No Difference Between Noxious and Innocuous Thermal Stimulation on Motor Recovery of Upper Extremity in Patients With Acute Stroke: A Randomized Controlled Trial With 6-Month Follow-up

Background: Thermal stimulation (TS) has been developed and incorporated into stroke rehabilitation. However, whether noxious and innocuous TS induce the same effects on motor function recovery after stroke is still unknown. A comparative study of different temperature combination regimens is needed. Objective: To compare the short- and long-term effectiveness between noxious and innocuous TS on motor recovery of upper extremity in patients with acute stroke. Design: Randomized, controlled trial with concealed allocation, intention-to-treat analysis and blinded outcome assessors. Setting: A university hospital rehabilitation department in Taiwan. Participants: A total of 79 patients with acute ischemic stroke were recruited. The majority had moderate to severe motor impairment of the upper extremity (UE). Intervention: In addition to traditional rehabilitation, the experimental group (n = 39) underwent noxious TS (heat pain 46-47°C/cold pain 7-8°C), and the control group (n = 40) received innocuous TS (heat 40-41°C/cold 20-21°C). TS intervention was applied for 30 minutes once per day and for a total of 20-24 times during hospital stay. A custom-made TS instrument, comprising 2 thermal stimulators and their respective thermal pads constructed in a closed-loop system, was used. Outcomes: The Fugl-Meyer upper extremity score (the primary outcome), Action Research Arm Test, Motricity Index, Barthel Index, and modified Ashworth scale (the secondary outcomes) were administered by a blinded assessor at baseline, post–12th TS, post-intervention, 1-month, and 6-month follow-ups. Results: No significant differences between groups were found on the primary outcome at postintervention and follow-up assessments. At 1-month follow-up, the innocuous group showed a small effect (partial η² = 0.02) that was greater than that of the noxious group, but that effect was eliminated at 6 months. Both groups presented significant within-group improvements over time (both P <.001). Conclusions: Combining noxious TS with traditional rehabilitation did not yield better short-term or long-term results than combining innocuous TS with traditional rehabilitation on UE functional recovery for individuals with acute stroke.