Final answer:
The decline in hearing ability with age, known as presbycusis, is well-documented and affects high frequencies, making it harder to understand speech and appreciate music. Hearing tests often show a characteristic dip near the 4000 Hz frequency. Presbycusis is gradual and can be diagnosed with audiograms, which also differentiate between nerve and middle ear damage. Option b is the correct answer.
Step-by-step explanation:
The statement "It is a myth that hearing ability naturally declines with age" is false. The natural decline in hearing ability with age is a well-documented phenomenon known as presbycusis, or 'elder ear.' This type of hearing loss is characterized by a progressive loss of the ability to hear higher frequencies, often making it difficult to understand speech, particularly the higher-pitched voices of women, and to appreciate music. Audiograms, which graphically display hearing tests over a range of frequencies from 250 Hz to 8000 Hz, commonly illustrate this decline. Specifically, hearing tests may show a dip near the 4000 Hz frequency, which is unrelated to the underlying cause of hearing loss that often affects both ears.
While we do not often utilize our full range of hearing under normal circumstances, this does not mean that hearing does not deteriorate. For most conversational sounds, which fall within the frequency and intensity region that is less affected by age, a loss of up to 40 phons can still enable a person to perceive conversation, albeit more quietly. However, with a more significant loss, such as 60 phons or higher, even normal conversation becomes difficult to comprehend without additional volume, and sounds may become indistinct.
Moreover, while some people may have a hearing threshold of 0 dB at 250 Hz, this number describes sensitivity relative to a standard normal hearing level, rather than an absolute absence of sound. On the audiogram, it is conventional to mark normal hearing as 0 dB across all frequencies, enabling the deviation from normal hearing to be easily identified. The concept of bone conduction tests is also pertinent, as these can help differentiate between nerve damage and middle ear damage as the cause for hearing loss.