Sural nerve conduction: Amplitude and distal latency of sensory nerve action potential

Background: The sensory nerve action potential (SNAP) is an important factor in the electro diagnostic evaluation of a patient with suspected peripheral neuropathy. Sural nerve is the most frequently studied nerve in the electrophysiology. For proper diagnosis sural sensory conduction abnormalities, a reference data are required for each electrophysiology laboratory. Aims and Objectives: The aim of the study was to find out normative reference data of amplitude and distal latency (DL) of sural SNAP for Northern Kerala population. Materials and Methods: The study was designed as cross-sectional and observational study and analysis of values was done using SPSS version 16. A total of 250 healthy subjects of age 15–50 from Northern Kerala participated in the study which included equal number of males and females. Results: Normative reference data for sensory amplitude and DL were derived in the present study. Sensory amplitude was more and DL was found to be less in female population, indicating faster nerve conduction in female. Conclusion: The reference data derived here can be utilized to detect any abnormality sural nerve sensory conduction. The gender effect on sural nerve sensory conduction parameters can be attributed to the height difference, as nerve conduction velocity is inversely proportional to height.

The correlation of distal latency and esophageal motility under esophageal high resolution manometry in gastroesophageal reflux disease / 中华消化内镜杂志

Objective To investigate the relationship between esophageal motility and distal latency (DL) in gastroesophageal reflux disease (GERD) using high resolution manometry (HRM).Methods A total of 51 GERD patients underwent HRM and 24 h-esophageal pH monitoring.According to the HRM topography (characterized as either break peristalsis or normal esophageal movement),all GERD patients were divided into two groups:hypomotility group (n =28) and normal group (n =23).Fourteen non-GERD controls were enrolled.The monitoring results were analyzed.Results The HRM DL of 28 esophageal hypomotility patients(54.9％,28/51) were the longest (7.27 ± 1.44) s.Patients with normal peristalsis also had longer latency (6.70 ± 1.41)s than the non-GERD controls (5.86 ± 0.96)s.All the differences were statistically significant (P ＜ 0.01).DCI of hypotensive peristalsis patients (712.49 ± 703.10) mmHg · s · cm was lower compared with the other groups [(1 285.85 ± 850.83) mmHg · s · cm,(1 109.74 ± 611.70) mmHg · s · cm] (P ＜0.O1).Other indicators such as LES pressure,CFV and IBP showed no significant differences among groups (P ＞ 0.05).Conclusion Esophageal manometry of GERD patients indicates that esophageal hypomotility is accompanied with prolonged DL.Because DL of all GERD sufferers are extended,esophageal dysmotility has great implications for GERD's development.

Comparative Analysis of Electrophysiological Parameters of Median Nerve in Normal and Diabetic Subjects.

Peripheral neuropathy is a common complication in diabetic patients. Nerve conduction study is widely used for the assessment of diabetic polyneuropathy. This study was designed to characterize motor nerve conduction abnormalities in subjects having relatively shorter duration (2.28 ± 1.51 years) of type 2 diabetes mellitus. The median motor nerve conduction study was carried out on 40 male type 2 diabetic patients attending diabetic clinic in the department of medicine and 40 healthy male volunteers who served as control. Motor Distal latency (MDL), Amplitude (Amp) and Conduction Velocity (CV) were measured. On comparing the parameters of median nerves of both the groups, it was found that motor distal latency of (right and left) median nerves was higher in diabetics than in non diabetics with statistically significant difference. Results also showed decreased amplitude and conduction velocities of median nerve of both sides in diabetics (statistically significant). All the parameters were found correlated with blood sugar levels in diabetics.

Establishment of the normative ranges for nerve conduction values of distal compound muscle action potential / 西安交通大学学报(医学版)

Objective To establish the normative ranges for nerve conduction values of distal compound muscle action potential(CMAP) latency and amplitude and to provide evidence for diagnosing peripheral neuropathy.Methods A total of 245 normal volunteers were recruited,and nerve conduction study was carried out on median nerve,ulnar nerve,tibial nerve and peroneal nerve.The distal latency and amplitude were analyzed.The data collected were tabulated and analyzed based on age,sex and weight in the EXCEL and SPSS systems.Results Gender,weight and sidedness had no effects on CMAP distal latency and amplitude.However,age had a significant effect on CMAP amplitude and median nerve distal latency.This age effect was more obvious for people around 40 years old.Distal latency was prolonged and amplitude was decreased with age increasing.Conclusion It is reasonable and clinically practicable to establish the normative ranges of distal CMAP according to two age groups: above and below 40 years old.