Published by Communications and Public Affairs (519) 824-4120, Ext. 56982 or 53338
August 25, 2000
Talking to stroke victims could lead to earlier speech recovery, researchers find
Healthcare workers and loved ones could speed up a stroke victim’s speech recovery by therapy as simple as speaking to them regularly, according to findings by University of Guelph psychology professor Dan Meegan reported in the current issue of Nature (neuroscience) magazine, published this week.
The groundbreaking discovery by Meegan and colleagues at the University of Rochester finds there is a link between how the brain perceives incoming information from the senses and controls the production of bodily movement. They found improvements in motor timing following exposure to auditory stimulation, such as speech. This finding suggests that exposure to speech or other forms of sensory stimulation might lead to speedier and improved motor skill rehabilitation.
“Our study shows that the brain’s ability to perceive time and our ability to control the timing of our bodily movements are closely connected,” says Meegan, “and in fact motor learning can occur without motor training. This means a stroke patient could be practicing motor timing even while they are still unable to move their limbs or muscles. The result might be an accelerated recovery. It’s a major finding for those of us in the cognitive and neural sciences and provides a potential wealth of implications for rehabilitative cases.”
Speech and music are two examples of auditory stimuli with motor rehabilitation potential, because the sounds that are produced are tied temporally to the bodily movements required to produce them.
In addition, in the continuing quest to unlock the mind’s mysteries, the researchers also suggest that this discovery could mean that one part of the brain, the cerebellum, acts as the crucial point where time is both understood and controlled.
Timing control is crucial to even the simplest of human functions. “Even walking requires that our muscles and limbs are exquisitely controlled and timed, otherwise we’d fall flat on our faces,” he says.
In “Motor timing learned without motor training,” Meegan and Rochester colleagues Richard Aslin and Robert Jacobs exposed 12 study participants to auditory stimuli with similar and dissimilar timing characteristics to given motor skills. Measuring the motor skills before and after, Meegan and his colleagues found improvements to the motor skills as a result of the motor timing practice where the timing of the stimuli closely matched the timing required for the motor task. “We believe that this is direct evidence that timing representations are stored in a network within the brain that is shared by both sensory and motor systems,” says Meegan.
“To the loved ones of a stroke victim who has temporarily lost the ability to speak, I encourage them to speak to the patient, as our research suggests that exposure to speech input may hasten their recovery to produce speech output. Similarly, to the pianist with injured hands, I would advise listening to those pieces that you hope to play again, because resulting practice of your motor timing may lead to a quicker physical recovery of your playing skills.”
For years it has been known that the cerebellum, located at the base of the brain, acts as the control point for motor control and where skills are learned to perform movement. Recently, it has been suggested from indirect evidence that it also serves as the point at which motor timing -- and perhaps our sense of timing overall -- also occurs.
This study is the first to show a clear causal link.
“Whatever the anatomical location, our results suggest that the sensory and motor timers are closely interconnected, possibly through some form of network, so that changes to sensory representations directly affect motor skill movements,” says Meegan.
Besides its implications for rehabilitation, the research could also benefit our understanding of how normal speech development occurs, because exposure to the speech of others could aid the neural control of speech before the voice is physically ready to speak.
The research was supported by the U.S. National Institutes of Health and the National Science Foundation.
For more information, contact Prof. Dan Meegan, Department of Psychology, 519-824-4120, Ext. 4998 or Communications and Public Affairs at 519-824-4120, Ext. 3338/6982. The Nature article can be found at www.nature.com/neuro.