Atypical Theta and Low Gamma Band Auditory Sampling in Chinese Children With Developmental Dyslexia: An ASSR Study

Children with developmental dyslexia (DD) exhibit deficits in auditory temporal processing, potentially linking to their difficulties in reading. Previous studies in alphabetic languages have reported atypical neural synchronization to low-frequency rhythms. For non-alphabetic languages like Chinese, however, the specific frequency bands involved and the cognitive mechanisms through which such abnormalities might relate to reading outcomes are less clearly understood. In this study, we recorded Auditory Steady-State Responses (ASSRs) from 64 Chinese children, including 38 with DD, in response to white noise amplitude-modulated (AM) at 4 Hz (syllabic rhythm) and 30 Hz (phonemic rhythm). Findings revealed that children with DD exhibited atypical auditory temporal sampling patterns, marked by a trend toward excessive responses in the temporal cortex at 4 Hz and diminished responses in the frontal cortex at 30 Hz, particularly among older children in Grades 3-6 (DD: n = 12, M_age = 10.88 years; typical development [TD]: n = 15, M_age = 11.00 years). In addition, in TD children, temporal-region ASSRs elicited by 4 Hz AM noise were indirectly associated with reading fluency via rapid automatized naming (RAN), whereas this pathway was not evident in children with dyslexia. These dual anomalies at the theta and low gamma bands may reflect a developmental failure in neural entrainment, disrupting both syllabic and phonemic-level speech processing. This study provides novel evidence for frequency- and region-specific auditory processing deficits in Chinese children with DD, which also highlight the importance of considering both language-specific characteristics and age-related modulation in understanding the neural oscillatory mechanisms underlying dyslexia. SUMMARY: Chinese children with dyslexia showed atypical auditory temporal sampling in theta and low gamma bands. Auditory Steady-State Responses (ASSRs) revealed neural deficits at 4 and 30 Hz in dyslexia. Language-specific phonological features influence auditory processing in developmental dyslexia. The results underscore the importance of language context and age-related modulation in understanding the neural oscillatory underlying dyslexia.