Baseline characteristics
A total of 503 patients with VM and 1,125 patients with MD were included in the study. The average age of onset for the VM group was 45.89 ± 18.16 years, whereas the average age of onset for the MD group was 51.63 ± 14.29 years. A significant difference was observed between the two groups (P < 0.001). The proportion of women in the VM group was 76.1%, significantly higher than the 59.3% in the MD group (P < 0.001) (Table 1, Figure 1).
Vestibular function test results
The Total Labyrinthine Response (TLR) formula is as follows:
SPV (all) = RC + LC + RW + LW (°/s)
where RW = right warm; LW = left warm; RC = right cool; LC = left cool.
For the cutoff related to hyperactivity, each cool irrigation should exceed 50°/s, or the SPV should be greater than 80°/s for each of the warm irrigations18.
The Unilateral weakness (UW) formula is as follows:
UW (%) = {[(RC + RW) - (LC + LW)]/ (RC + RW + LC + LW)} × 100%
where RW = right warm; LW = left warm; RC = right cool; LC = left cool.
The UW value ≥ 25% is considered abnormal18.
Based on the severity of UW, subjects are divided into four groups19: Group 1: 0-24% UW (normal calorific response); Group 2: 25-50% UW (mild unilateral weakness); Group 3: 51-75% UW (moderate unilateral weakness); Group 4: 76-100% UW (severe unilateral weakness).
The Directional preponderance (DP) formula is as follows:
DP (%) = {[(RC + LW) - (LC+ RW)]/ (RC + RW + LC + LW)} × 100%
where RW = right warm; LW = left warm; RC = right cool; LC = left cool.
The DP value greater than 30% is considered abnormal18.
In patients with positive SN, 9.3% (47/503) in the VM group and 27.2% (306/1125) in the MD group exhibited peripheral nystagmus (unidirectional, regular rhythm, with reduced fixation suppression). The positive rate in the MD group was significantly higher than that in the VM group (P < 0.001) (Table 2). No central nystagmus characteristics were observed in either group.
The average SPV in the VM group was 81.0 ± 49.3°/s, significantly higher than that in the MD group (P < 0.001) (Figure 2A). The abnormal rate of UW in the MD group (59.1%) was significantly higher than that in the VM group (29.8%) (P < 0.001) (Table 2, Figure 2B). Additionally, the incidence of labyrinth hyperactivity disorder was significantly higher in the VM group compared to the MD group (P < 0.001). (Figure 2B). Significant differences were observed between the MD and VM groups in the normal UW group. Furthermore, there were notable differences between the MD and VM groups in the mild heat test UW group (Group 2), as well as in the moderate and severe fever groups (Groups 3 and 4) (Figure 2C). The positive rate of DP in the MD group was 26.0%, significantly higher than the 11.7% in the VM group (P < 0.001) (Table 2). The differences in PTA results between the VM and MD groups of patients is shown in Table 3.
A multivariable analysis controlling for age and sex showed no significant gender differences in SPV (P = 0.36) (Table 4), which is consistent with previous studies indicating that air calorics do not exhibit gender-related variability in nystagmus intensity20 .
Audiological characteristics
According to the World Health Organization's revised standards in 2022, the average hearing threshold was classified as follows: (i) Normal hearing: Hearing level less than 20 dB; (ii) Mild hearing loss: Hearing level of 20-35 dB; (iii) Moderate hearing loss: Hearing level of 35-50 dB; (iv) Moderate to severe hearing loss: Hearing level of 50-65 dB; (v) Severe hearing loss: Hearing level of 65-80 dB; (vi) Very severe hearing loss: Hearing level of 80-95 dB; (vii) Complete hearing loss (total deafness): Hearing level greater than 95 dB. The following types of hearing loss are defined based on the frequency range in which the maximum deviation of the hearing threshold occurs: (i) Low-frequency drop type: Drop at 0.25 kHz, 0.5 kHz, and 1 kHz; (ii) Full-frequency drop type: Drop across the entire 0.25 kHz to 8 kHz range; (iii) High-frequency drop type: Drop at 4 kHz and 8 kHz.
A total of 265 patients in the VM group and 1,060 patients in the MD group underwent pure tone audiometry at our center. The abnormal hearing rate in the MD group was 90.4%, significantly higher than the 54.3% in the VM group (P < 0.001)(Figure 3A). There were no significant differences between the MD and VM groups in low-frequency and high-frequency hearing loss (P > 0.05), but the MD group had a significantly higher rate of full-frequency hearing loss compared to the VM group (P < 0.001) (Figure 3B).
In our study, we performed a multivariable logistic regression analysis, controlling for potential confounding factors such as age and gender. The results indicated no significant differences. The analysis confirmed no significant confounding effects of age or gender on vestibular and audiometric parameters (Table 4).

Figure 1: Comparison of results between male and female patients with VM and MD. VM: Vestibular Migraine, MD: Meniere's Disease. Please click here to view a larger version of this figure.

Figure 2: Caloric test-derived nystagmus and vestibular function comparisons between vestibular migraine (VM) and Meniere's disease (MD) patients. Please click here to view a larger version of this figure.

Figure 3: Pure tone audiometry test result comparisons between vestibular migraine (VM) and Meniere's disease (MD) patients. Please click here to view a larger version of this figure.
Table 1: Demographic information. Please click here to download this Table.
Table 2: VNG test results of the two groups of patients (n,%) Please click here to download this Table.
Table 3: Differences in PTA results between the two groups of patients (n,%). Please click here to download this Table.
Table 4: A multivariate model employed to analyze the confounding variables, such as age and gender. Please click here to download this Table.