Age-Dependent Auditory Plasticity: Critical Periods in Subcortical and Cortical Encoding.

Auditory plasticity refers to the capacity of the auditory system to reorganize in response to experience and represents a fundamental feature of neural development. This scoping review synthesizes evidence on age-dependent plasticity at both subcortical and cortical levels, with a particular emphasis on critical and sensitive periods. A systematic search of PubMed/MEDLINE, Scopus, and Web of Science databases (1963-2025) was conducted in accordance with the PRISMA-ScR guidelines. A total of 2,437 records were screened, of which 78 studies were included in the review. Data were analyzed using thematic synthesis. Four major contributions are presented: 1) an appraisal of methodological limitations; 2) the Graded Windows Model (GWM), a conceptual framework proposing that plasticity may be organized as overlapping and interacting windows along the auditory neuraxis; 3) five testable hypotheses; and 4) clinical recommendations graded based on evidence level and study type. Human and animal evidence were distinguished. The traditional dichotomy that the brainstem matures early, whereas cortical plasticity persists later, may represent an oversimplification. Auditory plasticity appears to involve graded and hierarchically organized windows. Overall, this framework may inform the intervention timing and help prevent maladaptive plasticity.