Clinical Characteristics of Acute Vestibular Neuritis According to Involvement Site

Clinical Characteristics of Acute Vestibular Neuritis According to Involvement Site:



In Reply: Thanks for your comments. To answer the first issue, I agree that VEMP waveform could be poor in older people. But we excluded patients with bilateral no response of VEMP. Therefore, I think it could be divided into relatively accurate groups. As you told, vibration-induced nystagmus could be an option for differentiating the vestibular neuritis. However, although I don’t have many experiences about vibration-induced nystagmus in vestibular neuritis, I know that the direction of vibration-induced nystagmus in partial vestibular loss may vary.



For the second issue, isolated inferior vestibular neuritis (IVN) seems to be rare and diagnosis of IVN could be challenging because horizontal head impulse test is normal in IVN. As you told, although rotatory horizontal and down-beating nystagmus could be important in diagnosis, my experience suggests that spontaneous down beat nystagmus is often missed because of the relatively low amplitude of nystagmus. In addition, abnormal VEMP in the presence of normal caloric response is a relatively common finding. But, we excluded patients with bilateral no response of VEMP and only included subjects with interaural amplitude asymmetry greater than 50% in lesion side. Furthermore, we identified isolated VOR gain deficit of video head impulse test in posterior canal plane in those patients included in the IVN group. Therefore, I would like to say that it would be great to be able to diagnose IVN accurately by comprehensively judging the results.



Finally, I agree with your opinion for arterial supply in labyrinth. It may cause unilateral sudden hearing loss and vestibular loss, especially in posterior canal. However, we included patients with no hearing loss or other neurologic signs, and it is described in the Method section.



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