The primary function of the occupational therapist is evaluation, assessment and treatment of functional performances specific to a patient’s life roles when their roles have been disrupted by physical injury, illness or congenital impairment. This is accomplished by performance of tests and measurements, establishment of treatment goals and therapeutic intervention.The primary function of the occupational therapist is evaluation, assessment and treatment of functional performances specific to a patient’s life roles when their roles have been disrupted by physical injury, illness or congenital impairment. This is accomplished by performance of tests and measurements, establishment of treatment goals and therapeutic intervention.