Microstructural changes in the auditory pathway in children with hearing loss

2490 

Abstract Submission 

Peter Moon¹, Kristina Ward¹, Alan Cheng¹, Kristen Yeom¹, Iram Ahmad¹

¹Stanford University, Palo Alto, CA

Peter Moon  
Stanford University
Palo Alto, CA

Kristina Ward, PhD  
Stanford University
Palo Alto, CA

Alan Cheng, MD  
Stanford University
Palo Alto, CA

Kristen Yeom  
Stanford University
Palo Alto, CA

Iram Ahmad  
Stanford University
Palo Alto, CA

Early diagnosis of congenital sensorineural hearing loss (SNHL) is of paramount importance in preventing speech and language impairment. Prognostic factors following hearing rehabilitation are yet to be comprehensively standardized. Diffusion tensor imaging (DTI) MRI can identify brain microstructural changes that may potentially contribute towards prognosticating rehabilitation. As no previous study has assessed brainstem regions of the auditory pathway, the goal of our study was to investigate MRI-based microstructural changes along this pathway in pediatric patients with SNHL.

We retrospectively reviewed pediatric patients with SNHL who obtained DTI MRI between 2011 and 2019, identifying 16 pediatric patients (age <18 years) with at least moderate asymmetric/bilateral SNHL. , and gender-matched controls without neurological, developmental, or MRI-based brain macrostructural abnormalities. The following brainstem regions and tracts of the auditory pathway were assessed: superior olivary nucleus (SON), inferior colliculus (IC), ipsilateral tracts between the inferior colliculus and superior olivary nucleus (IC-SON). Diffusion values for bilateral regions and tracts were generated, then averaged to calculate a mean value for fractional anisotropy (FA) and mean diffusivity (MD) for each subject. We performed tractography of the brainstem auditory pathway. We evaluated audiometric outcomes for out patients by evaluating speech reception thresholds on the patients.

Significant differences were identified in FA values of the SON between the SNHL cohort and controls (0.3770.056 vs 0.4220.052; p=0.009). No other FA or MD values were significantly different. In children 5 years, MD was significantly decreased in the SNHL cohort compared to controls in the IC (0.9180.051 vs 1.1200.142; p<0.001). In children >5 years, there were no significant differences in MD (1.1240.198 vs 0.9970.103; p = 0.119). There were no significant differences in MD or FA in the white matter fibers of the IC-SON tract. When evaluating the audiometric findings, we noted a trending relation between speech awareness/recognition thresholds and mean FA SON.

This is the first study to assess microstructural changes in brainstem auditory pathway regions among children with SNHL. We also reconstructed and quantified diffusion along the fiber tracts between the IC and SON. Our results suggest abnormal neural tracts along the central auditory pathway among children with SNHL. Longitudinal studies should assess the prognostic value of these MRI-based findings for assessing long-term outcomes and determining intervention efficacy.

Diffusion MRI ²

Perception: Auditory/ Vestibular ¹

Brainstem

Hearing

MRI

WHITE MATTER IMAGING - DTI, HARDI, DSI, ETC