The curvature quantification of Wave I in auditory brainstem responses detects cochlear synaptopathy in the elderly

Age-related hearing loss is the most common sensory disorder in the elderly. During the early-stage elderly listeners often complain of degraded speech perception in adverse listening environment. Animal studies suggested that a cochlear synaptopathy might be one of the main mechanisms. A decreased Wave I amplitude in supra-threshold auditory brainstem responses (ABR) could diagnose this pathology non-invasively. However, the interpretation of the Wave I amplitude in humans is controversial. Recent work has established a robust and reliable mathematic algorithm, i.e. curve curvature quantification, with promising results in mice. The current study aimed to determine whether the curve curvature has also sufficient test-retest reliability to detect cochlear synaptopathy in aging human. Twenty-nine subjects with normal hearing were included into this study. All of them accepted an extended pure tone audiogram examination ranged from 0,125 to 16 kHz and an ABR with a stimulus of 80 dB nHL click. The amplitude, curvature at the peak and the area under the curve (AUC) of Wave I were calculated and analyzed. The Pearson correlation analyses clearly demonstrated a significant negative correlation between age and curvature (R= -0,33, p= 0,015), as well as between curvature and high-frequency thresholds (R= -0,36, p= 0,009). Additionally, there is also a negative correlation between the high-frequencies thresholds and AUC of the Wave I (R= -0,32, p= 0,02). Thus, these results suggest that curvature quantification and AUC of Wave I can be reliably used to diagnose a cochlear synaptopathy in aging human. It may be applied in the daily routine to diagnose early degenerations of the auditory nerve.

Publication History

Article published online:
12 May 2023