Investigation of the auditory pathway in asymmetric hearing-impaired patients with FDG-PET

Introduction:

The purpose of the presented study is to evaluate the glucose metabolism, as a marker of neural activity, of the auditory pathway, especially the inferior colliculi and primary auditory cortices, in asymmetric hearing-impaired subjects.

Methods:

The glucose metabolism of the two regions-of-interest (ROI), inferior colliculi and primary auditory cortices, was assessed in fifteen subjects using a clinical high-resolution scanner (Philips, Vereos PET/CT) and [18F]FDG PET. Differences between the normalized regional FDG uptake of the ipsi- and contralateral side (related to the more severely hearing-impaired ear) and correlations with the duration of hearing impairment were investigated.

Results:

The contralateral metabolism in both, inferior colliculi and primary auditory cortices was significantly reduced compared to the ipsilateral side. This hypometabolism of the primary auditory cortices was reduced with prolonged hearing impairment. In contrast, the duration of hearing impairment had no impact on the metabolism of the contralateral inferior colliculi. On the contralateral side, the metabolism of the inferior colliculi predicted that of the primary auditory cortices only when adjusting for the duration of hearing impairment.

Conclusions:

A fully digital, clinical PET scanner permits displaying, differentiating and measuring small brain stem nuclei such as the inferior colliculi. Asymmetric hearing loss and duration of deafness have a significant impact on the glucose metabolism of parts of the auditory pathway. This might be of clinical value concerning the prediction of the outcome after cochlear implantation.

Publication History

Publication Date:
23 April 2019 (online)