Figures for Chapter 8 Candidacy Dillon (2001) Hearing Aids

Figure 8.1 The long-term 1/3 octave speech spectrum for a) speech at 55 dB SPL in a quiet place, and b) speech at 85 dB SPL in a noisy place. Each speech spectrum includes the 30 dB dynamic range from the weakest useful elements of speech to the most intense elements (shown as the vertical lines). The portion of the speech range that is audible above noise and hearing thresholds is thickly shaded. The normal threshold of hearing is shown as the lower dotted line. Source: Dillon (2001): Hearing Aids Speech audibility in quiet and in noise

k2k4k8k Frequency (Hz) Hearing threshold (dB HL) or ee m p kt sh s f ar th Figure 8.2 The speech spectrum, including a 30 dB dynamic range at each frequency, for speech at a long- term level of 65 dB SPL. The approximate locations of the spectral centre of a few speech sounds are indicated. Source: Dillon (2001): Hearing Aids Speech sounds and the speech spectrum

Fig 8.3 Probability of implanted adults exceeding the indicated speech score for CNC (consonant-nucleus-consonant) words, CUNY/SIT sentences (City University of New York speech intelligibility test) in quiet, and CUNY/SIT sentences in noise with a 10 dB SNR. Source: Dillon (2001): Hearing Aids Cochlear implant speech-score probability

Figure 8.4 Probability of a speech identification score for an implanted adult or child being greater than the anticipated score obtained with hearing aids, as a function of pure tone hearing levels. Source: Dillon (2001): Hearing Aids Implant versus hearing aid probability

Figure 8.5 Average increase in scores (implant minus hearing aids) as a function of pre-implant hearing threshold. Source: Dillon (2001): Hearing Aids Implant improvement re hearing aids