Cortical latency predicts reading fluency from late childhood to early adolescence

The development of fluent literacy from childhood to adolescence is strongly constrained by the temporal dynamics of word recognition. Capturing the neural basis of these subtle timing changes reliably at the individual level has been challenging with EEG. Here, we leverage phase information from Steady-State Visual Evoked Potentials (SSVEPs) to derive precise and reliable temporal dynamics of neural signatures underlying visual word form recognition at the individual level and examine their relationship to reading fluency and comprehension. Typically developing readers (N = 68, aged 8–15), viewed a stream of four-character stimulus strings presented at 3 Hz. Significant SSVEP signals emerged for nearly all participants. Signals at 3, 6, and 9 Hz harmonics exhibited a phase pattern consistent with a delay model, indicating a mean latency of ~170 milliseconds. Individual latencies demonstrated (a) high internal consistency (R = .94); (b) robustness across letter string forms (words, nonwords, and pseudo-characters); (c) a linear relationship with age; and most remarkably, (d) a predictive relationship with individual differences in reading fluency and comprehension. These findings highlight SSVEP latency as a robust neural marker of reading development, offering a promising tool for translational applications in educational settings and interventions targeting reading difficulties.