Dear Shamil,


Here are my thoughts on this.

You're right to distuinguish total locked in from other locked-in categories. The literature on these definitions is very messy. You should scrutinize papers carefully.

Persons with the total locked-in syndrome (LIS), other than the classical LIS indeed have no residual movement whatsoever. They cannot blink anymore. Although there is practically zero research on sensory processing in *total* LIS, we suspect that they have vision impairment. Firstly, eye saccades may be impaired. Secondly, the patients cannot focus gaze on a screen and eyes roll back and forth invuluntarily. Third, these patients often develop eye diseases which further decrease their sight.

So visual P300-based BCI's are absolutely NOT usefull for *total* locked-in patients. Don't bet on tactile and auditory either. It's probably better to focus on locked-in patients who can still use their eyes and persons with quadraplegia. BCI's in combination with the input modailities these people normally use could add extra control over assistive technology.

Cheers

Femke