Abstract:

Prosody, which is defined as the variance in loudness or volume, changes in tempo or timing, and movement in pitch and intonation, plays an essential role in speech communication. The ability of speech communication, however, changes across the life span. It has been found that while word knowledge and syntactic processing during comprehension are largely preserved with aging, older individuals have deficits processing multiple acoustic cues about the intention and emotion of speakers, which can interfere with their perception of linguistic and affective prosodic cues, resulting in poor speech comprehension.

Older individuals have a diminished ability to decode linguistic prosody. They have difficulty processing pitch contour, word stress, intonation, and speeded utterances. Recent fMRI, ERPs, and EEG studies have demonstrated that younger and older individuals activate different brain regions or neural sensitivity in linguistic prosody perception. Furthermore, aging impairs older adults’ abilities to process affective prosody, particularly for the speech conveying negative emotions. Age has tremendous effects on the automatic encoding of emotional prosody, and there is a general decline in emotion recognition with aging.

Moreover, age-related diseases could have specific pathologic effects on prosody processing. Age-associated progressive deterioration of neuronal and physical functions affects older adults’ abilities to process time-frequency signals, especially for those with Parkinson’s disease, Alzheimer’s disease, and tinnitus. Studies on older individuals with age-related diseases have obtained significant findings regarding the brain regions involved in prosody processing. It has been observed that the superior temporal gyrus in the right hemisphere is predominantly linked to the processing of affective prosodic cues and that damage to the left hemisphere can result in similar deficits.

Overall, current studies have carried out extensive explorations on prosody perception by older individuals, with considerable attention to the effects of different first languages and complex auditory environments. However, we thought that more in-depth studies should be conducted on the following topics. First, further explorations are needed to examine prosody processing in older adults with Mandarin and other dialect backgrounds. Specifically, given that Chinese is a tonal language with many dialects, it is unknown whether differences in tone and dialect can influence older adults’ linguistic and affective prosody perception. Secondly, more studies might be carried out to clarify the effects of complex auditory environments on prosody perception in older individuals. Previous studies have examined the impact of several noise types, which are merely part of the challenging conditions in daily communication. It is important to reveal older individuals’ prosody perception in specific situations of context, such as doctor-patient scenarios and family scenarios that they constantly experience. Thirdly, it is imperative to deepen our understanding of neural mechanisms underlying perceptual performance in complex prosodic tasks. Considering that there has been a multitude of neurological research on older adults with age-related diseases, more attention needs to be paid to the neurological performance of their healthy counterparts. Fourthly, further studies might also focus on prosody processing difficulties associated with age-related diseases, as it is still difficult to determine to what extent impairments of prosody perception in daily communication can predict age-related diseases. Finally, special attention needs to be drawn to the early intervention and the rehabilitation of prosody perception impairments in older individuals. It is still uncertain to what extent older adults, especially those with age-related diseases, can maintain or recover their abilities for prosody perception. A corresponding key issue is how to develop effective training methods for Chinese prosody perception rehabilitation. To sum up, future studies are expected to apply interdisciplinary theories and methodologies to explore prosody perception in older adults, which is of both theoretical and practical significance.

Key words: prosody perception, aging effect, age-related diseases, emotions