Washington; In order to sing or speak, around one hundred muscles in our chest, neck, jaw, tongue and lips must work together to produce sound, say scientists who used a new super-fast MRI technique to capture the mechanism.
"The fact that we can produce all sorts of sounds and we can sing is just amazing to me," said Aaron Johnson, from the Beckman Institute for Advanced Science and Technology in US.
"Sounds are produced by the vibrations of just two little pieces of tissue," said Johnson.
The sound of the voice is created in the larynx, located in the neck. When we sing or speak, the vocal folds - the two small pieces of tissue - come together and, as air passes over them, they vibrate, which produces sound.
"The neuromuscular system and larynx change and atrophy as we age, and this contributes to a lot of the deficits that we associate with the older voice, such as a weak, strained, or breathy voice," said Johnson.
Thanks to the magnetic resonance imaging (MRI), Johnson could view dynamic images of vocal movement at 100 frames per second - a speed that is far more advanced than any other MRI technique in the world.
"Typically, MRI is able to acquire maybe 10 frames per second or so, but we are able to scan 100 frames per second, without sacrificing the quality of the images," said Brad Sutton, technical director of the Beckman's Biomedical Imaging Centre (BIC).
The dynamic imaging is especially useful in studying how rapidly the tongue is moving, along with other muscles in the head and neck used during speech and singing.
"In order to capture the articulation movements, 100 frames per second is necessary, and that is what makes this technique incredible," Johnson said.
Johnson is investigating whether group singing training with older adults in residential retirement communities will improve the structure of the larynx, giving the adults stronger, more powerful voices.
This research relies on pre- and post-data of laryngeal movement collected with the MRI technique.
The basis for the technique was developed by electrical and computer engineering professor Zhi-Pei Liang's group at the Beckman Institute.
"The technique excels at high spatial and temporal resolution of speech - it's both very detailed and very fast. Often you can have only one of these in MR imaging," said Sutton.
"We have designed a specialised acquisition method that gathers the necessary data for both space and time in two parts and then combines them to achieve high-quality, high-spatial resolution, and high-speed imaging," Sutton said.
The research was published in the journal Magnetic Resonance in Medicine.
