A child's success in school hinges on their ability to quickly grasp language and reading skills, abilities established even before formal education. Previous research has linked beat synchronization—integrating sensorimotor, auditory, and cognitive circuits—to preliteracy skills and auditory processing. Poor beat synchronization in young children often correlates with reading difficulties, potentially stemming from an auditory rhythm perception deficit affecting motor precision, an independent motor system deficit, or both. Studies comparing children with dyslexia and typically developing children on beat-related steady-state evoked potentials support an auditory rhythm perception deficit hypothesis, aligning with the Temporal Sampling Framework (TSF). The TSF proposes that dyslexia involves inefficiency in tracking low-frequency modulation (1.5–10 Hz) like the amplitude envelope onset of sounds. Prior work by the authors showed a link between neural encoding precision of speech syllable envelopes, phonological skills, and beat synchronization in preschoolers. The interrelationship among beat synchronization, neural sound processing, and phonological skills has been documented across age groups using varied methodologies. Frequency-following responses (FFRs), measuring synchronous sound-evoked neural activity primarily from the inferior colliculus, provide insights into temporal and spectral stimulus features. While some debate exists about cortical contributions to FFRs, the authors' previous work suggests a predominantly subcortical response. FFRs offer various analyzable measures of timing, magnitude, and response fidelity. Preschoolers are an ideal population for studying these relationships due to ongoing developmental changes and the clinical urgency of early identification of reading difficulties. Previous smaller studies by the authors revealed positive correlations between beat synchronization, preliteracy skills, and FFR measures. However, limitations included small sample sizes and focus on quiet listening conditions. This study aims to robustly establish these connections using a larger, diverse sample of preschoolers and considers challenging listening conditions.

Several studies have explored the relationship between beat synchronization, neural sound processing, and phonological skills. Colling, Noble, and Goswami (2017) found atypical neural entrainment to a beat in children with dyslexia, suggesting an auditory rhythm perception deficit. Carr et al. (2014, 2016) demonstrated associations between beat synchronization consistency, neural encoding of speech envelopes (measured by FFR), and preliteracy skills in preschoolers. Other research (Huss et al., 2011; Tierney and Kraus, 2013; Tierney et al., 2017) also supports the interconnectedness of these factors across different age groups and methodologies. However, these previous studies often had relatively small sample sizes and limited consideration of complex listening environments.

This study involved 156 preschoolers (ages 3-5) who completed a beat synchronization task, drumming consistently to two beat rates (400 and 600 ms inter-stimulus intervals [ISIs]). Participants were categorized into 'Synchronizers' (consistent drumming at both rates) and 'Non-synchronizers' (inconsistent drumming). Preliteracy skills were assessed using standardized tests measuring phonological awareness, auditory short-term memory, and rapid automatized naming. Musical perception was assessed using Gordon's AUDIE test. FFRs were recorded using surface electrodes, elicited by four speech stimuli ([ba], [da], [ga], and [da] in noise) presented in quiet and noisy conditions. FFRs were analyzed for envelope-encoding precision, response consistency (RC), and phase-locking consistency (PLC). Statistical analyses included one-way ANOVAs for preliteracy measures and repeated-measures ANOVAs for FFR measures, with synchronization group as the between-subjects factor and time region, presentation mode, polarity, and frequency range as within-subjects factors. Sex was controlled for in all analyses due to observed sex differences in drumming consistency.

Synchronizers outperformed Non-synchronizers on all preliteracy measures (phonological awareness, auditory short-term memory, rapid automatized naming of objects and colors, and rhythm discrimination in the music perception task). Synchronizers showed greater envelope-encoding precision, response consistency, and phase-locking consistency in their FFRs compared to Non-synchronizers across all stimuli. The differences between groups were particularly pronounced in the steady-state portion of the FFR, in high-frequency ranges, and in noisy conditions. Synchronizers exhibited less degradation of FFR measures in noisy conditions compared to Non-synchronizers. A subgroup of children, 'Synchronizers-at-one-rate-only', showed intermediate performance between Synchronizers and Non-synchronizers on both behavioral and electrophysiological measures, suggesting potential complexities in interpreting their rhythmic abilities. No significant group differences were found for age, verbal IQ, nonverbal IQ, or auditory brainstem response latencies between the main Synchronizer and Non-synchronizer groups. However, sex differences were noted in drumming consistency and group categorization.

The findings strongly support the interconnectedness of rhythm abilities, preliteracy skills, and auditory processing in preschool children. Superior beat synchronization skills are associated with enhanced preliteracy skills and more robust, less noise-sensitive auditory neural responses. The results align with previous research emphasizing the importance of subcortical neural synchrony and speech-envelope tracking in reading fluency and comprehension. The greater resilience of Synchronizers' FFRs to challenging conditions (noise, formant transitions) highlights the importance of robust auditory processing for literacy development, consistent with models proposing a link between impaired auditory processing and reading difficulties. The findings suggest that rhythmic ability and auditory neural responses may serve as early indicators of future reading success. The 'Synchronizers-at-one-rate-only' subgroup requires further investigation through longitudinal studies to clarify the developmental trajectory of their rhythmic skills. The observed sex differences merit further exploration.

This study provides robust evidence for the strong association between rhythm skills, preliteracy abilities, and auditory processing in preschoolers. The findings support the use of nonverbal rhythm tasks, combined with objective neural measures like FFRs, for early identification of children at risk for reading difficulties. Future research should investigate the longitudinal development of rhythmic abilities and their predictive value for literacy outcomes, explore the neural mechanisms underlying these associations, and examine the potential for rhythm-based interventions to improve literacy development.

While the study utilized a large and diverse sample, some limitations exist. The cross-sectional design limits conclusions about causal relationships. The 'Synchronizers-at-one-rate-only' subgroup requires further investigation. The study focused on specific preliteracy measures and did not comprehensively assess all aspects of reading development.