Abstract:
Chronic stress can contribute to an increase in disease frequency which can
debilitate the body. Increasingly prevalent in young adults, hearing loss remains endemic
to an aged population. Though effortful listening has been shown to decrease memory
performance, presently it is unclear if the cognitive demand implicit in effortful listening
takes a physiological toll on the body. To understand if and how effortful listening affects
relevant physiological functions, we tracked changes in cardiovascular and endocrine
stress systems. Participants were 12 young adults with normal hearing and 18 older adults
with a range of hearing acuity. Stimuli consisted of recorded six-word lists for free recall
presented in either a silent background or in an effortful condition in which the words
were partially masked by 20-Talker babble. All participants were exposed to both
conditions in randomized order. Heart rate variability and salivary alpha amylase were
monitored. A decrease in high frequency spectrum power during effortful listening as
compared to silent listening was found in young adults, reflecting decreased vagal
activation (p<.01). Higher alpha amylase secretion relative to baseline was found during
effortful listening in both young and older adults, evidencing greater sympathetic nervous
system (SNS) activation (p<.05). Also, a significant interaction between age group and
listening difficulty was found (p<.05). In older adults, poor hearing was associated with
higher alpha amylase levels during difficult listening (p<.05). While decreasing memory
performance, this study shows that effortful listening causes an activation of stress
systems. As auditory difficulties remain common in an aging population, attendant
physiological stress presents negative health outcomes.
