Researchers from Georgetown University Medical Center have discovered a correlation between motor skills and perception. This new study may be able to help doctors understand how the left and right hemispheres "hear."
"Language is processed mainly in the left hemisphere, and some have suggested that this is because the left hemisphere specializes in analyzing very rapidly changing sounds," says the study's senior investigator, Peter E. Turkeltaub, MD, PhD, a neurologist in the Center for Brain Plasticity and Recovery. This newly created center is a joint program of Georgetown University and MedStar National Rehabilitation Network.
The study consisted of 24 volunteers. Researchers hid rapidly and slowly changing sounds in background noise. Participants were then instructed to signal whether or not they heard the sounds by pressing a button.
"We asked the subjects to respond to sounds hidden in background noise," Turkeltaub explained. "Each subject was told to use their right hand to respond during the first 20 sounds, then their left hand for the next 20 second, then right, then left, and so on."
Turkeltaub observed when a subject was using their right hand; they heard the rapidly changing sounds. With the slowly changing sounds, researchers observed participants were more likely to use their left hand.
"Since the left hemisphere controls the right hand and vice versa, these results demonstrate that the two hemispheres specialize in different kinds of sounds-the left hemisphere likes rapidly changing sounds, such as consonants, and the right hemisphere likes slowly changing sounds, such as syllables or intonation," Turkeltaub explains. "These results also demonstrate the interaction between motor systems and perception. It's really pretty amazing. Imagine you're waving an American flag while listening to one of the presidential candidates. The speech will actually sound slightly different to you depending on whether the flag is in your left hand or your right hand."
Turkeltaub and his team hopes to eventually use these strategies as a way to help stroke patients recover their language abilities, as well as enhance the speech recognition in children who suffer from dyslexia.
The study was presented at the annual meeting of the Society for Neuroscience.