下肢偏癱為中風的主要障礙之一。電刺激（ES）根據肌肉收縮的相對應角度給予電刺激稱為功能性電刺激輔助踩車（FES-cycling），其可以幫助患者增強肌肉力輸出。電刺激的角度可以根據死點推估出最適當的範圍。在電刺激的情況下以扭力感測器來代替收取肌肉訊號來測量患者下肢運動的對稱性。近紅外光譜儀（NIRS）為近幾年來所發展之新型腦部造影技術，其最大優點能在動態活動下測量。然而，在之前研究上都注重在上肢復健的大腦皮質活化，FES-cycling下肢復健過程中的大腦活化很少受到研究。因此研究目的希望利用近紅外光譜的血流動力學變化觀察FES-cycling下的大腦活化。在近紅外光譜儀量測踩車實驗，在踩車中使用扭力感測器放置在踏板上來評估下肢踩車對稱性。首先，以14名正常人驗證由五桿連動所計算之理論與由腳踏車兩個力矩值之最低點為實際死點比較。其結果可以發現，此兩種測量死點方法並無顯著差異 (P>0.05)。因此，未來可以用被動踩車來替代五桿連動的方式計算死點。此外，驗證在電刺激情況下，扭力感測器以及腳踏車力矩值來代替肌電訊號。以模擬側癱的方式來探討形狀對稱指數（SSI）和區域對稱性指數（ASI）的對稱程度，其結果顯示有相互關係。因此，利用扭力感測器可以用來評估下個實驗的主動電刺激踩車之踩車對稱性。為了來驗證不同電量下主被動的影響招募五位來自高雄榮民總醫院的中風病人。受測者被要求六種不同踩車條件：不帶電或利用死點優化電刺激角度在帶電之10mA或30mA應用在患側股四頭肌的自主踩車及被動踩車。另外，扭力感測器用來測量下肢對稱的程度。同時，多通道近紅外光譜測量在感覺運動皮質區 (SMC), 運動輔助區 (SMA), 初級運動皮質區 (PMC), 及次級感覺皮質區 (S2) 的大腦區域。我們的研究結果顯示，在被動踩車情況下，10mA比與noES( P<0.05) 及30mA (P<0.05) 會導致較高的大腦活化反應。然而，在主動踩車情況下，在皮質活化中，30mA比10mA (P<0.05) 以及沒電量輔助 (P<0.05) 情況下會導致較差的大腦活化反應。下肢運動的對稱性指數以及腳踏車力矩值都沒有顯著差異。因此我們的研究結論是在高強度的刺激應用未能提供較好的神經復健方式，反而會抑制大腦活化。未來在低強度的刺激應用在偏癱患者之患側被動踩車可以被採納為神經復健方式，以利於中風患者的大腦活化以及能提供更好踩車模式。

Hemiplegia especially on lower extremity is one of the primary disabilities induced by stroke. Functional electrical stimulation assisted cycling (FES-cycling), application of electrical stimulation (ES) during cycling under certain angle corresponding to muscle contraction, can help patients to enhance muscle force output. The timing for ES can be calculated by dead spots. Under the active cycling with ES, electromyography (EMG) is replaced by the load cell to measure the symmetry of lower limbs movement of patients. A novel technology, near infrared spectroscopy (NIRS), was a useful clinical tool for noninvasive measurement of brain oxygenation under body movement. However, previous studies focused on upper limbs of cortical activations, brain activity changes during the effect of FES-cycling using NIRS have seldom been investigated. The aim of study is to investigate the effect of FES cycling on brain activities observed from hemodynamic changes using NIRS. During NIRS measurement of cycling, the cycling performance was observed from symmetry of pedaling force measured from load cells placed on pedal of ergometer. First, the theoretical dead spots, calculated from five-bar linkage, was compared with experimental dead spots obtained from two local minimum of torque during passive cycling observed from fourteen normal subjects. Our results showed that there is no significant difference (p>0.05) between the two methods indicating that the detection of dead spot can be easily replaced by torque measurement from passive cycling. Furthermore, the symmetry of cycling performance was verified from torque obtained from load cells versus that obtained from bilateral electromyogram (EMG). By using the torque measurement for symmetrical cycling can facilitate our next experiment of measuring the symmetry index during active cycling with ES. To investigate the effect of different intensities of ES during passive and active cycling, 5 stroke survivors were recruited from Kaohsiung Veterans General Hospital. Subjects were asked to pedal in six conditions: volitional and passive cycling without or with ES of 10 mA or 30 mA applied on quadriceps of affected side. The shape symmetry index (SSI) and area symmetry index (ASI) were used to quantify the level of symmetry obtained from load cells. Multichannel NIRS measurements were applied on brain region of sensorimotor cortex (SMC), supplementary motor area (SMA), primary motor cortex (PMC), and secondary sensory cortex (S2). Our results showed that passive cycling under ES of 10 mA could lead to higher cortical activation compared to those without ES and stimulation at 30 mA during passive cycling (p<0.05). However, the active cycling with 30 mA of ES reduced cortical activation compared with active cycling with 10 mA and without ES (p<0.05). The lower limbs movement showed no significant difference among three intensities. Our study concludes that active cycling with high intensity stimulation in affected side of hemiplegic subject could not provide better facilitation to brain activity, but low intensity under passive cycling in affected side could provide better facilitation which could be adopted as future neuro-rehabilitation protocol for stroke subject.

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