In the early stage of presbyacusis, patients often experience reduced speech perception in noisy environments despite normal audiometry, a condition known as ‘hidden hearing loss’. Diagnostic indicators like reduced amplitude of the ABR wave I, elevated hearing thresholds in the extended high-frequency range and decreased middle ear muscle reflex amplitudes aims to identify biomarkers for peripheral auditory pathology but remain inconsistent. Mismatch negativity (MMN) is a cortical auditory evoked potential generated when the brain detects sound changes. This study aimed to assess MMN as a diagnostic tool for hidden hearing loss in adults. Seventy-three subjects with normal hearing underwent an extended pure-tone audiogram examination ranging from 0.125 to 16 kHz and a subsequent MMN assessment with 2 different stimuli: two verbal (ba/da) and two non-verbal stimuli (1/2 kHz). The MMN’s amplitude and latency were measured and analyzed. A significant age-related effect on the MMN amplitude in the speech condition was found (χ² = 13.0, p = 0.002). Additionally, no further effects of age were observed on the cortical potentials examined. Also, no significant influence of EHT on the amplitude or latency of either the MMN or the P300 was detected in both the tone and speech paradigms. Thus, EHFT was used as an indirect biomarker to detect pathology, specifically cochlear synaptopathy, in the peripheral auditory system, but it is not suitable for detecting changes in the central auditory system. The amplitude of MMN, however, can be used to detect early pathological changes in the central auditory system.