Biomedical subjects

Erhan Kiziltan

Publications and source records attributed to Erhan Kiziltan.

5 recordsLinked to original sources

PubMed2006

A high-precision, low cost system for evaluating finger-tapping tasks.

Finger-tapping test is extensively employed to assess motor asymmetry in brain damaged patients and also to study the relationship between handedness and performance in normal subjects. The aim of this study was to develop a computer based finger-tapping system that could provide quantitative measures of finger-tapping performance. The system is designed to be used in a standard personnel computer without the need of any other hardware. The software is written in Borland Delphi 6.0 for Microsoft Windows 98 and higher operating systems. Beginning with the Pentium processor, it could be possible to access a time-stamp counter. The time-stamp counter is a 64-bit machine specific register that is incremented by every clock cycle, and keeps an accurate count of every cycle that occurs on the processor. By using a computer with 1 GHz processor speed it is possible to reach a high precision time resolution of 1 mus in finger-tapping tests. Our future prospects for the system are to improve it with various tools such as synchronized recording of electromyography, tapping force monitoring, monitoring of finger angle, and the response to different stimulus parameters by adding appropriate hardware and procedure.

Adolescent↗

PubMed2006

Assesment criteria for experimental demyelination induced in frog peripheral nerve.

In ideal conditions the area under compound action potential may be used as an index for the number of activated fibers in a nerve trunk whereas peak amplitude, maximum time derivative, and duration may be used as an indicator for the rate of contribution to compound action potential and the degree of velocity dispersion. In this study, the time domain effect of demyelination on compound action potential has been investigated in experimentally demyelinated frog sciatic nerve. The results were analyzed in order to suggest criteria for demyelination. The results suggest that the changes in peak amplitude and maximum time derivative of compound action potential that is made up by the contribution of the active fibers may be more useful in the assessment of early phase of demyelination. Therefore, it may be concluded that these two parameters, intrinsically, carry augmented information on the velocity dispersion originated from larger-diameter fibers.

Action Potentials↗

PubMed2004

Does the conduction velocity distribution change along the nerve?

Nerve 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.

Action Potentials↗

PubMed2004

Deep peroneal motor nerve conduction velocity distribution and correlation between nerve conduction groups and the number of innervated muscle fibers.

In this study, the distribution of peroneal-nerve conduction velocity was studied in 17 normal subjects, using the collision method. Paired supramaximal stimuli with predetermined interstimulus 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.

Action Potentials↗

PubMed2003

[Does collagenase affect the electrophysiological parameters of nerve trunk?].

Collegenase is widely used in the process of teasing a nerve in order to perform single fiber action potential (SFAP) recordings. In this study, the effects of collagenase on nerve conduction parameters were investigated. To accomplish this, normal compound action potentials (nCAPs) were recorded from isolated frog sciatic nerve at various distances using the suction technique. Then, the same nerve was treated with collagenased Ringer's solution (3.5 mg/ml, Sigma Type XI) for 90 minutes and action potentials (cCAPs) were recorded again. Numerical analysis of these records was performed and the results were compared. Using the nCAP and cCAP recordings, the conduction velocity distributions (CVD) of the individual nerve trunks were determined by a method that we have previously described. Statistical results indicated significant differences (p < 0.05) between the nCAP and cCAP CVD data. From these findings it is concluded that, when used for teasing the nerve fibers, collagenase may affect the nerve trunk conduction parameters. Specifically, a significant amount of decrease has been observed in conduction velocities of myelinated fibers having diameters smaller than 8 microns.

Action Potentials↗