[Comparison of caloric responses between vestibular migraine and Ménière disease patients]

To compare the features of caloric tests in vestibular migraine (VM) and Menière's disease (MD) patients, and provide objective evidence for differentiating the 2 groups of patients.

This case-control study included 11 MD patients with left ear involved and mild to moderate impaired hearing, and 18 matched cases with VM. All participants received caloric tests. Maximum slow phase velocities (SPVmax) were used to describe horizontal and vertical nystagmus respectively and were compared between the 2 groups. Horizontal and vertical canal parasis(CP) were calculated according to respective SPVmax. Unilateral (UW-VR) or bilateral (BW-VR) weakness of vestibular response, and positive unilateral (UVR) or bilateral (BVR) vertical response or negative bilateral vertical response (NBVR) were judged by the boundary point of SPVmax of 5°/s respectively. Total left (LV) or right (RV) Vertical reactions were calculated accoeding to vertical SPVmax,and inter ears difference of vertical responses (IED-VR) calculated from LV minus RV.

There were no significant differences in age and gender between the 2 groups. Horizontal SPVmax of all of caloric tests of VM group,except the left cold (LC), were statistically larger than that of MD group (P < 0.05) and the maximum responses of right warm (RW) caloric test in VM group (34.50 ± 17.77) were significantly greater than that in MD group (12.82 ± 6.69) (P < 0.01). Only the vertical SPVmax of RW of all caloric tests has statistically difference between the 2 groups (P < 0.01), and the maximum responses of RW caloric test in VM group (6.00 ± 4.45) were significantly stronger than that of LC in MD group (1.27 ± 2.00) (P < 0.01). Horizontal CP ≥ 25% of the 2 groups(VM: 72.22%, MD: 54.55%) were not statistically different, while the proportions of UW-VR and BW-VR in VM group (5.56%, 0) were significantly lower than that in MD group (27.27%, 18.18%) (P < 0.05). Vertical CP ≥ 25% of the 2 groups (VM: 94.44%, MD: 27.27%) were significantly different (P < 0.01), and the proportions of positive UVR (left: 5.56%, right: 77.78%) and BVR (0) and NBVR (16.67%) in VM group were significantly different from that in MD group (UVR (left: 9.09%, right: 0), BVR (0), NBVR (90.91%)) (P < 0.01). There was statistically difference between LV and RV in VM group (P < 0.01, LV < RV), while no difference were showed in MD group. IED-VR in VM group (left intenser: 16.67%, right intenser: 83.33%) was statistically different from that in MD group (left intenser: 36.36%, right intenser: 9.09%, both no difference: 54.55%) (P < 0.01).

Vestibular responses of caloric test are more sensitive, and vertical reactions are more easily induced in VM patients than in MD. Caloric test can be used to differentiate the 2 groups of diseases.