Beyond the Audiogram: Current Evidence on Hidden Hearing Loss, Cochlear Synaptopathy, and Emerging Diagnostic Strategies

Resumen

Hidden hearing loss (HHL) has emerged as an important topic in auditory medicine because many individuals experience significant communication difficulties despite presenting normal pure-tone audiometric thresholds. This review critically analyzes current international evidence regarding the epidemiology, pathophysiology, clinical manifestations, diagnostic challenges, and therapeutic perspectives associated with HHL, with particular emphasis on cochlear synaptopathy and its implications for clinical practice. A narrative literature review was conducted using the Scientific Method as the methodological framework. Scientific publications indexed in PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar were reviewed, prioritizing original investigations, systematic reviews, meta-analyses, and clinical guidelines published in peer-reviewed journals. The evidence indicates that speech-in-noise perception deficits, tinnitus, listening fatigue, and temporal auditory processing impairments represent the most frequently reported manifestations among individuals with suspected HHL. Occupational and recreational noise exposure, together with physiological aging, were consistently identified as the principal risk factors. Although conventional pure-tone audiometry remains essential for hearing assessment, it demonstrates limited sensitivity for detecting early neural dysfunction. Complementary evaluations, including speech-in-noise testing, auditory brainstem responses, extended high-frequency audiometry, and other electrophysiological techniques, provide additional diagnostic information; however, no single method currently constitutes a definitive diagnostic standard. The reviewed literature supports the implementation of multimodal diagnostic strategies integrating behavioral, physiological, and clinical findings. Furthermore, the analysis highlights the need for standardized diagnostic criteria, objective biomarkers, multicenter investigations, and increased scientific participation from Latin America. Hidden hearing loss represents an evolving multidisciplinary concept that expands the understanding of auditory dysfunction beyond conventional audiometry and emphasizes the importance of comprehensive patient-centered evaluation to improve early recognition, clinical management, and future research.