The realistic yield of lower leg SNAP amplitudes and SRAR in the routine evaluation of chronic axonal polyneuropathies

Vrancken, Alexander F.J.E.; Notermans, Nicolette C.; Wokke, John H. J.; Franssen, Hessel

doi:10.1007/s00415-008-0817-7

Cited by 20 publications

(16 citation statements)

References 41 publications

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“…The diagnosis of CIAP was defined according to the following criteria (4,6): presence of symmetrical distal sensory or sensorimotor symptoms such as numbness, pins and needles, tightness, coldness, unsteadiness, muscle cramps, and weakness with onset in the lower limbs, compatible with polyneuropathy; presence of symmetrical distal sensory or sensorimotor signs with evidence of large nerve fiber involvement such as decreased sense of touch, vibration, and propriocepsis, usually in the presence of decreased pin prick/temperature sense, decreased/absent tendon reflexes, or slight muscle weakness on neurologic examination, compatible with polyneuropathy; an insidious onset and slow or no progression of the polyneuropathy over the course of at least 6 months; no identifiable cause for the polyneuropathy after thorough history-taking, clinical examination, and extensive laboratory testing; no suggestion of a hereditary polyneuropathy based on detailed kinship history (i.e., one or more affected family member), neurologic examination, or confirmation by genetic analysis; and nerve conduction studies excluding a demyelinating polyneuropathy and confirming large nerve fiber involvement if the findings on neurologic examination were equivocal considering the patient’s age (16–19). Electrophysiological criteria for demyelination provided that distal compound motor action potential (CMAP) baseline to negative peak amplitude >1 mV were: reduction of motor nerve conduction velocity to <80% of lower limit of normal value (LLN) if distal CMAP >80% of LLN, or to <70% of LLN if CMAP was <80% of LLN; prolongation of distal motor latency to >125% of upper limit of normal value (ULN) if CMAP >80% of LLN, or to >150% of ULN if CMAP <80% of LLN; prolongation of F-waves to >120% of ULN if CMAP >80% of LLN, or to >150% of ULN if CMAP <80% of LLN; conduction block >50% area reduction or, in upper limb nerves, >30% amplitude reduction in proximal CMAP relative to distal; and abnormal temporal dispersion in upper limb nerves >30% duration increase or in lower limb nerves >100% duration increase in proximal CMAP relative to distal (20).…”

Section: Methodsmentioning

confidence: 99%

Chronic Idiopathic Axonal Polyneuropathy Is Associated With the Metabolic Syndrome

et al. 2013

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OBJECTIVEThis study aims to investigate the association between chronic idiopathic axonal polyneuropathy (CIAP) and the metabolic syndrome or its individual components.RESEARCH DESIGN AND METHODSA total of 249 patients with CIAP and 709 controls underwent fasting laboratory studies, and blood pressure and waist circumference were measured. The metabolic syndrome was diagnosed if three or more of the following Adult Treatment Panel III criteria were present: impaired fasting glucose, hypertension, abdominal obesity, reduced HDL cholesterol, and hypertriglyceridemia. Subgroup analysis was performed for patients with a painful predominantly sensory CIAP, because this phenotype is most similar to diabetic polyneuropathy. Statistical analysis was performed with adjustment for age and gender.RESULTSFifty-five percent of all patients fulfilled the metabolic syndrome criteria compared with 34% of controls (odds ratio 2.2 [95% CI 1.7–3.0]). Multivariate analysis shows hypertension (2.9 [1.7–4.9]) and abdominal obesity (3.3 [2.4–4.6]) to be significantly more prevalent in patients than in controls. Of the patients classified as having a painful predominantly sensory CIAP, 62% fulfilled the metabolic syndrome criteria (3.1 [2.0–4.8]). In this subgroup, hypertension and abdominal obesity also were significantly more prevalent compared with controls.CONCLUSIONSAbdominal obesity and hypertension seem to be the most consistent contributing components of the metabolic syndrome in patients with CIAP. Evaluation and appropriate treatment of these risk factors in patients with CIAP would be advocated.

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Section: Methodsmentioning

confidence: 99%

Chronic Idiopathic Axonal Polyneuropathy Is Associated With the Metabolic Syndrome

et al. 2013

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“…Nerve conduction studies and needle electromyography (EMG), collectively referred to as electrodiagnostic study (EDX) have traditionally been used to confirm the diagnosis of PN . Although large prospective studies of accuracy are lacking, the sensitivity of EDX has been estimated at approximately 70% . Confounding these estimations is the presence of exclusively or predominantly small fiber neuropathies, for which EDX is unrevealing, because small nerve fibers (as those found intraepidermally) are not amenable to traditional nerve conduction studies …”

Section: Introductionmentioning

confidence: 99%

Utility of electrodiagnostic studies in patients referred with a diagnosis of polyneuropathy

Ginsberg

Morren

2019

Muscle and Nerve

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Background Peripheral polyneuropathies (PN) are common neuromuscular conditions. The role of electrodiagnostic study (EDX) in diagnosis of PN is not well‐defined. Methods We performed a retrospective chart review of patients referred for EDX evaluation of PN. Results Of 162 patients analyzed, 23 had pure peripheral neuropathy (pPN; 14.2%), 29 had peripheral neuropathy and another diagnosis (PN+; 17.9%), 51 had an alternative diagnosis (nonPN; 31.5%), and 59 had normal studies (36.4%). In univariable analysis, age (P < .001) and gender (P = .004) were weakly associated with final diagnosis. In multinomial logistic regression analysis, significant predictors included age (odds ratio [OR] for nonPN/PN+:1.07 per year; 95% confidence interval [CI], 1.03–1.11), gender (OR for PN+:0.2, 95% CI, 0.07–0.61), and diabetes/prediabetes (OR for pPN:3.29; 95% CI, 1.17–9.27). Conclusions These data suggest that EDX commonly yields additional or nonPNs in patients referred with a diagnosis of PN, and although some variables predict electrodiagnosis, none have a large enough effect to suggest poor utility in any subpopulation.

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“…[6] In one study, they observed that in 26% of their referents dorsal sural SNAP was not obtained, so they concluded that dorsal sural SNAP did not add to the diagnosis of a distal peripheral neuropathy. [22] In our population, there appears to be a risk factor of sitting cross legged on the floor for long hours, which may cause a focal neuropathy of the dorsal sural nerve. This needs to be investigated by further studies.…”

Section: Discussionmentioning

confidence: 88%

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

Chaudhari

Mansukhani

Sharma

et al. 2017

Ann Indian Acad Neurol

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Background:Dorsal sural sensory nerve action potential (SNAP) could help diagnose early or subclinical peripheral neuropathy.Objectives:To establish reference data for dorsal sural SNAP amplitude, latency, and velocity in healthy participants.Materials and Methods:A prospective study was conducted in 45 nerves from healthy participants between 18 and 90 years and stratified into three age groups (a = 18–40 years, b = 41–60 years, and c>60 years). StataCorp 12.2 statistical program was used for all statistical analyses. Mean-2 standard deviation was used to generate reference values for the lower limit of amplitude and velocity in each age group. ANOVA with Bonferroni correction was used for intergroup comparisons of amplitude and velocity. Regression analysis was used to compute an equation for the predicted amplitude with age, height, and weight as the covariates.Results:The lower limit for amplitude (uv) in Groups a, b, and c was 2.57, 1.97, and 1.01, respectively. The lower limit for velocity (m/s) was 33.6, 32, and 22.8, respectively. Statistical significance was noted between the amplitudes of participants in Groups b and c (P = 0.039) and a and c (P = 0.001). Similarly, velocity was significantly different between Groups b and c (P = 0.04) and a and c (P = 0.008). Age was the covariate with maximum effect on the dorsal sural amplitude. Gender and side-to-side comparison did not show statistical significance for amplitude and velocity measurements. Linear regression analysis of the transformed amplitude gave the predictive equation as (y) =3.338 + age (−0.0167) + height in meters (−0.209) + weight (0.001).Conclusion:This study provides reference data for dorsal sural SNAP in Indian population stratified by age.

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The realistic yield of lower leg SNAP amplitudes and SRAR in the routine evaluation of chronic axonal polyneuropathies

Abstract: To confirm distal axonal polyneuropathy in routine clinical practice the sural and superficial peroneal SNAP had equal and complementary yield, whereas the SRAR and dorsal sural SNAP had limited additional yield.

Cited by 20 publications

References 41 publications

Chronic Idiopathic Axonal Polyneuropathy Is Associated With the Metabolic Syndrome

Chronic Idiopathic Axonal Polyneuropathy Is Associated With the Metabolic Syndrome

Utility of electrodiagnostic studies in patients referred with a diagnosis of polyneuropathy

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

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