Exploration of inter-individual variability in cortical responses to natural English sentences

Abstract

Objectives: Grand average cortical responses to speech have shown the possibility to analyse perceived intelligibility. Cortical responses to sentences are explored to determine their variability amongst subjects and therefore their applicability in clinic. Methods: EEG responses to 100 repeats of three English sentences were recorded for 16 subjects with normal hearing thresholds. Responses were detected using a Hotelling’s T2 test on 100 ms low-pass filtered (30 Hz) segments (two 50 ms features per segment). Results: Participants showed a clear response at segments including the stimulus onset (p<0.01). Later segments showed strong variability in detection between participants, with less significant responses and more repeats needed compared to onset detection. Conclusion: Onset responses to natural sentences can be detected within 100 repeats (100 s), which is relevant for clinical use. The possibility of detecting robust responses beyond the onset at an individual level need to be further investigated