The Selection of the Appropriate Computer Interface Device for Patients With High Cervical Cord Injury
A 49-year-old man injured his cervical cord from a fall 3 months ago. According to the American Spinal Injury Association Impairment Scale (ASIA)-A, he had a neurological level of injury C4, motor level C5/4, and sensory level C4/4. The surviving muscular strength was grade 3 of right-side C5, grade 1 of C6, and grade 2 of left-side C5. Pronation and supination of the right forearm were possible. Spasticity in the left and right upper arms was Modified Ashworth Scale (MAS) 0 and 1, respectively, and as he had been in management before the accident, he needed to use a computer to continue his work.\nFirst, we tried a big-ball mouse, used with the right upper arm, but it did not work well. Seeing that his work required the use of both the computer and conversation, we tried out interface devices that sense the movement of specific body parts on the patient.\nThe patient was able to move the cursor by using the Camera Mouse and webcam with ease. However, while using the MintoClick 1.0 (), a mouse button (), to stop the cursor on the screen when clicking icons, because of vibrations of the tracking point, there were difficulties.\nTo move the left mouse button with pronation movements of the right forearm, we used micro light switch (), but there were problems with accuracy and difficulty of repetitive motions due to narrow part of clicking. For this reason, the micro light switch was modified to make the block on which putting the whole of hands and to push one side or it with the whole of hands (). By making this modification, the functions of click, double clicks and drag were easily performed through pronation movements of the forearm.\nThe cursor movement and clicking function were also implemented by applying Head Z mouse and SmartNav 4AT, but it was the easiest to input information though the Camera Mouse and modified micro light switch. He practised typing short sentences three times with the Camera Mouse, webcam, modified micro light switch, and screen keyboard (), and as a result of the training, a typing speed of 16 wpm for typing with 100% accuracy was reported, which enabled him to control the business remotely.\nFor patients who can move one of their forearms, the Camera Mouse is an appropriate computer interface device, and it can be downloaded for free and can be used with any computer simply by changing the way clicks are made.