Identification and Prediction of Diabetic Sensorimotor Polyneuropathy Using Individual and Simple Combinations of Nerve Conduction Study Parameters

Objective

Evaluation of diabetic sensorimotor polyneuropathy (DSP) is hindered by the need for complex nerve conduction study (NCS) protocols and lack of predictive biomarkers. We aimed to determine the performance of single and simple combinations of NCS parameters for identification and future prediction of DSP.

Materials and Methods

406 participants (61 with type 1 diabetes and 345 with type 2 diabetes) with a broad spectrum of neuropathy, from none to severe, underwent NCS to determine presence or absence of DSP for cross-sectional (concurrent validity) analysis. The 109 participants without baseline DSP were re-evaluated for its future onset (predictive validity). Performance of NCS parameters was compared by area under the receiver operating characteristic curve (AROC).

Results

At baseline there were 246 (60%) Prevalent Cases. After 3.9 years mean follow-up, 25 (23%) of the 109 Prevalent Controls that were followed became Incident DSP Cases. Threshold values for peroneal conduction velocity and sural amplitude potential best identified Prevalent Cases (AROC 0.90 and 0.83, sensitivity 80 and 83%, specificity 89 and 72%, respectively). Baseline tibial F-wave latency, peroneal conduction velocity and the sum of three lower limb nerve conduction velocities (sural, peroneal, and tibial) best predicted 4-year incidence (AROC 0.79, 0.79, and 0.85; sensitivity 79, 70, and 81%; specificity 63, 74 and 77%, respectively).

Discussion

Individual NCS parameters or their simple combinations are valid measures for identification and future prediction of DSP. Further research into the predictive roles of tibial F-wave latencies, peroneal conduction velocity, and sum of conduction velocities as markers of incipient nerve injury is needed to risk-stratify individuals for clinical and research protocols.     

Clinical and electrophysiologic findings in dialysis patients

The aim of this study was to quantitatively determine the electrophysiologic changes occurring in the peripheral nerves and muscles in patients with chronic renal failure (CRF) treated with haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD), and to determine which electrophysiologic parameters are most commonly abnormal in uraemic patients. We investigated the relationship between the parameters of neurography and quantitative electromyography (QEMG) and clinical findings.The study included 42 patients with CRF (30 on HD and 12 on CAPD). Nerve conduction studies (NCSs) of the median, ulnar, tibial, peroneal, and sural nerves, and QEMG of the tibialis anterior and biceps brachii muscles were performed.We found axonal and/or demyelinating polyneuropathies in 97.6% of the patients (100% of HD and 91.7% of CAPD patients), but were not able to verify any significant differences between the HD and CAPD patients using NCS or QEMG. Median, ulnar, sural sensory nerve action potential (SNAP) amplitudes, peroneal CV and F-latency were the most common abnormal parameters in sensory and motor NCSs, respectively. The clinical findings only correlated with the parameters of neurography, and not with the parameters of QEMG. Sural SNAP amplitudes, peroneal and tibial CVs, F-latencies also correlated with the severity of the clinical findings in these patients, suggesting that these parameters can be used in follow up studies in these patients.In this study, most of the uraemic patients were found to have already mild or moderate neuropathies in which the objective clinical signs might be absent, even if they have some clinical symptoms. NCS showed abnormality indicating polyneuropathy in 24 out of 25 patients with clinical neuropathy signs and in 17 out of 17 patients with no clinical signs. Thus, in subclinical conditions NCS is useful to detect the abnormalities in peripheral nerves of the ureamic patients under chronic dialysis.     

Multichannel surface electrodes increase the sensitivity of diagnosis of neuropathy in diabetic patients

This prospective study investigated the diagnostic sensitivity of a novel multichannel surface electrode for detecting electrophysiologic changes in symptomatic diabetic neuropathy. We recruited healthy subjects without neuropathic complaints and diabetic patients with distal symmetric sensory symptoms who had normal nerve conduction studies (NCS). Eight compound muscle action potentials (CMAPs) were recorded using a multichannel electrode from each subject’s abductor pollicis brevis muscle by stimulating the median nerve at the wrist. Latency- and amplitude-related variables were obtained and analyzed to compare the two groups. We used the Classification and Regression Tree (CART) algorithm to determine the cut-off values for selected predictors of diabetic neuropathy. All of the variables related to CMAP latency showed statistically significant differences between the median values for the diabetic group and the healthy control group. For example, the median value of the maximum latency and standard deviation of the eight CMAP onset latencies in diabetic patients (3.82 ms and 0.15 ms, respectively) were significantly larger than those in controls (3.26 ms and p < 0.001; 0.09 ms and p < 0.001, respectively). The CART analysis revealed that these variables were the most sensitive and specific variables for discriminating between patients with diabetic neuropathy and normal subjects. The multichannel surface electrode demonstrated both high sensitivity and specificity in detecting neurophysiologic abnormality of diabetic neuropathy, even when conventional NCS did not detect the abnormality.     

Diabetic polyneuropathy. 4. Synopsis of electroneurographic findings in diabetics]

Sensory conduction velocity of the median nerve, motor conduction velocity of both median and tibial nerves, and corresponding distal laterncies are sufficient parameters to establish the diagnosis of polyneuropathy almost with certainty. Considering these six parameters yielded in detection of peripheral nerve dysfunction in 22% of diabetic patients who were free from clinical signs of polyneuropathy. Electroneurographical findings in 340 out of 677 patients with diabetes mellitus were interpreted as evidence of segmental demyelination. Within this group there was the majority of patients with clinical signs of polyneuropathy and with subclinical signs of peripheral nerve dysfunction. There existed a positive correlation between signs of nerve dysfunction with angiopathy, age and duration of the disease. A second group consisting of 243 diabetics with signs of incipient segmental demyelination with or without signs of axonaal degeneration mainly included juvenile patients with a short duration of the disease and with a low frequency of angiopathy.     

Treatment with statins and involvement of the peripheral nervous system: results of a prospective clinical and neurophysiological follow-up

Aims: To study the pathological changes in neurophysiological examination of lower-limb peripheral nerves in patients with long-term statin treatment. Methods: Forty-two patients (23 males, 19 females, mean age 51.9 and 52.3 years) with a definitive diagnosis of combined hyperlipidemia were studied. Other metabolic disorders or chronic ethanol abuse were excluded. Initial examinations included laboratory and neurophysiological measures (peroneal and tibial nerves: MNCV, CMAP, Fwave mean latency; superficial peroneal and sural nerve: SNCV, SNAP). Subsequently, treatment with simvastatin 20mg daily was initiated. Patients were followed for 24 months with examinations at 1, 6, 12 and 24 months after statin treatment initiation. Results: None of the patients reported subjective symptoms typical for polyneuropathy. In laboratory findings, there was no elevation of muscle enzymes. Nevertheless, electrophysiological examination of lower-limb peripheral nerves demonstrated statistically significant prolongation of F-wave mean latency on peroneal and tibial nerves (p < 0.0001, paired t-test). A control group of 50 patients with combined hyperlipidemia but no statin treatment showed no changes over the same time interval. The study demonstrated that long-term Conclusions: The study demonstrated that long-term treatment with statins might cause a clinically silent but still electrophysiologically definite damage to peripheral nerves.     

The effects of zenarestat, an aldose reductase inhibitor, on minimal F-wave latency and nerve blood flow in streptozotocin-induced diabetic rats

The effects of zenarestat, 3-(4-bromo-2-fluorobenzyl)-7-chloro-3,4-dihydro-2,4-dioxo-1(2H)-quinazolineacetic acid, an aldose reductase inhibitor (ARI), on F-wave conduction abnormalities, nerve blood flow (NBF) reduction and sorbitol accumulation were studied in streptozotocin-induced diabetic rats. Two weeks after the induction of diabetes, zenarestat was given once a day for two weeks. In diabetic control rats, marked accumulation of sorbitol, reduction of NBF and prolongation of minimal F-wave latency (FWL) were observed as compared to normal rats. Zenarestat, at a dose of 32 mg/kg, inhibited sorbitol concentration to nearly the normal rat level and significantly improved not only NBF but also minimal FWL. At a dose of 3.2 mg/kg, sorbitol accumulation was inhibited by approximately 40% and there was a tendency to increase in NBF; however, minimal FWL was not improved at all. These data suggest that a highly inhibition of the nerve sorbitol accumulation is requisite for the treatment of diabetic peripheral neuropathy.     

The diabetic polyneuropathy. II. Polyneuropathy, angiopathy and nerve conduction velocity

789 patients with diabetes mellitus were studied by clinical and electroneurographical examination. Motor conduction velocity of the median and the tibial nerve and sensory conduction of the median nerve were determined. 81.1% of the patients we suffering from diabetes which began in childhood or adolescence, 13.9% were suffering from maturity onset diabetes. Average duration of the disease was 9.5 years, average age was 26.7 years. Clinical signs of polyneuropathy were found in 19.1%. Typical findings were pain and paraesthesia, lack or abolition of triceps surae reflexes, impaired pallaesthesia on lower extremities. 48.3% of 151 patients with clinical signs of polyneuropathy were suffering from combined angiopathy, 32.5% from microangiopathy, 7.9% from macroangiopathy. Severity of complicating retinopathy and macroangio,athy were found to be correlated with polyneuropathy. 58.2% of 323 diabetics with at least one delayed nerve conduction velocity exhibited signs of angiopathy. In nearly 30% of children and adolescents after comparatively short duration of the disease at least one conduction velocity was delayed. In diabetic children and adolescents metabolic disturbances are assumed to cause peripheral nerve dysfunction.     

手足温针灸联合步行阶梯训练对老年糖尿病周围神经病变患者步态异常、血流动力学和感觉及运动神经传导的影响

摘要 目的：观察手足温针灸联合步行阶梯训练对老年糖尿病周围神经病变（DPN）患者步态异常、血流动力学和感觉及运动神经传导的影响。方法：按照随机数字表法将上海市第六人民医院2020年3月~2022年1月期间收治的119例老年DPN患者分为对照组（n=59,步行阶梯训练）和研究组（n=60,手足温针灸联合步行阶梯训练）。对比两组疗效、步态异常、血流动力学、临床症状改善情况和感觉及运动神经传导变化情况。结果：研究组91.67%的临床总有效率高于对照组72.88%（P<0.05）。研究组干预后的密歇根糖尿病神经病变评分（MDNS）和多伦多临床评分系统（TCSS）评分低于对照组（P<0.05）。研究组干预后的腓总神经及胫神经的感觉神经传导速度（SNCV）、运动神经传导速度（MNCV）高于对照组（P<0.05）。研究组干预后的全血黏度、血浆比黏度、纤维蛋白原低于对照组（P<0.05）。研究组足底压力中心轨迹（COP）曲线异常、全足平衡性曲线异常、全足压力变化曲线异常例数少于对照组（P<0.05）。结论：手足温针灸联合步行阶梯训练可促进老年DPN患者步态异常、血流动力学和感觉及运动神经传导恢复,疗效较好。     

Treatment of diabetic polyneuropathy with the antioxidant thioctic acid (alpha-lipoic acid): a two year multicenter randomized double-blind placebo-controlled trial (ALADIN II). Alpha Lipoic Acid in Diabetic Neuropathy.

Short-term trials with the antioxidant thioctic acid (TA) appear to improve neuropathic symptoms in diabetic patients, but the long-term response remains to be established. Therefore, Type 1 and Type 2 diabetic patients with symptomatic polyneuropathy were randomly assigned to three treatment regimens: (1) 2 x 600(mg of TA (TA 1200), (2) 600)mg of TA plus placebo (PLA) (TA 600) or (3) placebo and placebo (PLA). A trometamol salt solution of TA of 1200 or 600 mg or PLA was intravenously administered once daily for five consecutive days before enrolling the patients in the oral treatment phase. The study was prospective, PLA-controlled, randomized, double-blind and conducted for two years. Severity of diabetic neuropathy was assessed by the Neuropathy Disability Score (NDS) and electrophysiological attributes of the sural (sensory nerve conduction velocity (SNCV), sensory nerve action potential (SNAP)) and the tibial (motor nerve conduction velocity (MNCV), motor nerve distal latency (MNDL)) nerve. Statistical analysis was performed after independent reviewers excluded all patients with highly variable data allowing a final analysis of 65 patients (TA 1200: n = 18, TA 600: n = 27; PLA: n = 20). At baseline no significant differences were noted between the groups regarding the demographic variables and peripheral nerve function parameters for these 65 patients. Statistically significant changes after 24 months between TA and PLA were observed (mean +/- SD) for sural SNCV: +3.8 +/- 4.2 m/s in TA 1200, +3.0+/-3.0m/s in TA 600, -0.1+/-4.8m/s in PLA (p < 0.05 for TA 1200 and TA 600 vs. PLA); sural SNAP: +0.6+/-2.5 microV in TA 1200, +0.3+/-1.4 microV in TA 600, -0.7 +/- 1.5 microV in PLA (p = 0.076 for TA 1200 vs. PLA and p < 0.05 for TA 600 vs. PLA), and in tibial MNCV: +/- 1.2 +/- 3.8 m/s in TA 1200, -0.3 +/- 5.2 m/s in TA 600, 1.5 +/- 2.9 m/s in PLA (p < 0.05 for TA 1200 vs. PLA). No significant differences between the groups after 24 months were noted regarding the tibial MNDL and the NDS. We conclude that in a subgroup of patients after exclusion of patients with excessive test variability throughout the trial, TA appeared to have a beneficial effect on several attributes of nerve conduction.     

Treatment of symptomatic diabetic neuropathy by surgical decompression of multiple peripheral nerves.

Symptomatic diabetic sensorimotor polyneuropathy is considered progressive and irreversible. The hypothesis that symptoms of diabetic neuropathy may be due to entrapment of peripheral nerves was investigated in a prospective study from 1982 to 1988 in which diabetics (38 type I, 22 type II) had surgical decompression of 154 peripheral nerves in 51 upper extremities and 31 lower extremities. Mean postoperative follow-up was 30 months (range 6 to 83 months). Considering the entire series, an excellent final result was noted for motor function in 44 percent and for sensory function in 67 percent of the decompressed nerves. Ten percent of the patients were not improved, and 2 percent were worse in sensorimotor function. Upper extremity nerve decompressions achieved better results than lower extremity nerve decompressions. Improvement in postoperative electrodiagnostic studies varied in relationship to the preoperative electrodiagnosis. Improvement was noted in 100 percent of those nerves with the preoperative diagnosis of "localized entrapment," 80 percent for "peripheral neuropathy with superimposed entrapment," and 50 percent for "peripheral neuropathy." Progressive neuropathy occurred in a nontreated limb of 50 percent of those patients whose surgically treated limb maintained improvement. The results of this study suggest that symptoms of sensorimotor diabetic neuropathy may be due partly to compression of multiple peripheral nerves. The results further suggest that surgical decompression of such nerves may result in symptomatic improvement.     

丹蛭降糖胶囊联合硫辛酸、依帕司他对气阴两虚夹瘀型糖尿病周围神经病变患者血糖水平和下肢神经功能的影响

摘要 目的：探讨丹蛭降糖胶囊联合硫辛酸、依帕司他治疗气阴两虚夹瘀型糖尿病周围神经病变（DPN）的临床疗效,并分析其对血糖和下肢神经功能的影响。方法：按照随机数字表法将81例DPN患者分成对照组40例和观察组41例,对照组在2型糖尿病治疗基础上使用硫辛酸静滴联合依帕司他口服治疗,观察组在对照组治疗基础上,加用丹蛭降糖胶囊口服治疗。比较两组治疗前后中医证候积分、双下肢肌电图[腓总神经运动神经传导速度（MCV）、腓肠神经感觉神经传导速度（SCV）]、电流感觉阈值（CPT值）、血糖指标[空腹血糖（FPG）、餐后2小时血糖（2 hBG）、糖化血红蛋白（HbA1c）]水平变化,并对比两组总有效率和治疗方案安全性。结果：观察组总有效率为90.24%（37/41）,明显高于对照组的70.00%（28/40）,差异有统计学意义（P＜0.05）;治疗8周后,两组肢体麻木、肢体末梢疼痛、神疲乏力、气短懒言、腰膝酸软、失眠烦躁积分,FPG、2 hBG、HbA1c水平均明显降低（P＜0.05）,且观察组各项中医证候积分和血糖指标水平均明显低于对照组（P＜0.05）;治疗8周后,观察组相同频率正弦交流电刺激下的第一脚趾远端趾节甲小皮基部近端的CPT值均明显低于对照组（P＜0.05）,腓总神经MCV、腓肠神经SCV均明显高于对照组（P＜0.05）;两组治疗过程中均未发生明显药物不良反应。结论：丹蛭降糖胶囊口服联合硫辛酸、依帕司他治疗气阴两虚夹瘀型DPN,能够有效缓解患者的临床症状和体征,控制血糖水平,改善下肢神经功能,疗效明显优于单纯西药治疗,且安全性高。     

Evaluation of Proxy Tests for SFSN: Evidence for Mixed Small and Large Fiber Dysfunction

Background

Though intra-epidermal nerve fiber density (IENFD) is considered the gold standard for diagnosis of small fiber sensory neuropathy (SFSN), we aimed to determine if novel threshold values derived from standard tests of small or large fiber function could serve as diagnostic alternatives.

Methods

Seventy-four consecutive patients with painful polyneuropathy and normal nerve conduction studies (NCS) were defined as SFSN cases or controls by distal IENFD <5.4 and ≥5.4 fibers/mm, respectively. Diagnostic performance of small fiber [cooling (CDT) and heat perception (HP) thresholds, axon reflex-mediated neurogenic vasodilatation] and large fiber function tests [vibration perception thresholds (VPT) and sural nerve conduction parameters] were determined by receiver operating-characteristic (ROC) curve analyses.

Results

The 26(35%) SFSN cases had mean IENFD 3.3±1.7 fibers/mm and the 48(65%) controls 9.9±2.9 fibers/mm. Male gender (p = 0.02) and older age (p = 0.02) were associated with SFSN cases compared to controls. VPT were higher and CDT lower in SFSN cases, but the largest magnitude of differences was observed for sural nerve amplitude. It had the greatest area under the ROC curve (0.75) compared to all other tests (p<0.001 for all comparisons) and the optimal threshold value of ≤12 µV defined SFSN cases with 80% sensitivity and 72% specificity.

Conclusion

In patients presenting with polyneuropathy manifestations and normal NCS, though small fiber function tests were intuitively considered the best alternative measures to predict reduced IENFD, their diagnostic performance was poor. Instead, novel threshold values within the normal range for large fiber tests should be considered as an alternative strategy to select subjects for skin biopsy in diagnostic protocols for SFSN.     

Corneal Confocal Microscopy Detects Neuropathy in Patients with Type 1 Diabetes without Retinopathy or Microalbuminuria

Objective

Corneal innervation is increasingly used as a surrogate marker of human diabetic peripheral neuropathy (DPN) however its temporal relationship with the other microvascular complications of diabetes is not fully established. In this cross-sectional, observational study we aimed to assess whether neuropathy occurred in patients with type 1 diabetes, without retinopathy or microalbuminuria.

Materials and Methods

All participants underwent detailed assessment of peripheral neuropathy [neuropathy disability score (NDS), vibration perception threshold (VPT), peroneal motor nerve conduction velocity (PMNCV), sural sensory nerve conduction velocity (SSNCV) and in vivo corneal confocal microscopy (IVCCM)], retinopathy (digital fundus photography) and albuminuria status [albumin: creatinine ratio (ACR)].

Results

53 patients with Type 1 diabetes with (n=37) and without retinopathy (n=16) were compared to control subjects (n=27). SSNCV, corneal nerve fibre (CNFD) and branch (CNBD) density and length (CNFL) were reduced significantly (p<0.001) in diabetic patients without retinopathy compared to control subjects. Furthermore, CNFD, CNBD and CNFL were also significantly (p<0.001) reduced in diabetic patients without microalbuminuria (n=39), compared to control subjects. Greater neuropathic severity was associated with established retinopathy and microalbuminuria.

Conclusions

IVCCM detects early small fibre damage in the absence of retinopathy or microalbuminuria in patients with Type 1 diabetes.     

Treatment of diabetic polyneuropathy with the antioxidant thioctic acid (α-lipoic acid): A two year multicenter randomized double-blind placebo-controlled trial (ALADIN II)

Short-term trials with the antioxidant thioctic acid (TA) appear to improve neuropathic symptoms in diabetic patients, but the long-term response remains to be established. Therefore, Type 1 and Type 2 diabetic patients with symptomatic polyneuropathy were randomly assigned to three treatment regimens: (1) 2 × 600 mg of TA (TA 1200), (2) 600 mg of TA plus placebo (PLA) (TA 600) or (3) placebo and placebo (PLA). A trometamol salt solution of TA of 1200 or 600 mg or PLA was intravenously administered once daily for five consecutive days before enrolling the patients in the oral treatment phase. The study was prospective, PLA-controlled, randomized, double-blind and conducted for two years. Severity of diabetic neuropathy was assessed by the Neuropathy Disability Score (NDS) and electrophysiological attributes of the sural (sensory nerve conduction velocity (SNCV), sensory nerve action potential (SNAP)) and the tibial (motor nerve conduction velocity (MNCV), motor nerve distal latency (MNDL)) nerve. Statistical analysis was performed after independent reviewers excluded all patients with highly variable data allowing a final analysis of 65 patients (TA 1200: n = 18, TA 600: n = 27; PLA: n = 20). At baseline no significant differences were noted between the groups regarding the demographic variables and peripheral nerve function parameters for these 65 patients. Statistically significant changes after 24 months between TA and PLA were observed (mean ± SD) for sural SNCV: +3.8 ± 4.2 m/s in TA 1200, +3.0 ± 3.0 m/s in TA 600, -0.1 ± 4.8 m/s in PLA (p < 0.05 for TA 1200 and TA 600 vs. PLA); sural SNAP: +0.6 ± 2.5 μV in TA 1200, +0.3 ± 1.4 μV in TA 600, -0.7 ± 1.5 μV in PLA (p = 0.076 for TA 1200 vs. PLA and p < 0.05 for TA 600 vs. PLA), and in tibial MNCV: +1.2 ± 3.8 m/s in TA 1200, -0.3 ± 5.2 m/s in TA 600, -1.5 ± 2.9 m/s in PLA (p < 0.05 for TA 1200 vs. PLA). No significant differences between the groups after 24 months were noted regarding the tibial MNDL and the NDS. We conclude that in a subgroup of patients after exclusion of patients with excessive test variability throughout the trial, TA appeared to have a beneficial effect on several attributes of nerve conduction.     

不同剂量甲钴胺联合GM1治疗糖尿病周围神经病变疗效观察

目的:探讨不同剂量甲钴胺联合单唾液酸四己糖神经节苷脂(GM1)治疗糖尿病周围神经病变的疗效。方法:收取2013年3月至2016年3月我院收治的糖尿病周围神经病变患者116例作为研究对象,按照随机数字表法分为A、B组各58例。A组患者使用高剂量甲钴胺联合GM1治疗,B组患者使用常规剂量甲钴胺联合GM1治疗。对两组治疗效果、神经电生理、不良反应以及患者生活质量进行观察与比较。结果:A组患者治疗显效率和总有效率分别为63.79%和96.55%,显著高于B组的39.66%和84.48%,差异有统计学意义(P0.05)。治疗后两组患者腓神经及正中神经运动神经传导速度(MCV)以及感觉神经传导速度(SCV)均显著提高,与治疗前相比有显著差异,且A组变化幅度明显高于B组,差异有统计学意义(P0.05)。A组不良反应发生率为6.70%,B组为3.45%,两组相较差异不显著(P0.05)。治疗后A组生活质量得分高于B组,差异有统计学意义(P0.05)。结论:高剂量甲钴胺联合GM1治疗糖尿病周围神经病变与常规剂量相比具有更好的疗效,有助于患者生活质量的提高,值得临床推广应用。     

Protective effects of 4-amino1,8-napthalimide, a poly (ADP-ribose) polymerase inhibitor in experimental diabetic neuropathy

Peripheral diabetic neuropathy is a heterogeneous group of disorders, and is known to affect 50-60% of diabetic patients. Poly (ADP-ribose) polymerase (PARP) activation has been identified as one of the key components in the pathogenesis of diabetic neuropathy. In the present study we have targeted PARP overactivation in diabetic neuropathy using a known PARP inhibitor, 4 amino 1, 8-napthalimide (4-ANI). Streptozotocin induced diabetic rats developed neuropathy within 6 weeks, which was evident from significant reduction in motor nerve conduction velocity (MNCV), nerve blood flow (NBF) along with neuropathic pain and abnormal sensory perception. Six weeks after diabetes induction Sprague Dawley rats were treated with 4-ANI (3 and 10 mg/kg, p.o.) for a period of two weeks (seventh and eighth weeks). Two week treatment with 4-ANI showed improvement in nerve conduction, nerve blood flow and reduction in tail flick responses and mechanical allodynia in diabetic animals. 4-ANI also attenuated PAR immunoreactivity and NAD depletion in nerves of diabetic animals. Results of present study suggest the potential of PARP inhibitors like 4-ANI in the treatment of diabetic neuropathy.     

Neurophysiological study to assess the severity of each site through the motor neuron fiber in entrapment neuropathy

The purpose of this study is to evaluate prospectively the sensitivities of conventional and new electrophysiological techniques and to investigate their relationship with the body mass index (BMI) in a population of patients suspected of having carpal tunnel syndrome (CTS). In this study, 165 hands of 92 consecutive patients (81 female, 11 male) with clinical diagnosis of CTS were compared to reference population of 60 hands of 30 healthy subjects (26 female and 4 male). Extensive sensory and motor nerve conduction studies (NCSs) were performed in the diagnosis of subtle CTS patients. Also, the patients were divided into subgroups and sensitivities were determined according to BMI. The mean BMI was found to be significantly higher in the CTS than in the control group (p < 0.001). The sensitivity of the median sensory nerve latency (mSDL) and median motor distal latency (mMDL) were 75.8% and 68.5%, respectively. The most sensitive parameters of sensory and motor NCSs were the difference between median and ulnar sensory distal latencies to the fourth digit [(D4M-D4U), (77%)] and the median motor terminal latency index [(mTLI), (70.3%)], while the median-to-ulnar sensory action potential amplitude ratio (27%) and the median-thenar to ulnar-hypothenar motor action potential amplitude ratio (15%) were least sensitive tests. Sensory tests were more sensitive than motor NCSs. Combining mSDL with D4M-D4U, and mMDL with mTLI allowed for the detection of abnormalities in 150 (91%) and 132 (80%) hands, respectively. Measurements of all NCSs parameters were abnormal in obese than in non-obese patients when compared to the BMI. The newer nerve conduction techniques and combining different NCSs tests are more sensitive than single conventional NCS test for the diagnosis of suspected CTS. Meanwhile, CTS is associated with increasing BMI.     

Primary Hyperparathyroidism is Associated With subclinical Peripheral Neural Alterations

ObjectiveSome case reports have suggested primary hyperparathyroidism (PHPT) and peripheral polyneuropathy (PPN) are associated; however, there are no reports of studies examining this possible relationship. The aim of this study was to evaluate peripheral nerve conduction in subjects with PHPT.MethodsThe study involved 17 patients with PHPT. Mean patient age was 60.5 ± 12.9 years, serum calcium concentration was 11.5 ± 1.0 mg/dL, and the serum parathyroid hormone (PTH) level was 315 ± 569 pg/dL. The control group comprised 17 individuals without PHPT. The mean age of controls was 60.8 ± 12.5 years and the serum calcium concentration was 9.8 ± 0.3 mg/dL. Motor and sensory nerve conduction was assessed by electroneurography (ENG).ResultsThe following ENG parameters differed significantly between the PHPT and control groups: right (R) sural sensory nerve action potential conduction velocity (52.7 ± 6.3 m/s versus 58.0 ± 8.0 m/s; P = .041); R median compound muscle action potential (CMAP) amplitude (7.4 ± 1.6 mV versus 8.9 ± 1.7 mV; P = .002); R median CMAP latency (4.3 ± 1.2 ms versus 3.6 ± 0.6 ms; P = .032); R tibial CMAP latency (4.2 ± 1.1 ms versus 3.3 ± 0.4 ms; P = .001). The neurological examination was normal in all patients.ConclusionOur data demonstrate an association between PHPT and peripheral neurological alterations, consistent with subclinical sensory-motor PPN. (Endocr Pract. 2013;19:219-225)     

An Electrophysiological Study of Acute Tetrodotoxin Poisoning

To evaluate the electrophysiological changes in patients with acute tetrodotoxin (TTX) poisoning from ingestion of globefish (Tetraodontidae) patients exposed to TTX were compared with age-matched controls. The cohort of TTX-poisoning cases was clinically subdivided into mild, moderate, or severe cases. The motor nerve conduction velocity (MCV), sensory nerve conduction velocity (SCV), F-wave, H-reflex, and somatosensory-evoked potentials (SEP) of the median, ulnar, and common peroneal nerve (CPN) were determined using established techniques. Four of the 64 (6.3%) TTX-poisoning cases died and were omitted from the final analysis. The MCV and SCV of the median, ulnar, and CPN nerves in all the TTX-poisoning cases were significantly slower than the healthy controls. Severe cases of TTX poisoning had more significant reduction in nerve function. Thus, electroneurophysiological analysis could be used to determine the extent, course, and range of nerve system damage in patients with acute TTX poisoning.     

Dermatomal and mixed nerve somatosensory evoked potentials in the diagnosis of neurogenic thoracic outlet syndrome

To evaluate the diagnostic utility of dermatomal and mixed nerve somatosensory evoked potentials (SEPs) in patients with thoracic outlet syndrome (TOS) and to compare their value with routine electrodiagnostic methods, we studied a group of 44 patients with neurogenic TOS and 30 healthy controls. In addition to bilateral median and ulnar SEPs, evoked potentials were recorded after stimulation of C6 and C8 dermatomes from the first and fifth digits, respectively. The patients were classified into 3 groups according to the nature of their clinical condition. The abnormality rate for both ulnar and C8 dermatomal SEPs was 100% in a small group of patients with severe neurological signs like atrophy. In groups of patients with lesser degrees of neurogenic damage, abnormality rates for ulnar and C8 dermatomal SEPs on affected limb(s) were 67 and 50%, respectively. Same abnormality rates were 25 and 18% in patients with only subjective symptoms. In patients with objective neurological signs, the major increase in sensitivity was with electromyography (EMG). Abnormalities of routine nerve conduction studies and F-wave latency were observed in patients with severe neurogenic damage. We concluded that the most useful tests in the diagnosis of neurogenic TOS are needle EMG and ulnar SEPs.