Video head impulse test can detect brainstem dysfunction in multiple sclerosis

Abstract

Background: The aim of this study was to investigate the potential role of video head impulse test (vHIT) in the detection of brainstem lesions in patients with multiple sclerosis (MS).

Methods: Sixty-eight participants were enrolled and divided into two groups: 39 healthy subjects (HC) (78 ears, 20 females, mean age 25,3±6,3) and 29 MS patients (58 ears, 14 females, mean age 33,7±7,7). Both groups underwent vHIT, and in MS group MRI was analyzed for the presence of brainstem lesions. vHIT pathology was defined as presence of overt saccades (<200ms) or lateral gain lower than 0.8 for lateral canal, and presence of overt saccades (<200ms) or posterior/anterior slope lower than 0.7.

Results: In HC, decreased gain on horizontal canals was found in 8 out of 78 ears (11%), while 16 out of 58 ears (38%) had pathological results in the MS group. Mean gain of the lateral canals (60ms) was significantly reduced in MS group compared to HC (0.874±0143 vs. 0.954±0,170, p=0.004, respectively). Compared to HC overt saccades <200ms in the lateral canals (p=0.018) and in the posterior canals (p=0.011), overt saccades >200ms in lateral (p<0.001), anterior (p=0.019) and posterior canals (p=0.009), and covert saccades in the anterior (p=0.042) and posterior canals (p=0.046) were more frequent in the MS group. There was statistically significant association between the presence of BS MR lesions and bilateral pathology on vHIT for lateral semicircular canal (χ(1)=3.982, p=0.046).

Conclusion: These results indicate that vHIT can detect brainstem dysfunction in patients with MS.

Keywords: Multiple sclerosis; Vestibulo-ocular reflex; Video head impulse test.