Relationship Between Cervical Nerve Root Entrapment Due to Cervical 6-7 Foraminal Stenosis and Sensory Nerve Action Potentials in Nerve Conduction Study

Background: Nerve conduction study (NCS) assesses peripheral nerve functions and has clinical implication. Objective: To study effect of gender on NCS variables in healthy adults. Settings and Design: Department of Physiology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. Material and Method: The study was done in 34 (m=19, 32±11 years; f=15, 32±12 years) consenting healthy adults. The compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) were recorded. Statistical analysis: The effect of gender on NCS variables was analyzed using Mann Whitney U test. Results: Male vs. female: males had increased CMAP and F-wave latencies (ms) in all tested motor nerves. CMAP duration (ms) was longer in males (p<0.05) in all tested motor nerves: right median (5.9±1.3 vs. 4.92±0.65), left median (5.54±0.91 vs. 4.72±0.57), right ulnar (5.55±1.01 vs. 4.56±0.59), left ulnar (5.71±0.97 vs. 4.64±0.51), right tibial (6.58±0.95 vs. 5.95±0.71), and left tibial (6.98±1.31 vs. 6.21±0.78). Females showed higher sural SNAP amplitude (µV) (23.26±9.23 vs. 15.94±8.42). SNAP duration (ms) was longer in males: right ulnar (1.16±0.19 vs. 1.03±0.06). SNAP latencies (ms) were also longer in males: right sural (2.61±0.44 vs. 2.21±0.36). Males had greater height (165.9±4.74 vs. 149.3±7.24) and weight (60.4±7.2 vs. 53±7.2).Conclusion: Gender has definite effects on NCS variables. Males had higher CMAP amplitude, longer latencies and duration. SNAP latencies and duration were longer in males whereas amplitude was higher in females. Without adjustment for these factors, the sensitivity and specificity of NCS will decrease when using the same reference data in patients with different gender. Keywords: compound muscle action potential; gender; nerve conduction study; sensory nerve action potential DOI: 10.3126/hren.v8i3.4210Health Renaissance, September-December 2010; Vol 8 (No.3);169-175

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Sensory Nerve Conduction Studies

Clinical Neurophysiology ◽

10.1093/med/9780190259631.003.0018 ◽

2016 ◽

pp. 292-311

Author(s):

Eric J. Sorenson

Keyword(s):

Nerve Conduction ◽

Action Potentials ◽

Sensory Nerve ◽

Nerve Conduction Studies ◽

Nerve Action ◽

Compound Muscle Action Potentials ◽

Sensory Nerve Action ◽

Electrical Generator ◽

Nerve Dysfunction ◽

Potential Waveform

Sensory nerve action potentials (SNAPs) are an important component of an electrodiagnostic test of peripheral nerves and can localize lesions either proximal or distal to the dorsal root ganglia. They are among the most sensitive measures of peripheral nerve dysfunction, and can provide information about the pathophysiology of the neuropathy, suggesting demyelination or axonal loss in some cases. Because SNAPs are much smaller than compound muscle action potentials, they are technically more difficult to study. Temperature will have a greater impact on SNAPs than motor potentials, with cooler limb temperatures leading to longer latencies, slower conduction velocities, and larger amplitudes. Responses are commonly averaged 3 to 5 times to minimize the effect of the background noise on the waveforms. Distance from the electrical generator and inter-electrode distance will also impact the appearance and size of the nerve potential waveform. This chapter reviews the concepts and applications of sensory nerve action potentials and sensory nerve conduction studies.

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Sensory Nerve Action Potentials

Clinical Neurophysiology ◽

10.1093/med/9780195385113.003.0017 ◽

2009 ◽

pp. 239-256

Author(s):

Eric J. Sorenson

Keyword(s):

Nerve Conduction ◽

Action Potentials ◽

Sensory Nerve ◽

Nerve Conduction Studies ◽

Clinical Electrophysiology ◽

Specific Measure ◽

Myelinated Axons ◽

Sensory Pathways ◽

Sensory Nerve Action ◽

Peripheral Sensory

Nerve conduction studies are an invaluable addition to clinical electrophysiology testing. SNAPs are a sensitive and specific measure of function in the peripheral sensory pathways. These studies confirm whether large myelinated axons are affected by an underlying abnormality. When an area that is affected is clinically tested, nerve conduction studies can help to distinguish between a preganglionic (i.e., root level or higher) and a postganglionic (i.e., peripheral) process.

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Sensory nerve conduction in the caudal nerves of rats with diabetes

Acta Cirurgica Brasileira ◽

10.1590/s0102-86502011000200008 ◽

2011 ◽

Vol 26 (2) ◽

pp. 121-124 ◽

Cited By ~ 1

Author(s):

Celina Cordeiro de Carvalho ◽

Juliana Netto Maia ◽

Otávio Gomes Lins ◽

Sílvia Regina Arruda de Moraes

Keyword(s):

Nerve Conduction ◽

Action Potentials ◽

Regression Line ◽

Sensory Nerve ◽

Diabetic Rats ◽

Male Rats ◽

Control Group ◽

Conduction Velocities ◽

Sensory Nerve Action ◽

Diabetes Induction

PURPOSE: To investigate sensory nerve conduction of the caudal nerve in normal and diabetic rats. METHODS: Diabetes was induced in twenty 8-weeks old Wistar male rats. Twenty normal rats served as controls. Caudal nerve conduction studies were made before diabetes induction and the end of each week for six consecutive weeks. The caudal nerve was stimulated distally and nerve potentials were recorded proximally on the animal's tail using common "alligator" clips as surface electrodes. RESULTS: After induction, nerve conduction velocities (NCV) increased slower in the diabetic than in the control group. Sensory nerve action potentials (SNAP) conduction velocities increased slower in the diabetic than in the control group (slope of regression line: 0.5 vs 1.3m/s per week; NCV in the 15th week = 39±3m/s vs 44±4m/s). Tukey's tests showed differences between groups at the 11th, 13th and 15th weeks old. From the 10th week on, SNAP amplitudes increased faster in the diabetic than in the control group (slopes of the regression line: 10 vs 8µV per week; SNAP amplitudes in the 15th week: 107±23µV vs 85±13µV). Differences at the 12th, 13th and 15th weeks were significant. CONCLUSION: In diabetic rats nerve conduction velocities were slower whereas amplitudes were larger than in normal rats.

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