Sural Sensory Nerve Action Potential Research Articles

High serum levels of CCL11/Eotaxin-1 are associated with diabetic sensorimotor polyneuropathy and peripheral nerve function but not with cardiac autonomic neuropathy in people with type 2 diabetes

ABSTRACT Aims To investigate whether higher serum CCL11/Eotaxin-1, a biomarker for aging and neurodegenerative and neuroinflammatory disorders, is associated with diabetic sensorimotor polyneuropathy (DSPN), peripheral nerve dysfunction, and cardiac autonomic neuropathy in people with type 2 diabetes. Methods This cross-sectional study included 106 patients with type 2 diabetes and 40 healthy controls, matched for the age and sex distribution of the diabetes group as a whole. The CC chemokines CCL11/Eotaxin-1 and CCL22/MDC were measured in fasting serum samples. DSPN and peripheral nerve function were assessed by neurological examination and nerve conduction studies, and cardiac autonomic function, by heart rate variability (HRV) and corrected QT (QTc) time. The cardio-ankle vascular index (CAVI) was measured as a marker for arterial stiffness Results Serum CCL11/Eotaxin-1 levels were significantly higher in diabetic patients than in healthy controls (183 ± 63.5 vs. 113.1 ± 38.5 pg/ml, p < 0.001), but serum CCL22/MDC levels were not significantly different between the two groups. In the diabetes group, the serum CCL11/Eotaxin-1 level was positively correlated with ulnar and sural nerve conduction velocities (p = 0.0009, p = 0.0208, respectively) and sensory nerve action potential (p = 0.0083), and CAVI (p = 0.0005), but not with HRV indices or QTc time, and serum CCL22/MDC was not significantly correlated with any indices of nerve conduction. In a model adjusted for age and duration of diabetes, serum CCL11/Eotaxin-1 was still associated with ulnar nerve conduction velocity (p = 0.02124). Serum CCL11/Eotaxin-1, but not CCL22/MDC, was significantly higher in patients with than in those without DSPN (208.2 ± 71.6 vs. 159.1 ± 45.1 pg/ml, respectively; p < 0.0001). Conclusions Serum CCL11/Eotaxin-1 is elevated in patients with DSPN and is associated with peripheral nerve dysfunction, in particular sensory nerve conduction velocity, suggesting that serum CCL11/Eotaxin 1 May be a potential biomarker for DSPN. Clinical Trial Registration University Hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN000040631).

Alcohol-related peripheral neuropathy: Clinico-neurophysiological characteristics and diagnostic utility of the neuropathy symptoms score and the neuropathy impairment score

Alcohol overconsumption is well known to cause damage to the peripheral nervous system, affecting both small and large nerve fibers. The aim of this descriptive study was to investigate peripheral nerve damage, and to correlate clinical, epidemiological and neurophysiological findings, in patients diagnosed with Alcohol Use Disorder (AUD). Ninety alcohol-dependent subjects on inpatient basis were enrolled in this prospective study over a 3-year period. Every subject was assessed by the Neuropathy Symptoms Score (NSS) questionnaire and the Neuropathy Impairment Score (NIS) clinical examination grading scale, followed by Nerve Conduction Studies, Quantitative Sensory Testing and Sympathetic Skin Response (SSR) testing. Peripheral neuropathy was diagnosed in 54 subjects (60%), by abnormal neurophysiological tests and presence of clinical signs or symptoms. Among them, pure large fiber neuropathy (LFN) was found in 18 subjects, pure small fiber neuropathy (SFN) in 12 subjects, and both large and small fiber neuropathy was diagnosed in 24 subjects. Using linear regression, we found that higher NSS and NIS scores correlated with lower amplitudes of the sural sensory nerve action potential and of the SSR. We also found a significant longer duration of alcohol abuse in subjects with neuropathy, using Student's t-test (p = 0.024). Additionally, applying NIS abnormal cut-off score ≥4, using ROC analysis, we predicted the majority of subjects with LFN, confirming 95.23% sensitivity and 93.75% specificity. Our study confirmed that peripheral neuropathy involving large and small nerve fibers, with a symmetrical length-dependent pattern, is common between patients with AUD and related to the duration of the disorder. We suggest that NSS and NIS scales could be used for the assessment of neuropathy in clinical practice, when the essential neurophysiological testing is not available.

Central nervous system involvement in chronic inflammatory demyelinating polyradiculoneuropathy—MRS and DTI study

ObjectiveThe current research aimed to analyze the alterations within the motor cortex and pyramidal pathways and their association with the degree of damage within the peripheral nerve fibers in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). To achieve that goal, we investigated the microstructural changes within the pyramidal white matter tracts using diffusion tensor imaging (DTI) parameters, evaluated metabolic alterations in both precentral gyri using magnetic resonance spectroscopy (MRS) ratios, and correlated them with the neurographic findings in patients with CIDP.MethodsThe spectroscopic ratios of NAA/Cr, Cho/Cr, and mI/Cr from both precentral gyri and the values of fractional anisotropy (FA), axial diffusivity (AD), and mean diffusivity (MD) from both of the corticospinal tracts were correlated with the results of neurological and neurographic findings. The comparison of DTI parameters between the patients and controls was performed using Student’s t-test or the Mann–Whitney U test. Due to the lack of normal distribution of most variables, Spearman’s Rho rank coefficient was used to test all correlations. All analyses were performed at a significant level of alpha = 0.05 using STATISTICA 13.3.ResultsCompared to the control group (CG), the patient group showed significantly lower ratios of NAA/Cr (1.66 ± 0.11 vs. 1.61 ± 0.15; p = 0.022), higher ratios of ml/Cr in the right precentral gyrus (0.57 ± 0.15 vs. 0.61 ± 0.08; p = 0.005), and higher levels of Cho/Cr within the left precentral gyrus (0.83 ± 0.09 vs. 0.88 ± 0.14, p = 0.012). The DTI parameters of MD from the right CST and AD from the right and left CSTs showed a strong positive correlation (0.52–0.53) with the sural sensory nerve action potential (SNAP) latency of the right sural nerve. There were no other significant correlations between other DTI and MRS parameters and neurographic results.SignificanceIn our study, significant metabolic alterations were found in the precentral gyri in patients with CIDP without clinical symptoms of central nervous system involvement. The revealed changes reflected neuronal loss or dysfunction, myelin degradation, and increased gliosis. Our results suggest coexisting CNS damage in these patients and may provide a new insight into the still unknown pathomechanism of CIDP.

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

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&lt;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.

Age-Related Changes in Neurologic Examination and Sensory Nerve Amplitude in the General Population: Aging of the Peripheral Nervous System.

Chronic axonal polyneuropathy is a common disease of the peripheral nervous system with increasing prevalence with age. Typical neurologic signs are present in patients with polyneuropathy but may also occur in individuals without disease. Owing to limited knowledge on normal aging of the peripheral nervous system, it can be difficult to distinguish peripheral nerve dysfunction due to disease from variations in normal aging. Therefore, we described the changes in neurologic examination and nerve conduction studies that accompany aging in the general population. In this cross-sectional population-based study, we screened participants for chronic polyneuropathy in a controlled environment using standardized methods including a symptom questionnaire, neurologic examination, and nerve conduction studies (NCS). Inclusion criteria were 40 years or older and living in a suburb of Rotterdam, the Netherlands. Participants not diagnosed with chronic polyneuropathy, based on the discussion of findings in the screening by an expert team, were included to determine the effect of age (range 41-96 years) on features of neurologic examination and NCS using frequency calculations and quantile regression analysis. In total, 4,179 participants (mean age 64.5 ± 12.7 years, 54.9% female) were included of whom 3,780 (90.5%) did not fulfil the criteria for polyneuropathy. In the population without polyneuropathy, the frequency of normal features at neurologic examination declined with age, most pronounced for vibration sense at the hallux (from 6.6 [SD ± 1.5] in 40-49 years to 3.6 [SD ± 3.1] in 80 years or older) and Achilles tendon reflexes (absent in 9% in 40-49 years up to 33% in 80 years or older). Superficial pain sensation and patellar tendon reflexes remained stable over time. Sural sensory nerve action potential (SNAP) amplitude declined with age from 11.2 μV in 40-49 years to 3.3 μV in 80 years or older. Nonrecordable SNAP amplitudes were found in 25.1% of the participants older than 80 years, more often in men (30.3%) than in women (21.0%). This study showed the effect of age on features of neurologic examination and sural nerve amplitude in the general population. These findings are helpful to distinguish features suggesting polyneuropathy from variations of normal aging of the peripheral nervous system.

The Rise Slope of the Compound Sensory Nerve Action Potential in Normal and Pathological Human Nerves

ABSTRACT In spite of the diagnostic importance of the early phase of the sensory nerve action potential (SNAP), reliable electrodiagnostic metrics for this part of the recorded waveform are lacking. The average rise slope of the SNAP appreciates the steepness of the initial negative deflection of the waveform, which might be a useful metric for the first part of the potential. Sural nerve sensory neurography was performed in patients with various axonal neuropathies, and median nerve sensory studies were carried out in patients with carpal tunnel syndrome. Age-matched healthy individuals served as controls. The rise slope was compared to conventional SNAP parameters such as conduction velocity, latency, duration, and rise time. Overall, 537 sensory studies were prospectively analyzed. The rise slope of the sural SNAP demonstrated superior classification performance in terms of sensitivity (92.5%), specificity (97%), and area under the receiver operating characteristic curve (0.986), as compared to conventional SNAP parameters. Its diagnostic power was similarly excellent in median nerve studies, whereas here a slightly better classification performance was obtained by SNAP latency and conduction velocity. The average rise slope appears to do justice to the tight interplay between amplitude and rise time of the initial negative spike deflection, outperforming many conventional measures. This composite metric proved high diagnostic potency in particular with regard to axonal sensory nerve dysfunction.

321-OR: Differential Associations of Obesity and Metabolic Syndrome with Polyneuropathy in Early Type 2 Diabetes and Normal Glucose Tolerance

There is increasing evidence for a role of the metabolic syndrome (MetS) during development of distal sensorimotor polyneuropathy (DSPN). We hypothesized that MetS components are differentially associated with measures of DSPN in individuals with normal glucose tolerance (NGT) and early type 2 diabetes (T2D). Electrophysiological and quantitative sensory testing was performed in 180 participants with NGT and 355 with recent-onset T2D (known diabetes duration &amp;lt;1 year) matched for age from the German Diabetes Study (NGT/T2D [mean±SD]: age: 43.9±14.0/45.1±7.7 years; sex: 61/65% male; BMI: 26.8±5.0/32.3±6.5 kg/m²; HbA1c: 5.2±0.3/6.5±1.0%). Intraepidermal nerve fiber density (IENFD) was assessed in 218 individuals (NGT/T2D: n=117/101). Subsets of participants were followed for 5 years (NGT/T2D: n=48/53). MetS was defined according to International Diabetes Federation (2006) and DSPN according to Toronto consensus criteria (2011). After adjustment for age, sex, height, smoking and HbA1c, a lower IENFD was associated with higher weight (β=-0.306), number of MetS components (NMetSC; β=-0.222) and presence of central obesity (β=-0.292), while higher malleolar vibration perception threshold was associated with weight (β=0.219) in NGT (P&amp;lt;0.05), but not in T2D. Median motor nerve conduction velocity and sural sensory nerve action potential were inversely associated with weight (β=-0.182/-0.286), NMetSC (β=-0.127/-0.128), presence of central obesity (β=-0.163/-0.165), and MetS (β=-0.169/-0.203) in T2D (P&amp;lt;0.05). Higher weight predicted the presence of DSPN at 5 years (β=0.652, P=0.001) in NGT, while increasing NMetSC and MetS prevalence predicted a decline in IENFD over 5 years (β=-0.533/-0.388, P=0.001/0.013) in T2D. This suggests that obesity indices can predict DSPN over 5 years in NGT, while MetS and its components are differentially associated with measures of DSPN in early, well-controlled type 2 diabetes compared with NGT. Disclosure G.Sipola: None. A.Strom: None. M.Bombrich: None. R.Wagner: Advisory Panel; Daiichi Sankyo, Speaker's Bureau; Novo Nordisk, Sanofi. D.Ziegler: None. M.Roden: Advisory Panel; Eli Lilly and Company, Consultant; TARGET PharmaSolutions, Inc., Research Support; Boehringer-Ingelheim, Novo Nordisk, Novartis, Sanofi. G.J.Bönhof: None. Gds group: n/a. Funding German Federal Ministry of Health; Ministry of Innovation, Science, Research and Technology of the state North Rhine-Westphalia; German Federal Ministry of Education and Research

Optimizing the technique for eliciting antidromic sural and superficial fibular sensory nerve action potentials.

Lower limb sensory nerve action potentials are an important component of nerve conduction studies. Most testing of the sural and superficial fibular nerves involves antidromic techniques above the ankle, which result in a falsely unobtainable response in 2%-6% of healthy people. Cadaver, surgical, and more recent ultrasound series suggest this may relate to the site of fascia penetration of the nerve, and it is hypothesized that a modified technique may be more likely to produce reliable responses and reduce false-negative errors. This article evaluates a variety of recording distances for both nerves in 100 healthy controls, including varying recording electrode positions and techniques, to provide the optimal electrodiagnostic information in healthy control subjects. Shorter stimulation distances produce higher-amplitude responses but become confounded by increasing stimulation artifact at very short distances, with the best balance found at around 10 cm. In both sural and superficial fibular nerves, amplitude increases by approximately 10%/cm compared with the standard 14 cm distance. The Daube superficial fibular technique produced a higher amplitude than the Izzo Intermediate technique (by 22.46%, p < .001). The calculated upper limit of normal for side-to-side variation in amplitude was around 50% in the sural nerve but over 70% in the superficial fibular nerve. It is proposed that the 10 cm recording distance for both nerves is optimal, with minimal false-negatives and a higher amplitude elicited than with existing techniques.

Electrophysiology of ataxia-telangiectasia-like disorder 1.

Ataxia-telangiectasia-like disorder-1 (ATLD1, OMIM # 604391) is a very rare clinical condition, characterized by slowly progressive ataxia with onset in childhood, associated with oculomotor apraxia and dysarthria. Laboratory findings reveal increased susceptibility to radiation, with a defect in DNA repair. Patients with ATLD1 show no telangiectasia, have no immunodeficiency, and also have preserved cognition. Reflexes might be initially brisk and later becomes reduced associated with axonal sensorimotor neuropathy. Brain magnetic resonance imaging (MRI) detects cerebellar atrophy. The condition is caused by mutations in the meiotic recombination 11 (MRE11A) gene. The present study reports on the neurophysiologic finding in eight Saudi patients, belonging to three Saudi families, who have genetically confirmed ATLD1. All investigated patients had cerebellar atrophy on brain MRI (5/5). Electrophysiologic studies showed normal motor conduction velocity (MCV) of the median (8/8) and tibial (2/2) nerves, while 5/6 (83%) had normal peroneal nerve MCV. The distal motor latency (DML) for median, tibial, and peroneal nerves was within the normal range in all examined patients. The amplitude of compound muscle action potential (CMAP) of median and tibial nerves was also normal, while that of the peroneal nerve was normal in 3/6 (50%). Two of seven (29%) patients had reduced amplitude of median nerve sensory nerve action potential (SNAP) while 3/8 (38%) had a reduction in the amplitude of sural nerve SNAP. These findings favour an axonal type of neuropathy predominately affecting the sensory fibres (axonal sensorimotor neuropathy). The present study constitutes the largest cohort of ATLD1 patients worldwide who had electrophysiologic tests.

Sural nerve conduction: Amplitude and distal latency of sensory nerve action potential

Background: The sensory nerve action potential (SNAP) is an important factor in the electro diagnostic evaluation of a patient with suspected peripheral neuropathy. Sural nerve is the most frequently studied nerve in the electrophysiology. For proper diagnosis sural sensory conduction abnormalities, a reference data are required for each electrophysiology laboratory. Aims and Objectives: The aim of the study was to find out normative reference data of amplitude and distal latency (DL) of sural SNAP for Northern Kerala population. Materials and Methods: The study was designed as cross-sectional and observational study and analysis of values was done using SPSS version 16. A total of 250 healthy subjects of age 15–50 from Northern Kerala participated in the study which included equal number of males and females. Results: Normative reference data for sensory amplitude and DL were derived in the present study. Sensory amplitude was more and DL was found to be less in female population, indicating faster nerve conduction in female. Conclusion: The reference data derived here can be utilized to detect any abnormality sural nerve sensory conduction. The gender effect on sural nerve sensory conduction parameters can be attributed to the height difference, as nerve conduction velocity is inversely proportional to height.

Serum neurofilament light chain: a novel biomarker for early diabetic sensorimotor polyneuropathy

Aims/hypothesisNo established blood-based biomarker exists to monitor diabetic sensorimotor polyneuropathy (DSPN) and evaluate treatment response. The neurofilament light chain (NFL), a blood biomarker of neuroaxonal damage in several neurodegenerative diseases, represents a potential biomarker for DSPN. We hypothesised that higher serum NFL levels are associated with prevalent DSPN and nerve dysfunction in individuals recently diagnosed with diabetes.MethodsThis cross-sectional study included 423 adults with type 1 and type 2 diabetes and known diabetes duration of less than 1 year from the prospective observational German Diabetes Study cohort. NFL was measured in serum samples of fasting participants in a multiplex approach using proximity extension assay technology. DSPN was assessed by neurological examination, nerve conduction studies and quantitative sensory testing. Associations of serum NFL with DSPN (defined according to the Toronto Consensus criteria) were estimated using Poisson regression, while multivariable linear and quantile regression models were used to assess associations with nerve function measures. In exploratory analyses, other biomarkers in the multiplex panel were also analysed similarly to NFL.ResultsDSPN was found in 16% of the study sample. Serum NFL levels increased with age. After adjustment for age, sex, waist circumference, height, HbA1c, known diabetes duration, diabetes type, cholesterol, eGFR, hypertension, CVD, use of lipid-lowering drugs and use of non-steroidal anti-inflammatory drugs, higher serum NFL levels were associated with DSPN (RR [95% CI] per 1-normalised protein expression increase, 1.92 [1.50, 2.45], p<0.0001), slower motor (all p<0.0001) and sensory (all p≤0.03) nerve conduction velocities, lower sural sensory nerve action potential (p=0.0004) and higher thermal detection threshold to warm stimuli (p=0.023 and p=0.004 for hand and foot, respectively). There was no evidence for associations between other neurological biomarkers and DSPN or nerve function measures.Conclusions/interpretationOur findings in individuals recently diagnosed with diabetes provide new evidence associating higher serum NFL levels with DSPN and peripheral nerve dysfunction. The present study advocates NFL as a potential biomarker for DSPN.Graphical abstract

Sjogren’s Sensory Neuropathy: A Potentially Treatable Condition with Early Intervention

Objective To describe 2 cases of Sjögren's syndrome sensory neuronopathy (SSSN) in which early intervention resulted in excellent clinical outcomes. Background Acquired sensory neuronopathies (i.e. dorsal root ganglionopathies) are rare sensory neuropathies most commonly associated with Sjögren's syndrome (SS) and paraneoplastic syndromes. Design/Methods We describe 2 patients who presented with painful sensory symptoms, sicca symptoms and with positive SSA and antinuclear antibodies. The first patient presented with perceived symmetric hand weakness (despite no motor nerve conduction abnormalities), total body numbness and paresthesia, as well as sensory ataxia, while the other presented with asymmetric numbness and pain in the left foot and hand. The electrophysiological profiles varied considerably between the 2 patients. The first patient demonstrated complete absence of sensory nerve action potentials (SNAPs) whereas the second patient had only asymmetrical superficial peroneal and sural SNAPs, corresponding with his clinical deficit. The first patient was diagnosed with SSSN, while the other was diagnosed with asymmetrical sensory neuropathy in SS. The first patient was treated with mycophenolate mofetil (MMF) with dramatic symptomatic improvement and near recovery of clinical deficits. The second patient was treated with prednisone, methotrexate, and ultimately switched to MMF and rituximab with significant improvement in symptoms. Results NA. Conclusions SS is commonly associated with sensory neuropathies including sensory neuronopathies. Both patients met diagnostic criteria for SSSN, though with differing severities. To date, there has been no randomized controlled trial evaluating treatments of SSSN. However, our findings suggest that early use of MMF could result in considerable benefit in a disease that is often functionally devastating.

Characterization of the Sensory Nerve Action Potential of the Sural Nerve in Patients Over 60 Years of Age without Peripheral Neuropathy

ABSTRACT Demonstration of the possibility to obtain the sensory nerve action potential (SNAP) of sural nerve in patients over 60 years old, without peripheral neuropathy. Prospective study on 101 patients older than 60 years of age. Stimulation was applied 12 cm proximal to the recording point. Two hundred and two SNAPs of the sural nerve were collected with an average peak latency of 3.2 ms, onset latency of 2.6 ms, peak-to-peak amplitude of 15.2 μV and velocity of 45.7 m/s. It was possible to obtain the sural nerve SNAP in all tested patients older than 60, without peripheral neuropathy. The values obtained in this study prove to be useful as a reference in the evaluation of patients older than 60 years of age.

Different patterns of sensory nerve involvement in chronic inflammatory demyelinating polyneuropathy subtypes.

Among subtypes of chronic inflammatory demyelinating polyneuropathy (CIDP), different immune pathophysiologies have been proposed. In this study, sensory nerve conduction studies were compared among clinical subtypes to attempt to better understand the underlying pathophysiology. A total of 138 patients with CIDP was classified into clinical subtypes: typical CIDP (N=68), multifocal CIDP (N=27), or other (N=2). Patients with immunoglobulin M (IgM) neuropathy anti-myelin-associated glycoprotein neuropathy (MAG; N=19) were also included as disease controls. Sensory nerve action potentials (SNAPs) were recorded in the median, ulnar, and superficial radial and sural nerves. SNAP amplitudes (P < .05) and conduction velocities (P < .01) in the median nerve and conduction velocities (P < .05) in the ulnar nerve were lower in typical CIDP than in multifocal CIDP, whereas those in the radial and sural nerves were comparable in each group. Low median and normal sural SNAP amplitudes were more common in typical CIDP (P < .005) than in multifocal CIDP, suggesting predominant involvement at terminal portions of the nerves. Terminal portions of sensory nerves are preferentially affected in typical CIDP compared with multifocal CIDP. These findings might be partially explained by the hypothesis of antibody-mediated demyelination in typical CIDP at the regions where the blood-nerve barrier is anatomically deficient, whereas multifocal CIDP predominantly affects the nerve trunks, largely due to cell-mediated demyelination, with disruption of the blood-nerve barrier.

Prognostic value of cutaneous reinnervation with GAP-43 in oxaliplatin-induced neuropathy

Background and purposeOxaliplatin-induced neuropathy (OIN) implies axonal damage of both small and large sensory nerve fibers. We aimed at comparing the neurophysiological changes occurred after treatment and the capability to recovery based on histological marker of re-innervation GAP-43.Methods48 patients with cancer were assessed before and after chemotherapy (at 3 months and 12 months if available). We recorded ulnar and sural sensory nerve action potentials (SNAP), determined quantitative sensory thresholds for warm and cold (WDT, CDT), pain thresholds and collected a distal biopsy of skin to assess the intra-epidermal nerve fiber density (IENFD) with PGP9.5 and GAP-43 markers (in a subgroup of 19 patients).ResultsIncreased WDT and CDT as well as diminished IENFD at distal leg were already found in 30% of oncologic patients before treatment. After oxaliplatin, there was a significant increase in thermal thresholds in 52% of patients, and a decrease of SNAP amplitude in the sural nerve in 67% patients. IENFD was reduced in 47% and remained unchanged in 37% after oxiplatin. The density of GAP-43 + fibers and GAP-43/PGP 9.5 ratio was similar before and after treatment showing that cutaneous re-innervation is preserved despite no clinical recovery was observed after one year.ConclusionNon-selective axonal loss affects sensory fibers in OIN. However, the presence of intra-epidermal regenerative sprouts detected by GAP-43 may reduce the impact of neurotoxicity in the small fibers with long-term sequelae mostly on myelinated nerve endings. Pre-oxaliplatin GAP-43 failed to identify patients with higher risk of damage or worse recovery after treatment.

Sural Sensory Nerve Action Potential: A Study in Healthy Indian Subjects at Tertiary Care Center of North-West India.

This study was done to obtain the reference data for the sural SNAP amplitude and latency at distances of 14, 12, and 10 cm from the active recording electrode in Indian healthy subjects for different age groups. Two hundred forty-four healthy subjects (18-80 years) were included in this cross-sectional study. Subjects were divided into six groups according to age. Sural SNAP was recorded antidromically stimulating at three sites (14, 12, and 10 cm from the recording electrode). The quantitative variables were expressed as Mean ± SD/Median (IQR) and compared using t test/ANOVA. Transformed data for amplitude were analyzed with the use of paired t test. P < 0.05 was considered statistically significant. SPSS version 20.0 software was used for statistical analysis. Mean age of included subjects was 43.28 years. Maximum leg girth was at 14 cm. Analysis showed a significant difference in the leg girth at all three sites (P < 0.001). Sural SNAP latency at each stimulating site was compared in different age groups, no significant difference was found between groups (P = 0.19). Maximum amplitude was in the 18-30-years age group and amplitude was minimum in the 71-80-years age group (4.34 and 2.79, respectively). The difference in the amplitude recorded in the different age groups was found to be statistically different (P < 0.001). The difference in the amplitude recorded at each site was found to be statistically different (P < 0.001). This is the first study with a large sample size (244 subjects) to provide age-stratified reference data for SNAP in the Indian population by using three sites of stimulation at distances of 14, 12, and 10 cm from the recording electrode. This study shows that sural SNAP amplitude varies with the age of the subject and distance from stimulation.

Age-related sensory neuropathy in patients with spinal muscular atrophy type 1.

Spinal muscular atrophy type 1 (SMA 1) is a devastating motor neuron disorder that leads to progressive muscle weakness, respiratory failure and premature death. Although sensory electrophysiological changes have been anecdotally found in pediatric SMA 1 patients, the age of onset of sensory neuropathy remains unknown. Sensory nerve conduction studies of the median and sural nerves were performed in 28 consecutive SMA 1 patients of different ages. Sensory nerve conduction velocities and sensory nerve action potential (SNAP) amplitudes recorded in these patients were compared with those obtained from 93 healthy subjects stratified by age. SNAP amplitudes decreased with increasing age in the sural and median nerves, without any significant difference between upper and lower limbs. Our data suggest that sural and median nerve SNAP amplitudes are normal in younger patients, while an axonal neuropathy appears in older ones.

Evaluation of quality of life in patients with type 2 diabetes Mellitus with symptomatic distal symmetric polyneuropathy / Avaliação da qualidade de vida em doentes com diabetes Mellitus tipo 2 com polineuropatia simétrica distal sintomática

INTRO/BACKGROUND The complications of Diabetes Mellitus (DM) are traditionally categorized as micro and macrovascular disorders. Among them, diabetic polyneuropathy (DPN) is one of the most common, presenting with or without associated neuropathic pain, and its morbidity exerts a significant impact on the quality of life (QOL) of these patients. About 50% of individuals with type 2 DM (T2DM) suffer from this condition and the distal symmetric polyneuropathy (DSPN) constitutes its most frequent clinical form. OBJECTIVE: To demonstrate the effect of symptomatic DSPN on the QOL of T2DM patients in a sample of the Brazilian population, correlating clinical and electrophysiological findings, besides comparing the results obtained by the Medical Outcomes Study Questionaire 36-Item Short Form Health Survey (SF-36) among patients with painful and non-painful diabetic DSPN. METHODS: This study comprised 25 outpatients with DSPN and T2DM submitted to a detailed anamnesis to identify clinical and demographic characteristics, besides comorbidities and complications of DM. Clinical evaluation was performed through neurological physical examination, in addition to specific scales for neuropathy as the Neuropathy Disability Score (NDS). In order to assess the health-related quality of life (HRQoL) of these patients, the SF-36 translated and adapted for the Brazilian population was applied. Nerve conduction study (NCS) was performed for the examined nerves (motor part of peroneal nerve and sensory part of the sural nerve). The following parameters were assessed: motor conduction velocity (MCV), amplitude of the compound muscle action potentials (CMAP) and amplitude of the sensory nerve action potentials (SNAP). RESULTS: Role Physical (RP) domain of SF-36 was significantly related to some of the clinical and electrophysiological factors measured. RP had an inverse and significant relationship with the NDS values (Rho: -0.44), showing the impact of neuropathy severity on these patients’ QOL. The sural nerve SNAP and peroneal nerve MCV showed a significant and positive relationship with RP (Rho: 0,52 and 0,36, respectively). The Mental Health (MH) domain showed a statistically significant difference between those patients with pain and without pain (p = 0.002), and patients without pain had higher mean values, as well as a higher minimum and maximum value. The Role Emotional (RE) domain also showed a significant difference between patients with and without pain, and patients with pain had a lower mean value (p = 0.04). For all other domains, patients with pain showed lower mean values than those without pain, however without statistical difference in the test performed. Between DM complications, only nephropathy presented statistically different RP scores from those without nephropathy (p = 0.02). CONCLUSION: There was a significant inverse relationship between the severity of DSPN and the QOL of the evaluated patients, as evidenced by lower values in the SF-36 specific RP domain, as polyneuropathy becomes more severe. This domain also presented significantly lower values in patients with associated nephropathy. The presence of pain negatively affected the QOL of patients with painful DPN, who presented significantly lower mean values in the MH and RE domains when compared to patients without pain.

The relationship between nerve conduction studies and neuropathic pain in sciatic nerve injury due to intramuscular injection.

BackgroundSciatic nerve injury due to intramuscular injection (SNIII) is still a health problem. This study aimed to determine whether there is a correlation between neuropathic pain and electrodiagnostic findings in SNIII.MethodsPatients whose clinical and electrodiagnostic findings were compatible with SNIII participated in this retrospective cohort study. Compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the sural, superficial peroneal, peroneal, and tibial nerves were graded from 1 to 4. Leeds assessment of neuropathic symptoms and signs scale (LANSS) was applied to all patients.ResultsForty-eight patients were included in the study, 67% of whom had a LANSS score ≥ 12. Sural SNAP amplitude abnormalities were present in 8 (50%) out of 16 patients with a LANSS score < 12, and 28 (87.5%) out of 32 patients with a LANSS score ≥ 12, with significant differences between the groups (P = 0.011). There was a positive correlation between the LANSS score and the sural SNAP amplitude grading (P = 0.001, r = 0.476). A similar positive correlation was also found in the LANSS score and the tibial nerve CMAP amplitude grading (P = 0.004, r = 0.410).ConclusionsThis study showed a positive correlation between the severity of tibial nerve CMAP/sural SNAP amplitude abnormality and LANSS score in SNIII. Neuropathic pain may be more common in SNIII patients with sural nerve SNAP amplitude abnormality.

Reference values of dorsal sural sensory nerve action potential: A useful tool to diagnose peripheral neuropathy

Background: Dorsal sural sensory nerve is the most distal nerve of the lower limb for which its sensory nerve action potential (SNAP) could be helpful for the diagnosis of early and subclinical peripheral neuropathy. The objective of this study was to estimate the age and sex reference data of amplitude (Amp), onset latency (OL), and conduction velocity (CV) of SNAP. Materials and Methods: A prospective cross-sectional study was conducted among 50 healthy subjects (28 male and 22 female). Participants were stratified into Group A (≤50 years) and Group B (>50 years) according to their age. Student's t-test was used to compare the data between Group A and B, between male and female and Pearson correlation was used to analyze the correlation between age and SNAP parameters. Results: OL of Group A and Group B was 2.80 ± 0.36 ms and 3.11 ± 0.55 ms, respectively (P = 0.037). CV of Group A and Group B was 45.6 ± 3.33 m/sec and 39.5 ± 1.17 m/sec, respectively (P = 0.000). Amp of Group A and Group B was 6.63 ± 0.73 μV 4.99 ± 0.47 μV, respectively (P = 0.000). OL of male and female was 2.59 ± 0.28 ms 3.34 ± 0.25 ms, respectively (P = 0.000). Pearson correlation coefficient “r” between “age– OL,” “age– CV,” and “age– Amp” was 0.135 (P = 0.351), −0.759 (P = 0.000), 0.953 (P = 0.000), respectively. Conclusion: This study provides age and sex reference values of dorsal sural SNAP in the eastern part of the Indian population.