Long lasting Improvement

Patients from an early clinical study were recalled up to three years later, and it was found that patients who received robotic therapy sustained their improvement over those who did not. Moreover, subsequent follow-up studies re-examining these patients also confirmed the finding. [2] [3]

Improvement occurs even several years post onset or injury

Patients who had suffered a single unilateral stroke one to five years earlier, and who were demonstrated to be in a “stable phase,” showed significant improvement after receiving robotic therapy three times a week for six weeks.
These findings also suggest that such patients have a potential for further recovery, which conventional therapy has been unable to tap into. [4] [5] [6]

Recommended by the American Heart Association
In a 2010 Scientific Statement, the AHA recommended varied repetitive task practice, such as robot-assisted therapy, for upper extremity impairments in stroke patients.  The AHA assigned the highest classification of recommendations and level of evidence, Level A, Class I, for care in the outpatient and chronic care settings, and the next highest level for care, Class IIA,  in the inpatient setting.  [7]

Recommended by the Veterans Affairs/ Department of Defense
In a 2010 Guideline Summary, the Department of Veterans Affairs and The Department of Defense “recommend robot-assisted movement therapy as an adjunct to conventional therapy in patients with deficits in arm function to improve motor skill at the joints trained.”  The strength of the recommendation is a level B, which states that “…fair evidence was found that the intervention improves health outcomes…” [8]

References:

[1] (Volpe, B.T., Krebs, H.I., Hogan, N., Edelstein, O.L., Diels, C. and Aisen, M., A novel approach to stroke rehabilitation:robot-aided sensorimotor stimulation, Neurology, 54 (2000) 1938-44.)
[2](Volpe, B.T., Krebs, H.I., Hogan, N., Edelsteinn, L., Diels, C.M. and Aisen, M.L., Robot training enhanced motor outcome in patients with stroke maintained over 3 years, Neurology, 53 (1999) 1874-6.)
[3](Volpe, B.T., Krebs, H.I., Hogan, N.; "Is robot-aided sensorimotor training in stroke rehabilitation a realistic option?", Current Opinion in Neurology, Lippincott Williams & Wilkins, 14:745-752, 2001)
[4] (Fasoli, S.D., Krebs, H.I., Stein, J., Frontera, W.R. and Hogan, N., Effects of Robotic Therapy on Motor Impairment and Recovery in Chronic Stroke, Archives of Physical Medicine and Rehabilitation ; 84(2003)477-82.)
[5](Fasoli, S.E., Krebs, H.I., Stein, J., Frontera, W.R., Hughes, R., and Hogan, N., “Robotic Therapy for Chronic Motor Impairments after Stroke: Follow-Up Results,” Archives of Physical Medicine and Rehabilitation; 85:1106-1111, 2004.)
[6](Ferraro, M., Palazzolo, J.J., Krol, J., Krebs, H.I., Hogan, N., Volpe, B.T., “Robot Aided Sensorimotor Arm Training Improves Outcome in Patients with Chronic Stroke,” Neurology, 61:1604-1607, 2003.)
[7] Miller EL, et al., on behalf of the American Heart Association Council on Cardiovascular Nursing and the Stroke Council, “Comprehensive Overview of Nursing and Interdisciplinary Rehabilitation Care of the Stroke Patient: A Scientific Statement From the American Heart Association,” Stroke, 41:2402-2448, 2010.
[8] Dept. of Veterans Affairs and Dept. of Defense, Management of Stroke Rehabilitation Working Group.  VA/DoD Clinical Practice Guideline for the Management of Stroke Rehabilitation, Guideline Summary. Washington, D.C.: Government Printing Office, October 2010. Vers. 2.0, p. 37  URL:  http://www.healthquality.va.gov.