Motor Nerve Conduction Studies Research Articles

A revised electrodiagnosis-based severity classification for carpal tunnel syndrome

BACKGROUND: An electrodiagnostic evaluation is conducted to diagnose carpal tunnel syndrome (CTS) and evaluate its severity. OBJECTIVE: This study proposes a revised approach for classifying the severity of electrophysiological findings for patients with CTS. METHODS: This retrospective cross-sectional study included patients with CTS confirmed through electrodiagnostic evaluations. Based on the Stevens’ classification, the patients were divided into three groups (mild/moderate/severe). A new intermediate group was defined to identify patients with normal motor nerve conduction studies and abnormal electromyographic results. CTS pain was evaluated using a numeric rate scale. Physical examinations and sonographic evaluation were performed to detect anatomical abnormalities. RESULTS: Overall, 1,069 CTS hands of 850 CTS patients were included. The mean age was 57.9 ± 10.8 years, and 336 (39.5%) were men. There were 522 (48.8%) mild cases; 281 (26.3%) moderate cases; and 266 (24.9%) severe cases. In the severe group, 49 cases were reclassified into the intermediate group. The median cross-sectional area in the intermediate group significantly differed from that in the severe group. However, the pain score significantly differed from that of the moderate group. CONCLUSION: The intermediate CTS group showed clinical features that were intermediate to those of the moderate and severe CTS groups.

Role of minimal F-wave latency in the electrodiagnosis of polyneuropathy

Background and objective: Polyneuropathy is a debilitating condition that causes damage to more than two peripheral nerves in the body. The objective of this research was to detect the role of minimal F-wave latency as compared with other nerve conduction parameters for the electro-diagnosis of polyneuropathies. Methods: In this descriptive, prospective cross-sectional study, 80 consecutive patients with clinical diagnosis of polyneuropathy (both acute and chronic) between July and December 2023, presenting to the Neurology Department at King Edward Medical University were enrolled. Patients with clinical diagnosis of cervical/lumbar radiculopathies, plexopathies, compressive myelopathy , neuromuscular junction diseases, motor neuron disorders, or localized neuropathies were excluded from this research. NCS and EMG were carried out using conventional procedure. The results were recorded in the predesigned pro forma along with the history and demographic information. Statistical software SPSS 25.0 was used for the analysis of the recorded data. Results: F-wave abnormality was detected in 57 (71.3%) for median nerve, 57 (71.3%) for ulnar nerve, 79 (98.7%) for tibial nerve and in 79 (98.7%) patients for peroneal nerve. Nerve-specific motor nerve conduction study (MNCS) abnormality was found in 47 (58.8%) for median nerve, 43/80 (53.8%) for ulnar nerve, 59 (73.7%) for tibial nerve and in 57(71.3%) patients for peroneal nerve. Nerve-specific sensory nerve conduction study (SNCS) abnormality was present in 43 (53.3%) for median nerve, 43 (53.3%) for ulnar nerve, 50 (62.5%) for sural nerve, and in 49 (61.3%) patients for superficial peroneal nerve. Overall rate of abnormality was 85% for F-wave minimal latencies in comparison with 64% for MNCS and 56% for SNCS. Conclusion: Minimal F-wave latency can be an effective diagnostic parameter for detection of polyneuropathy. This can facilitate in early detection and management of polyneuropathy.

The difference in nerve ultrasound and motor nerve conduction studies between autoimmune nodopathy and chronic inflammatory demyelinating polyneuropathy.

Nerve enlargement has been described in autoimmune nodopathy and chronic inflammatory demyelinating polyneuropathy (CIDP). However, comparisons of the distribution of enlargement between autoimmune nodopathy and CIDP have not been well characterized. To fill this gap, we explored differences in the ultrasonographic and electrophysiological features between autoimmune nodopathy and CIDP. Between March 2015 and June 2023, patients fulfilling diagnostic criteria for CIDP were enrolled; among them, those with positive antibodies against nodal-paranodal cell-adhesion molecules were distinguished as autoimmune nodopathy. Nerve ultrasound and nerve conduction studies (NCS) were performed. Overall, 114 CIDP patients and 13 patients with autoimmune nodopathy were recruited. Cross-sectional areas (CSA) at all sites were larger in patients with CIDP and autoimmune nodopathy than in healthy controls. CSAs at the roots and trunks of the brachial plexus were significantly larger in patients with anti-neurofascin-155 (NF155), anti-contactin-1 (CNTN1), and anti-contactin-associated protein 1 (CASPR1) antibodies than in CIDP patients. The patients with anti-NF186 antibody did not have enlargement in the brachial plexus. NCS showed more frequent probable conduction block at Erb's point in autoimmune nodopathy than in CIDP (61.9% vs. 36.6% for median nerve, 52.4% vs. 39.5% for ulnar nerve). Markedly prolonged distal motor latencies were also present in autoimmune nodopathy. Patients with autoimmune nodopathies had distinct distributions of peripheral nerve enlargement revealed by ultrasound, as well as distinct NCS patterns, which were different from CIDP. This suggests the potential utility of nerve ultrasound and NCS to supplement clinical characteristics for distinguishing nodopathies from CIDP.

COVID-19 disease severity and affectations in electroneuromyographic studies

IntroductionEmerging research has highlighted COVID-19's profound impact on the nervous system, with ongoing debate regarding its severity and the emergence of peripheral neurological disorders. This study delves into the correlation between COVID-19 severity and electromyographic abnormalities in hospitalized patients, aiming to elucidate the nature and extent of neuromuscular dysfunction associated with the disease. MethodsIn a retrospective, cross-sectional, observational study, we analyzed data from 170 patients treated at the North Physical Medicine and Rehabilitation Unit between July 2020 and April 2021. Post-COVID-19 patients underwent comprehensive motor and sensory nerve conduction studies. Spearman's correlation and Kruskal–Wallis tests were used to examine the relationship between disease severity and electromyographic findings. ResultsOf the 170 patients in the study, 71.17% were male and 28.82% female, with an average age of 48 years; the subgroup of patients with severe clinical classification predominated at 68.23%. Spearman's correlation yielded values higher than 0.5 for all parameters analyzed concerning severity classification. A significant difference was found in the average of non-evoked motor and sensory nerves, motor nerves with latency, amplitude, and conduction velocity impairment, and affected muscles regarding critical classification. ConclusionOur study showed a relationship between the severity of COVID-19 and an increase in non-evoked motor and sensory nerves, impaired motor nerve latency, amplitude, and velocity, and more affected muscles, particularly in critical cases.

A study of neurological functions in construction work painters

BackgroundPainters are constantly exposed to organic solvents containing volatile organic compounds (VOCs), a primary source of indoor air pollution. Prolonged exposure to solvents generates significant health repercussions on pulmonary and neurological functioning. Few studies have assessed the neurological function of unorganized sector painters objectively, especially in developing nations. The current research evaluates the effects of organic solvents on neurological functions in painters working in unorganized sectors like construction sites in Chennai. MethodsA validated questionnaire was used to assess solvent-exposed neurological symptoms in full-time painters (n = 75) aged 25–55, stratified by years of exposure (≤10 years, >10 years). A subset of 35 painters underwent bilateral median nerve motor and sensory nerve conduction studies. Personal exposure monitors measured VOC concentration during the painting processes. ResultsToluene and benzene concentrations were greater in paint scraping. 47% of painters reported neurological symptoms, and those with >10 years of experience had a higher AOR (95%CI): 3.4 (1.3, 9.6). 13% had diplopia, 18% had ocular discomfort. Painters with more than 10 years of experience had longer motor and sensory onset latency of the left median nerve, as well as decreased bilateral sensory conduction velocities (Right median nerve: 53.8 ± 13.9 vs 64.2 ± 5.2; Left median nerve: 55.75 ± 6.5 vs 64.3 ± 6.2). ConclusionPaint emits toluene, a major solvent. The impact of occupational exposure to organic solvents on neurological functions has been observed to exhibit a progressive deterioration over time. Health awareness and strict protective measure legislation are needed to reduce morbidity and mortality in these unorganized sectors.

Nonalcoholic Fatty Liver Disease in Shift Workers and Its Effect on Peripheral Nerve Conduction: A Cross-Sectional Study.

Introduction Nonalcoholic fatty liver disease (NAFLD) presents as a multisystem disorder, heightening the risk of developing type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVDs). Occupation emerges as a significant factor influencing the occurrence of NAFLD. Research indicates that individuals engaged in shift work face an elevated risk of NAFLD, alongside obesity and T2DM, attributed to disruptions in their circadian rhythm, which precipitate hepatic steatosis and inflammation. Remarkably, peripheral neuropathy has been observed in conjunction with advanced liver disorders and NAFLD in the general population. However, the correlation between NAFLD and peripheral neuropathy remains unestablished in shift workers. Objective To identify NAFLD in seemingly healthy rotating shift workers and assess any potential impact of NAFLD on nerve function in this demographic. Methods This cross-sectional study involved 73 apparently healthy nonalcoholic security guards (aged 35 to 60 years) working in rotating shifts. The study included a comprehensive assessment, beginning with a medical history, an evaluation of physical activity, and anthropometric measurements. Confirmation of NAFLD was achieved through abdominal ultrasonography (USG), followed by the analysis of biochemical parameters. Motor and sensory nerve conduction studies (NCS) were conducted on participants with normal vitamin B12 levels using the Aleron electromyograph (EMG) machine (Recorders and Medicare Systems Private Ltd, Budanpur, India). The evaluation encompassed the Median and Common Peroneal motor nerves, as well as Median and Sural sensory nerves. Recorded parameters for motor nerves included distal motor latency (DML), compound muscle action potential (CMAP) amplitude, conduction velocity (CV), and F-wave minimum latency (F-wave), while sensory nerve parameters comprised sensory onset latency (SOL), sensory nerve action potential (SNAP) amplitude, and CV. Results Among 73 healthy security guards working in rotating shifts, 76.1% were diagnosed with NAFLD through abdominal ultrasound. Following participant withdrawals and exclusions due to vitamin B12 deficiency, a comparison of NCS parameters between NAFLD (n=24) and Non-NAFLD (n=12) groups revealed no significant disparities in motor or sensory parameters, except for a slightly diminished CMAP amplitude in the peroneal nerve of NAFLD subjects (8.21±2.83mV vs ±10.22±2.30 mV, p< 0.040). However, these differences fell within normal ranges, indicating no notable impact on peripheral nerve conduction in the presence of NAFLD. Conclusion The results indicate a high prevalence of NAFLD among individuals working rotating shifts. Moreover, the investigation suggests that despite the presence of NAFLD, there is no discernible influence on motor and sensory peripheral nerve conduction, particularly in common peroneal, median, and sural nerves.

Traumatic and iatrogenic sciatic nerve injury in 38 dogs and 10 cats: Clinical and electrodiagnostic findings.

Reports describing sciatic nerve injuries (SNI) and their outcome are scarce in veterinary medicine. Describe the causes of traumatic and iatrogenic SNI and evaluate which clinical and electrodiagnostic findings predict outcome. Thirty-eight dogs and 10 cats with confirmed SNI referred for neurologic and electrodiagnostic evaluation. Clinical and electrodiagnostic examination results, including electromyography (EMG), motor nerve conduction studies, muscle-evoked potential (MEP), F-waves, sensory nerve conduction studies, and cord dorsum potential (CDP), were retrospectively evaluated. Quality of life (QoL) was assessed based on owner interviews. Surgery (42%) and trauma (33%) were the most common causes of SNI; in dogs, 24% were caused by bites from wild boars. Ability to flex and extend the tarsus was significantly associated with positive outcome in dogs. Mean time from onset of clinical signs until electrodiagnostic evaluation was 67 ± 65 (range, 7-300) days and 65 ± 108 (range, 7-365) days for dogs and cats, respectively. A cut-off amplitude of 1.45 mV for compound motor action potentials (CMAP) was predictive of positive outcome in dogs (P = .01), with sensitivity of 58% and specificity of 100%. Clinical motor function predicts recovery better than sensory function. Electrodiagnostic findings also may play a role in predicting the outcome of SNI. Application of the proposed CMAP cut-off amplitude may assist clinicians in shortening the time to reassessment or for earlier suggestion of salvage procedures. Owners perceived a good quality of life (QoL), even in cases of hindlimb amputation.

Early Neurophysiological Abnormalities in Suspected Acute Canine Polyradiculoneuropathy.

Acute canine polyradiculoneuritis (ACP) is a common peripheral neuropathy in dogs, and is generally self-limiting and benign. Electrodiagnostic (EDX) tests are typically performed after 7-10 days. Delaying the definitive diagnosis may hamper the treatment of other causes of acute weakness, which may require specific treatments and may carry different prognoses. This retrospective multicenter study aims to assess whether EDX performed within the first 6 days of clinical signs onset can detect alterations indicative of ACP, and aims to characterize the most prevalent alterations. A total of 71 dogs with suspected ACP were retrospectively analyzed and classified into two groups based on EDX timing: early group (EG, 1-6 days after symptom onset) and late group (LG, 7-15 days after symptom onset). In our study, no significant differences were found between the two groups in motor nerve conduction studies (MNCSs) and F-wave analysis, indicating that EDX is able to demonstrate abnormalities even in the first 6 days from onset. Although the LG showed significantly greater degrees of electromyographic (EMG) alterations compared to the EG, frequent muscle alterations were still observed in the EG group. These findings support the use of EDX in patients with suspected ACP within the first 6 days from the clinical onset. Prompt neurophysiological examinations for suspected ACP patients can be performed effectively and can help allow for early diagnosis and facilitate appropriate treatment.

Outcome measures in pediatric chronic inflammatory demyelinating polyradiculoneuropathy.

Objective outcome measures in children undergoing treatment for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) are lacking. The aim of the study was to record serial grip strength and motor nerve conduction studies to assess interval change. This was a retrospective review of 16 children (8 females and 8 males; median age, 9.7 years; interquartile range, 6-13 years) with CIDP followed at a tertiary children's hospital from 2013 to 2021. Subjects were treated with intravenous immunoglobulin (IVIG). Right and left grip strength measurements were obtained at each clinic visit using a handheld dynamometer. Annual right median motor nerve conduction study data were recorded during the study period. Mean duration of follow-up was 2.9 years. Grip strength (right: 0.19 kg/month, p < 0.001; left 0.23 kg/month, p < 0.001) and median F-wave latencies (-0.23/month, p = 0.015) showed significant improvement over time. Akaike information criterion showed time + IVIG frequency <21 days as best fit for grip strength and distal compound muscle action potential amplitude. Our study results indicate serial grip strength measurements are a feasible and objective way to assess motor strength improvement in children with CIDP receiving immunotherapy.

Pathologic classification of a late-onset peripheral neuropathy in a spontaneous Labrador retriever dog model.

Late-onset peripheral neuropathy (LPN) is a heritable canine neuropathy commonly found in Labrador retrievers and is characterized by laryngeal paralysis and pelvic limb paresis. Our objective was to establish canine LPN as a model for human hereditary peripheral neuropathy by classifying it as either an axonopathy or myelinopathy and evaluating length-dependent degeneration. We conducted a motor nerve conduction study of the sciatic and ulnar nerves, electromyography (EMG) of appendicular and epaxial musculature, and histologic analysis of sciatic and recurrent laryngeal nerves in LPN-affected and control dogs. LPN-affected dogs exhibited significant decreases in compound muscle action potential (CMAP) amplitude, CMAP area, and pelvic limb latencies. However, no differences were found in motor nerve conduction velocity, residual latencies, or CMAP duration. Distal limb musculature showed greater EMG changes in LPN-affected dogs. Histologically, LPN-affected dogs exhibited a reduction in the number of large-diameter axons, especially in distal nerve regions. In conclusion, LPN in Labrador retrievers is a common, spontaneous, length-dependent peripheral axonopathy that is a novel animal model of age-related peripheral neuropathy that could be used for fundamental research and clinical trials.

Value of MUNE versus compound muscle action potential in assessing motor unit loss in patients with carpal tunnel syndrome

BackgroundThe most prevalent nerve entrapment disorder, known as carpal tunnel syndrome (CTS), is brought on by wrist-based median nerve compression. Focal demyelination progresses to axonal dysfunction as the condition worsens. In order to detect motor unit (MU) loos, this study compares two motor unit number estimation (MUNE) techniques with compound muscle action potential (CMAP) amplitude. The CMAP amplitude and MUNE of the median nerve in 137 hands of 70 neurophysiologically approved CTS patients, aged 40.27 ± 10.06 years were examined. Another 90 hands from 56 healthy volunteers who are age- and gender-matched serve the control group.ResultsIn contrast to 192.5 and 248.5 in controls, the median nerve values of incremental and adapted multipoint stimulation (aMPS) MUNE in CTS patients were, respectively, 111 and 133 (p < 0.0001). Patients with severe CTS compared to those with mild CTS using both methods had significantly lower MUNE. MUNE values are the same regardless of gender or hand dominance. In comparison to MUNE methods (cutoff values of 106.5 and 203, respectively), CMAP amplitude had a sensitivity and specificity of more than 60% in detecting MU loss (cutoff value of 6.85 mV). The CTS grading had no effect on the CMAP amplitude. MUNE values had positive with CMAP amplitude and negative with CTS grading and Phalen test positivity.ConclusionsWhen identifying motor nerve involvement in CTS patients, the MUNE technique is more accurate than a standard motor nerve conduction study (NCS). It was emphasized that MUNE evaluation in determining MU loss in the early stages of CTS may be helpful in diagnosis and treatment. There was no correlation between handedness and the number of MUs as determined by MUNE techniques. Both methods almost equally identify MU loss and have the same sensitivity and specificity.

The Relationship Between Smartphone Usage Duration with Hand Grip, Pinch Grip Strength and It’s Impact on NCS Motor Parameters of Median Nerve in Young Population – An Observational Study

Background: There seems to be a lack of literature regarding the association between handgrip strength and nerve conduction parameters of the median nerve among smartphone users in the young population. There is a need to investigate the inter-relation of grip strength with smartphone usage and motor parameters of the median nerve by carrying out a nerve conduction study. Aims: The study aims to find out the correlation between hand-grip and pinch-grip strength on nerve conduction study motor parameters among smartphone users. Methods and Material: 112 young adult participants were included. Hang grip strength and pinch grip strength were assessed for both hands and after three trials, the average was calculated. The average screen time of their smartphones over the past week was noted, and simultaneously, the motor nerve conduction study parameter of the median nerve was performed. Statistical analysis: Pearson’s correlation was applied to find out the correlation between the component of the handgrip, pinch grip, and motor nerve conduction velocity of the median nerve. The p-value of &lt; 0.001 was considered statistically significant. Results: The study obtained a significant negative correlation between smartphone usage with amplitude and nerve conduction velocity and a significant positive correlation with the latency of the median nerve. Conclusions: The study concluded that smartphone usage reduces the hand grip and pinch grip strength and significantly affects the motor parameters of the median nerve. KEYWORDS: Smartphone screen time, hand grip strength, pinch grip strength, median nerve.

Sensory Chronic Inflammatory Demyelinating Polyradiculoneuropathy: Neglected Immunotherapy-Responsive Sensory Neuropathy.

To report an improvement with immunotherapy in 34 (85%)/40 patients who required an immunotherapy among 56 patients with sensory chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Sensory CIDP was diagnosed when two inclusion criteria are met: 1) acquired, chronic progressive or relapsing symmetrical or asymmetrical sensory polyneuropathy that had progressed for >2 months; and 2) definite electrophysiological and/or biopsy evidence of demyelinating neuropathy. Fifty-six patients with sensory CIDP were identified. Evidence of demyelination was obtained from by the routine motor nerve conduction study (NCS) in 39 (70%) patients, from a nerve biopsy in 10, and from a near-nerve needle sensory NCS in 7 patients. The most prominent laboratory abnormality was a high protein level in the cerebrospinal fluid in 21 (49%) of 43 tested patients. Immunotherapy was required in 41 (79%) of the 52 followed-up patients. An improvement with immunotherapy was observed in 36 (88%)/41 patients. In three patients, motor weakness developed in 5-8 years' follow-up period and so, their diagnosis was changed to CIDP. Sensory CIDP is responded to an immunotherapy in 88% of the treated patients. Sensory CIDP was diagnosed by the routine motor NCS in 70% of patients and by a sural nerve biopsy in 18% of patients. Thus, sensory CIDP should be recognized as a treatable CIDP variant among the different types of "idiopathic sensory neuropathy."

The Value of Muscle Thickness of Lower Limbs in Detection of Diabetic Peripheral Neuropathy

&#x0D; Background: Neuropathy stands out as the highest-prevalence diabetes-related complication, impacting no less than 50% of individuals with diabetes throughout their lifespan. As The most common reason for disability due to walking difficulties, foot ulcerations, and limb loss, DPN is worthy of study, and early diagnosis of DPN signs is required.&#x0D; Objectives: This study aims to aid in the identification of diabetic peripheral neuropathy (DPN) by determining the muscle thickness of the lower extremities in patients with DPN.&#x0D; Patients and Methods: The study included 24 subjects with diabetic peripheral neuropathy (DPN) and 25 individuals as a control group, subdivided into 8 diabetic patients without DPN and 17 healthy individuals. Both control and DPN subjects underwent bilateral peroneal and tibial motor nerve conduction studies (NCS) and high-resolution muscle ultrasounds to measure muscle thickness. Abductor hallucis muscle (AH), extensor digitorum brevis muscle (EDB), extensor hallucis longus muscle (EHL), tibialis anterior muscle (TA), and rectus femoris muscle (RF) were evaluated on both sides using ultrasound.&#x0D; Results: Comparing the tested muscles to the control group, the study revealed a statistically significant decrease in the thickness of many of the muscles being tested when compared to the control group.&#x0D; Conclusions: These findings point to the possibility that quantitative muscle ultrasound could be beneficial in identifying muscle changes associated with DPN. It is necessary to conduct additional studies to verify the results in larger samples of diabetic patients.&#x0D; Keywords: Neuromuscular Ultrasound, Muscle Thickness, Diabetic Peripheral Neuropathy

Normative parameters of motor nerve conduction studies in infants

Introduction. Electromyography (EMG) is a modern method of instrumental neurophysiological diagnostics, which includes two main techniques as nerve conduction studies and needle EMG. Parameters of motor nerve conduction studies have been used in a number of clinical studies to evaluate the effectiveness of treatment in children with spinal muscular atrophy (SMA) during the use of pathogenetic therapy (nusinersen). Now, in our country there are no verified normative parameters of motor nerve conduction studies in infants. It is also worth saying that neonatal screening for identifying SMA patients started in 2023 in our country, and currently gene therapy for this disease is increasingly used, so improving methods for instrumental assessment of the dynamics of the condition during treatment, including using EMG, is relevant. &#x0D; Objective: to determine the normative parameters of motor nerve conduction studies in 1–6 months, 7–12 months, and 13–24 months infants without neurological pathology.&#x0D; Materials and methods: The motor nerve conduction studies were carried out using a 2-channel electromyograph Neuro-MVP-Micro (Russia) with electrical stimulation of the ulnar nerve and registration of the compound muscle action potential (CMAP) from the abductor digiti minimi muscle. This made it possible to determine the main parameters of the negative peak of the CMAP — distal latency, amplitude and area, and calculate the motor nerve conduction velocity (MNCV) along the distal part of the ulnar nerve. The obtained data for each parameter were subject to normal distribution and presented in the form of mean and standard deviation (M±SD), minimum and maximum values (min – max).&#x0D; Results: In the age range of 1–6 months, the amplitude of the CMAP (mV) was 5.0±1.0 (3.0–8.0); CMAP area (ms∙mV) — 9.1 ± 2.1 (5.5–12.9); distal latency (ms) — 2.2 ± 0.2 (1.6–2.5), MNCV (m/s) — 37.5 ± 5.4 (27.5–48.9).&#x0D; In the age range of 7–12 months, the amplitude of the CMAP (mV) was 6.2 ± 1.3 (3.8-9.3); CMAP area (ms∙mV) — 11.7 ± 3.0 (6.5–18.6); distal latency (ms) — 2.0 ± 0.2 (1.4–2.4), MNCV (m/s) – 48.4 ± 4.1 (42.1–55.2).&#x0D; In the age range of 13-24 months, the amplitude of the CMAP (mV) was 6.4 ± 0.6 (5.0-7.3); CMAP area (ms∙mV) — 13.3 ± 2.8 (9.8–18.2); distal latency (ms) — 2.2 ± 0.2 (1.8–2.5), MNCV (m/s) – 52.6 ± 3.8 (41.8–57.3).&#x0D; Conclusion. For the first time, normative parameters of motor nerve conduction studies were obtained in 1–6, 7–12, and 13–24 months infants without neurological pathology. This will make it possible to objectify neurophysiological parameters in neuromuscular diseases in infants.

Relationship Between Clinical Outcomes and Nerve Conduction Studies Before and After Viral Infections in Healthy Individuals: Case Series.

The neurological effect of viral respiratory infections has been acknowledged in many studies.However, patients who recovered from this infection show neurological manifestations and are not being routinely transferred for electrodiagnostic evaluation. This study aimed to examine the neurological effect of viral respiratory infections on the nerve function using electrophysiology in patients fully recovered from viral respiratory infections. To limit bias in the results, the authors decided to choose patients who recovered from one virus in all participants (coronavirus).Medical records were screened for patients who performed nerve conduction studies (NCSs) before the coronavirus pandemic.Thirty patients met our inclusion criteria, and only 10 showed up to perform NCS.Data of the NCS was compared before and after the coronavirus infection for motor and sensory NCS parameters. An increase in both the median and ulnar sensory nerve latencies and a decrease in the sensory nerve amplitude was observed.Also, there was a decrease in the motor conduction velocity (MCV) of the ulnar nerves and motor amplitude in the median nerve.In the lower limbs, there was a decrease in the sural nerve latency, increased MCV in the tibial nerves, and decreased MCV in the peroneal nerves.The proximal amplitudes of the tibial and peroneal nerves were increased, but the distal amplitude was increased only in the peroneal nerves and decreased in the tibial nerves. There is a significant impact of viral infections on the peripheral nerves.Large-scale prospective studies are required to investigate the pathogenesis of the neuropathy and myopathy after viral infections.

Psychophysiological and Neurophysiological Correlates of Dropping Objects from Hands in Carpal Tunnel Syndrome.

Dropping objects from hands (DOH) is a common symptom of carpal tunnel syndrome (CTS). We evaluated the clinical, neurophysiological, and psychophysiological features of 120 CTS patients to elucidate the DOH pathophysiology. Forty-nine healthy controls were included. In the patients, the Boston Carpal Tunnel Questionnaire (BCTQ), the Douleur Neuropathique 4 questions (DN4), and a numeric rating scale for pain (NRS) were evaluated. In patients and controls, we evaluated bilateral median and ulnar motor and sensory nerve conduction studies, cutaneous silent period and cutaneomuscular reflexes (CMR) of the abductor pollicis brevis, cold-detection threshold (CDT) and heat-pain detection threshold (HPT) at the index, little finger, and dorsum of the hand, and vibratory detection threshold at the index and little finger by quantitative sensory testing. CTS with DOH had higher BCTQ, DN4 and NRS, lower median sensory action potential, longer CMR duration, lower CDT and higher HPT at all tested sites than controls and CTS without DOH. Predictive features for DOH were abnormal CDT and HPT at the right index and dorsum (OR: 3.88, p: 0.03) or at the little finger (OR: 3.27, p: 0.04) and a DN4 higher than 4 (OR: 2.16, p < 0.0001). Thermal hypoesthesia in median and extra-median innervated territories and neuropathic pain are predictive of DOH in CTS.

Femoral neuropathy: A clinical and electrodiagnostic review.

Femoral neuropathies can cause severe, prolonged debility, yet there have been few clinical and electrodiagnostic (EDx) studies addressing this condition. The aim of this study was to better understand the etiologies, EDx features, and clinical course of femoral neuropathy. We identified patients evaluated at Mayo Clinic Rochester between January 1, 1999 and July 31, 2019, with possible new femoral neuropathy ascertained via International Classification of Diseases-versions 9 and 10 diagnosis codes presenting within 6 months of symptom onset. A retrospective review of 1084 records was performed and we ultimately identified 159 patients with isolated femoral neuropathy for inclusion. The most common femoral neuropathy etiologies were compressive (40%), perioperative stretch (35%), and inflammatory (6%). Presenting symptoms included weakness (96%), sensory loss (73%), and pain (53%). Presenting motor physical exam findings demonstrated moderate weakness (34%) or no activation (25%) of knee extension and mild (32%) or moderate (35%) weakness of hip flexion. Seventy-two percent of patients underwent EDx testing, including 22 with femoral motor nerve conduction studies. Treatment often involved physical therapy (89%) and was otherwise etiology-specific. In patients with follow-up data available (n = 154), 83% had subjective clinical improvement at follow-up with a mean time to initial improvement of 3.3 months and mean time to recovery at final follow-up of 14.8 months. Only 48% of patients had nearly complete or complete recovery. In our cohort, the most common etiologies of femoral neuropathy were compression or perioperative stretch with high initial morbidity. Although motor recovery is common, improvement is often prolonged and incomplete.

An assessment of Martin-Gruber anastomosis discrepancies between healthy individuals and patients with carpal tunnel syndrome in motor nerve conduction studies.

Background: The Martin-Gruber anastomosis (MGA) represents a nerve innervation anomaly in the upper extremity, potentially leading to misinterpretation during standard nerve conduction studies (NCSs). This study aims to characterize the electrophysiological attributes of MGA in both healthy subjects and individuals diagnosed with carpal tunnel syndrome (CTS). Methods: This case-control study involved the electrophysiological assessment of 506 forearms, segregated into two distinct groups: a CTS positive (+) case group and a CTS negative (-) control group. The evaluations were conducted over an average period of 8 months in the neurophysiology laboratory. The study encompassed 294 forearms from 147 healthy individuals without CTS and 212 forearms from 106 patients diagnosed with CTS, both clinically and electrodiagnostically. Results: The relationship between the presence of type I MGA and the CTS (+) group was statistically significant (P = 0.002). Similarly, the relationship between the presence of type II MGA and the CTS (+) group was statistically significant (P = 0.013). On the other hand, the relationship between the presence of type III MGA and the CTS (+) group was not statistically significant (P = 0.208). Likewise, the relationship between the presence of type IV MGA and the CTS (+) group was not statistically significant (P = 0.807). The correlation between the side of type I MGA and the groups did not reach statistical significance (P = 0.770). The relationship between the side of type II MGA and the groups also did not attain statistical significance (P = 0.990). Similarly, the side of type III MGA and its association with the groups did not yield statistical significance (P = 0.402). Finally, the relationship between the side of type IV MGA and the groups was not statistically significant (P = 0.166). Conclusion: The MGA represents a relatively frequent anatomical variation observed in the upper extremity. Notably, its presence demonstrated significance in the first dorsal interosseous (FDI) muscle (type II) and the abductor digiti minimi (ADM) muscle (type I) among patients with CTS. The present study emphasizes the importance of recognizing this variation during upper extremity NCSs for a correct diagnostic approach and treatment plan to avoid misdiagnosis of median-ulnar peripheral neuropathy.

Afterdischarges in myotonic dystrophy type 1.

Electrodiagnostic testing is an important screening test for myotonic dystrophy type 1 (DM1). Although myotonic discharges are observed on electromyography in cases of DM1, it is difficult to distinguish DM1 from other myotonic disorders clinically. In the present study, afterdischarges, another type of pathological potential revealed by electrodiagnostic testing, were analyzed, and their role in distinguishing DM1 from other myotonic disorders was explored. Data from 33 patients with myotonic discharges on electromyography were analyzed retrospectively. According to gene testing, the patients were divided into DM1 (n = 20) and non-DM1 myotonia (n = 13) groups. Afterdischarges were investigated by retrospectively evaluating the electrodiagnostic findings of motor nerve conduction studies, F-waves, and repetitive nerve stimulations. Afterdischarges were observed in 17 of the 20 patients with DM1, with an occurrence rate of approximately 85%. However, afterdischarges were absent in all patients with non-DM1 myotonia. There were significant differences in the occurrence rate between the two groups (P < 0.01). Afterdischarges may serve as a suggestive role in clinical diagnosis of DM1. The discovery that DM1 can present with afterdischarges may pave a new way to study the pathogenesis of DM1.