Speech sounds different depending on what your left and right hand is doing, a study shows. The finding could help stroke patients be better communicators and improve speech recognition in children with dyslexia. Researchers at Georgetown University in New Orleans linked motor skills and perception by showing how the left and right hemispheres of the brain ‘hear.’ Neuroscientist Dr Peter Turkeltaub said: ‘Language is processed mainly in the left hemisphere and some have suggested this is because the left hemisphere specialises in analysing very rapidly changing sounds.’ His team hid quickly and slowly changing sounds in background noise and asked 24 volunteers to simply indicate whether they heard the sounds by pressing a button.
Dr Turkeltaub said: ‘Each subject was told to use his or her right hand to respond during the first 20 sounds, then the left hand for the next 20 seconds, then right, then left, and so on.’
When a subject was using their right hand they heard the rapidly changing sounds more often than when they used their left hand – and vice versa for the slowly changing sounds.
‘Since the left hemisphere controls the right hand and vice versa these results demonstrate the two hemispheres specialise in different kinds of sounds,’ Said Dr Turkeltaub.
‘The left hemisphere likes rapidly changing sounds, such as consonants, and the right hemisphere likes slowly changing sounds, such as syllables or intonation.’
The researchers said if you’re waving an American flag while listening to one of the presidential candidates the speech will actually sound slightly different depending on which hand it is in.
Dr Turkeltaub said: ‘If we can understand the basic brain organisation for audition this might ultimately lead to new treatments for people who have speech recognition problems due to stroke or other brain injury.’
The study was presented at Neuroscience 2012 in New Orleans, the annual meeting of the Society for Neuroscience.