Neural speech encoding advantages associated with higher socioeconomic status extend to noise conditions with differential susceptibility

Abstract

Introduction. Speech perception in noise (SPiN) relies on precise neural encoding of periodic speech cues, which can be assessed using the frequency-following response (FFR). The robustness and fidelity of this encoding vary with maturation, environmental factors, and life experiences. Socioeconomic status (SES), a major contextual determinant of these influences, has been associated with more consistent and higher-quality FFRs in higher-SES individuals. However, it remains unclear whether SES-related advantages in quiet extend to noise. The primary aim was to determine whether SES predicts susceptibility to noise-related degradation in neural encoding, and a secondary aim was to examine whether SES-linked neural differences correspond to behavioral or self-reported SPiN performance. Materials and methods. Seventy higher-education students with normal hearing were classified into low-and high-SES groups based on maternal education. Speech-evoked FFRs to a 170-ms synthetic /da/ were recorded in quiet and in +10 dB SNR babble. Neural timing, magnitude, and fidelity measures were analyzed. Behavioral SPiN was assessed using a monosyllabic adaptive speech-recognition-threshold task, and self-reported SPiN with the SSQ12. Linear mixed-effects models were used to examine SES effects and their modulation by noise on FFR parameters, and ordinary least-squares regressions were used to test whether these FFR metrics predicted behavioral and self-reported SPiN performance. Results. Significant interactions between SES and noise indicated differential neural susceptibility to degradation, with higher-SES participants showing smaller noise-related delays in onset and transition timing and reduced declines in fidelity. Larger response magnitudes were also observed in the higher-SES group across segments. Behavioral SPiN showed no consistent group differences, although onset-latency and stimulus-to-response correlation predicted performance. No significant associations were detected for self-reported SPiN. Discussion. Neural findings indicate that socioeconomic background shapes long-term susceptibility to noise, with higher-SES individuals exhibiting smaller timing delays in both onset and mid-syllabic encoding and more preserved neural fidelity. These advantages may arise from differences in subcortical and cortical phase-locked activity, reflecting neural patterns shaped over development. Maternal education may serve as a proxy for early-life conditions shaped by environmental factors and life experiences during sensitive periods when neural encoding is highly malleable, leaving durable imprints into adulthood.