Ulnar Motor Nerve Conduction Velocity Research Articles

Gene Distribution in Pediatric-Onset Inherited Peripheral Neuropathy: A Single Tertiary Center in Thailand.

Inherited peripheral neuropathy presents a diagnostic and therapeutic challenge due to its association with mutations in over 100 genes. This condition leads to long-term disability and poses a substantial healthcare burden on society. This study aimed to investigate the distribution of genes and establish the genotype-phenotype correlations, focusing on pediatric-onset cases. Exome sequencing and other analytical techniques were employed to identify pathogenic variants, including duplication analysis of the PMP22 gene. Each patient underwent physical examination and electrophysiological studies. Genotypes were correlated with phenotypic features, such as age at disease onset and ulnar motor nerve conduction velocity. We identified 35 patients with pediatric-onset inherited peripheral neuropathy. Pathogenic or likely pathogenic variants were confirmed in 24 out of 35 (68.6%) patients, with 4 of these variants being novel. A confirmed molecular diagnosis was achieved in 90.9% (10/11) of patients with demyelinating Charcot-Marie-Tooth disease (CMT) and 56.3% (9/16) of patients with axonal CMT. Among patients with infantile-onset CMT (≤2 years), the most common causative genes were MFN2 and NEFL, while GDAP1 and MFN2 were frequent causes among patients with childhood- or adolescent-onset CMT (3-9 years). The MFN2 gene was the most commonly implicated gene, and the axonal type was predominant in this cohort of Thai patients with pediatric-onset inherited peripheral neuropathy.

Effect of backpack load on nerve conduction velocity and risk of peripheral neuropathy in upper extremities of undergraduate medical students carrying backpack

Background: Prolonged load carriage can potentially affect hand and upper limb use through compression of the nerves, reduction in blood flow, and muscle fatigue. Backpacks of undergraduate medical student are not much different from their syllabus. They carry heavy backpacks on regular basis and many times they wear it incorrectly. Aims and Objectives: We aimed to see the effect of backpack load on motor nerve conduction velocity and hand grip strength in the upper extremities. Materials and Methods: The present study included 31 undergraduate medical students between the age of 18 and 25 years. The procedure is conducted in three phases on different days. In each phase, participants were asked to walk for 5 min with load. In Phase 1, nerve conduction velocity and grip strength weere measured in unloaded condition and after carrying load <10% of body weight. To limit the effect of fatigue, participants are instructed to return to laboratory in next consecutive weeks to repeat the procedure for Phase 2 and 3 as in Phase 1 by increasing load to 10–20% and 20–30% of their body weight respectively. Results: Values of median and ulnar motor nerve conduction velocity obtained without and with increasing % of backpack load after 5 min walk were decreased non-significantly as load increased. There was significant (P>0.001) difference in grip strength of medical students carrying backpack with increasing load after 5 min walk. Conclusion: In this study, we aimed at quantifying the effects of load carriage on overall upper limb performance, with a focus on conduction velocity of motor nerves. This has implications for occupations such as soldiers, firefighters, paramedics, and others who may be required to operate machinery, equipment, tools, or systems that require precise motor control.

Clinical and genetic characterization of NEFL-related neuropathy in Taiwan

Mutations in the neurofilament light polypeptide gene (NEFL) are an uncommon cause of Charcot-Marie-Tooth disease (CMT). The aim of this study is to elucidate the clinical characteristics and genetic spectrum of NEFL-related neuropathy in a Taiwanese CMT cohort. Mutational analysis of the coding regions of NEFL was performed by Sanger sequencing or targeted resequencing. Twenty-one patients from nine CMT pedigrees, identified from a cohort of 508 unrelated CMT patients, were found to have a NEFL mutation. Genetic, clinical and electrophysiological features were analyzed. Six NEFL mutations were identified, including two novel ones (p.P8S, p.N98Y). NEFL p.E396K was the most common mutation, accounting for 33.3% of the patients in our cohort. All patients manifested sensorimotor polyneuropathy with a mean age of disease onset of 13.5±9.6 (1-40) years. Their motor nerve conduction velocities (MNCVs) of the ulnar nerve ranged from 22.1 to 48.7m/s. Seventy percent of the patients could be classified as intermediate CMT with ulnar MNCVs between 25 and 45m/s. Six of the 21 patients (28.6%) had additional features of central nervous system (CNS) involvement, including motor developmental delay, spasticity, cerebellar signs, neuropathic pain and scoliosis. NEFL mutations account for 1.8% (9/508) of the CMT patients in Taiwan. The present study delineates the clinical and genetic characteristics of NEFL-related neuropathy in Taiwan, and highlights that ulnar MNCV above 25m/s and CNS involvement may serve as diagnostic clues for NEFL-related neuropathy.

Relationship between Anconeus Epitrochlearis and Ulnar Motor Nerve Conduction Velocity

Relationship between Anconeus Epitrochlearis and Ulnar Motor Nerve Conduction Velocity

Length of affected nerve segment in ulnar neuropathies at the elbow

ObjectiveTo establish length of the affected nerve segment (LANS) in ulnar neuropathy at the elbow (UNE). MethodsIn a group of our previously reported UNE patients we identified 2-cm segments with reduced motor nerve conduction velocity (MNCV) on electrodiagnostic (EDx) studies and increased nerve cross-sectional areas (CSA) on ultrasonographic (US) studies. LANS was obtained by summation of these abnormal 2-cm segments separately for each approach. We also studied effect of selected independent parameters on LANS. ResultsAltogether we studied 189 patients (194 arms). Mean (SD) LANS determined in 171 arms with reduced ulnar MNCV was 4.15 (1.89) cm, and was similar (p = 0. 21) to LANS obtained in 147 arms with increased CSA 4.46 (2.29) cm. Longer LANS were found in right arms, clinically severe UNE, axonal UNE and UNE due to entrapment. The most commonly affected 6 cm segment included 89% of abnormal 2-cm segments, with 50% of included 2-cm segments being normal. By contrast, the whole 10 cm segment included all abnormal 2-cm segments, with 66% of included segments being normal. ConclusionsIn UNE both EDx and US studies revealed average LANS of around 4 cm. LANS was longer in more severe UNE. SignificanceLANS needs to be taken into account in discussion of the mechanisms of UNE and approach to EDx diagnosis of UNE, particularly length of the segment used in nerve conduction studies across the elbow.

Physiological variations in nerve conduction velocity do not reflect diurnal trend

Background: Nerve conduction studies (NCSs) are performed for diagnosis and prognosis of disorders of the peripheral nervous system. Most physiological parameters show diurnal fluctuations. The time at which nerve conduction velocity (NCV) is performed may influence the recorded values if there are diurnal variations in NCV. Diurnal variations in NCV have not been studied in detail and there is a paucity of literature for the same. Aims and Objectives: This study aims to investigate the diurnal variations in ulnar motor NCV (MNCV). Materials and Methods: NCSs were performed on 89 healthy volunteers (76 males and 13 females) of age range from 18 to 22 years. Results: The mean age, height, weight, and body mass index of our study group were 20.68 ± 1.77 years, 168.02 ± 8.03 cm, 59.57 ± 10.31 kg, and 21.11 ± 3.11 kg/m2, respectively. Motor NCSs for ulnar nerve revealed no statistically significant diurnal variation in either limb. MNCV was also found to be similar for both genders. Increasing height of the subjects was associated with decrease in MNCV for ulnar nerve while raised pulse rates were found associated with increasing MNCVs. Conclusion: Our study suggests that there is no significant diurnal variation in ulnar MNCVs.

Nerve size correlates with clinical severity in Charcot-Marie-Tooth disease 1A.

Nerve cross-sectional area (CSA) is larger than normal in Charcot-Marie-Tooth disease 1A (CMT1A), although to a variable extent. We explored whether CSA is correlated with CMT clinical severity measured with neuropathy score version 2 (CMTNS2) and its examination subscore (CMTES2) in CMT1A. We assessed 56 patients with CMT1A (42 families). They underwent nerve conduction study (NCS) and nerve high-resolution ultrasound (HRUS) of the left median, ulnar, and fibular nerves. Univariate analysis showed NCS and HRUS variables to be significantly correlated with CMTNS2 and CMTES2 and with each other. Multivariate analysis showed that ulnar motor nerve conduction velocity (β: -0.19) and fibular compound muscle action potential amplitude (-1.50) significantly influenced CMTNS2 and that median forearm CSA significantly influenced CMTNS2 (β: 5.29) and CMTES2 (4.28). Nerve size is significantly associated with clinical scores in CMT1A, which suggests that it might represent a potential biomarker of CMT damage and progression.

Ulnar Nerve Enlargement at the Medial Epicondyle Negatively Correlates With Nerve Conduction Velocity in Cubital Tunnel Syndrome.

Background: In cubital tunnel syndrome (CuTS), chronic compression often occurs at the origin of the flexor carpi ulnaris at the medial epicondyle. Motor nerve conduction velocity (NCV) across the elbow is assessed preoperatively to corroborate the clinical impression of CuTS. The purpose of this study was to correlate preoperative NCV to the direct measurements of ulnar nerve size about the elbow at the time of surgery in patients with clinical and/or electrodiagnostic evidence of CuTS. Methods: Data from 51 consecutive patients who underwent cubital tunnel release over a 2-year period were reviewed. Intraoperative measurements of the decompressed nerve were taken at 3 locations: at 4 cm proximal to the medial epicondyle, at the medial epicondyle, and at the distal aspect of Osborne fascia at the flexor aponeurotic origin. Correlation analysis was performed comparing nerve size measurements to slowing of ulnar motor nerve conduction velocities (NCV) below the normal threshold of 49 m/s across the elbow. Results: Enlargement of the ulnar nerve at the medial epicondyle and nerve compression at the flexor aponeurotic origin was a consistent finding. The mean calculated cross-sectional area of the ulnar nerve was 0.21 cm2 above the medial epicondyle, 0.30 cm2 at the medial epicondyle, and 0.20 cm2 at the flexor aponeurotic origin (P < .001). There was an inverse correlation between change in nerve diameter and NCV slowing (r = -0.529, P < .001). Conclusions: For patients with significantly reduced preoperative NCV and clinical findings of advanced ulnar neuropathy, surgeons can expect nerve enlargement, all of which may affect their surgical decision-making.

Interrater Repeatability of Motor Nerve Conduction Velocity of the Ulnar Nerve.

The purpose of this study was to obtain data on interrater repeatability of the motor nerve conduction velocity (NCV) of the ulnar nerve of different segments, ulnar distal motor latency (DML), and compound muscle action potential (CMAP) amplitudes. Twenty-four healthy volunteers were examined in consecutive order. Ulnar motor NCV of different segments, ulnar DML, and CMAP amplitudes were determined. Based on a randomization list of various combinations and sequences, 1 of 3 examiners performed the first measurement. A second examiner repeated the evaluation within half an hour. There were no significant differences between the first and second measurements for all parameters. For the ulnar motor NCV of the different segments, the intraclass correlation coefficient (ICC) ranged from 0.38 to 0.51, and the coefficient of repeatability (CR) ranged from 8.0 to 11.6 m/s. For the ulnar DML, the ICC was 0.44, and the CR was 0.49 millisecond. For the CMAP amplitudes at the different stimulation sites, the ICC ranged from 0.53 to 0.76, and the CR ranged from 1.5 to 2.3 mV. A moderate amount of interrater variability of the ulnar motor NCV must be taken into account. Compared with the CMAP amplitudes, the interrater repeatability of the ulnar motor NCV is poorer.

Ulnar nerve motor conduction velocity correlates with body mass index in Indian young healthy subjects

Background: The prevalence of obesity is on rise globally, which poses a risk of vascular inflammation and metabolic dysregulations. Nerve conduction is affected by altered lipid metabolism, inflammation, and oxidative stress. Motor nerve conduction velocity (NCV) is a routine electrodiagnostic technique for detecting changes in nerve conduction parameters. There are contrasting results in studies done to investigate the relationship between NCV and body mass index (BMI). Few studies show increased conduction velocity with an increase in BMI, while others found either decreased or no change in conduction velocity with change in BMI. Aims and Objectives: The objective of this study was to investigate the relationship between motor NCV and BMI. Materials and Methods: In this study, we selected 27 individuals with normal weight, overweight, and obese categorized based on BMI and performed ulnar and median NCV. Correlation statistics were applied to see the relationship between BMI and motor NCV. Results: We found significant positive correlation between BMI and ulnar motor NCV (P = 0.027, r = 0.43). Ulnar and median NCV was also found correlating significant (P = 0.021, r = 0.45). Conclusion: The findings of our study suggest that the NCV correlates with BMI in lower BMI groups due to the maintenance of local optimum temperature, while in people with higher BMI inflammatory changes impair nerve conduction, a comparison in larger sample size is required to substantiate this observation is required though.

Prolonged phone-call posture causes changes of ulnar motor nerve conduction across elbow.

Postures and work-hobby activities may play a role in the origin and progression of ulnar neuropathy at the elbow (UNE), whose occurrence appears to be increasing. The time spent on mobile-phone has increased in the last decades leading to an increased time spent with flexed elbow (prolonged-phone-posture, PPP). We aimed to assess the effect of PPP both in patients with symptoms of UNE and in symptom-free subjects. Patients with pure sensory symptoms of UNE and negative neurophysiological tests (MIN-UNE) and symptom-free subjects were enrolled. We evaluated ulnar motor nerve conduction velocity across elbow at baseline and after 6, 9, 12, 15, and 18min of PPP in both groups. Fifty-six symptom-free subjects and fifty-eight patients were enrolled. Globally 186 ulnar nerves from 114 subjects were studied. Conduction velocity of ulnar nerve across the elbow significantly changed over PPP time in patients with MIN-UNE, showing a different evolution between the two groups. PPP causes a modification of ulnar nerve functionality in patients with MIN-UNE. PPP may cause transient stress of ulnar nerve at elbow.

38. Prolonged phone-call posture as risk factor for developing ulnar nerve entrapment at elbow: A dynamic neurophysiological study

Ulnar neuropathy at elbow (UNE) is often related to postures and work-hobby activities. The use of mobile-phones has drastically increased in the last decades leading to prolonged phone posture (PPP) with flexed elbow. We aimed to assess the effect of PPP in patients with symptoms of UNE and in symptom-free subjects. Patients with pure sensory symptoms of UNE and negative neurophysiological tests (min-UNE) and symptoms-free subjects were enrolled. We evaluated ulnar motor nerve conduction velocity across elbow at baseline and after 6, 9, 12, 15, 18 min of PPP. Thirty-eight symptom-free subjects and thirty-eight patients were enrolled and 121 ulnar nerves were studied. Conduction velocity of ulnar nerve across the elbow significantly changed over PPP time both in control group and, at a greater extent, in patients with min-UNE. Conduction velocity during PPP showed different evolution between the two groups. The changes became significantly different after 6 min of PPP and progressively increased, with the greatest difference at 15 min. In conclusion, PPP causes a modification of nerve function, expressed by slowing of motor nerve conduction velocity, which is greater in patients with min-UNE although it also occurs in symptom-free subjects. Excessive PPP should be avoided in patients with UNE-symptoms.

The effect of ubiquinone in diabetic polyneuropathy: A randomized double-blind placebo-controlled study

IntroductionDiabetic polyneuropathy aetiology is based on oxidative stress generation due to production of reactive oxygen species. Ubiquinone is reduced to ubiquinol and redistributed into lipoproteins, possibly to protect them from oxidation. AimsTo evaluate the impact of oral ubiquinone in diabetic polyneuropathy, and the role of lipid peroxidation (LPO) and nerve growth factor (NGF-β). MethodsWe conducted a double-blind, placebo-controlled clinical trial, patients were randomized to ubiquinone (400mg) or placebo daily for 12weeks. Main outcomes were clinical scores, nerve conduction studies, LPO, NGF-β and safety. ResultsTwenty four patients on experimental group and twenty five on control group met the inclusion criteria (mean age 56years, 22% male and 78% female, mean evolution of type 2 diabetes mellitus 10.7years). Significant improvement on experimental vs control group was found in neuropathy symptoms score (from 2.5±0.7 to 1±0.8, p<0.001), neuropathy impairment score (5.5±4 to 3.1±2.6, p<0.001), sural sensory nerve amplitude (13.0±6.1 to 15.8±5.1μV, p=0.049), peroneal motor nerve conduction velocity (39.7±5.0 to 47.8±4.9m/s, p=0.047), and ulnar motor nerve conduction velocity (48.8±6.8 to 54.5±6.1m/s, p=0.046). There was a significant reduction of LPO in subjects treated with ubiquinone vs placebo (16.7±8.6 and 23.2±15.8nmol/mL, respectively) with p<0.05, and NGF-β did not change (control 66.5±26.7 vs. experimental 66.8±28.4pg/mL, p=0.856). No drug-related adverse reactions were reported. ConclusionsTwelve weeks treatment with ubiquinone improves clinical outcomes and nerve conduction parameters of diabetic polyneuropathy; furthermore, it reduces oxidative stress without significant adverse events.

Genotype–phenotype correlations in early onset ataxia with ocular motor apraxia and hypoalbuminaemia

Early onset ataxia with ocular motor apraxia and hypoalbuminaemia/ataxia-oculomotor apraxia 1 is a recessively inherited ataxia caused by mutations in the aprataxin gene. We previously reported that patients with frameshift mutations exhibit a more severe phenotype than those with missense mutations. However, reports on genotype-phenotype correlation in early onset ataxia with ocular motor apraxia and hypoalbuminaemia are controversial. To clarify this issue, we studied 58 patients from 39 Japanese families, including 40 patients homozygous for c.689_690insT and nine patients homozygous or compound heterozygous for p.Pro206Leu or p.Val263Gly mutations who were compared with regard to clinical phenotype. We performed Kaplan-Meier analysis and log-rank tests for the ages of onset of gait disturbance and the inability to walk without assistance. The cumulative rate of gait disturbance was lower among patients with p.Pro206Leu or p.Val263Gly mutations than among those homozygous for the c.689_690insT mutation (P=0.001). The cumulative rate of inability to walk without assistance was higher in patients homozygous for the c.689_690insT mutation than in those with p.Pro206Leu or p.Val263Gly mutations (P=0.004). Using a Cox proportional hazards model, we found that the homozygous c.689_690insT mutation was associated with an increased risk for onset of gait disturbance (adjusted hazard ratio: 6.60) and for the inability to walk without assistance (adjusted hazard ratio: 2.99). All patients homozygous for the c.689_690insT mutation presented ocular motor apraxia at <15 years of age. Approximately half the patients homozygous for the c.689_690insT mutation developed cognitive impairment. In contrast, in the patients with p.Pro206Leu or p.Val263Gly mutations, only ∼50% of the patients exhibited ocular motor apraxia and they never developed cognitive impairment. The stepwise multivariate regression analysis using sex, age and the number of c.689_690insT alleles as independent variables revealed that the number of c.689_690insT alleles was independently and negatively correlated with median motor nerve conduction velocities, ulnar motor nerve conduction velocities and values of serum albumin. In the patient with c.[689_690insT]+[840delT], p.[Pro206Leu]+[Pro206Leu] and p.[Pro206Leu]+[Val263Gly] mutations, aprataxin proteins were not detected by an antibody to the N-terminus of aprataxin. Furthermore Pro206Leu and Val263Gly aprataxin proteins are unstable. However, the amount of the 689_690insT aprataxin messenger RNA was also decreased, resulting in more dramatic reduction in the amount of aprataxin protein from the c.689_690insT allele. In conclusion, patients with early onset ataxia with ocular motor apraxia and hypoalbuminaemia homozygous for the c.689_690insT mutation show a more severe phenotype than those with a p.Pro206Leu or p.Val263Gly mutation.

Review of Different Electrodiagnostic Studies in Mild Carpal Tunnel Syndrome

Aims The objective of this study was to evaluate different sensory electrodiagnostic tests in mild carpal tunnel syndrome (CTS). Methods Forty-seven patients (45 females and 2 males) with a total of 65 hands who attended the electrodiagnosis laboratory with the complaints of paresthesia, tingling, and pain in the median nerve distribution area for at least 1 month, at least 3 times/wk were included in the study. Patients with a history of CTS surgery, decreased ulnar sensory nerve action potential amplitude (<12 μV), increased ulnar sensory nerve onset latency (>3.7 ms), increased median motor distal latency (>4.2 ms), polyneuropathy and/or radiculopathy, pacemaker users, and pregnant women were excluded from the study. Electrodiagnostic studies including median and ulnar motor nerve conduction velocities; median sensory nerve conduction velocity (SNCV) of the first, second, and third digit to wrist (D1-W, D2-W, and D3-W) and palm to wrist; sensory median-radial latency difference (MRD) from the thumb; sensory median-ulnar latency difference (MUD) across the wrist over 8-cm segment; and sensory median-ulnar latency difference (MUDF) from the fourth digit were performed. Results Median SNCV of D1-W was found pathologic in all patients, MRD in 92.3%, MUDF in 92%, median SNCV of D2-W in 81.5%, MUD in 78.5%, and median SNCV of palm to wrist in 55.62%. In the case where a second test including median SNCV of D1-W, MUDF, or MRD is conducted with median SNCV of D3-W, 100%, 98%, and 97% of patients, respectively, having mild CTS could be diagnosed electrodiagnostically. Conclusions For the electrophysiologic diagnosis of patients with probable mild CTS, adding median SNCV of D1-W, MUDF, MRD, and median SNCV of D3-W study could be suggested to increase the accuracy of the diagnosis.

Two measurement methods of motor ulnar nerve conduction velocity at the elbow: A comparative study

Electrodiagnostically, localization of ulnar nerve lesions, which commonly occurs at the elbow, is sometimes problematic. Measurement of motor ulnar nerve conduction velocity (NCV) at the elbow is amongst the most popular techniques to diagnose ulnar neuropathy. In this method, recording from the first dorsal interosseous muscle (FDI) is suggested to be more sensitive than the abductor digiti minimi (ADM). However, the criterion for abnormality is based on the normal values recorded from ADM. To determine the normal values of Ulnar motor NCV using FDI and ADM and the difference between the values obtained from FDI and ADM. Additionally, to measure the amount of reduction of NCV across the elbow for each recording site. This was a cross-sectional study performed on 50 healthy volunteers (100 nerves). All subjects were in the same condition regarding joint position and surface hand temperature. We recorded ulnar NCV at forearm and across the elbow with recording electrode on both FDI and ADM, simultaneously. The mean NCV at the elbow recorded from ADM and FDI were 62.65 +/- 7.62 m/s and 60.49 +/- 7.42 m/s respectively, showing significant difference. The ulnar minimum normal NCVs recorded from ADM and FDI were 47.4 m/s and 45.6 m/s, respectively. If the normal values of ADM are used as the basis for recording from FDI, it could lead to false-positive diagnosis of cases suspicious of ulnar neuropathy. Therefore it is preferred to use the normal values of FDI itself while recording.

Effect of body mass index on ulnar nerve conduction velocity, ulnar neuropathy at the elbow, and carpal tunnel syndrome

Both high and low body mass index (BMI) have been reported as risk factors for ulnar neuropathy at the elbow (UNE), and a high BMI as a risk factor for carpal tunnel syndrome (CTS). To determine whether the extremes of BMI are risk factors for UNE or CTS, and whether BMI affects calculation of median and ulnar motor nerve conduction velocity (NCV), we retrospectively analyzed the electrodiagnostic records of control patients, UNE patients, and CTS patients. The BMI was calculated for 50 patients with a sole diagnosis of UNE and compared to the BMI of 50 patients with CTS and 50 control subjects. The mean BMIs were 25.9 +/- 4.4, 30.1 +/- 5.5, and 28.3 +/- 5.6 for the UNE, CTS, and controls, respectively. By one-way analysis of variance, the difference in BMI between the UNE patients and the normal patients was significant (P < 0.01). In the control groups, increasing BMI directly correlated with increasing ulnar motor NCV across the elbow but not with forearm NCV. Across-elbow (AE) ulnar motor NCV may be falsely increased in patients with a high BMI, probably due to distance measurement factors. Not only do relatively slender individuals have comparatively slower AE ulnar NCVs, they are also at increased risk for developing UNE. Patients with a high BMI are at increased risk for CTS.

Intermediate and long-term outcomes following simple decompression of the ulnar nerve at the elbow

There is currently little consensus regarding the appropriate surgical approach to treatment of cubital tunnel syndrome (CubTS), and few studies have reported long-term follow-up of patients who have received surgical treatment for ulnar nerve compression at the elbow. Seventy-four patients with a total of 102 cases of CubTS treated with simple decompression of the ulnar nerve were examined 1.0-12.4 years postoperatively. Ulnar nerve conduction studies (slowest conducting 5 cm segment of ulnar nerve motor fibers measured at the elbow) were performed both pre- and postoperatively. The primary clinical outcome was percentage relief of symptoms, divided into "excellent" outcome group or less (> or = 90% improvement or < 90% improvement). Ulnar nerve conduction improved pre- to postoperatively, but clinical improvement was not related to changes in velocity. Women reported greater clinical improvement than men, and weight gain in men (but not women) predicted less improvement. Relief of cubital tunnel symptoms was greatest for those arms receiving carpal tunnel release surgery simultaneous or subsequent to cubital tunnel release. Simple decompression may offer excellent intermediate and long-term relief of symptoms associated with CubTS. Although improvement in ulnar motor nerve conduction velocity occurs following treatment of CubTS, it may not be a consistent marker of perceived symptom relief. Finally, these findings suggest that less complete relief of symptoms following ulnar nerve decompression may be related to unrecognized carpal tunnel syndrome or weight gain.

Which motor nerve conduction study is best in ulnar neuropathy at the elbow?

There is debate regarding how best to utilize ulnar motor nerve conduction velocity (MNCV) to identify ulnar neuropathy at the elbow (UNE). We used receiver operator characteristic (ROC) curves to compare absolute across-elbow MNCV with MNCV difference between elbow and forearm segments (VDIF) when recording from abductor digiti minimi (ADM) and first dorsal interosseous (FDI) muscles. Also, we determined how their utility was impacted by low amplitudes of compound muscle action potentials (CMAPs). We studied 85 subjects with UNE and 77 subjects with carpal tunnel syndrome but without clinical evidence of UNE. The UNE group was divided into three subgroups based on CMAP amplitude. At 95% specificity, MNCV sensitivities were 80% at ADM and 77% at FDI, and VDIF sensitivities were 51% at ADM and 38% at FDI. The ROC curves showed MNCV to be superior to VDIF across all amplitude subgroups; however, confidence intervals overlapped when amplitude was high.

Motor nerve conduction velocity in very preterm infants.

Sufficient reference values for motor nerve conduction velocity (MNCV) in very preterm infants are not yet available. In the placebo infants within an L-thyroxine supplementation trial, born at less than 30 weeks' gestation, ulnar and posterior tibial MNCV measurements were performed shortly after birth. Repeated measurements were done at 2 weeks, at term, and at 6 months corrected age. Cross-sectional MNCV values obtained in 50 infants and longitudinal MNCV values obtained in 15 infants were analyzed in relation to postmenstrual age (PMA). Mean ulnar MNCV increased from 13 to 44 m/s and mean tibial MNCV from 11 to 37 m/s. Motor nerve conduction velocity was clearly related to PMA. Longitudinal MNCV values were consistent with cross-sectional MNCV values. Possible confounding factors did not have any significant effect on MNCV. In the ulnar nerve, extrauterine maturation during the first 2 weeks of life was delayed compared with intrauterine maturation.