Comparing the Accuracy of a P300 Speller for People with Major Physical Disability

摘要

A Brain-Computer Interface (BCI) can provide an additional option for a person to express himself/herself if he/she suffers a disorder like amyo-trophic lateral sclerosis (ALS), brainstem stroke, brain or spinal cord injury or other diseases affecting the motor pathway. For a P300 based BCI a matrix of randomly flashing characters is presented to the participant. To spell a character the person has to attend to it and to count how many times the character flashes. The aim of this study was to compare performance achieved by subjects suffering major motor impairments with that of healthy subjects. The overall accuracy of the persons with motor impairments reached 70.1% in comparison to 91% obtained for the group of healthy subjects. When looking at single subjects, one interesting example shows that under certain circumstances, when the patient finds difficult to concentrate on one character for a long period of time, reduce the number of flashes can increase the accuracy. Furthermore, the influence of several tuning parameters is discussed as it shows that for some participant's adaptations for achieving valuable spelling results are required. Finally, exclusion criteria for people who are not able to use the device are defined.