Language challenges can mask decision-making skills in people with aphasia: U of A researchers

Aphasia is the loss of ability to understand or express speech as a result of brain damage, which can happen after a stroke.

U of A researchers have found that people with aphasia perform similarly to those without aphasia in nonlinguistic decision making tasks, but show deficits when decisions involve language. 

“Speech-language pathologists have always assumed that people with aphasia can actually make their own decisions,” explained Esther Kim, a professor in the Department of Communication Sciences and Disorders, Faculty of Rehabilitation Medicine. “They just have trouble communicating them.” 

Aphasia is the loss of ability to understand or express speech as a result of brain damage, which can happen after a stroke. 

Kim explained that people who experience a stroke or brain injury may undergo a capacity assessment to see if they are capable of making their own decisions. This can be difficult for some patients because the assessments require verbal communication. If patients have trouble verbalizing speech, it could affect whether they are deemed capable of making their own decisions. 

Because of this, speech-language pathologists and aphasia advocates have been looking at how to make capacity assessment protocols more accessible and provide better communication support for people with aphasia. 

“We’ve always thought that if you take away the language component, then decision making would be the same between someone with aphasia and someone who doesn’t have a brain injury,” said Kim. “We decided we needed to look at that a little more systematically.” 

In this study, researchers compared decision making between people with aphasia and control participants on both linguistic and nonlinguistic tasks. In one task, participants listened to a recording of elderly parents speaking with their son before choosing a gift to give to the couple. Both participant groups made accurate gift choices based on the information they had heard in the recording. However, people with aphasia scored lower on the second part of the task that required them to explain the rationale behind their choices, demonstrating a deficit in their ability to communicate their decisions.

In two additional nonlinguistic tasks, the scores of the people with aphasia did not differ from those of the people without aphasia. 

“On a base level, the study’s results provide some empirical evidence for what clinicians already assumed, which is that people with aphasia can make their own decisions,” said Kim. “Decision making is intact as long as there are not a lot of language requirements.”

Kim explained that the goal of her research is to increase participation and communication accessibility for people with aphasia. Communication accessibility can be improved with visual supports such as writing down keywords, using picture supports, simplifying speech and emphasizing body language like nodding or hand gestures. These visual components of communication can help people with aphasia better participate in conversation. 

“I think one good thing about the way we’re communicating these days over Zoom is that you can see peoples’ faces and you can see those non-verbals,” explained Kim. “People can also show others objects, which you can’t do over the phone when you only have the auditory signal.”

Although the study found no statistical differences between the people with aphasia and the controls on the nonlinguistic tasks, Kim explained that there appeared to be some variation in cognitive abilities between the two groups, which should be explored in future studies. 

“We need these lab-based, empirical studies to provide the data to show that people with aphasia can actually make these decisions,” she said. “This research also demonstrates the importance of supporting people with aphasia so they can participate in their everyday environments.”