Median Nerve Conduction in Healthy Nigerians: Normative Data

Intraoperative somatosensory evoked potential (SEP) monitoring: an updated position statement by the American Society of Neurophysiological Monitoring

Somatosensory evoked potentials (SEPs) are used to assess the functional status of somatosensory pathways during surgical procedures and can help protect patients' neurological integrity intraoperatively. This is a position statement on intraoperative SEP monitoring from the American Society of Neurophysiological Monitoring (ASNM) and updates prior ASNM position statements on SEPs from the years 2005 and 2010. This position statement is endorsed by ASNM and serves as an educational service to the neurophysiological community on the recommended use of SEPs as a neurophysiological monitoring tool. It presents the rationale for SEP utilization and its clinical applications. It also covers the relevant anatomy, technical methodology for setup and signal acquisition, signal interpretation, anesthesia and physiological considerations, and documentation and credentialing requirements to optimize SEP monitoring to aid in protecting the nervous system during surgery.

Reference Standard of Median Nerve Conduction Study in Korea

OBJECTIVE

To establish the reference standard of the median nerve conduction study (NCS) in Korea.

METHODS

A total of 648 median motor and 602 median sensory NCSs from 349 Korean healthy volunteers were tested and analyzed prospectively. Equipment calibration, assessment of intraand inter-rater reliability, and the NCSs per se were conducted according to a predetermined protocol. A reference standard was established from uncertainty components for the following parameters: the onset and peak latencies; the baseline-to-peak and peak-to-peak amplitudes; the area and duration of the negative wave; and the nerve conduction velocity. The effects of sex, age and stimulation intensity were analyzed.

RESULTS

Each measured value of 648 median motor and 602 median sensory nerves were obtained and presented with both mean and expanded uncertainties, as well as mean and standard deviations. The cut-off values with expanded uncertainty were determined for different age and sex groups. After adjusting for anthropometric covariates, all parameters except duration were affected by age, and sex appeared to influence both duration and area. While stimulation intensity significantly affected some parameters including latencies, the effect sizes were negligible.

CONCLUSION

We propose the median NCS reference standard using the largest Korean dataset ever available. The use of the traceable and reliable reference standard is anticipated to promote more accurate and dependable diagnosis and appropriate management of median neuropathies in Korea.

Normative data for ulnar nerve conduction and the influence of gender and height on ulnar nerve conduction velocity in healthy Nigerians

Background

Despite the usefulness of ulnar nerve conduction studies in identifying disorders of ulnar nerves, there is a lack of normative values for the ulnar nerve in Nigerian population.

Objective

The objective of the study was to generate normative values for motor and sensory ulnar nerve conduction studies (NCSs) in Nigerian population and to determine the influence of gender and height on ulnar nerve conduction velocity (NCV).

Materials and Methods

A total of 200 healthy volunteers were selected after clinical evaluation to exclude common causes of ulnar neuropathy. We carried out NCS of ulnar nerves on all the healthy volunteers according to a standardized protocol. The NCS parameters included in the final analysis were amplitude, latency, NCV, and f-wave latency. Ethical approval was obtained for the study.

Results

The mean ulnar nerve sensory velocity was 55.22 ± 5.67 with 2.5 and 97.5 percentile of 46.9 and 70.1, respectively. The mean latency of the ulnar nerve (sensory) was 2.97 ± 0.62 with 2.5 and 97.5 percentile of 2.00 and 4.52, respectively. The mean amplitude of the ulnar nerve (sensory) was 35.56 ± 9.97 with 2.5 and 97.5 percentile of 15.9 and 57.7, respectively). The ulnar NCV was significantly (P = 0.0202) higher in male. Mild inverse correlation (r = 0.2) was found between ulnar NCV and height of the participants (P = 0.0089).

Conclusion

In the Nigerian population, normative values of motor and sensory ulnar nerve conduction parameters are similar to the existing values in the literature. The ulnar NCV appeared to be influenced by height and gender.

Normal reference value of orthodromic and antidromic sensory nerve conduction velocity of median nerve with intact palmaris longus tendon in apparently healthy individuals

OBJECTIVES

The aim of this study was to determine normative electrophysiological reference values of median sensory nerve conduction studies among security guards with the palmaris longus tendon (PLT).

METHODS

Sensory nerve conduction studies of the median nerve using antidromic and orthodromic methods were conducted in the upper limbs of 101 healthy male security guards between the ages of 21 and 42 years. The presence of the PLT was recorded in both hands using a standard test. A scatter plot was used to determine the correlation between different parameters using the ortho and antidromic methods.

RESULTS

The mean age (years), weight (kg), height (cm), and BMI (kg/m2) were 28.77 ± 5.14, 70.53 ± 11.28, 171.71 ± 7.12, and 23.91 ± 3.45, respectively. In the median nerve (sensory) by antidromic method, the mean distal latency (DL) was 2.65 ± 0.33 ms and 2.64 ± 0.37, SNCV (sensory nerve conduction velocity) was 53.45 ± 5.28 m/s and 53.84 ± 5.68 and the amplitude was 27.33 ± 12.38 µV and 29.41 ± 12.97 in the left- and right-hand wrist, respectively. By orthodromic method the DL was 2.54 ± 0.53 ms and 2.51 ± 0.44, SNCV was 55.93 ± 6.09 m/s and 55.93 ± 5.24 and the sensory nerve action potential amplitude was 12.00 ± 8.82 µV and 11.72 ± 6.24 in the left and right hand, respectively. Spearman correlations were used to determine the variables influenced by hand sidedness.

CONCLUSIONS

The normative reference parameters of sensory nerve conduction velocity of the median nerve were established by both methods using a standardized technique.

Electrodiagnostic consultations in Zambia: Referral characteristics and neuromuscular disorders

INTRODUCTION

Research on neuromuscular disorders in sub-Saharan Africa is scarce. We aimed to delineate referral characteristics and the neuromuscular disorders observed among electrodiagnostic (EDX) consultations in a tertiary care setting in Zambia.

METHODS

EDX records were reviewed for all specialist-performed studies after the establishment of the laboratory. The frequency of demographic, medical characteristics, and final EDX impressions are presented.

RESULTS

Among 108 referrals, 52% were male, 84% were adults (mean age 44 years). Referrals were predominantly outpatients (85%) and sent by neurologists (68%). HIV infection was common (12%). Diabetes was rare (3%). Overall, 77% of studies were abnormal. Polyneuropathy was the most common abnormal EDX finding, followed by motor neuron disease.

DISCUSSION

A diverse range of neuromuscular diseases was evaluated among EDX referrals in Zambia. Though labor and expertise intensive, access to EDX consultation can enhance clinical care and facilitate research and surveillance of neuromuscular disorders in the region.

Normative Data for Median Nerve Conduction in Healthy Young Adults from Punjab, India

BACKGROUND

Nerve conduction studies (NCSs) are essential for diagnosing various kinds of focal and diffuse neuropathies. Due to the paucity of local NCS data, electrodiagnostic laboratories in Punjab rely on values from Western and other Indian studies.

AIM

This study was conducted to provide normative data for median nerve conduction parameters (motor and sensory) in Punjabi populace.

MATERIALS AND METHODS

A cross-sectional study was done on 290 participants (150 males and 140 females), aged 17-21 years, as per standardized protocol. The data were analyzed separately for both genders using SPSS version 20. It consisted of distal latencies and conduction velocities of motor and sensory divisions of median nerve. Student's unpaired t-test was used for statistical analysis.

RESULTS

There was no effect of gender on any of the median nerve conduction parameters. Height and weight had nonsignificant negative and positive correlation, respectively (P > 0.05), with conduction velocity in both motor and sensory median nerves. For median motor nerve, the values of distal latency and conduction velocity in males were 2.9 ± 0.16 ms and 60.25 ± 2.99 m/s, respectively, whereas, in females, they were 2.6 ± 0.43 ms and 59.83 ± 2.82 m/s. Similarly, for median sensory nerve, the latency and velocity values in males were 2.8 ± 0.56 ms and 54.81 ± 3.70 m/s, whereas, in females, they were 2.4 ± 0.33 ms and 54.56 ± 3.65 m/s, respectively.

CONCLUSION

The data in this study compared favorably with already existing data. It would help the local electrodiagnostic laboratories in assessing the median nerve abnormalities with greater accuracy in this population subset.