Effect of spectral degradation on speech intelligibility and cortical representation

• DOI: 10.3389/fnins.2024.1368641
• Publication Date: 2024-04-05T13:20:34Z
• Authors: Hyo Jung Choi; Jeong-Sug Kyong; Jong Ho Won; Hyun Joon Shim
• Keywords: P3b; Intelligibility (philosophy); Oddball paradigm

Noise-vocoded speech has long been used to investigate how acoustic cues affect understanding. Studies indicate that reducing the number of spectral channel bands diminishes intelligibility. Despite previous studies examining band effect using earlier event-related potential (ERP) components, such as P1, N1, and P2, a clear consensus or understanding remains elusive. Given our hypothesis degradation affects higher-order processing beyond mere perception, we aimed objectively measure differences in abilities discriminate interpret meaning. Using an oddball paradigm with stimuli, examined neural signals correlate evaluation stimuli based on measuring N2 P3b components. In 20 young participants normal hearing, measured intelligibility responses one-syllable task animal non-animal across four vocoder conditions 4, 8, 16, 32 bands. Behavioral data from word repetition clearly affected bands, all pairs were significantly different ( p < 0.001). We also observed significant effects channels peak amplitude [ F (2.006, 38.117) = 9.077, 0.001] latency (3, 57) 26.642, component. Similarly, component showed main (2.231, 42.391) 13.045, 2.968, 0.039]. summary, findings provide compelling evidence profoundly influence cortical processing, reflected cognitive process. conclude spectrally degraded primarily during semantic integration.