Comparison with other studies
A significant difficulty in establishing the sensitivity and specificity of MRI for VS, is that the prevalence of VS is consistent across adult populations, while the prevalence of ASNHL is highly variable. Efforts have been made to establish auditory criteria for the selection of patients who require further evaluation.
Pena10 reported that a criterion of 45 dB results in a low specificity for detecting VS. In a retrospective chart review, Saliba11Saliba I, Bergeron M, Martineau G, Chagnon M. Rule 3,000: a more reliable precursor to perceive vestibular schwannoma on MRI in screened asymmetric sensorineural hearing loss. Eur Arch Otorhinolaryngol. 2011 Feb;268(2):207-12. observed that 74 patients with VS (diagnosed by MRI) had the greatest asymmetry at 3 kHz.
Our vestibular findings echo those observed by Blödow22Blödow A, Helbig R, Wichmann N, Wenzel A, Walther LE, Bloching MB (2013) Video head impulse test or caloric irrigation? Contemporary diagnostic tests for vestibular schwannoma. HNO 61:781–785 who, using only horizontal vHIT, reported a reduced gain of 0.76 ± 0.28 and sensitivity of 41.0% in a group of 46 VS patients. Similarly, Taylor et al4reported a high prevalence of vestibular abnormality among VS patients. They included patients with VS and symmetrical hearing (21.4% of the study population), which could explain some differences with our study regarding the prevalence of vestibular dysfunction.
Although several authors have studied VIN in patients with VS33Lee JM, Kim MJ, Kim JW, Shim DB, Kim J, Kim SH.Vibration-induced nystagmus in patients with vestibular schwannoma: Characteristics and clinical implications. Clin Neurophysiol. 2017 Jul;128(7):1372-1379. , none have investigated the potential role of the VIN test as a screening tool for VS in an ASNHL population.
Lücke44Lücke K. [A vibratory stimulus of 100 Hz for provoking pathological nystagmus (author’s transl)].Z Laryngol Rhinol Otol. 1973 Oct;52(10):716-20 Legends Figure 1. Asymmetric NSHL patients were initially included. Patients with previous otologic surgeries, acoustic trauma, and previous vertigo symptoms were excluded of the study; NSHL: Neurosensorial hearing loss Figure 2. Bar graph representing sensitivity and specificity for every vibration mastoid stimulation. The presence of the vibration induced nystagmus represents the sensitivity. The absence of the vibration induced nystagmus in the control group represents the specificity. A: 30 Hz ipsilateral mastoid vibration; B: 60 Hz ipsilateral mastoid vibration; C:100 Hz ipsilateral mastoid vibration Table 1. Mean VOR gain for horizontal, posterior and superior semicircular canal in both Control and Vs groups. VS: vestibular Schwannoma Table 2. The ROC curves and the areas under the curves with sensitivity and specificity results for each of its cut points. AUC: Area under the curve; HSC: Horizontal canal; PSC: posterior semicircular canal; SSC: superior semicircular canal was the first to describe a correlation between vibratory stimulation and vestibular lesions, concluding that VIN reflects peripheral vestibular imbalances.