According to Health Canada, hearing loss is the most common sensory impairment in adults over the age of 65, affecting more than 30 per cent.

Hearing impairment can lead to a communication breakdown, being that speech is the most important and efficient means by which to communicate.

However, communication problems are not due solely to mechanical problems in the ear that block speech. There are also emotional and perceptual complications that are tied to hearing impairment as people age. Speech intelligibility – the accuracy with which a listener can understand a spoken word or phrase – is also compromised as we age.

PhD candidate Kate Depuis shared her research with Memorial’s psychology department this past Thursday, presenting her findings from the Human Communications Lab within University of Toronto.

In this lab, there is a broad range of research conducted on human communication, using participants of all ages, some with impairments and others without.

Dupuis began studying psychology at Concordia University, and later obtained a master’s from the University of Toronto. She is expecting to complete her PhD in November 2009.

Dupuis’s research focus is on the age-related differences in the interpretation of prosodic factors in speech with emotional content.

“No one has really looked specifically at the lexical content as it relates to emotion. And I thought, there’s a little hole in the research, and that’s where I’ll begin for my dissertation,” Dupuis said.

“Older adults in our lab frequently tell us that although they can hear what’s being said, they have difficulty understanding,” she said.

“This can be related to specific perceptual factors, such as a breakdown in high frequency hearing that occurs unfortunately after the age of 60. It can also have to do with changes in tempo processing,” she said, referring to the timing of how information is collected.

“There are also cognitive factors that begin to deteriorate as we age…as well, speed of processing declines as we age. So, if you can’t keep up with the conversation you can have difficulty when you get to the end of the sentence.”

Often, older adults will require a few repetitions of a sentence before fully understanding. This can create embarrassment and confusion.

As well, Dupuis highlighted that there are different levels of language, such as the linguistic level, which includes the words and sentences (lexical cues). Communication also exists at a paralinguistic level, which includes the nonverbal cues like tone of voice and body language.

The paralinguistic level includes prosodic factors that include rhythm, stress, and intonation of connected speech.

Prosodic factors reflect emotional states, commands, or whether a sentence is a question. Also, they communicate something that the words and grammar sometimes cannot, such as in the case of sarcasm.

“This interplay between the lexical content and affective cues is really what I am interested in,” Dupuis said. “What are the emotional affects of prosodic terms, and how do we interpret them?”

It has also been found that older adults tend to remember positive information, whereas younger adults remember the more negative information. A number of theories have been suggested to explain this.

“The socio-emotional selectivity theory suggests that as we age, we tend to focus more on positive interactions…[also] older people tend to be better at down regulating negative emotions.”

In the first experiment, Dupuis asked questions to determine if the lexical content of an existing speech intelligibility task actually had an effect on speech intelligibility.

“We wanted to see whether valence and arousal ratings would actually influence intelligibility.”

Younger and older participants rated visual and auditory information in terms of the arousal factor of the stimuli.

Dupuis found that older adults rated the stimuli as more positive and arousing than the younger adults. As age increased, ratings of valence increased. As well, as perceived health decreased, valence ratings also increased, supporting the socio-emotional selectivity theory.

In another experiment, Dupuis says that emotional ratings were given by both age groups to see how stimuli were matched to emotions.

“We were looking to see whether there were age-related differences in how well people are able to identify emotions, as this would support previous findings in the literature,” Dupuis said.

After young and old participants listened to a recorded sentence, they were asked to describe how they thought the speaker felt. The findings were that older adults performed more inaccurately.

Dupuis noted, “while people are better at rating angry, sad, and fearful information, older adults are typically worse at judging emotions.”

Future directions of Dupuis’ research will investigate whether intelligibilities differ between emotions. As well, there are implications in memory and attention for acoustically produced emotional speech.

“One of the nice things about this research is that it has relevance to clinical populations. One of the most commonly described communication deficits occurs in seniors with cognitive impairment and their caregivers. They are no longer able to understand the emotion being portrayed in speech,” said Depuis.

This information may be particularly useful in understanding emotional miscommunications experienced by seniors, as well as people suffering from chronic neurodegenerative diseases, such as Alzheimer’s.