Amyloid and tau deposition is associated with performance on tests of auditory processing in the brain

Abstract

AbstractBackgroundAlzheimer’s disease pathophysiology may affect sound processing (central auditory function) in the brain. This study aims to investigate the link between tests of central auditory function, such as dichotic digits, and brain pathology in older adults at high risk for developing dementia.Method28 individuals (13 cognitively unimpaired (CU) and 15 mild cognitively impaired (MCI)) were enrolled (Table 1). Amyloid deposition was assessed with [18F] AZD4694 PET and tau accumulation was assessed with [18F]MK6240 PET. Standard uptake value ratios (SUVR) were determined using the cerebellar and the inferior cerebellar cortex as reference region for amyloid and tau PET, respectively. Hearing assessments were conducted using a custom audiological testing system from Creare LLC. Voxel‐based regression models evaluated the association between dichotic digit scores and amyloid and tau deposition as assessed by PET, adjusting for Pure Tone Average (PTA) and a control condition for speech in noise (Triple digits score). Random field theory (RFT) was used to correct for multiple comparisons.ResultIn the voxel‐wise analysis, negative associations between dichotic digits scores and amyloid‐PET were found in the temporal, occipital and parietal areas. Negative associations between dichotic digits scores and tau‐PET were present in the temporal area, with higher t‐values in the primary and secondary somatosensory cortices (Figure 1, panel A). Negative correlations were found between dichotic digits scores and both amyloid (p<0.001) and tau (p<0.05) SUVRs (Figure 1, panel B). In addition, dichotic digits scores were significantly lower in MCI individuals (p<0.001) (Figure 1, panel C).ConclusionThis study is the first to assess associations between central auditory hearing in CU and MCI individuals using PET biomarkers. These findings highlight the link between central auditory deficits and AD hallmarks in auditory processing‐related brain regions. This suggests a potential decreased capacity for interhemispheric transfer in mildly cognitively impaired individuals.