|Year : 2022 | Volume
| Issue : 1 | Page : 40-43
Normative value of sensory nerve action potential of median and ulnar nerves: A cross-sectional study among healthy adults
Sunil Kumar Jena1, Manoranjan Acharya2
1 Department of Physiology, Veer Surendra Sai Institute of Medical Sciences and Research, Burla, Odisha, India
2 Department of Neurology, Veer Surendra Sai Institute of Medical Sciences and Research, Burla, Odisha, India
|Date of Submission||27-Feb-2022|
|Date of Acceptance||28-Jun-2022|
|Date of Web Publication||02-Sep-2022|
Dr. Manoranjan Acharya
Department of Neurology, Veer Surendra Sai Institute of Medical Sciences and Research, Burla - 768 017, Odisha
Source of Support: None, Conflict of Interest: None
Background: Demographic factors such as age, height, weight, and body mass index are important to affect nerve conduction study. Hence, each neurology laboratory should establish its own normative reference data to evaluate the functional status of peripheral nerves. The aim of this study was to establish the normative value of sensory nerve action potential (SNAP) parameters of median and ulnar nerves. Materials and Methods: This study included 92 healthy adults (52 males and 40 females) between the age group of 20 and 60 years. They were classified into three groups A, B, and C. Body mass index was matched for the selection of study participants. SNAP was recorded as per the standard protocol and room temperature was maintained as per the standard guidelines. Onset latency (OL), amplitude (Amp), and conduction velocity (CV) were recorded for data analysis. One-way ANOVA and post hoc analysis were used for statistical analysis. P < 0.05 was considered to be statistically significant. Results: OL in the older age group was prolonged than younger both in the median and ulnar nerves. CV and Amp were less in the older age group than younger both in the median and ulnar nerves. The increasing tendency of OL was observed after 35 years of age. The decreasing tendency of Amp and CV was observed after 50 years of age. Conclusion: SNAP parameters vary according to demographic region. Hence, each laboratory should establish its own normative data to evaluate the functional status of peripheral nerves.
Keywords: Amplitude, conduction velocity, median nerve, onset latency, sensory nerve action potential, ulnar nerve
|How to cite this article:|
Jena SK, Acharya M. Normative value of sensory nerve action potential of median and ulnar nerves: A cross-sectional study among healthy adults. Muller J Med Sci Res 2022;13:40-3
|How to cite this URL:|
Jena SK, Acharya M. Normative value of sensory nerve action potential of median and ulnar nerves: A cross-sectional study among healthy adults. Muller J Med Sci Res [serial online] 2022 [cited 2022 Oct 6];13:40-3. Available from: https://www.mjmsr.net/text.asp?2022/13/1/40/355290
| Introduction|| |
Peripheral nerves behave as electric wires to carry nerve impulses from the peripheral part of the body to the higher center of the nervous system. A threshold strength of stimulus when apply to the peripheral nerve generates impulse. Nerve conduction study is an important investigation methodology to evaluate the functional status of peripheral nerves. It has both diagnostic and prognostic value for clinicians. Median and ulnar nerves of the upper limb are mixed nerves responsible for the movement of limbs and cutaneous sensation. Several factors such as age, gender, height, body mass index, and temperature may influence nerve conduction study. Therefore, these factors are to be considered while doing a nerve conduction study to get an unbiased result. These factors vary according to demographic region.,,, Hence, every laboratory should have its own normative data of different parameters of sensory nerve action potential (SNAP) for diagnosis and prognosis of peripheral nerve diseases. The primary objective of this study was to generate normative data of different parameters of SNAP of median and ulnar nerves to evaluate their functional status.
| Materials and Methods|| |
The present study was done among 92 healthy young adults which included 52 males and 40 females. This study was done in an institute in Odisha which is a part of eastern India. It was worked in the neurology laboratory in collaboration with the department of physiology. The present study was a cross-sectional study among healthy adults between the age of 20 and 60 years and completed between September 2020 and August 2021. The study was approved by the institutional ethical committee of the institute study conducted. The study participants were explained thoroughly about the study protocol and its output. Each participant signed the written consent form before being recruited into the study. The study participants were selected from the patient attendants attending the neurology outpatient department and from the public of the locality by a simple random sampling method. Investigators did face-to-face interviews and general examinations for the selection of study participants. Healthy persons without any history of neurological disease and without a history of any chronic disease were selected for the study. Persons who were smokers, alcoholics, history of chronic disease, and neurological disease were excluded from the study. During the selection, body mass index was matched and all participants were of normal body mass index. They were classified into groups A, B, and C according to their age. Group A (20–35 years), Group B (36–50) years), and Group C (>50 years) included 36, 36, and 20 study participants, respectively [Figure 1].
|Figure 1: Classification of study participants into groups on the basis of age|
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Principles of sensory nerve action potential recording
SNAP recording was done by a trained technician under the supervision of investigators. Study participants were explained the technique of recording. As a general principle, the room temperature of the laboratory was maintained at a temperature between 21°C and 23°C. During recording, if it was found the skin temperature was below 34°C then the skin temperature of the limbs was increased by immersion in warm water. Recording of nerve conduction was done by RECORDERS and MEDICARE SYSTEMS (P) LTD, Haryana, India by RMS software. Stimulation system and recording system of the machine were checked thoroughly before recording. The filter setting was 10–20 kHz, sweep speed 1–2 ms/division, and gain 1–5 μV/division. The parameters of SNAP were onset latency (OL), amplitude, and conduction velocity (CV). Median sensory conduction was recorded by antidromic stimulation. The recording ring electrode was placed at the interphalangeal joint of the index finger and stimulation was applied at the wrist. Ulnar sensory conduction was recorded by antidromic stimulation. The recording ring electrode was placed at the interphalangeal joint of the little finger and stimulation was applied at the wrist.
IBM SPSS 20 version (IBM Corporation, Armonk, New York, USA) software was used for the analysis of data. OL, amplitude, and CV of SNAP of median and ulnar nerves were analyzed between groups A, B, and C, respectively. Statistical test one-way ANOVA was used for this study. P < 0.05 was considered to be statistically significant.
| Results|| |
In this study, we did not find any significant difference between the right and left side nerves of the upper limbs. Hence, the sensory parameters of the right median and right ulnar nerve were analyzed here. Furthermore, we did not find any significant results between males and females. [Table 1] depicts the OL of SNAP of the median and ulnar nerves. The mean OL of the median nerve was 2.40 ± 0.30 ms, 2.49 ± 0.36 ms, and 3.12 ± 0.53 ms in groups A, B, and C, respectively, at a significant level. Mean OL of the ulnar nerve was 2.05 ± 0.18 ms, 2.25 ± 0.54 ms, and 2.8 ± 0.48 ms in groups A, B, and C, respectively, at a significant level. [Table 2] depicts the amplitude of SNAP of the median and ulnar nerves. The mean amplitude of the median nerve was 48.2 ± 4.4 μv, 35.9 ± 5.3 μv, and 26.9 ± 3.1 μv in groups A, B, and C, respectively at a significant level. The mean amplitude of the ulnar nerve was 40.9 ± 8.2 μv, 35.6 ± 5.4 μv, and 27 ± 2.8 μv in groups A, B, and C, respectively, at a significant level. [Table 3] depicts the CV (CV) of SNAP of the median and ulnar nerves. The mean CV of the median nerve was 60 ± 10 m/s, 53 ± 10 m/s, and 51 ± 13 m/s in groups A, B, and C, respectively at a significant level. Mean CV of the ulnar nerve was 55 ± 16 m/s, 44 ± 15 m/s, and 39 ± 7 m/s in groups A, B, and C, respectively at a significant level. [Table 4] depicts a post hoc analysis of all three parameters of SNAP, i.e., OL, Amp, and CV. A significant change in OL and amplitude was seen between Group B versus C and Group A versus C both in the median and ulnar nerves. However, in the CV the significant change was between Group A versus B and Group B versus C.
| Discussion|| |
This study evaluated the sensory parameters of the most common nerves of upper limbs. OL, amplitude, and CV of median and ulnar nerves were compared between Group A (20–35 years), B (36–50 years), and C (>50 years). In median SNAP, OL was more in older age group than younger, the amplitude was less in older age group than younger and CV was low in older age group than younger. In ulnar SNAP, OL was more in the older age group than younger, the amplitude was less in the older age group than younger and CV was low in the older age group than younger.
Several studies have done by different groups of researchers and they have observed the nerve CV and amplitude in decreasing trend with increasing age.,, Our results were in a similar trend to the studies done by researchers. Stetson et al. performed the effect of anthropometric parameters, sex, and age on nerve conduction among 105 adult workers. They reported a 0.13 m/s per year of age decline in CV of the median nerve and a 0.099 m/s decrease CV per year of age in the ulnar nerve. Dorfman and Bosley have conducted a study of age-related changes in central and peripheral nerve conduction among 30 adults which included 15 young and 15 old. They suggested a 0.16 m/s per year of age decrease in median nerve CV. Letz and Gerr have done a cross-sectional study among 4000 adults and observed a 0.13 m/s decrease of CV per year of age in the median nerve and a 0.14 m/s decrease in CV per year of age in the ulnar nerve. Tong et al. in their prospective study, found 0.13 m/s decrease in CV per year of age in the median nerve and a 0.13 m/s reduction in CV in the ulnar nerve. Our study did not observe the change of CV per year of age but we observed that it decreased from younger to older age groups. In our study, we observed by post hoc analysis that the significant reduction trend in CV and amplitude after the age of 35 years. In some other studies, the researchers suggested 40 years is the age of decreasing trend in reduction of CV and amplitude which is very close to our result.,, In our study, we found 50 years is the age for an increasing trend in latency of median and ulnar sensory conduction. This finding is in accordance with the findings of Tong et al. Aging is a progressive and generalized state associated with abnormal body functions ultimately results to decrease in adaptation to stress. At the same time, aging is associated with the risk of age-related pathological changes leading to different diseases. The increase in latency, decrease in CV, and decrease in amplitude in old age group subjects than younger is due to a decrease in the number of nerve fibers, the thin diameter of nerve, and change in nerve fiber membrane because of aging.,, In our study, we did not find any gender variation of different parameters of sensory conduction of median and ulnar nerves which is against the result reported by previous studies., We found no significant variation of sensory conduction parameters of the median and ulnar nerves between the right and left sides. This finding is against the result reported by others where they have shown variation between the left and right sides.
Limitations of the study
Height is an important factor of nerve conduction study which could not be considered in this study. It could have been provided better analysis if linear regression was implemented.
| Conclusion|| |
SNAP parameters vary according to demographic region. Hence, there should be separate normative data in different laboratories according to demographic region. Hence, normative reference data of this study will guide the clinicians to evaluate the functional status and abnormality of median and ulnar nerves.
The authors are very much thankful to the laboratory technicians of the neurology department of the institute for their support toward this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]