The Effect On Central Nervous System Of Ankle Active Motions And Electrical Stimulating Common Perneal Nerve

Objectives: Ankles motor functions play an important role in hemiplegic gait, and most hemiplegic patients are left with ankle dorsiflexion disorder and Achilles's tendon contracture after rehabilitation. Purposes of this experiment are: (1) What cortical areas are involved when respectively in processing of ankle active dorsiflexion, ankle active planter flexion and ankle passive dorsiflexion through electrical stimulating common peroneal nerve. (2) Whether it is the difference in cortical areas in processing of ankle active dorsiflexion and planter flexion which results in the difference in rapidity and level of restoration of these two motions. (3)The neuromuscular electrical stimulation(NMES) therapy has effect on hemiplegic patients, which has better synergetic effects if alone with rehabilitation training.What is the cause on brain function anatomy that NMES can help hemiplegic patients restore faster, and whether NMES can partly substitute active exercise.Methods: Six health subjects were studied under three conditions: (1) ankle avtive dorsiflexion; (2) ankle active planter flexion; (3) ankle passivedorsiflexion through electrical stimulating common peroneal nerve. And functional MRI at 1.5 T was performed. Through MRICro software, the results will be transformed into what can be dealed with and statistics analysised by SPM99.(p=0.001)Results: (1) ankle active dorsiflexion. Excited areas: bilaterally in primary motor cortex(M I ) and primary somatosensory cortex(S I ), in which the area on contralateral side is bigger than on ipsilateral side, as well as chief visual cortexes and vermis of cerebellum. Inhibited areas: area 19,area 20 and area 39. (2)Ankle active planter flexion. Excited areas: contralateral secondary motor area(M II ) and striate body, and ipsilateral supplementary motor area(SMA) and limbic system. Inhibited areas: bilaterally in upper middle precentral gyrus and postcentral gyrus, superior parietal lobule, inferior parietal lobule and prefrontal cortex. (3) ankle passive dorsiflexion through electrical stimulating common peroneal nerve. Excited areas: contralateral S I and secondary somatosensory area(S II ), ipsilateral S II and M II , bilateral superior parietal lobule and inferior parietal lobule. Inhibited areas: if p=0.001, no positive findings, if p=0.05, contralateral area was found in which superior parietal lobule and inferior parietal lobule meet(area 7).Conclusion: There are great differences in the brain function images respectively in processing of ankle active dorsiflexion and ankle active planter flexion. The excited or inhibited areas in processing of ankle active planter flexion are more separate and greater in number than in processing of ankle active dorsiflexion and include subcortical structures (striatum), which could be the anatomical reason that ankle active planter flexion can be restored better and faster than dorsiflexion for hemiplegic patients. Ankle passive dorsiflexion through electrical stimulating common peroneal nerve can effect many brain function areas. The cause that NMES can help hemiplegic patients restore faster could be what can stimulating motor program and external sensory feedback in movement loop. But it is different from active motion, from which we can conclude that electrical stimulating the peripheral nerves could not replace the active motions, which have a complement effect for each other in rehabilitation.