Swallowing is a complicated process fulfilled by specific parts of the human body and certain brain activity processes. Fortunately, research has managed to clarify which areas of the brain are responsible for it. In case anything goes wrong during this process, dysphagia, or difficulties with swallowing may occur. This condition negatively affects the quality of life and may lead to serious health problems. The current methods of curing dysphagia rely on restoring the function of that process, as opposed to fixing the central nervous system, hence said methods end up being long-term and almost futile. Said futile results of the methods of curing dysphagia are the reason why further research is required.
In order to further explore the swallowing process, twenty-nine healthy people volunteered to take part in an experiment. It required them to watch a video of swallowing and an image with the Chinese character for that process while simultaneously getting brain scans. The experiment received approval from the Medical Ethics Committee of a local medical college and was completed while following the necessary ethical standards. Before the experiment, the volunteers had to undergo operant training to make sure that the process was comprehended properly.
While the participants were being scanned, they were told to lie down silently and comfortably on an MRI scanner. Then, they watched the session by using a tilted mirror placed above their eyes on the head coil. In total, it took them 14.4 minutes to complete it, while receiving three different sets of tasks of thirty-six seconds, with half of that time including a short break.
The multiple sets of tasks had three different stimuli shown to the participants: a video of a person eating an apple, biting into it, chewing and swallowing, an ordinary image of a desk with the Chinese character for the word “watching” and the same picture with only that word and without the desk. During the eighteen-second breaks, scientists were showing the volunteers a dark image.
When the video was shown, the volunteers were required to pay attention and understand the swallowing movements of the person on the screen. Upon showing the image of the desk with the character for “swallowing” on it, the participants were told to complete the swallowing action slowly and comfortably, as they normally would. After showing the volunteers the image with the character for “watching”, they were told to stay silent and look attentively at the screen.
Each set of tasks was shown repeatedly, with the randomization of the sequence following a list of random numbers generated by a computer. At first, a ten second empty set was permitted in order to eliminate the influence of blood signal saturation and the participants getting used to the MRI. A ten second blank set was similarly incorporated to prevent inaccurate data at the end of the session. The two actions were concluded with a T1 scan to create a structural image by the end of the session. During this scan, volunteers were required to stay awake in a calm position and their eyes closed, staying as still as they could.
The results of the research show that the action observation with the usage of a video of said action stimulates the brain neurons connected to swallowing in healthy people. Action observation can provide a proper cure for dysphagia by healing the damages in the swallowing network. For upcoming examinations of patients, two specific regions of the brain (BA6 and BA21), which were frequently used in the process of the action execution and observation of swallowing, require close attention.