Brain connectivity | 2021
Long-Range Auditory Functional Connectivity in Hearing Loss and Rehabilitation
Abstract
BACKGROUND\nPatients with age-related sensorineural hearing loss (HL) may benefit from auditory input amplification by using hearing aids (HA). However, the impact of both HL and HA-based rehabilitation on central auditory functional connectivity (FC) is not clear.\n\n\nMETHODOLOGY\n62 HL (22 females, age 64.4±7.6 years, pure tone average 50.9±14.7 dB right ear, 50.7±12.9 dB left ear) and 32 normal hearing (NH) subjects (22 females, age 59.3±7.3 years) were examined in a 3T MRI study. HL patients were analyzed cross-sectionally at baseline (vs. NH subjects), and longitudinally at 6-month follow-up. Between the two scans, 31/62 patients used HA 9.5±3.8 hours a day. Arterial spin labeling and blood oxygen level dependent resting-state functional MRI was performed to measure regional perfusion in primary auditory cortex and, from here to the whole brain, seed-based FC. Before each scan, HL patients underwent audiological and neurological assessments.\n\n\nRESULTS\nAt baseline, HL condition was associated with regional hypoperfusion in right Heschl s gyrus (seed) and negative seed-based FC (anti-correlation) in posterior brain regions. Long-range FC in precuneus correlated negatively with pure tone and speech recognition average thresholds. At 6-month follow-up, HA usage was associated with seed-based FC increase in right superior frontal gyrus and seed-based FC reduction in right middle temporal gyrus. Long-range FC changes in superior frontal gyrus correlated positively with executive function improvements.\n\n\nCONCLUSIONS\nThese findings suggest that HA-based rehabilitation may not reverse HL-related neural effects and yet carry neurological benefits by retuning long-range FC of the auditory system.