Visualization of Endolymphatic Hydrops in Patients With Unilateral Idiopathic Sudden Sensorineural Hearing Loss With Four Types According to Chinese Criterion

Abstract

Objective: The aim of this study is to evaluate the possible value of endolymphatic hydrops (EH) in patients with unilateral idiopathic sudden sensorineural hearing loss (UISSNHL) with four types according to audiometry.Methods: Seventy-two patients (40 men and 32 women; age range, 28–78 years; mean age: 50.0 ± 12.9 years) with UISSNHL were admitted retrospectively into this study. Based on the pure tone audiometry before treatment, the hearing loss of all these patients were categorized into four types: low-frequency group (LF-G), high-frequency group (HF-G), flat group (F-G), and total deafness group (TD-G). The average time from symptom onset to the first examination was 6.9 ± 4.4 days (1–20 days). 3D-FLAIR MRI was performed 24 h after intratympanic injection of gadolinium (Gd) within 1 week after the UISSNHL onset. The incidence of EH in the affected ears based on four types of hearing loss were analyzed using the Chi-square test, and the possible relationship with vertigo and prognosis were also assessed.Results: Eleven of 21 patients (52.4%) in LF-G had the highest EH-positive rate, followed by 18.2% in HF-G, 11.8% in F-G, and 17.4% in TD-G. The significant difference was found in the four groups (P = 0.018). The EH rate of LF-G was statistically significantly higher than that of F-G and TD-G (P = 0.009, P =0.014), respectively. After being valued by the volume-referencing grading system (VR scores), the EH level was represented by the sum scores of EH. In LF-G, no statistically significant difference was found in the prognosis of ISSNHL patients between with the EH group and the no EH group (P = 0.586). The symptom “vertigo” did not correlate with EH and prognosis.Conclusions: EH was observed in UISSNHL patients by 3D-FLAIR MRI. EH may be responsible for the pathology of LF-G but not related to prognosis. It might be meaningless to assess EH in other hearing loss types, which might be more related to the blood-labyrinth dysfunction.

Vestibular assessment in sudden sensorineural hearing loss: Role in the prediction of hearing outcome and in the early detection of vascular and hydropic pathomechanisms

“…These results are consistent with previously reported data highlighting how HL is worse, in particular the highest frequencies, in patients with vertigo compared to non-vertigo ( 27 , 32 , 37 , 51 ). Nevertheless, even a part of patients with MD exhibited down-sloping and flat HL, in accordance with other reports on “MD-like” patients ( 20 , 21 ). Among otolith receptors, cVEMPs were more affected in patients with “SSNHL + vertigo” than other subgroups ( p = 0.027) and, similarly, this population exhibited the highest rate of combined impairment of both cVEMPs and oVEMPs and showed the lowest percentage of isolated utricular deficit ( p = 0.022), confirming how vestibular end-organs close to the cochlea tend to be preferentially affected in patients with vertigo ( 46 ).…”

“…In fact, different types of oculomotor findings, SC involvement and otolith alterations have been described based on the stage of the disease and the extent of EH ( 16 , 20 , 80 – 87 ). Although 3T MRI with delayed acquisition following Gadolinium infusion has demonstrated to detect EH in most patients with MD ( 13 , 16 , 17 , 21 , 24 ), physiological confirmation of EH is still useful for the diagnosis of MD in clinical setting. Due to the anatomical alterations that the hydropic inner ear develops over time, the coexistence of a reduced caloric response and normal HSC-VOR gin at the vHIT has been considered a hallmark of MD ( 17 , 88 ).…”

“…On the other hand, the visualization of EH through 3T Gadolinium-enhanced brain MRI in 65% of asymptomatic contralateral ears could account for the presence of a tuning shift toward higher stimulation frequencies also in non-MD subjects ( 13 , 17 ). Another factor accounting for the presence of a positive tuning curve in non-MD patients might be the evidence of EH even in a subgroup of patients with idiopathic SSNHL, likely as a secondary reaction following a damage of inner ear sensors ( 21 , 24 ). Interestingly, 14 patients exhibited an AR ≤ -33% either for cVEMPs or oVEMPs.…”

“…Since auditory function in MD behaves differently from other SSNHL, as it tends to recover spontaneously and better than other conditions, some Authors usually prefer to rule out patients with low-frequency HL from inclusion criteria of idiopathic SSNHL to avoid bias. Nevertheless, it is well-known how the first episode of acute HL in MD might not only affect the low tones, but also middle and/or higher frequencies ( 20 , 21 ). In addition, it has been described that only part of subjects with low-tone SSNHL develops a clinical picture consistent with MD over time and, on the other hand, that an additional subgroup of patients with idiopathic SSNHL later develop MD in the ipsilateral ear (ipsilateral delayed EH) ( 19 , 22 – 24 ).…”

Pathophysiological analysis of idiopathic sudden sensorineural hearing loss by magnetic resonance imaging: A mini scoping review

“…Qin et al ( 29 ) investigated the incidence of EH in affected ears based on four types of hearing loss and speculated that EH might be responsible for the pathology of the group with hearing loss at low frequencies, but that it was not related to prognosis. We investigated the existence of EH in ears with unilateral sensorineural hearing loss, including ISSNHL ( 30 ), and detected significant cochlear or vestibular EH in 24 and 14%, respectively, of the unaffected side of ears with ISSNHL.…”