) | |
| Age of onset (years) | 30 (3.5) | 240°/s gain, right | 0.59 (0.03) |
| Frequency (days per month) | 6.5 (1.8) | 60°/s TC, left | 18.09 (1.30) |
| Intensity (1 to 10) | 5.7 (0.5) | 60°/s TC, right | 17.45 (1.30) |
| n (%) | 240°/s TC, left | 12.82 (1.00) | |
| Lasts 4 h or more | 14 (60.8) | 240°/s TC, right | 12.99 (0.77) |
| Unilateral | 12(77.3) | 60°/s gain asymmetry | 0.12 (0.01) |
| Pulsatile or throbbing | 16 (61.5) | 240°/s gain asymmetry | 0.07 (0.02) |
| Aggravation by physical activity | 7 (33.3) | 60°/s TC asymmetry | 0.15 (0.02) |
| Visual aura | 11 (45.8) | 240°/s TC asymmetry | 0.07 (0.02) |
| Photophobia | 19 (79.2) | ||
| Phonophobia | 19 (79.2) | ||
| Nausea and/or vomiting | 7 (29.2) | ||
All patients had chronic daily dizziness and met the diagnostic criteria for vestibular migraine. The video head impulse testing (vHIT) results show normal vestibular gains (eye velocity/ head velocity) with both right and left head impulses (normal gain: 0.7–1) (20). The rotational chair results show normal vestibular gains (normal gain: 0.4–1) at both low and high velocity steps (60°/s & 240°/s). The time constant (TC), which is a measure of nystagmus duration induced by the rotational velocity step, is also within the normal range at both velocities (normal range: 8–25 s) (21). Overall, there are no significant asymmetries between the right and left vestibular gains (i.e., both vHIT and rotational chair testing) or time constants. n, Number of patients; SEM, Standard error of the mean.