Sensory Nerve Action Potentials Research Articles

Nerve conduction velocities in radiologic technologists: A pilot study

Objectives: Radiologic technologists (RTs) are typically exposed to low doses of radiations for longer periods, which have a health risk over many organs and tissues. Resistant tissues like nerves have shown neuropathic changes due to acute high-dose radiation exposure in the form of radiation therapy but the effect of low-dose chronic radiation exposure over peripheral nerves in RTs has been studied scantily. Materials and Methods: Nerve conduction parameters were recorded from 30 RTs and 30 age- and sex-matched healthy individuals who were not exposed to radiation. Motor nerve conduction study (NCS) of bilateral median, ulnar, radial, common peroneal and tibial nerves and sensory NCS of bilateral median, ulnar and radial nerves were recorded and compared. Results: Significant changes were observed in the form of reduction in motor and sensory nerve conduction velocity (P < 0.05) in all the examined nerves. Sensory nerve action potential (SNAP) amplitudes were reduced and latencies were prolonged significantly (P < 0.05) in all the examined sensory nerves. We also found reduced compound muscle action potential amplitude (significant in ulnar, radial, common peroneal and tibial nerves) along with prolonged motor distal latencies (significant in median, ulnar and tibial nerves) among RTs compared to healthy individuals. Conclusion: Chronic low-dose exposure of ionising radiation causes sub-clinical neuropathies affecting both sensory and motor nerves.

Prolonged median distal sensory nerve action potential duration in carpal tunnel syndrome.

Routine nerve conduction study (NCS) parameters are less sensitive in the early stage of carpal tunnel syndrome (CTS). Recently, some studies have shown that prolonged distal sensory nerve action potential (DSNAP) duration may be a more sensitive technique for the diagnosis of demyelinating peripheral neuropathies. We aimed to evaluate the sensitivity of median DSNAP duration in patients with CTS. DSNAP duration and routine NCS data of the median nerve were retrospectively collected in 173 CTS patients, 73 controls, and 78 cervical radiculopathy patients. Prolonged median DSNAP durations were found in 22 patients (22/35, 63%) and 36 patients (36/54, 67%) in the minimal and mild CTS groups respectively, which was more sensitive than routine NCS parameters. The percentage of patients demonstrating abnormalities in median NCS was significantly increased from 80% to 92% with the addition of DSNAP duration. Our results demonstrate the electrodiagnostic value of median DSNAP duration for the diagnosis of CTS, especially in early cases.

Chemotherapy-induced peripheral neuropathy: longitudinal analysis of predictors for postural control

Impaired postural control is often observed in response to neurotoxic chemotherapy. However, potential explanatory factors other than chemotherapy-induced peripheral neuropathy (CIPN) have not been adequately considered to date due to primarily cross-sectional study designs. Our objective was to comprehensively analyze postural control during and after neurotoxic chemotherapy, and to identify potential CIPN-independent predictors for its impairment. Postural control and CIPN symptoms (EORTC QLQ-CIPN20) were longitudinally assessed before, during and three weeks after neurotoxic chemotherapy, and in three and six months follow-up examinations (N = 54). The influence of peripheral nerve function as determined by nerve conduction studies (NCS: compound motor action potentials (CMAP) and sensory action potentials (SNAP)), physical activity, and muscle strength on the change in postural control during and after chemotherapy was analyzed by multiple linear regression adjusted for age and body mass index. Postural control, CIPN signs/symptoms, and CMAP/SNAP amplitudes significantly deteriorated during chemotherapy (p < .01). During follow-up, patients recovered from postural instabilities (p < .01), whereas CIPN signs/symptoms and pathologic NCS findings persisted compared to baseline (p < .001). The regression model showed that low CMAP and high SNAP amplitudes at baseline predicted impairment of postural control during but not after chemotherapy. Hence, pre-therapeutically disturbed somatosensory inputs may induce adaptive processes that have compensatory effects and allow recovery of postural control while CIPN signs/symptoms and pathologic peripheral nerve function persist. Baseline NCS findings in cancer patients who receive neurotoxic chemotherapy thus might assist in delineating individual CIPN risk profiles more precisely to which specific exercise intervention programs could be tailor-made.

Effects of acute glial cell activation on memory performance – Implications for treatment of cognitive symptoms in neurological and psychiatric disorders

Paclitaxel, a widely used anti-cancer drug, is frequently associated with prolonged and severe peripheral neuropathies (PIPN), associated with neuroinflammation. Currently, PIPN effective treatments are lacking. Peroxisome Proliferator-Activated Receptor-α (PPAR-⍺) can modulate inflammatory responses. Thus, the use of PPAR-⍺ agonists, such as fibrates (fenofibrate and choline-fenofibrate), currently used in dyslipidemia treatment, could represent an interesting therapeutic approach in PIPN.Our studies tested the efficacy of fenofibrate (150 mg/kg, daily, i.p.) and choline fenofibrate (60 mg/kg daily, p.o.) in reversing and preventing the development of PIPN (paclitaxel: 8 mg/kg, i.p., every other day for 4 days) in male and female C57BL/6J mice. Mechanical and cold hypersensitivity, conditioned place preference, sensory nerve action potential (SNAP), as well as the expression of PPAR-⍺, TNF-⍺, IL-1β and IL-6 mRNA were evaluated.While fenofibrate treatment partially reversed and prevented the development of mechanical hypersensitivity, this was completely reversed and prevented by choline-fenofibrate. Both fibrates were able to completely reverse and prevent cold hypersensitivity induced by paclitaxel. The reduction of SNAP amplitude induced by paclitaxel was also reversed by both fenofibrate and choline-fenofibrate. Our results indicate that suppression of paclitaxel-induced hypersensitivity by fibrates involves the regulation of PPAR-⍺ expression and decrease neuroinflammation in DRG. Finally, the co-treatment of Paclitaxel and fenofibric acid (fibrates active metabolite) was tested on different cancer cell lines, no decrease in the antitumoral effect of paclitaxel was observed.Taken together, our results show for the first time the therapeutic potential (prevention and reversal) of fibrates in PIPN and opens to a potential pharmacological repurposing of these drugs.

Ultrasound guidance may have advantages over landmark-based guidance for some nerve conduction studies.

Precise placement of stimulating and recording electrodes is vital when performing nerve conduction studies (NCSs). In this study, we aimed to determine whether ultrasonography (US) was more precise in localizing the superficial radial nerve (SRN), dorsal ulnar cutaneous nerve (DUCN), ulnar nerve (UN) crossing the cubital tunnel, and radial nerve (RN) crossing the spiral groove (SG) compared to conventional techniques. Thirty healthy young subjects (15 male) were recruited. Each subject underwent both landmark-based and US-guided NCS. Onset latencies and amplitudes of compound motor action potentials (CMAPs) and sensory nerve action potentials (SNAPs), and stimulation levels (ie, intensity × duration) required to obtain maximal CMAP amplitudes were compared between the two techniques. The mean CMAP amplitudes of the UN above the cubital tunnel (9.55 ± 1.96 vs 8.96 ± 1.94 mV, P = .030), UN below the cubital tunnel (10.11 ± 2.07 vs 9.37 ± 1.95 mV, P < .001), and RN below the SG (5.21 ± 1.56 vs 4.34 ± 1.03 mV, P < .001) were significantly greater using US-guided NCSs compared to landmark-based NCSs. The mean onset latency of the DUCN was significantly shorter using US-guided NCSs (1.49 ± 0.15 vs 1.57 ± 0.14 ms, P = .020). The required stimulation level in the UN and RN was significantly lower using US-guided NCSs. When performing NCSs, US guidance provides a more precise localization of the stimulator and electrodes for the DUCN, UN, and RN, while providing comparable localization for the SRN, compared to landmark-based techniques.

Targeting Peroxisome Proliferator-Activated Receptor-α (PPAR- α) to reduce paclitaxel-induced peripheral neuropathy

Background and purposePaclitaxel, a widely used anti-cancer drug, is frequently associated with prolonged and severe peripheral neuropathies (PIPN), associated with neuroinflammation. Currently, PIPN effective treatments are lacking. Peroxisome Proliferator-Activated Receptor-α (PPAR-⍺) can modulate inflammatory responses. Thus, the use of PPAR-⍺ agonists, such as fibrates (fenofibrate and choline-fenofibrate), currently used in dyslipidemia treatment, could represent an interesting therapeutic approach in PIPN. Experimental approachOur studies tested the efficacy of fenofibrate (150 mg/kg, daily, i.p.) and choline fenofibrate (60 mg/kg daily, p.o.) in reversing and preventing the development of PIPN (paclitaxel: 8 mg/kg, i.p., every other day for 4 days) in male and female C57BL/6J mice. Mechanical and cold hypersensitivity, conditioned place preference, sensory nerve action potential (SNAP), as well as the expression of PPAR-⍺, TNF-⍺, IL-1β and IL-6 mRNA were evaluated. Key resultsWhile fenofibrate treatment partially reversed and prevented the development of mechanical hypersensitivity, this was completely reversed and prevented by choline-fenofibrate. Both fibrates were able to completely reverse and prevent cold hypersensitivity induced by paclitaxel. The reduction of SNAP amplitude induced by paclitaxel was also reversed by both fenofibrate and choline-fenofibrate. Our results indicate that suppression of paclitaxel-induced hypersensitivity by fibrates involves the regulation of PPAR-⍺ expression and decrease neuroinflammation in DRG. Finally, the co-treatment of Paclitaxel and fenofibric acid (fibrates active metabolite) was tested on different cancer cell lines, no decrease in the antitumoral effect of paclitaxel was observed. Conclusions and implicationsTaken together, our results show for the first time the therapeutic potential (prevention and reversal) of fibrates in PIPN and opens to a potential pharmacological repurposing of these drugs.

Impact of shoulder subluxation on peripheral nerve conduction and function of hemiplegic upper extremity in stroke patients: A retrospective, matched-pair study

ABSTRACT Purpose: To investigate the impact of shoulder subluxation (SS) on peripheral nerve conduction and function of the hemiplegic upper extremity (HUE) in poststroke patients. Methods: Thirty post-stroke patients were selected (SS group: 15 patients, non-SS group: 15 patients, respectively). Evaluation of nerve conduction in upper limbs: the compound muscle action potential (CMAP) amplitude and latency of suprascapular, axillary, musculocutaneous, radial, median, and ulnar nerves; the motor and sensory conduction velocity and the sensory nerve action potential (SNAP) amplitude of median, ulnar, and radial nerves. The Brunnstrom stage scale was used to evaluate the HUE motor function. Results: Compared with the healthy side, the CMAP and SNAP amplitudes of tested nerves on the HUE in both groups were lower, and the CMAP latency of the suprascapular, axillary and musculocutaneous nerves on the HUE in the SS group was longer (P < 0.05). Compared with the HUE in non-SS group, the CMAP amplitude of tested nerves (except ulnar) was decreased more (P < 0.05), the motor conduction velocity of the median nerve was lower (P < 0.05), and the Brunnstrom stage of the HUE was lower in SS group (P < 0.05). Conclusions: Stroke may lead to extensive abnormal nerve conduction on the HUE, and SS may aggravate the abnormality, which may disturb the recovery of upper limb function.

Body mass index: A modifying factor of median nerve conduction

Background: Nerve conduction studies are important electrophysiological tests used to assess functional status of peripheral nerves. Entrapment of median nerve in carpal tunnel is a possibility in high body mass index (BMI). Aim and Objectives: The objective of this study was to determine BMI as a modifying factor of median nerve conduction. Materials and Methods: Forty-seven healthy male subjects were divided in three study groups, that is, normal, pre-obese, and obese according to BMI. Nerve conduction study was tested to compare different parameters of compound motor action potential (CMAP) and sensory nerve action potential (SNAP). Parameters used for SNAP were peak latency (PL), conduction velocity (CV), and amplitude (Amp). Parameters used for CMAP were distal motor latency (DML), CV, and amplitude (Amp). Results: In the right median nerve, CMAP between various groups represented significant prolongation of DML (P = 0.000) and slowing CV (P = 0.000) with increasing BMI. In the left median nerve, CMAP between various groups represented significant prolongation of DML (P = 0.000) and slowing CV (P = 0.000) with increasing BMI. In the right median nerve, SNAP between various groups represented significant prolongation of PL (P = 0.000) and slowing CV (P = 0.000) with increasing BMI. In the left median nerve, SNAP between various groups represented significant prolongation of PL (P = 0.000) and slowing CV (P = 0.000) with increasing BMI. Conclusion: Our study suggested BMI as the substantial factor to affect median nerve conduction at carpal tunnel. Thus, high BMI plays crucial role to develop carpal tunnel syndrome (CTS).

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.

Clinical Features of Ulnar Tunnel Syndrome and the Diagnostic Value of Nerve Conduction Measurements.

ABSTRACTObjectives:The purposes of this study were to assess the clinical features of ulnar tunnel syndrome (UTS) and to investigate the diagnostic value of nerve conduction measurements for UTS.Methods:Eighteen patients with UTS were reviewed retrospectively. Fifteen patients had intrinsic muscle atrophy and motor weakness, and 15 had numbness with hypesthesia. The compound muscle action potentials (CMAPs) from the first dorsal interosseous (FDI) muscle and the abductor digiti minimi (ADM) muscle and the sensory nerve action potential (SNAP) from the little finger were recorded and analyzed. All patients underwent ulnar tunnel release surgery and neurolysis. Static two-point discrimination test results and pinch strengths were assessed before and after surgery.Results:Before surgery, FDI-CMAP was recorded in 17 patients, and ADM-CMAP in 16, and all showed delayed latency and/or low amplitude. SNAP was recorded in eight patients and two showed delayed latency. The causes of ulnar nerve lesions were ganglion in five patients, traumatic adhesion in four, ulnar artery aberrancy in four, pisohamate arch in three, anomalous muscle in one, and ulnar vein varix in one. The sites of the lesions were in zone 1 of the ulnar tunnel anatomy in 12 patients, in zone 2 in 2, and in zones 1 and 2 in 4. After surgery, all patients obtained recovery of motor function and sensation; however, postoperative FDI-CMAP and ADM-CMAP did not improve to the normal range.Conclusions:The causes of UTS were ganglion, traumatic adhesion, ulnar artery aberrancy, and pisohamate arch. Both FDI-CMAP and ADM-CMAP were valuable for electrophysiological diagnosis of UTS.

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.

Relationship Between Cervical Nerve Root Entrapment Due to Cervical 6-7 Foraminal Stenosis and Sensory Nerve Action Potentials in Nerve Conduction Study

Objective To compare the sensory nerve action potentials (SNAPs) between patients with cervical 6-7 foraminal stenosis (FS) and those without. Methods We enrolled patients who underwent a bilateral nerve conduction study (NCS) between January 2016 and December 2017. The FS group (n=35) included patients whose lesion was located at C6-7 FS. The non-FS group (n=75) had no lesions at C6-7 foramen. The amplitudes and latencies of SNAPs on the affected side were compared between the two groups. The proportion of those with abnormal SNAP responses was also evaluated. Results Compared with the non-FS group, the FS group had a significantly lower amplitude (30.5 vs. 40.2 µV; age-adjusted p<0.001) and a longer latency (3.31 vs. 3.17 ms; age-adjusted p=0.001) of the median nerve. Abnormal amplitude was observed in 20.0% of the FS group and 4.0% of the non-FS group (age-adjusted p=0.007), and abnormal latency was observed in 45.7% of the FS group and 26.7% of the non-FS group (age-adjusted p=0.010). The median SNAP ratio between the affected side and the unaffected side was not significantly different between the two groups. Conclusion Patients with C6-7 FS had a lower amplitude and a longer latency of the median nerve than did those without. Abnormal SNAP amplitude and latency were significantly more common in patients with FS. SNAP amplitude may be used as a predictor of cervical FS. Keywords: Electrodiagnosis; Cervical foraminal stenosis; Sensory nerve action potential; Median nerve

Effect of Fascia Penetration in Lateral Femoral Cutaneous Nerve Conduction

ObjectiveTo evaluate the effect of fascia penetration and develop a new technique for lateral femoral cutaneous nerve (LFCN) conduction studies based on the fascia penetration point (PP) identified using ultrasound.MethodsThe fascia PP of the LFCN was localized in 20 healthy subjects, and sensory nerve action potentials (SNAPs) were obtained at four different stimulation points—2 cm proximal to the PP (2PPP), PP, 2 cm distal to the PP (2DPP), and 4 cm distal to the PP (4DPP). We compared the stimulation technique based on the fascia penetration point (STBFP) with the conventional technique.ResultsThe SNAP amplitude of the LFCN was significantly higher when stimulation was performed at the PP and 2DPP than at other stimulation points. Using the STBFP, SNAP responses were elicited in 38 of 40 legs, whereas they were elicited in 32 of 40 legs using the conventional technique (p=0.041). STBFP had a comparable SNAP amplitude and slightly delayed negative peak latency compared to the conventional technique. In terms of the time required, the time spent on STBFP showed a more consistent distribution than the time spent on the conventional technique (two-sample Kolmogorov–Smirnov test, p<0.05).ConclusionSNAP of the LFCN significantly changed near the fascia PP, and stimulation at PP and at 2DPP provided high amplitudes. STBFP can help increase the response rate and ensure stable and consistent procedure time of the LFCN conduction study.

A Fenofibrate Diet Prevents Paclitaxel-Induced Peripheral Neuropathy in Mice.

Simple SummaryPaclitaxel, a drug used in the treatment of malignancies such as lung, ovarian and breast cancer, often produces severe side effects, among which is peripheral neuropathy. This neuropathy involves diffuse or localized pain, notably burning pain, cold and mechanical hyperexcitability. Recently, fenofibrate, a Food and Drug Administration (FDA)-approved drug for the treatment of dyslipidemia, has been shown to reduce the severity of symptoms in other forms of peripheral neuropathy. In the current work, we tested whether fenofibrate could reverse mechanical and cold hypersensitivity and improve motivation and the reduction in nerve conduction in a mouse model of paclitaxel-induced neuropathy. Our behavioral, histological and molecular assessments indicate that fenofibrate prevents the development of paclitaxel-induced neuropathy. Taken together, our studies support the therapeutic potential of fenofibrate in the prevention of paclitaxel-induced neuropathy and suggest the possible repurposing of this drug for this purpose in the clinic.Background: Paclitaxel-induced peripheral neuropathy (PIPN) is a major adverse effect of this chemotherapeutic agent that is used in the treatment of a number of solid malignancies. PIPN leads notably to burning pain, cold and mechanical allodynia. PIPN is thought to be a consequence of alterations of mitochondrial function, hyperexcitability of neurons, nerve fiber loss, oxidative stress and neuroinflammation in dorsal root ganglia (DRG) and spinal cord (SC). Therefore, reducing neuroinflammation could potentially attenuate neuropathy symptoms. Peroxisome proliferator-activated receptor-α (PPAR-α) nuclear receptors that modulate inflammatory responses can be targeted by non-selective agonists, such as fenofibrate, which is used in the treatment of dyslipidemia. Methods: Our studies tested the efficacy of a fenofibrate diet (0.2% and 0.4%) in preventing the development of PIPN. Paclitaxel (8 mg/kg) was administered via 4 intraperitoneal (i.p.) injections in C57BL/6J mice (both male and female). Mechanical and cold hypersensitivity, wheel running activity, sensory nerve action potential (SNAP), sciatic nerve histology, intra-epidermal fibers, as well as the expression of PPAR-α and neuroinflammation were evaluated in DRG and SC. Results: Fenofibrate in the diet partially prevented the development of mechanical hypersensitivity but completely prevented cold hypersensitivity and the decrease in wheel running activity induced by paclitaxel. The reduction in SNAP amplitude induced by paclitaxel was also prevented by fenofibrate. Our results indicate that suppression of paclitaxel-induced pain by fenofibrate involves the regulation of PPAR-α expression through reduction in neuroinflammation. Finally, co-administration of paclitaxel and the active metabolite of fenofibrate (fenofibric acid) did not interfere with the suppression of tumor cell growth or clonogenicity by paclitaxel in ovarian and breast cancer cell lines. Conclusions: Taken together, our results show the therapeutic potential of fenofibrate in the prevention of PIPN development.

Dissociation of axo-glial junction in anti-neurofascin 155 chronic inflammatory demyelinating polyneuropathy.

A subset of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is characterized by the presence of anti-neurofascin 155 (anti-NF155) autoantibodies. In this paper, we investigated an anti-NF155 CIDP patient via clinical, electrophysiological, and neuropathological tests. The patient was a 15-year-old Chinese boy affected by distal limb weakness and tremor for a 6-month period. The patient was positive for serum anti-NF155 antibodies, high cerebrospinal fluid protein levels and symmetric hypertrophy of lumbosacral roots in MRI. Elongation of distal and F-wave latencies and decrease of compound muscle action potentials in motor nerves were recorded. Sensory nerve action potentials were absent. He accepted sural nerve biopsy. Sural nerve biopsy demonstrated the typical pathological change of loss of transverse bands with mild detachment of terminal myelin loop from axon at the paranode. Some thin myelinated fibers and axonal degeneration were recorded. Besides, we found some myelin balloon formations with compressed axons. We suggest that antibodies against F155 might be responsible for axo-glial junction disruptions leading to the dissociation of myelin and axon. Both conduction block and axonal impairment contributed to the neuropathy in anti-NF155 CIDP.

Electrophysiologically verified effects of acupuncture on diabetic peripheral neuropathy in type 2 diabetes: The randomized, partially double-blinded, controlled ACUDIN trial.

Acupuncture is commonly used in Traditional Chinese Medicine for treatment of diabetic peripheral neuropathy (DPN), but data from randomized controlled trials are rare. This randomized, placebo-controlled, partially double-blinded clinical trial randomly assigned adults with confirmed type 2 diabetes-induced DPN to receive 10 sessions of needle acupuncture, laser acupuncture, or placebo laser acupuncture for 10 consecutive weeks. Treatment was provided at bilateral acupoints Ex-LE-10 (Bafeng), Ex-LE-12 (Qiduan), and ST-34 (Lianqiu). Neurological assessments, including nerve conduction studies (NCS) of sural and tibial nerves, were performed at baseline and weeks 6 and 15. Primary outcome was delta of sural sensory nerve action potential (SNAP). Secondary outcomes included further NCS values, clinical scores, and patient-reported outcome measures (PROMs). Of 180 participants, 172 completed the study. Sural SNAP and sural and tibial nerve conduction velocities improved significantly after 10 treatments when comparing needle acupuncture to placebo. Needle acupuncture showed earlier onset of action than laser acupuncture. PROMs showed larger improvements following needle and laser acupuncture than placebo, reaching significant differences for hyperesthesia and cramps following needle acupuncture and for heat sensation following laser acupuncture. Classical needle acupuncture had significant effects on DPN. Improvement in NCS values presumably indicates structural neuroregeneration following acupuncture.

Effect of Platelet-Rich Plasma Injection on Mild or Moderate Carpal Tunnel Syndrome: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Objective To evaluate efficacy of platelet-rich plasma (PRP) injection in carpal tunnel syndrome (CTS), we conducted this meta-analysis, as well as proposed a protocol for its application in curative processes. Methods All randomized controlled trials (RCTs) of PRP for the management of mild or moderate CTS were included in this study. Database search was conducted from study inception to July 2020, including PubMed, Embase, Web of Science, and Cochrane Library. We used visual analogue scores (VAS) and the Boston Carpal Tunnel Questionnaire (BCTQ) as evaluation tools for primary outcomes. Second outcomes comprised cross-sectional area (ΔCSA) and electrophysiological indexes including distal motor latency (DML), sensory peak latency (SPL), motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), compound muscle action potential (CMAP), and sensory nerve action potential (SNAP). The pooled data were analyzed using RevMan 5.3. Subgroup and sensitivity analyses were conducted with the evidence of heterogeneity. Egger' test was used to investigate publication bias. Results 9 RCTs were finally screened out with 434 patients included. Control groups comprised corticosteroid injection in 5 trials, saline injection in 1 trial, and splint in 3 trials. At the 1st month after follow-up, only ΔCSA between the PRP group and the control group showed significant difference (P < 0.05). In the 3rd month, there were statistically significant differences in VAS, BCTQ, SPL, SNCV, and ΔCSA between two groups (P < 0.05), while no statistically significant differences were found in the remaining outcomes. In the 6th month, there were statistically significant differences at BCTQ (P < 0.05) in primary outcomes and ΔCSA (P < 0.05) in secondary outcomes between two groups. As to adverse events in PRP injection, only one study reported increased pain sensation within 48 h after injections. Conclusion This systematic review and meta-analysis demonstrates that the PRP could be effective for mild to moderate CTS and superior to traditional conservative treatments in improving pain and function and reducing the swelling of the median nerve for a mid-long-term effect. To some extent, the electrophysiological indexes also improved after PRP injection compared with others conservative treatments.

Clinical predictors of surgical outcomes of severe carpal tunnel syndrome patients: utility of palmar stimulation in a nerve conduction study

BackgroundCarpal tunnel syndrome is a common peripheral nerve compression disorder. However, there is no established opinion regarding the predictors of symptom improvement after surgery. This study aimed to identify the predictors of surgical outcomes of severe carpal tunnel syndrome patients.MethodsIn the patients who underwent a carpal tunnel syndrome surgery, we selected the patients who had a preoperative Bland’s classification of grade 5 or 6, and assessed for the changes in Bland’s classification grade before and after surgery. Those who showed improvement from preoperative grades 5–6 to postoperative grades 1–4 comprised the improvement group. In contrast, those who did not show improvement and had postoperative grades 5 or 6 comprised the non-improvement group. In a nerve conduction study, amplitudes of the compound muscle action potential and sensory nerve action potential of the palms were assessed between the improvement and non-improvement groups.ResultsAmong the 60 hands of 46 patients who had a preoperative Bland’s classification of grade 5 or 6, 49 hands of 37 patients comprised the improvement group, and 11 hands of 9 patients comprised the non-improvement group. The amplitudes of the compound muscle action potential and sensory nerve action potential of the palms before surgery were significantly higher in the improvement group. The degree of improvement in Bland’s classification grade was correlated with the degree of clinical symptom improvement.ConclusionsAmplitudes of compound muscle action potential and sensory nerve action potential before surgery induced by palmar stimulation can predict improvements in nerve conduction study scores and clinical findings after surgical treatment.

Associations between hand function and electrophysiological measurements in hand osteoarthritis patients of different ages with or without carpal tunnel syndrome

Osteoarthritis is a common degenerative disease that most frequently involves the hand. The objective was to compare clinical functional outcome measures including hand grip, pinch strength, and dexterity with various electrophysiological measures in patients of different ages with hand osteoarthritis with or without the presence of carpal tunnel syndrome (CTS). Patients with hand osteoarthritis (208 patients, 404 hands) who underwent hand-function tests and motor and sensory nerve conduction studies (NCS) between June 2015 and June 2016 were enrolled. The patients’ hands were assigned to carpal tunnel syndrome (CTS) (206 hands; mean age, 56.37 ± 10.52; male:female, 46:160) or control groups (198 hands; mean age, 57.88 ± 9.68; male:female, 55:143). The strength of hand grip and lateral pinch, the time required to complete the nine-hole pegboard test (9HPT), and motor and sensory nerve conduction parameters were measured and compared across age groups and between hands with or without CTS. The CTS group showed significantly lower hand grip and lateral pinch strength, and a longer time to complete the 9HPT in comparison with the control group. Female patients showed significantly lower hand grip and lateral pinch strength than male patients. However, there was no difference in the 9HPT completion time between genders. Multivariate regression analysis identified the amplitude of the median compound muscle action potential (CMAP), age, and male gender as independent predictors of grip strength (adjusted R2 = 0.679), and amplitude of median CMAP and male gender as independent predictors of KP strength (adjusted R2 = 0.603). Velocity of median CMAP, amplitude of median sensory nerve action potential, and age were identified as independent predictors of 9HPT time (adjusted R2 = 0.329). Nerve conduction measurements were significantly related to hand-function test results, and CTS induced significant deficits in strength and performance of the affected hand.

Vibratory testing with the 64 Hz Rydel-Seiffer tuning fork and its relation to the sural nerve action potential.

Despite its widespread use, little is known regarding the ability of the semi-quantitative Rydel-Seiffer tuning fork to designate peripheral nerve function. We sought to determine in a large sample of normal and abnormal nerves the relationship between vibration sense and compound sensory nerve action potential (SNAP) parameters recorded in a corresponding innervation area. Vibratory thresholds were determined on a scale of 0 to 8 with a 64 Hz Rydel-Seiffer tuning fork placed on the lateral malleolus of 303 subjects. Sural nerve sensory neurography was employed to derive SNAP parameters, which were related to vibration sense by means of multiple linear regression. ROC curve analysis was performed to determine the classification efficacy of the tuning fork in distinguishing normal from abnormal sural nerve responses. SNAP amplitude was the most significant predictor in the whole subjects group and in the subgroup of subjects with normal SNAPs, whereas conduction velocity played a major role in subjects with abnormal SNAPs. Age was significantly associated with vibration perception, particularly in subjects with normal SNAPs. With an area under the curve of 0.730, vibration sense was a fair classifier for decreased SNAP amplitudes. The optimal vibratory cutoff was 4.2. Age is a major determinant of vibratory test results, highlighting the importance of aging of central and peripheral pathways in mediating vibration sense. Hence, neurophysiological testing cannot be omitted in the context of polyneuropathy work-up, since even at the optimal cutoff threshold, vibratory examination still displays 40% false negative test results.