背景與目的：先前研究已驗證疼痛溫度刺激可以促進中風病患大腦皮質興奮性，進而改善患側肢體動作功能，但較少研究探討疼痛溫度刺激對於周邊脊髓神經迴路之影響。本研究目的為比較疼痛熱、疼痛冷及疼痛冷熱交替刺激中風患者之患側下肢對於脊髓神經迴路興奮性與交互抑制的立即效應。方法：徵召12位中風病患，每位參與研究個案在一週內不同三天依隨機順序選擇給予患側下肢30分鐘疼痛冷（2～3°C）、疼痛熱（46～47°C）或疼痛冷熱交替溫度刺激介入，並在三種不同形式溫度刺激前及刺激結束後，進行比目魚肌及脛前肌的脊髓神經迴路興奮性評估。使用周邊神經電刺激搭配生物肌電測量儀記錄比目魚肌最大H反射與M波之比值以評估神經脊髓興奮性；同時記錄電刺激間隔2毫秒、3毫秒、20毫秒、30毫秒之交互抑制百分比以評估神經脊髓抑制性。結果：接受疼痛熱刺激於最大H反射與最大M波之比值改變量，相較於疼痛冷熱交替刺激顯著下降（F_(（2,22）)=5.47, p=0.01）；接受疼痛熱刺激後，間隔30毫秒之交互抑制百分比顯著增加（p=0.02）；接受疼痛冷刺激後，最大H反射與最大M波之比值顯著增加（p=0.04）及間隔3毫秒之交互抑制百分比顯著下降（p=0.04）。結論：中風患者接受30分鐘疼痛熱刺激相較於疼痛冷熱交替刺激，能有效降低比目魚肌運動神經興奮性之立即效應；接受30分鐘疼痛冷溫度刺激能有效增加比目魚肌脊髓神經抑制性之立即效應。初步結果可以提供臨床中風患者選擇不同冷熱物理因子調控下肢脊髓神經迴路興奮性或交互抑制之參考依據。

Background and Purpose: Previous studies have verified that noxious thermal stimulation (TS) can promote the excitability of the cerebral cortex in stroke patients, thereby improving the motor function of the affected limb. However, the investigation on the modulation of noxious TS on spinal circuit is insufficient. The purpose of this study was to compare the immediate effects of different forms of noxious TS on the spinal circuit excitability and reciprocal inhibition of the lower limbs in stroke patients. Method: Twelve stroke patients were recruited. Each subject received 30-minute noxious cold (2 ~ 3 °C), noxious heat (46 ~ 47 °C) or alternate noxious cold-and-heat stimulation on the affected lower limbs in three different days within a week in a random order. The neuromuscular properties of the soleus and tibialis anterior were evaluated before and after receiving every form of the noxious TS. The spinal circuit excitability of the soleus was assessed by peripheral electrical stimulation to measure maximum H reflex/maximum M wave (Hmax/Mmax) ratio. At the same time, the percentages of reciprocal inhibition at the electrical stimulation interval of 2, 3, 20, and 30 ms were recorded to evaluate the spinal circuit inhibition. Results: The change of the Hmax/Mmax ratio for the noxious heat stimulation was significantly decreased than for the noxious alternate cold-and-heat stimulation (F_((2,22)) = 5.47, p = 0.01). The percentage of reciprocal inhibition at an interval of 30 ms was increased significantly after receiving the noxious heat stimulation (p = 0.02). The Hmax/Mmax ratio was significantly increased (p = 0.04) and the percentage of reciprocal inhibition at an interval of 3 ms decreased significantly (p = 0.04) after receiving the noxious cold stimulation. Conclusion: Compared with the noxious alternate cold-and-heat stimulation, 30-minute noxious heat stimulation is effective to reduce the excitability of the soleus alpha motor neurons in stroke patients immediately. Receiving 30-minute noxious cold stimulation also effectively increases the spinal circuit inhibition of the soleus muscle immediately. The preliminary findings may provide a reference basis to choose different cold and heat physical agents for stroke patients to regulate the spinal circuit excitability and reciprocal inhibition of the affected lower limbs.