Dorsal sural sensory nerve action potential: A study for reference values

Chaudhari, Sweta Chetan; Mansukhani, Khushnuma A; Sharma, Alika; Balakrishnan, Lajita; Sreenivasan, Aarthika

doi:10.4103/0972-2327.194313

Cited by 4 publications

(3 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4,5 In the absence of standard thresholds for sural sensory nerve actional potential (SNAP) and nerve conduction velocity (NCV) for Sri Lankan population; we used the cutoff as six micro vaults (µV) for SNAP and 40 m/s for NCV. 6,7 Distal sural response was considered as spared if both SNAP and NCV were same or above the cutoff levels. Sural SSEP latencies were assumed to be equal to tibial SSEP latencies as the distance between stimulation and cortical recording is almost equal.…”

Section: Methodsmentioning

confidence: 99%

Sural nerve involvement in patients with acute inflammatory demyelinating polyneuropathy variant of Guillain-Barre syndrome with sural sparing at initial presentation

Munasinghe,

Gunasekara,

Gunarathne

et al. 2023

Sri Lanka J. Neurology

View full text Add to dashboard Cite

Introduction: Neurophysiological testing is a valuable tool in the diagnosis of Guillain-Barre syndrome (GBS). Sural sparing is a usual feature of acute inflammatory demyelinating polyneuropathy (AIDP) type GBS. However, sural involvement has been reported in later stages of GBS. It is important to identify patterns of sural nerve involvement to differentiate GBS from its mimickers and to stage the disease. This research aimed to detect the pattern of sural nerve involvement in AIDP-GBS cases with normal electrophysiological responses in the sural nerve at the beginning.Objectives: To determine the location and timing of sural nerve involvement in AIDP-GBS.Methods: This prospective follow up study included diagnosed cases of AIDP-GBS with preserved bilateral sural responses. Nerve conduction and somatosensory evoked potentials (SSEP) were done on admission and weekly thereafter for four consecutive weeks. The last evaluation was done four weeks after the fourth study.Results: All patients (100%) showed normal distal sural responses over the initial four weeks of follow up. They continued to remain normal up to eight weeks in eight patients (53.3%). Two patients had gradual prolongation of their sural SSEP on consecutive studies. One of them had gradual reduction of sural sensory nerve action potential and nerve conduction velocity along with the prolongation of sural SSEP latencies. The difference of SSEP latency increments in the left sural nerve of these two patients was statistically significant (p<0.05). The right sural SSEP latency difference was not significant.Conclusion: Sparing of the distal sural sensory response was demonstrated in 100% of AIDP-GBS cases during the first four weeks of follow up. More than 50% of the cohort demonstrated preserved sural sensory responses for eight weeks from the initial presentation. Two out of fifteen patients showed statistically significant proximal sural sensory pathway involvement with increasing SSEP latencies. This finding suggests that in some patients, the sural sensory pathway may get affected at its proximal segments or at the central nervous system before the distal nerve is affected.

show abstract

Section: Methodsmentioning

confidence: 99%

Sural nerve involvement in patients with acute inflammatory demyelinating polyneuropathy variant of Guillain-Barre syndrome with sural sparing at initial presentation

Munasinghe,

Gunasekara,

Gunarathne

et al. 2023

Sri Lanka J. Neurology

View full text Add to dashboard Cite

show abstract

“…To aid early diagnosis of a peripheral neuropathy, more distal SNAPs are studied and they include the dorsal sural and medial plantar (MP) SNAPs. [ 6 7 8 9 10 11 12 13 14 15 16 17 ] Dorsal sural SNAP can be affected due to local foot injuries, ill- fitting foot wear, and callus formation due to sitting cross- legged on the floor. [ 6 ] MP SNAPs could be technically difficult to obtain, especially in persons with poor foot hygiene but in this study which included elderly subjects; we were able to obtain MP SNAPs in all our subjects.…”

Section: Introductionmentioning

confidence: 99%

“…[ 6 7 8 9 10 11 12 13 14 15 16 17 ] Dorsal sural SNAP can be affected due to local foot injuries, ill- fitting foot wear, and callus formation due to sitting cross- legged on the floor. [ 6 ] MP SNAPs could be technically difficult to obtain, especially in persons with poor foot hygiene but in this study which included elderly subjects; we were able to obtain MP SNAPs in all our subjects. MP SNAP is also useful in the diagnosis of a focal tibial or medial plantar neuropathy due to local causes e.g., tarsal tunnel syndrome, trauma or leprosy[ 18 19 ] The tibial nerve divides into its terminal branches, medial and lateral plantar nerves in the tarsal tunnel or just proximal to it, below the flexor retinaculum, at the medial malleolus-calcaneal axis.…”

Section: Introductionmentioning

confidence: 99%

Medial Plantar Sensory Nerve Action Potential

Sharma

Chavan

Mansukhani

2022

Annals of Indian Academy of Neurology

Self Cite

View full text Add to dashboard Cite

Context: The medial plantar nerve (MP) sensory nerve action potential (SNAP) has been shown to be a sensitive indicator for detecting a length-dependent axonal peripheral neuropathy. However, literature survey shows paucity of age stratified data. This study was undertaken to obtain age stratified reference data for MP SNAP amplitude and latency. Aim: To establish age-stratified reference data in Indian subjects for the MP SNAP. Study Setting and Design: The study was conducted in the electrodiagnostic laboratory of a tertiary city hospital and is retrospective study. Materials and Methods: A retrospective study was conducted using the nerve conduction study reports of 173 patients with only upper limb symptoms and findings. Patients were between the ages of 18 and 86 years, stratified into six groups, a = 18-30 years, b = 31- 40 years, c = 41-50 years, d = 51- 60 years, e = 61-70 years, f ≥70 years. Statistical Methods: Stata 12.1 statistical program was used. Lower limit of the SNAP amplitude was obtained using mean-2SD of transformed data. Analysis of variance defined the intergroup variability, linear regression and Pearson's correlation assessed the statistical significance. Results: The lower limit of normal MP SNAP amplitude for each age group is as follows: a: 8.7uv b: 7.5uv c: 3.7 uv d: 2.9uv e: 2.0 uv f: 1.4uv. The amplitude difference between the groups b & c, c & d and e and f using analysis of variance with Bonferroni correction and Tukey post-hoc test was not significant, but the other groups showed statistically significant variance. The equation of regression for the predicted amplitude value with age was defined as Y^ = {3.5 + age (-.0233) – 2 (0.389)} 3 . Conclusion: This study provides age stratified reference data for MP SNAP. There is evidence to suggest that MP SNAP amplitude varies with age hence age stratified data should be used to define abnormality.

show abstract