Auditory Threshold Variability in the SAMP8 Mouse Model of Age-Related Hearing Loss: Functional Loss and Phenotypic Change Precede Outer Hair Cell Loss

The study on SAMP8 mice, a model for age-related hearing loss (ARHL), found that auditory brainstem response (ABR) threshold variability was not directly linked to outer hair cell (OHC) loss. Instead, it was associated with phenotypic changes in OHCs and the stria vascularis (SV), particularly involving reduced expression of KCNQ4 and KCNQ1 potassium channels. These changes were more pronounced in mice with higher ABR thresholds, suggesting that functional impairment and phenotypic changes occurred before OHC loss. The study highlighted the rapid progression of hearing loss in SAMP8 mice and suggested that targeting potassium channels or increasing antioxidant activity might slow or prevent ARHL progression.