RESUMO
OBJECTIVE: The purpose of this study was to invent a new communication device by utilizing the function of anal sphincter muscles that was another residual motor function to the last in amyotrophic lateral sclerosis (ALS) patients. METHOD: We designed a sensor which worked by changing intensity of the contraction and was enable severely paralyzed patients to communicate by means of self-regulation of the anal sphincter contraction. This device made sentences through combination of selected Korean letters deprived from sphincter contractions. RESULTS: This device was composed of three parts. Anal sensor: the head part of the sensor regulated by sphincters was located in the rectum, signal processing module: the raw signal from the sensor was boosted up and set up on the baseline voltage equal to threshold by threshold detector, and device program: the icon mode which was composed of routine questions and requested to their care-givers. And in user-writing mode, patients could choose syllable elements using the sensor operating by sphincter. CONCLUSION: This system was designed for advanced ALS patients with only the available function of sphincter muscles and could give them another new option in selecting communication devices.