Assessment of cognitive function and communication ability in a completely locked-in patient

Abstract

The term “locked in” refers to a paralysis of voluntary muscular functions1 as a consequence of disease that leads to de-efferentation of the motor system. Although blinking and vertical eye movements are sometimes preserved, many patients such as those with advanced ALS may lose all voluntary muscular function. We report a 58-year-old patient who had ALS for 8 years, who was artificially fed and respirated and had lost all motor control 8 months before the assessment. Both peripheral (electromyogram, heart rate, electro-oculogram [EOG], skin conductance level [SCL]) and central (EEG) functions were tested to determine if there might be a possibility to use other means than the striate muscular system for communication purposes. Moreover, it was not clear to what extent the patient was still cognitively intact and might be able to learn to communicate via an EEG-based brain-computer interface (BCI).2–4 Indications about cognitive awareness can be derived from psychophysiologic event-related paradigms using the EEG5,6 or other measures. We found that the patient was unable to use any muscle, not even the anal sphincter …