Mean Values Of Latencies Research Articles

COMPARISON OF NERVE CONDUCTION STUDIES ON AFFECTED AND NON-AFFECTED SIDE IN THE PATIENTS OF SCIATICA

Background: Sciatic neuropathy is the one of the most common neuropathies of the lower extremities. Low-back pain (LBP) is a major health problem around the world and a major cause of medical expenses, absenteeism and disability. Although LBP is usually a self-limiting and benign condition that tends to improve spontaneously over time, a large variety of therapeutic interventions is available for treatment. Sciatica can result when the nerve roots in the lower spine are irritated or compressed. The aim of the study was to observe the effect of nerve conduction velocity in sciatica subjects. Method and materials: In this study we involved the participants either sexes; aged >21 years; treatment for LBP; in the acute, sub-acute or chronic phases, with sciatica. Patients were selected on the basis of routine clinical examination and complaint with pain during walking. The selected Patients initially send for Nerve conduction investigation in the department of Physiology. Nerve conduction study was done on RMS EMG EP Mark-II. The sites of stimulation for Sciatic nerves were ankle and at or below popliteal fossa and recording site were motor point of Extensor digitorum brevis and Abductor Hallucis respectively. Reference electrode was placed 4 cm distally over 4th metatarsophalangeal joint. Ground electrode was placed between stimulating and recording electrodes. Recording surface disc electrode was placed below lateral malleolus of ankle for sural nerve. Result: The mean value of latency was 3.152 + 0. 255 in normal side and it was 2.876 + 0.4002 on the affected side which was significantly decreased. Motor nerve conduction Velocity in the normal side was 51.27 + 3.98 and the Motor nerve conduction Velocity of sciatic patient was 47.34 + 5.659 on the affected side decreased significantly. Conclusion: In this study we concluded that, this will be helpful for the early detection of demyelination as well as it may be helpful for the detection of nerve injuries in the patient of sciatica.

Visual evoked potential changes among hypertensive and normotensive individuals: A cross-sectional study

Background: Visual evoked potential (VEP) is a highly advanced visual function measurement test that objectively measures functioning of entire visual pathway is working and results of it will help to diagnose early detection of visual pathway changes in the patients of hypertension (HTN). This property of VEP will be used to diagnose early changes in the visual field in the patient of HTN and use of this to deviate ophthalmic complications of HTN. Aims and Objectives: The objective of this study was to find out changes in the VEP among the primary hypertensive patients and its comparison with normotensive subjects. Materials and Methods: Eighty study participants (n = 40 normotensive and n = 40 hypertensive) were selected for this cross-sectional survey. Pattern reversal VEP test was performed for each participant and measurements (latency and amplitude) were recorded. Differences in latencies in both groups were assessed using unpaired t-test for continuous variables. P < 0.05 was considered to be criteria to prove statistical significance. Results: Mean values of latencies of waves N75 and P100 were found to be prolonged in the hypertensive group. It can be seen from correlation graph, as the value of blood pressure (mm of Hg) increases, latencies of VEP also increase, which is evident from the values of correlation factor (r). Conclusion: Results of the study express statistically significant association between increase in latencies of VEP and HTN. Thus, it could be recommended that VEP can be added as policy intervention among the primary hypertensive patients to detect early visual pathway changes and strategic implementation of the same.

Does transcutaneous nerve stimulation have effect on sympathetic skin response?

ObjectiveThis study examined the effects of transcutaneous electrical nerve stimulation (TENS) on the sympathetic nerve system by sympathetic skin response test. MethodsFifty-five healthy volunteers received either: (i) 30minutes TENS (25 participants) (ii) 30minutes sham TENS (30 participants) and SSR test was performed pre- and post-TENS. The mean values of latency and peak-to-peak amplitude of five consecutive SSRs were calculated. ResultsA significant amplitude difference was found between TENS and sham TENS group both in right and left hand (p=0.04, p=0.01, respectively). However there was no significant latancy difference between two groups (p>0.05 ). ConclusionTENS has an inhibitory effect on elicited SNS responses when compared with sham TENS control group.

Acute and Subchronic Toxicity Study of the Median Septum of Juglans regia in Wistar Rats.

Purpose: Median septum of Juglans regia L. (Juglandaceae) with anti-diabetic effects has been used in Iranian traditional medicine. The present study estimates both oral acute and subchronic toxicities. Methods: In the oral acute toxicity study, female Wistar rats were treated with doses of 10, 100, 1000, 1600, 2900 and 5000 mg/ kg of the Juglans regia septum of methanol extract (JRSME), and were monitored for 14 days. In subchronic study, JRSME was administered by gavage at dose of 1000 mg/kg daily in Wistar rats for 28 days. Antioxidant status and biochemical examinations were fulfilled, and the vital organs were subjected to pathological analyses. Results: The extract did not produce any toxic signs or deaths; the medium lethal dose must be higher than 5000 mg/kg. In subchronic study, No significant morphological and histopathological changes were observed in the studied tissues. There was a significant increase in serum malondialdehyde (MDA) level in treated group compared to control after 4 weeks of JRSME intake. The treatment of rats resulted in a significant reduction of serum urea level (p<0.05), kidney's xanthine dehydrogenase (XDH) activity (p<0.001) and elevation of aldehyde oxidase (AO) activity (p<0.05) in kidney. In the treated group, the mean diameter of glomerulus and proximal urine tube epithelium stature was slightly greater than control group. A significant increase in serum MDA level is subject for further studies. Conclusion: This study showed that the extract has no acute or subacute adverse effects with dose of 1000 mg/kg. The administration of JRSME may improve kidney structure and function and help in treatment of some chronic diseases.

Sympathetic skin response following single and combined sound and electrical stimuli in young healthy subjects

Introduction. Sympathetic skin response (SSR) is applied in evaluation of dysfunctions in autonomic nervous system. Among others, electrical and sound stimuli are most frequently used to evoke SSR. Aim. The aim of this study was to determine if the bell ring stimulus with parameters different from standard sound stimulation evokes similar reactions in autonomic system as electrical stimulus with defined parameters. Material and methods. SSR parameters were recorded following simultaneous sound and electrical stimulation. Twenty young volunteers (aged 23 ± 2.1 years) were examined once with SSR and R‑R interval variation (RRIV) tests in order to confirm lack of functional changes in autonomic nervous system. Results. Values of mean amplitudes of SSR were always higher during recordings from upper limbs than the lower ones irrespective of the three types of applied stimuli. Mean values of latencies were comparable when SSR were induced with acoustic, electrical and both stimuli during recordings performed from upper and lower extremities. Bell ring stimulus influenced only mean values of SSR area recorded both from upper (p ≤ 0.011) and lower (p ≤ 0.023) extremities. Heart beats variability in RRIV recordings changed at 13.5% which is comparable to results obtained by other authors. Conclusions. Results indicate that the application of different modalities stimuli evokes SSR with comparable parameters. Each of them can be used for objective evaluation of the sympathetic nervous system function. Both SSR and RRIV tests evaluating the function of two effector types should be applied for the diagnosis of the probable dysautonomia in patients who show unclear clinical symptoms.

Electrodermal activities and autonomic nervous system in Behçet's patients.

Behçet's disease is often a progressive disorder. In some cases, there is a possibility of subclinical involvement without neurologic signs and symptoms. The autonomic nervous system is affected in Behçt's disease. The aim of the present study was to investigate autonomic nervous system functions in Behçt's patients by analyzing electrodermal activities. A total of 16 patients and 16 healthy volunteers were accepted for the study. Skin potential recordings were taken at room temperature in a quiet place within a Faraday's cage. The mean values of basal skin potentials and skin potential responses in the patients' group were reduced when compared with those of the control group ( p=0.0001). There was no difference between the groups regarding the mean values of latency ( p=0.09). The findings suggest that electrodermal activities may reflect autonomic nervous system dysfunction in Behçet's patients, and the measurement of electrodermal activities may be useful for the assessment of autonomic nervous system involvement in Behçet's disease.

Latency and amplitude variability in serial median nerve SEP recordings

Objectives: Intra-individual variability of SEP parameters was investigated by serial SEP recordings.Methods: Median nerve SEP of 53 normal subjects (mean age 25.5±2.7 years) were evaluated. Recordings were repeated 1 week, 2 weeks, and 6 months after the initial recording.Results: Mean values of latencies from right median nerve stimulation were slightly longer (+0.1 ms) as compared to the left. The intra-individual (within stimulation side) variance did not depend on the time interval between recordings. The total within-stimulation-side variance of latencies was 0.056 ms2 for N20 (C3/4′ vs. Fz), 0.070 ms2 for N13 (C7 vs. Fz), 0.048 ms2 for N10 (Erb's point vs. Fz), 0.111 ms2 for P9 (C3/4′ vs. contralateral forearm), and 0.148 ms2 for P14 (C3/4′ vs. contralateral forearm), and was about 3 times smaller than between-side variability with regard to cortical or spinal potentials. Upper limits for latency differences and lower limits for amplitude ratios in repeated recordings, as well as upper and lower limits for between-side latency differences and amplitude ratios were calculated, using F distributions with worst-case assumptions for degrees of freedom and error probability P=0.05. Upper limits of within-stimulation-side latency differences were 0.55 ms for N20, 0.62 ms for N13, 0.51 ms for N10, 0.78 ms for P9, and 0.90 ms for P14, and corresponding lower limits of amplitude ratios were 0.69, 0.62, 0.66, 0.45, and 0.50, respectively.Conclusions: Our results demonstrate a small systematic, and a larger random difference between right and left side stimulation, one arising from the peripheral, and the other one from the central pathway proximal to the source of N10.

Possible mechanisms of disorders in saccadic eye movements in parkinsonian patients

Electrooculogram recording was used to examine the centrifugal horizontal saccades through an angle of 40° in patients with Parkinson's disease and healthy subjects. The patients demonstrated prolongation of latency and duration, as well as appearance of multiple saccades. The mean values of latency in the right and left saccades were significantly longer in patients than in normal subjects. Although the saccade duration in patients did not differ significantly from that in normal subjects, this parameter tended to increase in value and dispersion. The courses of the vision-controlled saccade disturbances in parkinsonian patients are discussed and hypothesis is forwarded on the disorder mechanisms with particular attention to GABAergic system.

Auditory brain stem responses of premature infants in the neonatal intensive care unit

Auditory brain stem responses were recorded in 114 ears of 63 high risk infants in NICU. The responses were evoked by 4kHz logon in 90dB.The mean values and standard deviations of wave 1 latencies were calculated in every con-ceptional age. The mean values of latencies and conceptional showed a linear relationship, which was roughly indicated by following formula; the latency of 1 wave=conceptional age X (-0.07)+4.13.Delay of wave 1 peak were found in cases of acute otitis media and Treacher Collins syndrome.Absence of wave 1 peak were found in cases of congenital rubella syndrome and kernicterus.The measurement wave 1 latency, which was elicited by intense tone such as used in present study, seemed to be useful to distinguish cochlear deafness from conductive deafness.

The Recordings and Cerebral Properties of Unaveraged Electroretinograms in Routine EEG's

The occurrence of single unaveraged ERG activity in routine EEG's is documented in this report. The ERG activity is focal at Fp1 or Fp2 and often restricted to these electrodes. Mean values of latency and amplitude are 51.5 mSec and 31.8 uv. Significant differences with age, sex and light intensity are shown identical to those of corneally-recorded ERG's.

Statistical Properties of Surface-Recorded Electrocochleographic Responses

If surface-recorded electrocochleographic responses are to be used as the basis of a diagnostic procedure, then the statistical properties of the responses obtained from normally-hearing subjects need to be known so that accurate comparisons with the responses obtained from patients can be made. The data were obtained from 6 normally-hearing subjects who were tested at four stimulus levels, each measurement being replicated twice in each of two test sessions. The distributions of the latency and amplitude values were tested for normality, and the restrictions required by the use of parametric statistical methods are defined. Analyses of variance were carried out to investigate subject, session and subject-session interaction effects. The relationships between response peak parameters, and the overall mean values of latency and amplitude were computed at each stimulus level. From these the joint distributions of latency and amplitude and their relationships were derived. The relationship between response a...