Median Sensory Nerve Action Potential Research Articles

Ultrasound-Guided Modified Thread Carpal Tunnel Release for Carpal Tunnel Syndrome: A Pilot Study.

This study aimed to investigate the effectiveness and safety of modified thread carpal tunnel release (mTCTR) using Smartwire-01 in patients with carpal tunnel syndrome (CTS). Patients with CTS who required CTR were enrolled. Symptom severity and functional status were assessed using the Boston Carpal Tunnel Syndrome Questionnaire-Symptom Severity Scale (BCTQ-SSS) and Functional Status Scale (BCTQ-FSS), and pain was assessed using a numerical rating scale (NRS) at 4, 8, and 12 weeks after mTCTR. The scores were compared with the pre-procedural scores. The electrophysiologic study and median nerve cross-sectional area (CSA) measurements at the wrist before and 12 weeks after mTCTR were compared. A total of 11 patients were included. No adverse effects were reported throughout the study period. The NRS, BCTQ-SSS, and BCTQ-FSS scores significantly improved at 4 weeks after mTCTR, and this improvement persisted throughout the follow-up period (NRS and BCTQ-SSS, P < 0.001; BCTQ-FSS, P = 0.012). After 12 weeks, the latency and velocity of the median sensory nerve action potential significantly improved, compared with those before mTCTR (latency, 5.4 ± 1.3 to 4.7 ± 1.1 ms, P = 0.01; velocity 27.8 ± 6.8 to 31.8 ± 7.4 m/s, P = 0.019). No significant change was observed in the median nerve CSA before and after mTCTR. mTCTR using Smartwire-01 is a safe and effective procedure and a possible alternative to surgery.

Evaluation of hand-arm vibration syndrome owing to nerve conduction study and cumulative exposure index -A 2.5-year cohort study.

This study aims to clarify the relationship between peripheral neuropathy in hand-arm vibration syndrome and cumulative exposure index. 68 participants without symptoms were surveyed. The participants were divided into three groups based on past and current vibration exposure (VE). Comparison among groups according to past VE showed that the median and ulnar sensory nerve conduction velocities and median sensory nerve action potential (SNAP) amplitude were significantly lower in past high and low exposure groups than in the past non-exposure group. Comparison among groups according to current VE showed that the median and ulnar SNAP amplitudes were significantly lower in the current high exposure group than in the current low or non-exposure group. Vibration tool handlers have potential peripheral nerve lesions at a certain stage without subjective symptoms of the finger.

Electrophysiology of ataxia-telangiectasia-like disorder 1.

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

Analysis of Electrodiagnostic Recovery after Carpal Tunnel Release: A Retrospective Study

Objective: We investigated the factors affecting electrodiagnostic (EDX) parameters after carpal tunnel release (CTR).Methods: Thirty-nine cases with clinically diagnosed carpal tunnel syndrome who received CTR and EDX studies before and after CTR were enrolled in this study. We analyzed EDX parameters such as distal onset latency and the amplitude of median compound motor action potentials (CMAPs) and sensory nerve action potentials (SNAPs).Results: Among 39 cases, 24 (61.5%) showed improvement of at least 1 grade, based on Bland’s scale, after CTR. Follow-up EDX studies were performed 6 to 36 months after CTR. Improvement on Bland’s scale was shown in 50% of patients who received follow-up EDX studies at 6 and 12 months after CTR and in all patients who received follow-up at 24 and 36 months. The EDX parameters showed significant recovery. Younger patients showed greater recovery of SNAP amplitude (p = 0.021, r = -0.369) after CTR. The preoperative severe group showed greater recovery of CMAP (both amplitude and latency) than the non-severe group (p = 0.011 and p = 0.038, respectively).Conclusion: We confirmed the effectiveness of CTR through EDX studies. Age and preoperative EDX severity can affect the recovery of EDX parameters after CTR.

Sural Sparing Pattern and Sensory Ratio as Electrodiagnostic and Prognostic Markers in Pediatric Guillain-Barré Syndrome.

We aimed to evaluate the presence of sural sparing pattern (SSP) and sensory ratio in pediatric Guillain-Barré syndrome (GBS), their distribution to subtypes, and their relationship with demographic and clinical features with a focus on the disability and muscle strength. This single-center retrospective study was conducted on pediatric GBS patients of both sexes with 2 years follow-up and two nerve conduction studies in which SSP and sensory ratio were calculated. Three subgroups of SSP were formed by separate calculation of median (SSP-m) and ulnar (SSP-u) and both median and ulnar sensory nerve action potentials (SNAPs; SSP-total). Muscle strength and disability were evaluated with the Medical Research Council (MRC) sum score and Hughes functional grading scale (HFGS), respectively. SSP total was identified in 70.6% (n: 24) of the patients, while sensory ratio >1 was observed in 20 (66.7%) patients. Patients with SSP-m, SSP-u, SSP-total, or sensory ratio >1 had higher HFGS scores, while patients with SSP-m, SSP-u, or SSP-total had lower MRC sum scores. SSP parameters were significantly associated with muscle strength and disability scores in acute motor axonal neuropathy patients. Both SSP and sensory ratio can be used for diagnostic and prognostic purposes. Disability and muscle strength are associated with SSP and sensory ratio in pediatric GBS.

Study of carpal tunnel syndrome in diabetic polyneuropathy with comparison of inching method and second lumbrical-interossei test.

Background: Since diabetic generalized neuropathy affects peripheral nerves, the diagnosis of carpal tunnel syndrome (CTS) with conventional electrodiagnostic techniques (EDX) [onset latency of median sensory nerve action potential (SNAP) or distal latency of median compound muscle action potential (CMAP)] is controversial. The aim of this study is to investigate the diagnostic values of two other techniques including inching method and second lumbrical-interossei test in patients with diabetic polyneuropathy (DPN) as well as signs or symptoms of CTS. Methods: Fifteen patients (30 hands) with definite diagnosis of generalized peripheral neuropathy secondary to diabetes who developed signs and symptoms of CTS were participated. For diagnosis of CTS, sensory and motor median distal latencies were considered by nerve conduction study. In the next step, inching method and second lumbrical-interossei test were performed for all hands. Finally, sensitivity and specificity of two tests were calculated. Results: Mean age of participants was 53.87 ± 11.53 years. The sensitivity and specificity of inching method in this study were 95.65% and 85.71%, respectively, and for the second lumbrical-interossei test, they were 73.91% and 71.42%, respectively. Conclusion: Inching method was more sensitive and specific than second lumbrical-interossei test in diagnosis of CTS among patients with diabetic peripheral neuropathy. Moreover, the sensitivity of inching method was greater than specificity.

Implications of median sensory study to the thumb and deltoid/biceps motor unit recruitment on identifying C6 root avulsion in upper neonatal brachial plexus palsy.

Anatomic representation suggests that a median sensory nerve conduction study recording the thumb (median D1 NCS) may effectively assess upper neonatal brachial plexus palsy (NBPP). We sought to determine the feasibility of technique, establish reference data, and assess its ability to: (a) identify focal upper plexus lesions; and (b) identify C6 root avulsion. In a secondary analysis, we explored the association between absence/presence of motor unit action potentials (MUAPs) during needle electromyography (EMG) of the deltoid and biceps brachii muscles and C6 avulsion status. A retrospective chart review was performed of surgical patients with severe upper NBPP who ultimately underwent surgical reconstruction (between 2017 and 2020). Median D1 sensory nerve action potential (SNAP) amplitude ranges were determined in affected and contralateral limbs and analyzed by C6 root avulsion status. Also, presence/absence of MUAPs during EMG of the deltoid and biceps brachii was compared between C6 avulsion patients and controls. Thirty-eight patients were included in our analysis. A median D1 NCS study was readily performed, showing a contralateral limb mean amplitude of 27.42 μV (range, 3.8-54.7μV). Most patients had a low ipsilateral median D1 SNAP amplitude, regardless of C6 avulsion status. Detectable MUAPs in either deltoid or biceps brachii on EMG were atypical in C6 root avulsion. The median D1 NCS identifies upper NBPP, but does not distinguish C6 avulsions from post-ganglionic lesions, likely due to the frequent co-occurrence of post-ganglionic axonal disruption. The presence of MUAPs on deltoid/biceps brachii EMG suggests C6 avulsion is unlikely.

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

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

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

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

P-PN007. A case presenting with clinical and laboratory characteristics of fisher syndrome and lambert-eaten myasthenic syndrome (LEMS)

Introduction . Although Fisher syndrome and LEMS are classified into autoimmune neuromuscular diseases, we cannot find the coincidence of them in a single patient in the previous literature. Results . A 70-year-old female was admitted to our hospital because of bilateral hand numbness, double vision and unsteadiness which had developed 2 weeks. She had no history of preceding infection and/or related illness. On admission, her condition was characterized by mydriasis, extraocular muscle weakness, mild proximal muscle weakness and truncal ataxia. In addition, the tendon reflexes were absent at rest, and improved with brief exercise. Motor nerve conduction studies showed significantly low compound muscle action potentials (CMAPs) and increments of more than 200% after brief exercise (post-exercise facilitation) in several nerves. Sensory nerve conduction studies showed significantly low sensory nerve action potential (SNAPs) of median and ulnar nerves, and normal SNAPs of sural nerves. We also demonstrated the impairment of neuromuscular transmission in several muscles based on abnormal decrements in the repetitive nerve stimulation (RNS) test and abnormal jitter in the single-fiber electromyography (SFEMG). Both anti-GQ1b and GT1a ganglioside antibodies and P/Q-type voltage-gated calcium channel (VGCC) antibodies were positive in her sera. Her conditions improved spontaneously. She accomplished walking alone in six weeks, and paralysis of the eye muscles recovered in five months. Median and ulnar SNAPs returned to normal in accordance with recovery of clinical findings. On the other hand, low CMAPs with post-exercise facilitation remained after complete recovery. Positron emission tomography and gastrointestinal endoscopy did not show any malignancy. Conclusion . Some electrophysiological studies revealed the impairment of neuromuscular transmission using RNS and/or SFEMG in patients with Fisher syndrome. Also, it has been known that autoimmune neurological phenotypes are diverse among patients with P/Q-type VGCC antibodies. This may be the first case who showed clinical and laboratory characteristics of Fisher syndrome and LEMS simultaneously.

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

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.

Normal neurophysiologic parameters of the median nerve among adult healthy Sudanese population

Background: Nerve conduction studies (NCSs) help in delineating the extent distribution of neural lesion, and the diagnosis of peripheral nerve disorders. Because normative nerve conduction parameters were not yet established in Sudan EMG laboratories, this study aims towards having our own reference values, as we are using the American and British parameters. This will allow avoiding the discrepancies that might be induced by many factors. Methods: NCSs were performed in 200 Median nerves of 100 adult healthy Sudanese subjects using standardized techniques. Results: The median SNAP (sensory nerve action potential) values were as follows: distal latency, 2.6±3 ms with a range of (2.3-2.9); peak latency, 3.5±0.5 ms (3.0-4.0); amplitude, 47.7±18.0μV (29.7-65.7); conduction velocity, 53.0±7.8 m/s (45.2-60.8). The following values were obtained for the Median nerve CMAP (compound muscle action potential) at wrist stimulation: distal latency, 3.5±0.5 ms with a range of (3.0-4.0); peak latency, 9.4± 1.0 ms (8.4-10.4); duration, 5.9±0.9 ms (5.0-6.8); amplitude, 12.3±2.5 mV (9.8-14.8); area, 43.0±10.4 mVms (32.6-53.4); conduction velocity, 63.6±6.2 m/s (57.4-69.8). The F wave was 28.4±1.8 ms (26.6-30.2). Conclusion: The overall mean sensory and motor nerve conduction parameters for the tested nerve compared favorably with the existing literature with some discrepancies that were justified.

A nerve conduction study predicts the prognosis of sporadic amyotrophic lateral sclerosis.

To clarify the relationship between nerve conduction study (NCS) and prognosis in patients with amyotrophic lateral sclerosis (ALS). We included 190 patients with sporadic ALS. We used onset age, sex, onset site (bulbar vs. spinal), revised El Escorial criteria category (definite vs. others), and the King's clinical systems, and the Milano-Torino (MiToS) functional staging systems, and decline rates of revised ALS functional rating scale (ALSFRS-R) as known prognostic factors. An NCS was performed on the median, ulnar, tibial, and sural nerves. The endpoint was death or the introduction of tracheostomy positive-pressure ventilation. Multivariate analysis for each NCS variable, known prognostic factors was performed using Cox stepwise proportional hazards analysis. Univariate analysis was performed for NCS variables that showed a significant association with prognosis in multivariate analysis. Survival was analyzed with a Kaplan-Meier curve and log-rank test. The Cox model identified the compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the median nerve as prognostic factors. In the log-rank test, patients with higher median nerve CMAP amplitude had a significantly better prognosis than those with lower amplitude, regardless of age. And prognosis was better in the group with lower median nerve SNAP amplitude only in patients younger than the 25th percentile (~ 57years). CMAP and SNAP amplitudes of the median nerve are considered to be independent prognostic factors of sporadic ALS.

Endothelial-Specific Molecule 1 (Endocan) as a Marker of Vascular Endothelial Regulation of Obesity-Associated Peripheral Polyneuropathy in the Non-Diabetic Obese Patients

Abstract Background: The increasing incidence of obesity and its co-morbid situations poses a great challenge to worldwide health. Obesity has numerous co-morbidities including airway illness, insulin resistance, type 2 diabetes, atherosclerosis, peripheral polyneuropathy (PN) and cancer. Endocan is a proteoglycan that could be used as a biomarker of endothelial dysfunction. Aim of Study: The current study aimed to investigate plasma endocan level in non-diabetic obese patients and to explore the association between circulatory endocan with the clinical and electrophysiological tests of PN in obese patients. Methods: This cross-sectional controlled study enrolled 170 obese patients and 100 control group. The obese group was sub-classified according to BMI (Body Mass Index) into three groups; all participants were subjected to a complete neurological examination. The motor nerve conduction study of [median nerve, ulnar nerve, and Common Peroneal Nerve (CPN)] and the sensory nerve conduction study of [median, ulnar and sural nerves] of all subjects were estimated. Blood sampling and biochemical analysis for parameters of metabolic syndrome (MetS) were done, in addition, Doppler evaluation of Carotid Intima Media Thickness (CIMT) using 0.9mm thickness as a cut-off point was used for identification of atherosclerosis. We measured plasma endocan by Enzyme-Linked Immunosorbent Assay (ELISA). Results: Obese patients with PN had statistically significant higher levels of plasma endocan (218.6±26.26) compared to obese patients without PN (135.5±21.6) and controls (13.1± 3.2). Plasma endocan level was positively correlated with Toronto Clinical Scoring System (TCSS) and negatively correlated with measures of electrophysiological tests; Motor Nerve Conduction Velocities (MNCV) of median, ulnar nerves, Sensory Nerve Conduction Velocities (SNCV) of median and ulnar nerves, Compound Muscle Action Potential (CMAP) amplitude of median and ulnar nerves and Sensory Nerve Action Potential (SNAP) amplitude of median, ulnar and sural nerves. The identification of optimum cut-off point of serum endocan could help in evaluating non-diabetic obese patients with PN in attempt to decrease health hazards related to neuropathy. Conclusion: Obese patients with PN had higher values of circulating endocan than obese patients without PN; the diagnostic power of circulating endocan was highly significant thus it could be used as a diagnostic biomarker of PN.

The nerve conduction study is the key tool for the assessment of a peripheral neuropathy after carbon monoxide intoxication in a young adolescent mimicking a central presentation

Background Peripheral neuropathy after carbon monoxide (CO) intoxication is rarely reported. A peripheral nerve dysfunction mimicking a central presentation has never been reported. Objectives To determine the place of nerve conduction studies (NCS) in the assessment of peripheral neuropathy following CO intoxication. Methods We reported the case of a young patient aged 21 years who was addressed to the electrophysiological department Sahloul to perform NCS one year after a severe CO intoxication. He developed during his hospitalization, a left hemiparesis (lower and upper limbs). The NCS was not performed at this time. The diagnosis was rhabdomyolysis complicated by an acute renal failure due to CO poisoning in a patient with central nervous system complication. Actually the physical examination revealed the left hemiparesis with conserved or even exaggerated reflexes. These clinical features were compatible with a central dysfunction. However, when performing NCS on the left side, sural, superficial peroneal, ulnar, and median sensory nerve action potentials were unobtainable, as well as peroneal and tibial compound muscle action potentials. Such findings evoke a diffuse peripheral neuropathy with axonal dysfunction. This association was not reported after CO intoxication. Results Although demyelinating neuropathy is the mostly common reported form of neuropathy after CO intoxication, axonopathy can also be occurred but needs more times to recover. Rhabdomyolysis and CO itself are the major factors leading to peripheral neuropathy. Conclusion A peripheral neuropathy mimicking a central presentation can occur after CO intoxication. Clinicians should be aware of the major implication of the peripheral nervous system in this context.

Effectiveness of combined ultrasound and exercise therapy in the treatment of carpal tunnel syndrome - randomized, placebo-controlled investigation

Introduction/Objective. The aim of the paper was to evaluate the short-term effectiveness of ultrasound treatment procedure on defined clinical parameters and changes of electrodiagnostic parameters at the median nerve in carpal tunnel syndrome patients. Methods. Thirty-five patients (50 hands) were randomly divided into two groups: the experimental group (EG) (20 patients (29 hands)) and the control group (CG) (15 patients (21 hands)). Twenty sessions of ultrasound treatment were performed over a period of seven weeks and control examination was performed during the eighth week from the initial session. Clinical assessment parameters (pain intensity, superficial sensibility, and Tinel sign), and electrodiagnostic parameters (motor distal latency ? mDL), median sensory nerve conduction velocity (SNCV), and median sensory nerve action potential (SNAP) were assessed both at baseline (T1) and at control (T2). Results. There is significant improvement of pain intensity (T1 ? 10.4/58.6/31; T2 ? 65.5/27.6/6.9; p &lt; 0.001) and superficial sensibility (T1 ? 3.4/69/27.6; T2 ? 44.8/34.5/20.7; p &lt; 0.001) in the EG after the treatment. In the EG, there is significant reduction in frequency of positive Tinel?s sign (T1 ? 100/0; T2 ? 62.1/37.9; p &lt; 0.001), and mDL significantly decreased after the treatment (T1 ? 4.7 ? 1.3; T2 ? 4.5 ? 1.2; p = 0.007), while SNAP (T1 ? 20.2 ? 15.4; T2 ? 24.4 ? 16.5; p &lt; 0.001) and SNCV (T1 ? 36.5 ? 9.8; T2 ? 42.6 ? 9.7; p &lt; 0.001) significantly increased. Conclusion. Ultrasound treatment along with exercises have positive short-term effects and benefits on improvement of clinical and electrodiagnostic findings in individuals with carpal tunnel syndrome.

82. Inter- and intraexaminer reliability of nerve conduction measurements in the upper limb of healthy subjects

To verify the test-retest, inter and intraexaminer variability of the Compound Muscle Action Potential (CMAP) and Sensory Nerve Action Potential (SNAP) within our neurophysiology laboratory; to identify the technical variables that can affect the reproducibility of signals in the follow-up studies. Distal CMAP of Median and Ulnar nerves and SNAP of radial nerve (I ° finger), median nerve (I° and IV° fingers), ulnar nerve (IV and V fingers) of the right hand were recorded by 9 operators (5 technicians of neurophysiology and 4 physicians) in healthy volunteers. Each test was repeated 3 times randomly within 4 months. The latency, amplitude, and intensity of stimulus were collected. The montages were photographed. Our data showed a discrete stability of CMAP parameters mainly for ulnar nerve. On the contrary the amplitudes of SNAPs were fairly variables. The results suggest that it is crucial to check the neurophysiological techniques commonly applied in laboratories were several operators work. More time must be dedicated to a common training, to get consistent results useful in repeated trials.

Role of "Sural Sparing" Pattern (Absent/Abnormal Median and Ulnar with Present Sural SNAP) Compared to Absent/Abnormal Median or Ulnar with Normal Sural SNAP in Acute Inflammatory Demyelinating Polyneuropathy.

Sural sparing defined as absent/abnormal median sensory nerve action potential (SNAP) amplitude or absent/abnormal ulnar SNAP amplitude with a normal sural SNAP amplitude is thought to be a marker for inflammatory demyelinating polyneuropathies. If sural sparing pattern specifically defined as absent/abnormal median and ulnar SNAP amplitude with normal sural SNAP amplitude (AMUNS) is sensitive and specific when compared with either absent/abnormal median and normal sural (AMNS) or absent/abnormal ulnar and normal sural (AUNS) for acute inflammatory demyelinating polyneuropathy (AIDP), chronic inflammatory demyelinating polyneuropathy (CIDP), select non-diabetic axonopathies (AXPs), and diabetic neuropathies (DNs). Retrospective analysis from 2001 to 2010 on all newly diagnosed AIDP, CIDP, select non-diabetic AXP, and DN. There were 20 AIDP and 23 CIDP. Twenty AXP and 50 DN patients between 2009 and 2010 were included as controls. AMUNS was seen in 65% of AIDP, 39% CIDP compared with 10% of AXP and 6% for DN with sensitivity of 51%, specificity of 92%, whereas the specificity of AMNS/AUNS was 73% and its sensitivity was 58%. If a patient has AMUNS they are >12 times more likely to have AIDP (p < 0.001). Sural sparing is highly specific but not sensitive when compared with either AMNS or AUNS in AIDP but does not add to sensitivity or specificity in CIDP.

Do Electrodiagnostic Variables Correlate with Functional Outcomes in Carpal Tunnel Syndrome?

Background: The most common entrapment neuropathy seen in electrodiagnostic (EDX) laboratories is carpal tunnel syndrome (CTS). The diagnostic value of EDX with regard to CTS is well-established, but EDX’s predictive value is unclear. To date, only one study has attempted to establish a relationship between EDX findings and a patient’s clinical status pre- and post-treatment, and there was no significant relationship found. Objective: To establish a relationship between EDX variables and clinical severity assessment with Disabilities of the Arm, Shoulder, and Hand (DASH) scores at a single point in time and over a period of time. Methods: The study was a prospective single group cohort. 41 patients referred to an EDX clinic with suspected diagnoses of CTS were enrolled. Patients underwent EDX studies and completed DASH questionnaires at initial and follow-up visits at 8-month to 12-month intervals. Data collected included median sensory, mixed, and motor latencies, amplitudes, conduction velocities, and needle electromyography (EMG). Correlation coefficients were determined between EDX data variables and severity assessment (independent variables) and patients’ DASH questionnaire measures (dependent variables) at initial and follow-up assessments. Results: Change in DASH score over time positively correlated with left distal median motor latency (DMML) decrement and right transcarpal median sensory conduction block and negatively correlated with left median sensory nerve action potential (SNAP) amplitude decrement percentage, right needle EMG motor unit morphology abnormality, and right median forearm motor conduction velocity increment. The correlations observed are of unclear significance since the DASH scores themselves did not change significantly over time. Conclusions: Objective EDX data coupled with patient-reported outcome (PRO) measures such as the DASH score may be more meaningful in directing clinical care than either of them alone.