Dorsal Sural Nerve Research Articles

N°300 – The value of the dorsal sural nerve in the evolutive diabetic peripheral polyneuropathy

N°300 – The value of the dorsal sural nerve in the evolutive diabetic peripheral polyneuropathy

Nerve Conduction Studies of Dorsal Sural Nerve: Normative Data and Its Potential Application in ATTRv Pre-Symptomatic Subjects.

The objective of the study is to provide age-related normative values for dorsal sural nerve (DSN) and to analyse its application during follow-up of hereditary transthyretin amyloidosis (ATTRv) pre-symptomatic subjects. We consecutively recruited ATTRv pre-symptomatic carriers in which clinical examination, cardiological evaluation, and nerve conduction studies of the sural nerve and DSN were performed. To provide normative data of DSN, neurophysiologic parameters from healthy controls referred to our service were entered into linear regression analyses to check the relative influence of age and height. A correction grid was then derived. We collected 231 healthy subjects: the mean DSN sensory nerve action potential (SNAP) amplitude was 9.99 ± 5.48 μV; the mean conduction velocity was 49.01 ± 5.31 m/s. Significant correlations were found between age and height with DSN SNAP amplitude. Fifteen ATTRv pre-symptomatic carriers were examined. Sural nerve NCS were normal in 12/15 and revealed low/borderline values in three subjects. Considering our correction grid, we found an abnormal DNS amplitude in 9/15 subjects and low/borderline values in 2/15. In ATTRv, early detection of peripheral nerve damage is crucial to start a disease-modifying treatment. DSN may be easily and reliably included in the routine neurophysiological follow-up of ATTRv pre-symptomatic subjects.

P.102 Role of interdigital sensory nerve conduction study as a noninvasive approach for early diagnosis of diabetic peripheral neuropathy

Background: Diabetes mellitus is a common cause of polyneuropathy. Despite numerous diagnostic tools such as routine electrophysiologic procedures, its early detection is challenging. This study compares a distal electrodiagnostic technique, with conventional approaches to investigate its role in confirming early polyneuropathy. Methods: Thirty-one symptomatic diabetic outpatients and 23 asymptomatic nondiabetic subjects were included in our study. We performed nerve conduction studies on the dorsal sural, medial plantar, and digital branches of the interdigital nerves to toes I, II, and III (as a new antidromic technique). All techniques were applied with the surface stimulator and pick-up electrodes. Results: Only 9 (29%) of patients had impaired routine NCSs. Interestingly, the results of interdigital nerve studies were abnormal in 17 out of 22 patients with normal routine NCSs. Also, 11 and 13 subjects had impaired medial plantar and dorsal sural nerves conduction studies, respectively. According to this method, the prevalence of detectable diabetic neuropathy increased from 46% to 83%. Conclusions: The digital sensory branches can be easily evaluated with the new antidromic SNAP technique for the early diagnosis of diabetic polyneuropathy, especially in presymptomatic and subclinical neuropathies. This method is simple, non-invasive, sensitive, and reproducible. There is no need for needle electrodes or averaging techniques.

Role of interdigital sensory nerve conduction study as a noninvasive approach for early diagnosis of diabetic peripheral neuropathy.

Diabetes mellitus is amongst the most common causes of polyneuropathy worldwide that can eventually terminate to irreversible complications. The remarkable impact of diabetic polyneuropathy as a debilitating condition on the healthcare system and total costs of diabetes care is undeniable. Despite the existence of numerous diagnostic tools such as routine electrophysiologic procedures, its early detection is challenging. This study designed to compare more distal techniques of electrodiagnostic testing, including interdigital sensory nerve conduction studies (NCSs), with conventional approaches and to investigate its role in confirming the early stages of polyneuropathy. This cross-sectional study was performed in the Physical Medicine and Rehabilitation Department of Hazrat Fatemeh Reconstruction Surgery Hospital. Thirty one symptomatic diabetic outpatients and 23 asymptomatic nondiabetic subjects included in our study. We performed nerve conduction studies on five sensory nerves consist of the dorsal sural nerve, medial plantar nerve, digital branches of the interdigital nerves to toes I, II, and III (as a new antidromic technique). In this study, all techniques applied with a surface stimulator and pick-up electrodes. In the group of patients, 9 (29%) and 22 (71%) subjects had impaired and normal routine NCSs, respectively. Interestingly, the results of interdigital nerve studies were abnormal in the 17 out of 22 patients with normal routine NCSs. Also, 11 and 13 subjects had impaired medial plantar nerve and dorsal sural nerve conduction studies, respectively. Accordingly, with this new method, the prevalence of detectable diabetic neuropathy increased from 46% to 83%. We conducted this study intending to demonstrate the application of a new technique for early diagnosis of diabetic polyneuropathy, especially in the presymptomatic and subclinical neuropathies. The digital sensory branches of IDNs known as the most distal sensory nerves, which can be easily evaluated with new antidromic SNAP technique. Our method is simple, non-invasive, suitable, sensitive, and reproducible. There is no need to needle electrode or averaging technique to record an appropriate amplitude of IDN. Thus, it is recommended as a convenient electrophysiological option for early diagnosis of DPN.

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.

Normative reference values for the dorsal sural nerve derived from a large multicenter cohort

ObjectivesDorsal sural nerve conduction studies (NCS) may increase the sensitivity for the diagnosis of polyneuropathy, but clinical use is limited by a lack of reliable normative reference values in all age-groups. The aim of our study was to develop reference values for the dorsal sural nerve, based on a large multicenter cohort of healthy subjects. MethodsBilateral antidromic NCS were performed using standard surface electrodes in 229 healthy subjects (aged 21–80 years; median: 54 years). We assessed the normality of data distribution for amplitudes and conduction velocity (CV) and for their logarithmic (ln) transformation. The effects of age and height were determined using linear regression analysis. ResultsSensory potentials were present in all subjects. Logarithmically transformed data were normally distributed. Age2 and height were most significantly associated with amplitude, and age and height with CV, respectively. There was no significant side-difference. Mean amplitudes (right and left) were 4.8 and 4.9 μV and mean CV 46.7 and 46.9 m/s. Reference limits were e (3.712515 – 0.0000956 * age2 – 0.0115883 * height ± 1.96 * 0.51137) for amplitude and e (4.354374 – 0.0021081 * age – 0.0023354 * height ± 1.96 * 0.11161) for CV. ConclusionsDorsal sural nerve NCS are robust and have well defined normative limits. SignificanceThe findings provide a basis for more sensitive NCS in clinical practice and future studies of the diagnostic accuracy of NCS in polyneuropathy.

P75-F Evaluation of deterioration in sensory nerve conduction studies in Amyotrophic Lateral Sclerosis

Background Many neurophysiological and pathological studies showed sensory abnormalities in ALS patients as a part of multisystem disease. In this study, we assessed progression of sensory changes in ALS patients, using nerve conduction studies (sNCS) in two consecutive visits. Material and methods sNCSs were evaluated based on amplitudes and velocities of bilateral dorsal sural (DS), medial plantar, superficial peroneal (SP), sural and left radial sensory nerves. In addition a global Total Sensory Score (TSens) was determined using the amplitudes of these nerves. Results Although, for both visits, TSens was smaller in patients (p = 0.04 and P = 0.01, for consecutive visits) then controls, there was no significant change between two visits of the patients (P = 0.19). ALS patients had significantly smaller amplitudes and slower velocities for bilateral DS, and left radial nerves for both visits. TSens was reduced in 7 (63.3%) but increased in 4 (36.6%) ALS patients. Conclusions Although, ALS patients showed considerable changes in NCS, sensory denervation is probably slowly progressive. The patients with improved sNCS were attributed to possible changes in sensory nerve excitability following corrective measures, e.g. administration of parenteral gastrostomy or high caloric diet.

Mid-term oral isotretinoin therapy causes a predominantly sensory demyelinating neuropathy.

The purpose of this prospective study was to investigate whether mid-term treatment with oral isotretinoin may impact peripheral nerve function. In this study, we included 28 patients with no apparent neurological or neurophysiological findings. The patients received treatment with oral isotretinoin for papulopustular or nodulocystic acne. The patients with normal findings in the first examination were given 1 mg/kg/day oral isotretinoin. Neurological examinations and electroneurographic studies were performed before and 6 months after the onset of isotretinoin treatment. Clinical examinations and electroneurographic evaluations prior to treatment revealed no abnormalities in any of the patients. However, 20 patients (72%) displayed one or more abnormal values in the tested parameters after treatment. Although the mean amplitudes of compound muscle action potential of the ulnar and median nerves did not vary, significant decreases were observed in the mean sensory conduction velocities of median, ulnar, sural, medial plantar, medial dorsal cutaneous, and dorsal sural nerves 6 months after the onset of treatment. Systemic use of isotretinoin may cause electroneurographic changes. Probable electroneurographic alterations may be detected at a much earlier period via dorsal sural nerve tracing when electrophysiological methods used in routine clinical practice cannot detect these changes.

Risk stratification of oxaliplatin induced peripheral neurotoxicity applying electrophysiological testing of dorsal sural nerve.

We aimed to verify the predictiveness of dorsal sural nerve neurophysiological monitoring in obtaining risk stratification for oxaliplatin-induced peripheral neurotoxicity (OXAPN). We conducted a secondary analysis on a cohort of 110 colorectal cancer patients who were evaluated clinically and neurophysiologically before chemotherapy, at mid-treatment and at discontinuation. We applied the classification tree analysis method to predict the end-of-treatment OXAPN neurophysiological diagnosis, using data recorded at mid-treatment. We then ascertained the correlation between the obtained classes and neurological impairment at the end of treatment (Fisher's exact test). Dorsal sural nerve monitoring enabled us to stratify oxaliplatin-treated patients into risk classes with an implemented approach to neurophysiology application in this setting. Neurological outcome at discontinuation was predicted by neurophysiological monitoring performed during chemotherapy administration. We demonstrated the role that neurophysiology may play in clinical trials as an early surrogate marker that can predict OXAPN development at the end of treatment. Specifically, we propose abnormal dorsal sural sensory nerve testing as an early biomarker in identifying patients at high risk of eventually developing OXAPN.

O6 The utility of distal nerve conduction studies and sural near-nerve needle recording in electrodiagnosis of polyneuropathy

Objectives To compare the diagnostic utilities of distal surface electrode recording of dorsal sural and medial plantar nerves and near-nerve technique (NNT) and conventional surface recording of sural nerve. Methods Ninety-one patients referred for electrodiagnostic examination of polyneuropathy (PNP) were included. Bilateral nerve conduction studies (NCS) of the sural nerve with NNT and surface recording, and of the distal nerves with surface recording were done in all patients. Results were compared to 37 age-matched healthy subjects. The final clinical diagnosis retrieved from the patients’ medical records as diagnostic reference standard showed PNP in 68 patients (PNP+) and 20 patients did not have PNP (PNP−). Results The sensitivities of the dorsal sural (68%) and medial plantar (70%) nerves were similar to that of NNT recording of the sural nerve (74%), while the sensitivity of surface recording of the sural nerve was lower (55%). High specificities (93–98%) were seen for sural NCS with both NNT and surface recording and for the dorsal sural nerve, while the specificity for medial plantar nerve was low (76%). Discussion In concert with previous reports, distal nerves have higher sensitivity than conventional sural nerve. Additionally, the sensitivity of distal nerves was found to be similar to examination of sural nerve with NNT. Conclusion NCS of the distal nerves, especially the dorsal sural nerve, have a high diagnostic power at an identical level of that of needle recording of the sural nerve. Significance Examination of distal nerves.should be included into routine electrodiagnostic evaluation of patients with suspected PNP.

Diagnostic utility of distal nerve conduction studies and sural near-nerve needle recording in polyneuropathy.

The electrodiagnosis of polyneuropathy (PNP) may benefit from examination using near-nerve needle technique (NNT) and from inclusion of distal nerves. This study compared the diagnostic utility of distal nerve conduction studies (NCS) and NNT recording. Bilateral NNT and surface recording of the sural nerve and surface recording of the dorsal sural and medial plantar nerves were prospectively done in 91 patients with clinically suspected PNP. Distal NCS were additionally done in 37 healthy controls. Diagnostic reference standard was the final clinical diagnosis retrieved from the patients medical records after 1-4years. The clinical follow-up diagnosis confirmed PNP in 68 patients. Equally high sensitivities of the dorsal sural (72%), medial plantar (75%), and sural nerve with NNT recording (77%) were seen, while the sensitivity of conventional surface recording of the sural nerve was lower (60%). Sural NCS with both NNT and surface recording and dorsal sural NCS showed high specificities (85-95%) and positive predictive values (94-98%), while a lower specificity was seen for the medial plantar nerve (68%). NCS of distal nerves, especially the dorsal sural nerve, have high diagnostic power equalling sural NNT recording. The electrodiagnostic evaluation of patients with suspected PNP benefits from NCS of distal nerves.

A new technique for dorsal sural nerve conduction study with surface strip electrodes.

To obtain higher amplitude of dorsal sural sensory nerve action potentials (SNAPs), we used a new method for dorsal sural nerve conduction study with surface strip electrodes (SSEs). Dorsal sural SNAPs were recorded orthodromically. The recording electrodes were placed behind the lateral malleolus. SSEs were attached to the laterodorsal aspect of the foot for stimulation of the dorsal sural nerve (DSN). We also used a conventional method with a standard bipolar stimulator and compared the findings. Dorsal sural SNAPs were recordable bilaterally from 49 healthy volunteers. Mean peak-to-peak amplitude for SNAPs was 12.9±6.3μV, and mean nerve conduction velocity was 44.8±5.5m/s. The mean amplitude of SNAPs obtained by our method was 118.6% higher than that of SNAPs obtained by the conventional method (12.9μVvs. 5.9μV; P<0.001). The highest amplitude of dorsal sural SNAPs was constantly obtained by SSEs since SNAPs arising from whole digital branches of the DSN could be elicited by placement of SSEs. When the DSN supplies more cutaneous branches to the lateral half of the foot, SSEs gives higher amplitude of dorsal sural SNAPs than that of the standard innervation type.

Dorsal Sural Sensory Nerve Action Potential: A Study for Reference Values.

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.

Variations in the distal branches of the superficial fibular sensory nerve.

We evaluated anatomic variations of distal branches of the superficial fibular sensory nerve electrophysiologically. Orthodromic nerve conduction studies (NCS) of the first and third branches (M-I, M-III) of the medial dorsal cutaneous nerve and the fourth and fifth branches (I-IV, I-V) of the intermediate dorsal cutaneous nerve (IDCN) were performed. To find anomalous innervations from the dorsal sural nerve (DSN) in the IDCN territory, NCS of the fourth and fifth branches (S-IV, S-V) of the DSN were also performed. All sensory nerve action potentials (SNAPs) of M-I and M-III could be obtained bilaterally from 31 healthy Japanese volunteers. SNAPs of I-IV and I-V were recordable in 85.5% and 43.5% of feet, respectively. Anomalous innervations from the DSN were confirmed in 71.0% of S-IV and 93.5% of S-V. These results suggest that anatomical variations in the IDCN territory are very frequent in Japanese subjects. Muscle Nerve 55: 74-76, 2017.

Role of inflammation in sensory neuropathy in prediabetes or diabetes.

Prediabetes includes individuals with impaired glucose metabolism, and it has been associated with various complications of diabetes mellitus (DM), including peripheral neuropathy. We aimed to investigate the associations between pro-inflammatory (TNF-α) and anti-inflammatory (IL-10) cytokines and neuropathy of very distal sensory nerves in patients with prediabetes or type 2 DM. We included 50 patients with prediabetes, 50 patients with type 2 DM, and 44 controls in the study. Plasma levels of HbA1c, TNF-α, and IL-10 were analyzed. Electrodiagnostic testing was performed on dorsal sural and medial plantar sensory nerves, which are the very distal sensory nerves of the feet. Abnormalities in nerve conduction studies (NCS) of the dorsal sural and medial plantar sensory nerves were substantially higher in patients with prediabetes or type 2 DM. In addition, plasma levels of TNF-α were significantly higher in patients with type 2 DM than in controls, whereas IL-10 levels were significantly lower in patients with both prediabetes and diabetes. However, we found no correlation between the levels of HbA1c, TNF-α, IL-10, and abnormalities in NCS of the dorsal sural or medial plantar sensory nerves in either patient group. To our knowledge, this is the first study to assess the relationships between TNF-α, IL-10, and NCS of the most distal sensory nerves in patients with prediabetes or type 2 DM. The mechanisms involved in the pathogenesis of DM and diabetic peripheral neuropathy are complex. The pro-inflammatory stage and the high incidence of neuropathy in patients with prediabetes may suggest a possible causative effect; however, the potential role of inflammation in the pathogenesis of peripheral neuropathy needs further clarification.

Side and time variability of intraepidermal nerve fiber density.

To assess the right-to-left and short-term variability of intraepidermal nerve fiber density (IENFD) at the distal site of the leg. Patients with possible or probable small fiber neuropathy (SFN) and healthy volunteers (HVs) underwent skin biopsies at the right and left distal leg. A subgroup of participants underwent follow-up biopsies 20 days later. Biopsies were immunostained by polyclonal anti-protein gene product 9.5 antibodies, and IENFD was quantified in nonconsecutive sections following published guidelines by operators blinded to the participants' condition (diagnosis, side, and time of biopsy). Findings were referred to sex- and age-adjusted normative values. Forty patients and 17 HVs underwent bilateral skin biopsies; 15 patients and 8 HVs underwent follow-up skin biopsies. Sural nerve and dorsal sural nerve conduction studies were normal in all participants. Interside IENFD did not differ both in patients (median 2.45 IENF/mm ± 1.45 SD right; 2.2 IENF/mm ± 1.32 SD left) and HVs (median 6.3 IENF/mm ± 2.81 right; 6.2 IENF/mm ± 2.3 SD left). The right-to-left correlation coefficients were excellent (Pearson 0.95 in SFN and 0.97 in HVs). The analysis of IENFD at 20-day follow-up biopsy showed no difference between sides in both groups and yielded excellent correlation coefficients. The diagnosis of SFN can be reliably ascertained by unilateral skin biopsy at the distal site of the leg, and IENFD is not expected to vary within 3 weeks.

Prevalence of neuropathy in patients with impaired glucose tolerance using various electrophysiological tests.

Neuropathy is often an associated feature woth long-standing type II diabetes mellitus. Neuropathy may occur even in subjects with impaired glucose tolerance. To study the prevalence of neuropathy using different electrophysiological techniques in subjects with impaired glucose tolerance (IGT) and no other identifiable cause of neuropathy. The study was conducted on 30 age-matched controls and 58 subjects with impaired oral glucose tolerance test (OGTT) attending diabetic awareness. Prediabetes was defined using World Health Organization (WHO) criteria. All subjects had normal glycosylated hemoglobin HbA (1c), vitamin B12 levels, and thyroid function. Neuropathy was evaluated by nerve conduction studies (NCS) performed on one upper and both lower limbs, dorsal sural nerve, medial and lateral planter nerve conductions using conventional techniques. Neuropathy was also evaluated by autononic function tests, and quantitative sensory testing (QST). The subjects were followed up for 4 years. Out of 58 subjects, 19 (32.8%) had neuropathy. Nerve conduction studies showed evidence of neuropathy in 14 (24.13%) subjects, autonomic neuropathy was detected in 8 (13.8%), and QST was found to be abnormal in 16 (27.6%) subjects. Twenty subjects (34.5%) developed diabetes mellitus in the follow-up period. Neuropathy was detected in 32.8% subjects with IGT. Small fiber neuropathy was most common. Of all the three parameters studied, QST was found to be most sensitive technique for the detection of neuropathy. Assessment of medial plantar and dorsal sural NCS increases the sensitivity in the detection of neuropathy.

Early predictors of oxaliplatin-induced cumulative neuropathy in colorectal cancer patients

ObjectivesPeripheral neuropathy ranks among the most common dose-limiting and disabling side-effect of oxaliplatin (OXA)-based chemotherapy. The aim of this prospective, multicentre study was to define early clinical and neurophysiological markers...

Neurophysiological examination of dorsal sural nerve

Nerve conduction study of the dorsal sural nerve (DSN) has been reported to be a sensitive method for early detection of peripheral neuropathies. However, normal reference values are scarce and vary greatly among the different studies. A comprehensive neurophysiological study, including nerve conduction velocity (NCV) and sensory nerve action potential (SNAP) recording, was performed in 294 healthy subjects (21-86 years) with no evidence of neuropathy. The amplitude of the DSN SNAP ranged from 2.50 to 15.90 μV, and NCV ranged from 28.9 to 52.8 m/s. A significant age-related decrease in DSN SNAP amplitude and NCV was observed. The mean ratio of sural NCV to DSN NCV was 1.33 ± 0.19, and the mean ratio of sural nerve SNAP amplitude to DSN SNAP amplitude was 3.17 ± 1.33. These normative data of the DSN might be used as reference values for the study of this very distal peripheral nerve.

Assessment of the Medial Dorsal Cutaneous, Dorsal Sural, and Medial Plantar Nerves in Impaired Glucose Tolerance and Diabetic Patients With Normal Sural and Superficial Peroneal Nerve Responses

OBJECTIVEThis study evaluated the nerve conduction study (NCS) parameters of the most distal sensory nerves of the lower extremities—namely, the medial dorsal cutaneous (MDC), dorsal sural (DS), and medial plantar (MP) nerves—in diabetic (DM) and impaired glucose tolerance (IGT) patients who displayed normal findings on their routine NCSs.RESEARCH DESIGN AND METHODSStandard NCSs were performed on healthy control (HC), DM, and IGT groups (N = 147). The bilateral NCS parameters of the MDC, DS, and MP nerves were investigated. The Toronto Clinical Scoring System (TCSS) was assessed for the DM and IGT groups.RESULTSThe mean TCSS scores of the IGT and DM groups were 2.5 ± 2.3 and 2.8 ± 2.2, respectively. No significant differences between the two groups were observed. After adjustment of age and BMI, the DM group showed significant NCS differences in DS and MDC nerves compared with the HC group (P < 0.05). These differences were also exhibited in the left DS of the IGT group (P = 0.0003). More advanced NCS findings were observed in the DM group. Bilateral abnormal NCS responses in these distal sensory nerves were found in 40 and 16% of DM and IGT patients, respectively.CONCLUSIONSThese results showed that the simultaneous assessment of the most distal sensory nerves allowed the detection of early NCS changes in the IGT and DM groups, even when the routine NCS showed normal findings.