Who May Benefit From Armeo Power Treatment? A Neurophysiological Approach to Predict Neurorehabilitation Outcomes

Background: The Armeo Power, a rehabilitation exoskeleton that allows early treatment of motor disabilities, provides intelligent arm support in a large 3-dimensional work space, thus enabling patients to perform intensive, repetitive, and goal-oriented exercises. This device could efficiently induce new connections and facilitate plasticity phenomena potentiation. Knowledge of the potential brain plasticity reservoir after brain damage constitutes a prerequisite for an optimal rehabilitation strategy. Objective: To identify potential neurophysiologic markers predicting the responsiveness of stroke patients to upper limb robotic treatment. Design: Prospective cohort study. Setting: Behavioral and Robotic Neurorehabilitation Laboratory of IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy. Patients: We enrolled 35 patients who had sustained a first-ever ischemic supratentorial stroke at least 2 months before enrollment and had unilateral hemiplegia. Methods: All patients underwent 40 Armeo Power training sessions that lasted 1 hour each (ie, 5 times a week for 8 weeks). Main Outcome Measurements: We assessed the spasticity and motor function of the upper limb by means of the Modified Ashworth scale and Fugl-Meyer assessment, respectively. Moreover, we evaluated the cortical excitability and plasticity potential of the bilateral primary motor areas in response to the repetitive paired associative stimulation paradigm using transcranial magnetic stimulation and Armeo Power kinematic parameters. Results: The patients who showed significant repetitive paired associative stimulation aftereffects at baseline exhibited an evident increase of cortical plasticity in the affected hemisphere (motor evoked potential amplitude increase, P = .03), a decrease of interhemispheric inhibition (affected hemisphere cortical silent period duration decrease, P = .01; unaffected hemisphere cortical silent period duration increase, P = .004; repetitive paired associative stimulation aftereffect increase, P = .008). Such findings were paralleled by clinical improvements (Fugl-Meyer, P = .04) and Armeo Power kinematic improvements (elbow flexion/extension, P = .02; shoulder range of movement, P = .002). Conclusions: Our data suggest that use of Armeo Power may improve upper limb motor function recovery as predicted by reshaping of cortical and transcallosal plasticity, according to the baseline cortical excitability. Level of Evidence: IV