Final answer:
Hearing-impaired individuals require a better signal-to-noise ratio (SNR) than those with normal hearing to understand speech. This is due to the difficulty they face in distinguishing speech from background noise, particularly at higher frequencies which convey speech clarity. Additionally, individual hearing thresholds may vary from standardized audiogram references.
Step-by-step explanation:
The statement 'hearing-impaired individuals do not need better signal-to-noise ratios (SNR) than normal hearing people' is false. Hearing-impaired individuals actually do require a better signal-to-noise ratio (SNR) compared to those with normal hearing to understand speech clearly, especially in noisy environments. For someone with a hearing impairment, background noise can make it much more difficult to distinguish speech, as their ability to hear certain frequencies, particularly the higher ones where much of the clarity of speech resides, is diminished. This is true even if the speech is loud enough, since loudness does not necessarily equate to clarity. Individuals with a hearing loss of 60 phons, for instance, might only hear the lowest frequencies and may find speech indistinct without a significantly better SNR. Moreover, if the speech includes higher frequencies, such as a female voice typically does, understanding conversation can become even more challenging.
In the context provided, hearing tests may show a threshold of hearing at 0 dB for 250 Hz, suggesting a very sensitive hearing at this frequency. However, this value might contrast with figures or standard audiograms indicating a higher dB level for the threshold of hearing at the same frequency, implying an inconsistency between individual hearing tests and standardized reference curves. The reference figures might suggest that no sound under 20 dB at this frequency should be audible, but individual variability in hearing sensitivity can result in some people having thresholds lower or at 0 dB.