Make this paragraph clearer:
In addition, PVS patients often open their eyes in response to feeding, which has to be done by others ; they are capable of swallowing,. Patients in a coma subsist with patients' eyes closed.
In addition, PVS patients often open their eyes in response to feeding, which has to be done by others ; they are capable of swallowing, whereas patients in a coma subsist with their eyes closed.