LITHUANIAN UNIVERSITY OF HEALTH SCIENCES LUHS LIBRARY REPOSITORY

Odos tyliojo periodo tyrimo reikšmė, nustatant periferinių nervų pažeidimą

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dc.contributor.author Švilpauskė-Laurynienė, Jovita
dc.date.accessioned 2017-08-21T08:22:53Z
dc.date.available 2017-08-21T08:22:53Z
dc.date.issued 2006
dc.identifier.uri http://repository.lsmuni.lt/handle/1/70022
dc.description.abstract Methods for assessing small peripheral nerve fiber function objectively are limited. The cutaneous silent period (CuSP), a transient supression of electromyographic voluntary activity that follows painful stimuli, could serve as an objective functional measure of the A delta fibers. The aim of this study was to evaluate function of small diameter A delta nerve fibers using the CuSP in normals and in patients with both focal (carpal tunnel syndrome - CTS) and generalised (polyneuropathies - PNP) peripheral nerve injuries. The objectives of the study were the following: 1. To determine the CuSP normal values by age, gender, side, height and weight in healthy controls. 2. To study the topography and extension of the CuSP by changing recording and stimulating sites in healthy controls. 3. To evaluate the CuSP in patients with CTS of different severity and to compare these results with those of healthy controls. 4. To estimate the CuSP onset latency and duration in relation with median nerve evoked compound muscle action potential amplitude, distal latency and conduction velocity in patients with CTS. 5. To evaluate the CuSP in patients with PNP of different types and to compare these results with those of healthy controls. 6. To estimate the CuSP onset latency and duration in relation with median nerve evoked compound muscle action potential amplitude, distal latency and conduction velocity in patients with PNP. We investigated the CuSP of the upper and lower limbs of 50 normal subjects. To assess the function of A delta fibers in peripheral nerve disorders, we compared the CuSP of normal subjects to that of 80 patients with carpal tunnel syndrome and 140 patients with PNP. Patients’ hands with CTS were divided into three groups based on electrophysiological data indicative of a myelinic dysfunction in “mild CTS”, of an additional moderate axonal lesion in “moderate CTS”, and of severe axonal lesion in “severe CTS”. Patients with PNP were divided into three groups based on conduction studies indicative of a myelinic dysfunction in “myelinic PNP”, of an axonal lesion in “axonal PNP”, and of mixed lesion in “axono-myelinic PNP”. CuSP latency varied mainly with height and slightly with age. CuSP duration did not differ significantly in relation with age, gender, side, height and weight. CuSP onset latency was shorter in women than in men. CuSP duration was similar in women and men. The latency and duration of CuSP were not statistically different on right and left limbs. The CuSP varied with the site of recording. Onset latency was shorter in proximal than in distal muscles. However, on muscles from which CuSP were difficult to obtain, latency was longer, probably because of the shorter CuSP duration. The CuSP duration decreased from distal to proximal muscles, as shown by the decreased CuSP duration. A CuSP was always recorded from the muscles of a limb when stimuli were applied on any distal sensory nerve of the same limb. The degree of inhibition varied in the upper limb depending on the stimulation site, being more marked when the stimulus was applied to the nerve innervating the muscle recorded. No such variation was found in the lower limb. Several spinal segments are concerned to give rise to the CuSP, at both cervical and lumbar levels. The spinal circuitry mediating the CuSP is mainly unilateral. CuSPs were almost absent when stimuli were applied to the contralateral limb, or when stimuli were to the arm and recording was from the leg, or vice versa. In these conditions, only very strong stimuli allowed to record a slight and short reduction of the EMG activity. In all CTS patients a CuSP was always obtained unless atrophic APB prevented from recording EMG activity. The increase of the CuSP latency, observed in all CTS patient groups when stimulating the median nerve fibers, may relate to conduction slowing, to loss of function of the fastest-conducting fibers within the carpal tunnel, and to a diminished voluntary activity. The duration of the CuSP was prolonged in mild and moderate CTS groups, whereas it was reduced in the severe CTS group, indicating a partial loss of conduction of A delta fibers. In patients with CTS, the CuSP latency and duration did not relate with the median nerve evoked compound muscle action potential amplitude, distal latency and conduction velocity. In most patients with PNP a CuSP could be obtained, unless muscle atrophy prevented its recording. This demonstrates that small A delta fibers are preserved in most PNP, even when the PNP is severe. Neverthless, CuSP could not be recorded from the lower limbs of 31% of PNP patients. In all PNP patient groups, CuSP had a markedly prolonged latency. A reduction of the CuSP duration was observed in the axonal PNP group, whereas the CuSP duration was increased in the myelinic and axono-myelinic PNP groups. In the patients with PNP the CuSP duration did not correlate with the compound muscle action potential amplitude, distal latency, and conduction velocity. In myelinic and axono-myelinic PNPs, the CuSP latency increased with the decrease of the nerve conduction velocity. Our study provides detailed results of CuSP from both upper and lower limbs in normal subjects. These could serve as a base for a standardization of CuSP study protocols required for a wider use of A delta fibers studies. CuSP study allows assessing the small diameter A delta nerve fibers in patients with peripheral nerve disorders. As CuSP recording is a relatively simple electrodiagnostic method, it could be applied in daily practice in electroneuromyography laboratories.
dc.language.iso lit
dc.subject Odos tylusis periodas
dc.subject OTP
dc.subject Cutaneous silent period
dc.title Odos tyliojo periodo tyrimo reikšmė, nustatant periferinių nervų pažeidimą
dc.title.alternative A study of peripheral nerve disorders using the cutaneous silent period
dc.type Disertacijos santrauka


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