Effects on Blood Neurodegeneration Biomarkers of a Randomized Hearing Rehabilitation Intervention

TL;DR

A hearing rehabilitation intervention slowed cognitive decline and reduced neurodegeneration biomarkers in older adults with untreated hearing loss.

Contribution

This study provides objective evidence that hearing intervention may reduce brain degeneration biomarkers in older adults.

Findings

Hearing intervention was associated with lower levels of GFAP and NfL biomarkers in ARIC participants after 3 years.

The intervention slowed the annualized increase in GFAP levels among ARIC participants.

Positive effects on biomarkers were observed only in participants from the ARIC study.

Abstract

The Aging and Cognitive Health Evaluation in Elders (ACHIEVE) study is a multicenter, parallel-arm, randomized trial (hearing intervention vs health education control) on 3-year cognitive decline among adults 70–84years with untreated hearing loss and without substantial cognitive impairment. Participants were recruited from: (1)a long-standing observational study (Atherosclerosis Risk in Communities [ARIC]), and (2)de novo community volunteers. In ACHIEVE, intervention slowed 3-year cognitive decline by 48% among ARIC participants only. To further investigate differences by treatment with respect to cognitive benefit, we tested the hypothesis that hearing intervention is associated with improved neurodegeneration blood biomarkers 3-years post-randomization. Plasma was collected in year 3 in a subsample (n = 540) while ARIC participants (n = 164) also had baseline plasma. Glial fibrillary acidic protein (GFAP) and neurofilament light (NfL) neurodegenerative biomarkers were derived using the Alamar CNS protein panel. Regression models estimated the association of treatment with 3-year biomarkers differences in the combined sample and by recruitment source and annualized change from baseline in the ARIC sample. Baseline characteristics were balanced by treatment. There were no significant differences on 3-year neurodegeneration biomarker levels by treatment in the combined or de novo groups. Among ARIC participants, intervention resulted in lower 3-year GFAP(mean:-0.415;95%CI:-0.712,-0.118) and NfL(mean:-0.349;95%CI:-0.652,-0.046). Annualized change from baseline analyses among ARIC participants revealed intervention was associated with a slower rate of increase in GFAP (difference-in-means: -0.060;95%CI:-0.112,-0.009). Hearing intervention was associated with positive 3-year effects on neurodegeneration blood biomarkers in ARIC participants which parallels cognitive decline results. Results provides objective evidence of brain changes following hearing intervention.