Vascular loops in cerebellopontine angle in patients with unilateral idiopathic sudden sensorineural hearing loss: Evaluations by three radiological grading systems

Abstract

Objective We aimed to investigate the impact of the position, configuration and neurovascular contact of the anterior inferior cerebellar artery (AICA) in cerebellopontine angle (CPA) and internal auditory canal (IAC) on the clinical features of patients with unilateral idiopathic sudden sensorineural hearing loss (ISSNHL). Methods One hundred and thirty‐six patients with unilateral ISSNHL were enrolled. All patients received detailed history inquiry and standard treatments. Pure tone audiometry and magnetic resonance imaging (MRI) of CPA‐IAC were performed. The MRI findings of both ears were evaluated by the Chavda, Gorrie and Kazawa systems. The association between radiological findings and clinical data were analyzed. Results (1) No significant interaural difference in the position, configuration and neurovascular contact of AICA was observed. (2) There was no significant association between the AICA loop and concomitant vertigo or pre‐treatment audiometric configuration in the affected ear. (3) Concomitant tinnitus seemed to be affected by the configuration of AICA categorized by Kazawa system, while the Chavda and Gorrie classification of AICA loop was unassociated with tinnitus. (4) Hearing outcomes were not compromised by the position or configuration of AICA based on the Chavda and Kazawa systems. Patients with Gorrie type B tended to have better hearing recovery than those with type C. Conclusions In patients with ISSNHL, the position, configuration and neurovascular contact of AICA in the CPA‐IAC were unassociated with the side of hearing loss, audiometric configurations, or concomitant vertigo. The neurovascular contact graded by Gorrie system might be associated with hearing outcomes.

Vascular Loop of the Anterior Inferior Cerebellar Artery (AICA) as a Cause of Sensorineural Hearing Loss (SNHL): A Case Report

“…A lack of uniform grading systems for vascular loops can also cause confusion. This is exemplified in another study that found that tinnitus was associated with the configuration of the AICA when using the Kazawa grading system, but not the Chavda or Gorrie classification [15]. Additionally, even with standardized grading systems, there is potential for inter-observer differences which may impact meta-analyses seeking to find associations between SNHL and vascular loops [14].…”

Altered static and dynamic intrinsic brain activity in unilateral sudden sensorineural hearing loss

“…Pure-tone audiometry was performed using seven different octave frequencies (0.125, 0.25, 0.5, 1, 2, 4, and 8 kHz) to measure the pure tone average (PTA) and determine the hearing level. As described in our previous study ( Leng et al, 2022 ), PTA was calculated as the simple arithmetic mean for these seven frequencies. The initial pure-tone audiometry curves were categorized into four types: (1) low-frequency hearing loss (the average threshold of 0.25 and 0.5 kHz is 20 dB higher than that of 4 and 8 kHz), (2) high-frequency hearing loss (the average threshold of 4 and 8 kHz is 20 dB higher than that of 0.25 and 0.5 kHz), (3) flat-type hearing loss (similar threshold is observed across the entire frequency range and the average threshold is less than 90 dB HL), and (4) profound hearing loss (the average threshold of 0.5, 1, 2, and 4 kHz exceeds 90 dB HL) ( Leng et al, 2022 ).…”

“…Pure-tone audiometry was performed using seven different octave frequencies (0.125, 0.25, 0.5, 1, 2, 4, and 8 kHz) to measure the pure tone average (PTA) and determine the hearing level. As described in our previous study (Leng et al, 2022), PTA was calculated as the simple arithmetic mean for these seven frequencies. The initial pure-tone audiometry curves were categorized into four types:…”

“…(1) low-frequency hearing loss (the average threshold of 0.25 and 0.5 kHz is 20 dB higher than that of 4 and 8 kHz), (2) high-frequency hearing loss (the average threshold of 4 and 8 kHz is 20 dB higher than that of 0.25 and 0.5 kHz), (3) flat-type hearing loss (similar threshold is observed across the entire frequency range and the average threshold is less than 90 dB HL), and (4) profound hearing loss (the average threshold of 0.5, 1, 2, and 4 kHz exceeds 90 dB HL) (Leng et al, 2022).…”