PT  - JOURNAL ARTICLE
AU  - Choi, Hyo Jung
AU  - Kyong, Jeong-Sug
AU  - Lee, Jae Hee
AU  - Han, Seung Ho
AU  - Shim, Hyun Joon
TI  - The Impact of Spectral and Temporal Degradation on Vocoded Speech Recognition in Early-Blind Individuals
AID  - 10.1523/ENEURO.0528-23.2024
DP  - 2024 May 01
TA  - eneuro
PG  - ENEURO.0528-23.2024
VI  - 11
IP  - 5
4099  - http://www.eneuro.org/content/11/5/ENEURO.0528-23.2024.short
4100  - http://www.eneuro.org/content/11/5/ENEURO.0528-23.2024.full
SO  - eNeuro2024 May 01; 11
AB  - This study compared the impact of spectral and temporal degradation on vocoded speech recognition between early-blind and sighted subjects. The participants included 25 early-blind subjects (30.32 ± 4.88 years; male:female, 14:11) and 25 age- and sex-matched sighted subjects. Tests included monosyllable recognition in noise at various signal-to-noise ratios (−18 to −4 dB), matrix sentence-in-noise recognition, and vocoded speech recognition with different numbers of channels (4, 8, 16, and 32) and temporal envelope cutoff frequencies (50 vs 500 Hz). Cortical-evoked potentials (N2 and P3b) were measured in response to spectrally and temporally degraded stimuli. The early-blind subjects displayed superior monosyllable and sentence recognition than sighted subjects (all p < 0.01). In the vocoded speech recognition test, a three-way repeated-measure analysis of variance (two groups × four channels × two cutoff frequencies) revealed significant main effects of group, channel, and cutoff frequency (all p < 0.001). Early-blind subjects showed increased sensitivity to spectral degradation for speech recognition, evident in the significant interaction between group and channel (p = 0.007). N2 responses in early-blind subjects exhibited shorter latency and greater amplitude in the 8-channel (p = 0.022 and 0.034, respectively) and shorter latency in the 16-channel (p = 0.049) compared with sighted subjects. In conclusion, early-blind subjects demonstrated speech recognition advantages over sighted subjects, even in the presence of spectral and temporal degradation. Spectral degradation had a greater impact on speech recognition in early-blind subjects, while the effect of temporal degradation was similar in both groups.