Neural speech encoding in fetal alcohol spectrum disorder: an exploratory study using frequency-following responses

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Developmental Neuroscience

Background:

• Fetal Alcohol Spectrum Disorder (FASD) is linked to neurodevelopmental issues, including auditory processing deficits not explained by peripheral hearing loss.
• Neural auditory processing, specifically speech encoding, may be impaired in individuals with FASD.
• The Frequency-Following Response (FFR) is an objective measure of neural speech encoding, offering insights into auditory function.

Purpose of the Study:

• To investigate neural speech encoding using FFR in individuals with FASD.
• To explore potential auditory biomarkers for FASD.
• To establish the feasibility of using FFR in FASD research.

Main Methods:

• Speech-evoked FFRs were recorded in 25 participants (11 with FASD, 14 controls) using a /da/ stimulus.
• Analysis included pitch tracking, stimulus-response correlation, response latency, and signal quality.
• Non-parametric statistics were used, acknowledging exploratory nature and potential confounds like age differences.

Main Results:

• Individuals with FASD exhibited reduced pitch-tracking consistency and lower stimulus-response correlation compared to controls.
• A significant reduction in F0-range correlation (70-120 Hz) was observed in the FASD group (p < 0.001).
• Prolonged latencies and lower signal-to-noise ratios were noted in the FASD group.

Conclusions:

• This study provides preliminary evidence of altered neural speech encoding in individuals with FASD, even with normal peripheral hearing.
• Observed differences require further controlled research for specific attribution to FASD due to confounding variables.
• FFR is feasible for use in the FASD population, laying groundwork for future research on auditory biomarkers and intervention monitoring.