There are many occurrences that might cause a patient to lose his/her ability to communicate (such as accidents that destroys the patient's throat or diseases that make the patients unable to move any of their muscle).
In such scenarios, speech recognition technology is used to communicate with the patient. Example of this technology would be a a device that they use to interpret the brain waves of the patient. They can connect the patient's brain with electrical device and enable the patient to answer yes or no question simply by thinking about it.
They allow both government and outside researchers to obtain estimates of a variety of health related topic or issue among either the entire nation or specific demographic group of the population.