Slide Slam J15 Sandbox Series
Neural cortical measures are associated with auditory improvement after cochlear implantation in young children with congenital hearing loss
Xiujuan Geng1, Wai Tsz Chang1, Peggy Chan1, Iris HY Ng1, Winnie CW Chu1, Nancy M Young2, Michael CF Tong1, Gangyi Feng1, Patrick CM Wong1; 1Chinese University of Hong Kong, 2Lurie Children's Hospital, Northwestern University
Auditory and spoken language outcome after cochlear implantation, the most effective treatment available for children with congenital profound bilateral sensorineural hearing loss, is quite variable even in early implanted children (Niparko et al 2010). There is great need to identify objective markers associated with outcome after implantation. Doing so would enable forecasting of individual risk for language development far below normal hearing children, providing an opportunity to develop customized treatment to improve outcome. Previous studies have shown the impact of auditory deprivation on brain regions involved in hearing, speech and language (Ratnanather et al 2020). Our previous studies (Feng et al 2018) have shown that gray matter density in preserved, not damaged, neural regions are more predictive to the language outcome measured 6 month after the implantation. In this study, we further validated our work using an external cohort to investigate whether the neural-based features are more predictive of the implantation outcome compared to non-neural characteristics, and whether the auditory regions or non-impaired neural regions are correlated with post-implantation outcome. A set of young children (mean age at implantation was 27.5-month-old) with congenital hearing loss was recruited in Hong Kong. The whole-brain MRI 3D T1-weighted images were obtained before implantation. The pre- and 6-month post-implantation auditory ability was measured by LittlEARS, validated to assess early auditory development in children with cochlear implantation (Obrycka et al 2017). The imaging data was processed with Infant Freesurfer (Zöllei et al 2020). The cortical thickness, a heritable and plastic measure sensitive to cognitive abilities and pathologies (Dickerson et al 2008; Shiohama et al 2019), was extracted from each individual subject and mapped to a standard space via surface registration. Two sets of regression analyses were conducted. The first was to test whether the implantation age was correlated with the baseline auditory outcome and 6-month-post-implantation auditory improvement (post-pre). The second set of analyses was to conduct vertex-based regression analyses between the cortical thickness and baseline and 6-month improvement of auditory outcomes while controlling the implantation age. The surface-based statistical results were corrected for multiple comparisons using Monte-Carlo simulation. Statistical results showed that the implantation age was not correlated with the baseline and improvement of auditory outcomes. Surface-based regression results showed that no significant clusters were correlated with baseline auditory outcome. The regression analysis between imaging and the auditory improvement showed that cortical thickness in left supramarginal, superior, middle and inferior temporal cortices, and right cuneus was significantly negatively correlated (corrected p<0.05) with the 6-month auditory improvement measured by LittlEARS. The findings suggest that, rather than age, neural cortical features in hearing loss children are correlated with the auditory improvement after implantation, indicating the superior of using neural measures (compared to non-neural characteristics) for the prediction of later auditory outcome. Moreover, not only the primary auditory regions, shown to be damaged in hearing loss children, but also secondary and associated cortices are correlated with auditory improvement, indicating the role of cortical re-organization in auditory improvement after cochlear implantation.