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Öğe Correlation of motor nerve conduction velocity and number of innervated muscle fibers(TAYLOR & FRANCIS LTD, 2004) Dalkilic, N; Yuruten, BDistal and proximal motor (M) responses were recorded from the "Abductor Pollicis Brevis" (APB) muscle by using the collision method,median motor nerve was stimulated at distal (elbow) and proximal (wrist) regions in a concurrent manner. The delay between two stimuli (ISI: Inter-stimulus Interval), beginning at 9 ins, was decreased by 0.1 ins steps, until the proximal potential completely disappeared. Areas of M responses recorded for each ISI were calculated. Because the area difference between two subsequent ISIs is proportional to the number of muscle fibers innervated by the conduction velocity group at that interval, the relative numbers of muscle fibers,for each velocity group were calculated. The results show that the motor nerve conduction velocities belonging to the innervating APB muscle vary between 38 tills and 57 m/s; the conduction velocity of the group innervating the greatest number of muscle nerves was,found to be 55-57 m/s, which comprised 10% of all fibers.Öğe Deep peroneal motor nerve conduction velocity distribution and correlation between nerve conduction groups and the number of innervated muscle fibers(TAYLOR & FRANCIS LTD, 2004) Bayramoglu, FG; Dalkilic, N; Kiziltan, E; Demirel, IIn this study, the distribution of peroneal-nerve conduction velocity was studied in 17 normal subjects, using the collision method. Paired supramaximal stimuli with predetermined interstimalus intervals (ISI) were applied at distal and proximal points of peroneal nerve and the resultant compound muscle action potentials (CMAPs) were recorded. The change in CMAP amplitudes and areas with ISI were deduced, and the relative number of fibers corresponding to each conduction velocity group (CVG) were computed. Conduction velocities of the peroneal motor nerve innervating the Extensor Digitorum Brevis (EDB) muscle were found to be in the range of 28-52 m/s and CVG innervating the greatest number appears to be in 40-48 m/s range, which consists of 70% of all fibers. These results show that, compared with the median motor nerve, deep peroneal motor nerve that innervates the EDB muscle consist of slow fibers.Öğe Does the conduction velocity distribution change along the nerve?(ELSEVIER SCI LTD, 2004) Pehlivan, F; Dalkilic, N; Kiziltan, ENerve conduction velocity distribution (CVD) is a very useful tool to examine the state and function of nerves. Only one record of compound action potential (CAP) may be sufficient to determine the CVD if the shape functions of the single fiber action potentials (SFAP) of fibers are known. Otherwise, CAP recordings from different locations are necessary to determine CVD. In this case, we confront the problem of whether the shape of the CVD changes along the nerve, because many methods that attempt to determine the CVD are based on the assumption that the CVD is invariant along the nerve. There is not a complete solution to this problem, but there are many suggestions allied with the recording conditions to minimise this effect. The other effect that may influence both shapes of CAP and CVD along the nerve is the volume conductor effect. If a suitable model could isolate and eliminate the volume conductor effect, then the spatial variation of CVD may be attributed to the natural conditions of the nerve. In this study, we followed a procedure to eliminate volume conductor effect and then applied our previously published model to examine the spatial variations in CVD. The results show that CVDs estimated at discrete points along the nerve trunk have significantly different patterns. Consequently, it may be concluded that CVD is not uniform along an isolated nerve trunk contrary to the assumptions of the most CVD estimation methods. (C) 2004 IPEM. Published by Elsevier Ltd. All rights reserved.Öğe The effect of bupivacaine on compound action potential parameters of sciatic nerve fibers(TAYLOR & FRANCIS LTD, 2004) Dalkilic, N; Bariskaner, H; Dogan, N; Demirel, I; Ilhan, BThe aim of this study was to document the effects of the local anesthetic agent bupivacaine on individual fibers of peripheral nerve. To accomplish this objective, compound action potentials (CAPs) were recorded from isolated frog sciatic nerves treated with bupivacaine for seven individual concentration levels. Numerical and fast Fourier transform (FFT) analysis were performed on these recordings. The areas, latency periods, maximum and minimum derivatives, and power spectrums of the CAPs were computed. The results show that the area and the absolute values of maximum and minimum derivatives decrease linearly as bupivacaine concentration increases. The power spectrum of the CAPs, which resides in the 0-1000 Hz interval, initially shifts to higher frequencies then returns to lower frequency region again with increasing bupivacaine concentration. Due to this result, it is thought that bupivacaine inhibits nerve fibers in a dose-dependent manner. It primarily affects the fibers having the least myelin sheets (motor fibers), then it begins to depress the fast conducting (neurosensorial) fibers as the bupivacaine concentration increases, and finally blocks the unmyelinated C-fibers.
