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'Speech entrainment' enhances research on aphasia
February 5, 2013
A group of patients with Broca’s aphasia -- a severe communication problem caused by damage to the brain’s left hemisphere and characterized by halting speech – has been shown to speak sentences fluently through a process called “speech entrainment,” developed by researchers at the Arnold School of Public Health.
The study of 13 adults who suffered a stroke and were virtually unable to speak shows for the first time that people with debilitating aphasia, could speak in fluent sentences by watching and hearing another person speak.
The results of the study are published in a recent issue of the journal Brain.
Dr. Julius Fridriksson, an Arnold School researcher who led the study, said, “This is the first time that we have seen people with Broca’s aphasia have been shown to speak in fluent sentences. It is a small study that gives us an understanding of how the brain functions after a stroke, and it offers hope for thousands of people who suffer strokes each year.”
Aphasia occurs in about one-third of people who have a stroke. Their inability to communicate affects personal and professional relationships, but usually has no effect on the person’s intelligence.
“Their intelligence is intact. Unlike someone who stutters, a condition that could be described as a ‘speech limp,’ patients with aphasia have ‘speech paralysis,’ “ said Fridriksson, a professor in the Arnold School’s department of communication sciences and disorders.
“Aphasia has a profound impact on their careers, personal relationships and quality of life. Many of the patients whom we see are relatively young and will spend decades without the ability to communicate and speak fluently,” he said. “It is devastating.”
During the study, patients were trained for six weeks to try and speak by listening through audio treatment. “We saw minimal improvement among most patients,” he said.
Then, all 13 patients completed three separate behavioral tasks that were used to understand the effects of speech entrainment on speech production. During the “speech entrainment–audio visual” portion of the study, participants attempted to mimic a speaker in real-time whose mouth was made visible on the 3.5-inch screen of an iPod 45 Touch and whose speech was heard via headphones, Fridriksson said.
The “speech entrainment–audio only” condition involved real-time mimicking speech presented via headphones with the screen of the iPod being blank.
Ultimately the patients were able to produce a short script about their stroke to tell to other people.
The online version of the article in Brain includes a video of a patient who participated in the study. A former Green Beret and career military officer, the patient suffered a stroke in his 50s and has been unable to speak for about 22 years, except for a couple of phrases. The video shows him speaking with and without audio-visual speech feedback. The patient struggles to produce spontaneous speech but is able to mimic fluent speech using audio-visual feedback.
“We describe this effect as ‘speech entrainment,’ meaning ‘drawing or pulling along,’ “ said Fridriksson.
Neuroimaging results have given Fridriksson and his research team a greater understanding of the mechanism involved in speech entrainment.
“Preliminary results suggest that training with speech entrainment improves speech production in Broca’s aphasia, providing a potential therapeutic method for a disorder that has been shown to be particularly resistant to treatment,” Fridriksson said.
During a talk at the at the 2012 TEDx Columbia, S.C., event, Fridriksson discussed his research on aphasia. A video of that program at http://www.youtube.com/watch?v=Cy6S7aMmUYo highlights a patient utilizing “speech entrainment.”
