Abstract
Persons diagnosed with disorders of consciousness (DOC) typically suffer from motor and cognitive disabilities. Recent research has shown that non-invasive brain-computer interface (BCI) technology could help assess these patients’ cognitive functions and command following abilities. 20 DOC patients participated in the study and performed 10 vibro-tactile P300 BCI sessions over 10 days with 8–12 runs each day. Vibrotactile tactors were placed on the each patient’s left and right wrists and one foot. Patients were instructed, via earbuds, to concentrate and silently count vibrotactile pulses on either their left or right wrist that presented a target stimulus and to ignore the others. Changes of the BCI classification accuracy were investigated over the 10 days. In addition, the Coma Recovery Scale-Revised (CRS-R) score was measured before and after the 10 vibro-tactile P300 sessions. In the first run, 10 patients had a classification accuracy above chance level (>12.5%). In the best run, every patient reached an accuracy ≥60%. The grand average accuracy in the first session for all patients was 40%. In the best session, the grand average accuracy was 88% and the median accuracy across all sessions was 21%. The CRS-R scores compared before and after 10 VT3 sessions for all 20 patients, are showing significant improvement (p = 0.024). Twelve of the twenty patients showed an improvement of 1 to 7 points in the CRS-R score after the VT3 BCI sessions (mean: 2.6). Six patients did not show a change of the CRS-R and two patients showed a decline in the score by 1 point. Every patient achieved at least 60% accuracy at least once, which indicates successful command following. This shows the importance of repeated measures when DOC patients are assessed. The improvement of the CRS-R score after the 10 VT3 sessions is an important issue for future experiments to test the possible therapeutic applications of vibro-tactile and related BCIs with a larger patient group.
Highlights
Results suggest that several sessions with the vibrotactile P300 paradigm and Coma Recovery Scale-Revised (CRS-R) are necessary, due to the high variability within this patient group
Future work should explore the speculative suggestion that BCI training might potentially have a therapeutic impact on Disorders of consciousness (DOC) patients
This would require a larger effort than the current study, with matched controls
Summary
Coma patients show closed eyes and no responsiveness to the environment. Patients in the unresponsive wakefulness state (UWS) present awakening (i.e., eye opening) without motor or verbal responses to command. Minimally conscious state (MCS) patients show inconsistent but reproducible signs of responsiveness, depending on their motor control and cognitive abilities. The fluctuation in responsiveness observed in these patients can make the diagnosis challenging. Neurobehavioral tools used for clinical diagnosis, such as the Glasgow Coma Scale, or the Coma Recovery Scale-Revised (CRS-R) (Giacino et al, 2002; Monti et al, 2010; Risetti et al, 2013; Gibson et al, 2014), are highly dependent on voluntary motor control
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
