Rehabilitation Assistants (RAs), also referred to as occupational therapist assistants (OTAs) and physiotherapist assistants (PTAs) are members of the health care team who work under the supervision of an occupational therapist or a physiotherapist to improve a client's or patient's quality of life. Rehabilitation Assistants (RAs), also referred to as occupational therapist assistants (OTAs) and physiotherapist assistants (PTAs) are members of the health care team who work under the supervision of an occupational therapist or a physiotherapist to improve a client's or patient's quality of life.