Final answer:
During middle adulthood, hearing abilities typically decline due to a natural aging process called presbycusis, which is a type of sensorineural hearing loss affecting high frequencies.
Step-by-step explanation:
The hearing ability typically changes during middle adulthood, and the correct answer to the question of how it changes is b. Hearing abilities decline. This decline in hearing is part of the natural aging process and is often referred to as presbycusis, which is a type of sensorineural hearing loss that becomes more severe at higher frequencies.
With presbycusis, loss of hair cells in the organ of Corti is a common underlying reason. Humans can normally hear frequencies between 20 Hz to 20,000 Hz, but as they reach middle age, their ability to hear higher frequencies diminishes. Hearing tests commonly measure across a range of 250 to 8000 Hz, and normal hearing is characterized by a hearing threshold of 0 dB across these frequencies. Age-related hearing loss may result in difficulty with music appreciation and speech recognition, as well as declines in the ability to hear high-frequency sounds.