The new super-fast magnetic resonance imaging (MRI) technique developed by scientists at the Beckman Institute for Advanced Science and Technology at University of Illinois, Urbana-Champaign, revealed that around 100 different muscles in chest, neck, jaw, tongue and lips must work together to produce sound. Scientists analyzed 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 image quality," said Brad Sutton, technical director of the Beckman's Biomedical Imaging Center (BIC).
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 new MRI technique excels at high spatial and temporal resolution of speech, it is both very detailed and very fast.
"We have designed a specialized 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 informed.
To combine the dynamic imaging with the audio, the researchers use a noise-cancelling fiber-optic microphone to pull out the voice and then align the audio track with the imaging.
"The fact that we can produce all sorts of sounds and we can sing is just amazing to me," added Aaron Johnson, assistant professor in speech and hearing science.
The neuromuscular system and larynx change and atrophy as we age. This contributes to a lot of the deficits that we associate with the older voice such as a weak, strained or breathy voice.
"I am interested in understanding how these changes occur and if interventions like vocal training can reverse these effects," Johnson pointed out.
The new imaging is 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," the authors noted.
The paper was published in the journal Magnetic Resonance in Medicine.