The sound of speech is carried through the brain by nerve fibers in regions known as the auditory pathway, and are processed in a region called the language network. Congenital SNHL, or hearing loss that is present from birth, has increased in prevalence over the past two decades, from 1.09 to 1.7 cases per 1,000 live births. A person with profound hearing loss is typically unable to hear any sounds, or at best, only very loud sounds. Sensorineural hearing loss (SNHL) occurs when the sensitive hair cells inside the cochlea are damaged, or when there is damage to the auditory nerve which transmits sound to the brain. The findings, published in eLife, highlight the importance of early interventions to give patients the ability to hear and understand speech, so that their auditory-language network can develop properly and their long-term outcomes are improved. Researchers have developed a non-invasive method for mapping the human auditory pathway, which could potentially be used as a tool to help clinicians decide the best surgical strategy for patients with profound hearing loss. CN, cochlear nucleus ICP, inferior cerebellar peduncle PBB, ponto bulbar body VSN, trigeminal spinal nucleus VST, trigeminal spinal tract IO, inferior olive SOC, superior olivary complex ML, medial lemniscus MCP, medial cerebellar peduncle IC, inferior colliculus CIC, commissure of IC LL, lateral lemniscus PAG, periaqueductal gray MGB, medial geniculate body LGB, lateral geniculate body SC, superior colliculus RN, red nucleus SN, substantia nigra CST, corticospinal tract St-DEC-TDI, short-tracks directionally encoded color track density imaging SNHL, sensorineural hearing loss.

Images from one normal hearing control (male, 32 months old) and one profound SNHL patient (male, 32 months old) were selected to show individual-level segmentation. Group-level segmentation was performed in the study-specific template averaged from all 10 normal-hearing controls. Schematic diagrams for the CN, SOC, and IC were redrawn from Moore, 1987 and for the MGB from Duvernoys Atlas of the Human Brain Stem and Cerebellum (2009).

Subcortical auditory regions are exhibited as red areas in the schematic diagrams and dotted lines in T1w images and st-DEC-TDI maps. Segmentation of the subcortical auditory regions at group and individual levels.

Auditory nerve pathway