Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Acute nerve stretch and the compound motor action potential. | Stecker et al. Journal of Brachial Plexus and Peripheral Nerve Injury 2011 6 4 http content 6 1 4 . JOURNAL OF BRACHIAL PLEXUS AND 11 PERIPHERAL NERVE INJURY RESEARCH ARTICLE Open Access Acute nerve stretch and the compound motor action potential Mark M Stecker Kelly Baylor Jacob Wolfe and Matthew Stevenson Abstract In this paper the acute changes in the compound motor action potential CMAP during mechanical stretch were studied in hamster sciatic nerve and compared to the changes that occur during compression. In response to stretch the nerve physically broke when a mean force of 331 gm N was applied while the CMAP disappeared at an average stretch force of 73 gm N . There were 5 primary measures of the CMAP used to describe the changes during the experiment the normalized peak to peak amplitude the normalized area under the curve AUC the normalized duration the normalized velocity and the normalized velocity corrected for the additional path length the impulses travel when the nerve is stretched. Each of these measures was shown to contain information not available in the others. During stretch the earliest change is a reduction in conduction velocity followed at higher stretch forces by declines in the amplitude of the CMAP. This is associated with the appearance of spontaneous EMG activity. With stretch forces 40 gm N there is evidence of increased excitability since the corrected velocities increase above baseline values. In addition there is a remarkable increase in the peak to peak amplitude of the CMAP after recovery from stretch 40 gm often to 20 above baseline. Multiple means of predicting when a change in the CMAP suggests a significant stretch are discussed and it is clear that a multifactorial approach using both velocity and amplitude parameters is important. In the case of pure compression it is only the amplitude of the CMAP that is critical in predicting which changes in the CMAP are associated with significant .
