Sensory Nerve Conduction Studies Research Articles

Sural sparing reversible sensorimotor abnormalities in hypokalemia: A close mimic of GBS

Nerve conduction studies (NCS) in hypokalemic paralysis usually show decreased compound muscle action potential (CMAP) which improves with correction of hypokalemia and normalizes in between the attacks. Inactivity of Na+ K+ ATPase pump due to hypokalemia results in decreased excitability of muscle fibers resulting in reduced CMAP on NCS. Sensory symptoms, as well as abnormalities in sensory NCS is a rare phenomenon. Here we describe a 40-year-old male who presented with acute onset rapidly progressive ascending quadriparesis with type 2 respiratory failure due to hypokalemia following hepatorenal dysfunction. NCS done before hypokalemia correction, suggested sural sparing with generalized reduced CMAPs, nonrecordable median and ulnar nerves sensory nerve action potential (SNAP) and abnormal F waves. After hypokalemia correction there was improvement in CMAPs as well as SNAPs. Thus, hypokalemia can present as an axonal sensorimotor involvement with sural sparing on NCS study similar to Guillain-Barré syndrome subtype.

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.

Dropping Objects in Carpal Tunnel Syndrome: Clinical and Electrophysiological Features.

Background Dysfunction in both afferent sensory and efferent motor components of the median nerve may contribute to the manifestation of the symptom of dropping objects (DO) in carpal tunnel syndrome (CTS). The objective of this study was to compare the clinical and electrophysiological characteristics of CTS patients with dropping objects (wDO) and those without dropping objects (w/oDO). The study evaluated the correlation between DO symptoms and median partial conduction block, as well as the reduction in median motor conduction velocity at the wrist. Methodology An examination for CTSand the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) were performed. Median and ulnar sensory and motor nerve conduction studies were conducted in both upper extremities, and the percentage decrease in the median compound motor action potential amplitude at the wrist level was calculated. Results The study included 201 female participants aged between 22 and 88 years, comprising 57 patients withCTSwDO, 78 patients with CTSw/oDO, and 66 healthy controls. In the CTSwDO group, compared to the CTSw/oDO group, BCTQscores were significantly higher, the prevalence of sensory deficits was more pronounced, and a larger number of hands, both dominant and non-dominant, were classified as stage 3 or higher in the clinical CTS classification. However, no correlation was found between the presence of DO symptoms and any neurophysiological findings. Conclusions DO may be a symptom of clinical severity in CTS, as previously reported.No neurophysiological parameter that could be associated with DO was identified.

Reference Standard of Median Nerve Conduction Study in Korea.

To establish the reference standard of the median nerve conduction study (NCS) in Korea. A total of 648 median motor and 602 median sensory NCSs from 349 Korean healthy volunteers were tested and analyzed prospectively. Equipment calibration, assessment of intraand inter-rater reliability, and the NCSs per se were conducted according to a predetermined protocol. A reference standard was established from uncertainty components for the following parameters: the onset and peak latencies; the baseline-to-peak and peak-to-peak amplitudes; the area and duration of the negative wave; and the nerve conduction velocity. The effects of sex, age and stimulation intensity were analyzed. Each measured value of 648 median motor and 602 median sensory nerves were obtained and presented with both mean and expanded uncertainties, as well as mean and standard deviations. The cut-off values with expanded uncertainty were determined for different age and sex groups. After adjusting for anthropometric covariates, all parameters except duration were affected by age, and sex appeared to influence both duration and area. While stimulation intensity significantly affected some parameters including latencies, the effect sizes were negligible. We propose the median NCS reference standard using the largest Korean dataset ever available. The use of the traceable and reliable reference standard is anticipated to promote more accurate and dependable diagnosis and appropriate management of median neuropathies in Korea.

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.

Insights into phenotypic variability caused by GARS1 pathogenic variants.

Pathogenic variants of the glycyl-tRNA synthetase 1 (GARS1) gene have been described as a cause of Charcot-Marie-Tooth disease type 2D, motor axonal neuropathy with upper limb predominance (distal hereditary motor neuropathy [dHMN] type V), and infantile spinal muscular atrophy. This cross-sectional, retrospective, observational study was carried out on 12 patients harboring the c.794C>T (p.Ser265Phe) missense pathogenic variant in GARS1. The patients' clinical data, nerve conduction studies, magnetic resonance imaging (MRI), and intraepidermal nerve fiber density in skin biopsies were reviewed. The mean age at onset was 9.5 years; the intrinsic hand muscles were affected before or at the same time as the distal leg musculature. The clinical examination revealed greater weakness of the distal muscles, with a more pronounced involvement of the thenar complex and the first dorsal interosseous in upper limbs. Electrophysiological studies were concordant with an exclusively motor axonal neuropathy. A pathologic split hand index was found in six patients. Muscle MRI showed predominant fatty infiltration and atrophy of the anterolateral and superficial posterior compartment of the legs. Most patients reported distal pinprick sensory loss. A reduced intraepidermal nerve fiber density was evident in skin biopsies from proximal and distal sites in nine patients. GARS1 variants may produce a dHMN phenotype with "split hand" and sensory disturbances, even when sensory nerve conduction studies are normal. This could be explained by a dysfunction of sensory neurons in the dorsal ganglion that is reflected as a reduction of dermal nerve endings in skin biopsies without a distal gradient.

Brachial Plexus Injury Influences Efferent Transmission on More than Just the Symptomatic Side, as Verified with Clinical Neurophysiology Methods Using Magnetic and Electrical Stimulation.

The variety of sources of brachial plexus injuries (BPIs) and the severity and similarity of their clinical symptoms with those of other injuries make their differential diagnosis difficult. Enriching their diagnosis with objective high-sensitivity diagnostics such as clinical neurophysiology may lead to satisfactory treatment results, and magnetic stimulation (MEP) might be an advantageous addition to the diagnostic standard of electrical stimulation used in electroneurography (ENG). The asymptomatic side in BPI cases sometimes shows only subclinical neurological deficits; this study aimed to clarify the validity and utility of using MEP vs. ENG to detect neural conduction abnormalities. Twenty patients with a BPI and twenty healthy volunteers with matching demographic and anthropometric characteristics were stimulated at their Erb's point in order to record the potentials evoked using magnetic and electrical stimuli to evaluate their peripheral motor neural transmission in their axillar, musculocutaneous, radial, and ulnar nerves. MEP was also used to verify the neural transmission in participants' cervical roots following transvertebral stimulations, checking the compatibility and repeatability of the evoked potential recordings. The clinical assessment resulted in an average muscle strength of 3-1 (with a mean of 2.2), analgesia that mainly manifested in the C5-C7 spinal dermatomes, and a pain evaluation of 6-4 (mean of 5.4) on the symptomatic side using the Visual Analog Scale, with no pathological symptoms on the contralateral side. A comparison of the recorded potentials evoked with magnetic versus electrical stimuli revealed that the MEP amplitudes were usually higher, at p = 0.04-0.03, in most of the healthy volunteers' recorded muscles than in those of the group of BPI patients, whose recordings showed that their CMAP and MEP amplitude values were lower on their more symptomatic than asymptomatic sides, at p = 0.04-0.009. In recordings following musculocutaneous and radial nerve electrical stimulation and ulnar nerve magnetic stimulation at Erb's point, the values of the latencies were also longer on the patient's asymptomatic side compared to those in the control group. The above outcomes prove the mixed axonal and demyelination natures of brachial plexus injuries. They indicate that different types of traumatic BPIs also involve the clinically asymptomatic side. Cases with predominantly median nerve lesions were detected in sensory nerve conduction studies (SNCSs). In 16 patients, electromyography revealed neurogenic damage to the deltoid and biceps muscles, with an active denervation process at work. The predominance of C5 and C6 brachial plexus injuries in the cervical root and upper/middle trunk of patients with BPI has been confirmed. A probable explanation for the bilateral symptoms of dysfunction detected via clinical neurophysiology methods in the examined BPI patients, who showed primarily unilateral damage, maybe the reaction of their internal neural spinal center's organization. Even when subclinical, this may explain the poor BPI treatment outcomes that sometimes occur following long-term physical therapy or surgical treatment.

Normative Data and Quantile Regression Analysis of the Sural-to-Radial Nerve Amplitude Ratio.

The aim of this study was to establish normative data for the sural-to-radial nerve amplitude ratio (SRAR) and develop a quantile regression model for individualized cutoff values. A cohort of 68 healthy individuals (36 female participants) aged 20 to 59 years was recruited. Sensory nerve conduction studies were conducted to measure sural and radial sensory nerve action potential amplitudes. Quantile regression analysis was used to determine the fifth percentile of SRAR after adjusting for age, sex, and other demographic variables. This study found significant differences in body height and weight between the sexes, with radial sensory nerve action potential being higher in female participants. The sural-to-radial nerve amplitude ratio was negatively correlated with age (r = -0.3, p = 0.007) and showed significant sex differences. The final regression equation, SRAR = 0.519 - 0.006 × age + 0.046 × sex (1 = male, 0 = female), was developed for the fifth percentile cutoff, accounting for age and sex. This study establishes normative SRAR data and introduces a novel quantile regression approach to determine individualized cutoff values. Age and sex are critical factors for SRAR variation, necessitating tailored diagnostic criteria for neuropathy assessment. This model enhances diagnostic accuracy and potentially reduces misdiagnosis in clinical settings. Further research is recommended to validate the clinical applicability of SRAR across different types of neuropathies.

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.

Therapeutic Effect of Schwann Cell-Like Cells Differentiated from Human Tonsil-Derived Mesenchymal Stem Cells on Diabetic Neuropathy in db/db Mice.

Diabetic neuropathy (DN) is the most common complication of diabetes, and approximately 50% of patients with this disease suffer from peripheral neuropathy. Nerve fiber loss in DN occurs due to myelin defects and is characterized by symptoms of impaired nerve function. Schwann cells (SCs) are the main support cells of the peripheral nervous system and play important roles in several pathways contributing to the pathogenesis and development of DN. We previously reported that human tonsil-derived mesenchymal stem cells differentiated into SCs (TMSC-SCs), named neuronal regeneration-promoting cells (NRPCs), which cells promoted nerve regeneration in animal models with peripheral nerve injury or hereditary peripheral neuropathy. In this study, NRPCs were injected into the thigh muscles of BKS-db/db mice, a commonly used type 2 diabetes model, and monitored for 26weeks. Von Frey test, sensory nerve conduction study, and staining of sural nerve, hind foot pad, dorsal root ganglia (DRG) were performed after NRPCs treatment. Von Frey test results showed that the NRPC treatment group (NRPC group) showed faster responses to less force than the vehicle group. Additionally, remyelination of sural nerve fibers also increased in the NRPC group. After NRPCs treatment, an improvement in response to external stimuli and pain sensation was expected through increased expression of PGP9.5 in the sole and TRPV1 in the DRG. The NRPCs treatment may alleviate DN through the remyelination and the recovery of sensory neurons, could provide a better life for patients suffering from complications of this disease.

Assessing Nerve Conduction Velocity as a Diagnostic and Prognostic Indicator in Leprosy Patients: A Cross-Sectional Study.

Introduction Hansen's disease is a condition in which patients develop peripheral neuropathy. In 1873, G. H. A. Hansen discovered Mycobacterium leprae, the causative agent of leprosy, a chronic infectious disease. These bacteria influence the peripheral nerves, which is likely to cause neuropathy. Sensory nerve conduction studies were performedin leprosy patients on the upper limb nerves of 30 patients in the rural area of the Wardha district in the Indian population. Methods In this study, we recruited 30 leprosy patients fromthe Department of Dermatology and A.V.B.R. Hospital, Sawangi Wardha. The patient's nerve conduction velocity (NCV) tests were carried out in the Department of Physiology at J. N. Medical College, Wardha. NCVs were obtained during these three years, beginning in 2009, while performing sensory nerve conduction velocity (SNCV) and motor nerve conduction velocity (MNCV). The latency, amplitude, and NCV parameters were recorded, and the data collection period ended in 2011. In this study, we measured both MNCVand SNCV. Results In our study, impairment of conductional velocity was observed. In leprosy patients, the MNCV values of latency, amplitude, and conductional velocity were 6.61, 3.89, and 46.92 m/s, respectively, whereas the SNCV values were 3.005, 25.17, and 38 m/s, respectively. Based on the results, it appears that the maximal sensory nerve involvement was recorded at 38 m/s conductional velocity.In NCVs, increased latency and decreased conductional velocity were found across the study. Conclusion It was concluded that nerve conduction studies are one of the non-invasive techniques for early diagnosis and management of leprosy. This study should be repeated with a larger sample size and should be multicentric.

Small and large fiber neuropathy in adults with myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disorder that affects multiple organs. In this study, we investigated symptoms of pain and presence of small and large fiber neuropathy in the juvenile and adult form of DM1. Twenty genetically verified DM1 patients were included. Pain was assessed, and neurological examination and investigations of the peripheral nervous system by quantification of small nerve fibers in skin biopsy, quantitative sensory testing and nerve conduction studies were performed. Results from skin biopsies were compared to healthy controls. Seventeen patients reported chronic pain. Large and/or small fiber abnormalities were present in 50% of the patients. The intraepidermal nerve fiber density was significantly lower in the whole group of patients compared to healthy controls. Small-fiber neuropathy might be an important cause of pain in DM1.

Sensory nerve conduction studies in infants, children and teenagers – An update

ObjectiveNerve conduction studies (NCS) in children remain technically challenging and depend on the cooperation of the child. Motor NCS are not compromised by analgosedation but data for sensory NCS are lacking. Here, we ask whether sensory NCS is influenced by analgosedation. We also compare the present data with NCS studies from the 1990s regarding anthropometric acceleration of the contemporary paediatric population. MethodsSensory NCS of the median nerve and sural nerve were performed in 182 healthy subjects aged 1 to 18 years during general anaesthesia and in 47 of them without analgosedation. ResultsSensory NCS was not influenced by midazolam or propofol. The sensory nerve action potential (SNAP) amplitude and the nerve conduction velocity (NCV) of the sural nerve as well as the SNAP of the median nerve show no significant age dependence in age range 1–18 years. The sensory NCV of the median nerve increased age-dependent. ConclusionsIn clinical practice, analgosedation can be used for diagnostic NCS. Sensory NCS data show no relevant secular trend over the last 30 years. Differences due to technical inconsistency predominate. SignificanceAnalgosedation can improve diagnostic quality of sensory NCS in children. Additionally, we provide sensory NCS values from a large pediatric cohort.

Chapter 12 - Meralgia paresthetica

Meralgia paresthetica is a common but probably underrecognized syndrome caused by dysfunction of the lateral femoral cutaneous nerve. The diagnosis is based on the patient's description of sensory disturbance, often painful, on the anterolateral aspect of the thigh, with normal strength and reflexes. Sensory nerve conduction studies and somatosensory evoked potentials may be used to support the diagnosis, but both have technical limitations, with low specificity and sensitivity. Risk factors for meralgia paresthetica include obesity, tight clothing, and diabetes mellitus. Some cases are complications of hip or lumbar spine surgery. Most cases are self-limited, but a small proportion of patients remain with refractory and disabling symptoms. Treatment options include medications for neuropathic pain, neurolysis, neurectomy, and radioablation, but controlled trials to compare efficacy are lacking.

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."

Electrophysiological and Ultrasonographic Evaluation of Palmar Digital Nerve Injury in Distal Finger

Electrophysiological evaluation of distal lesions in the palmar digital branch of the median nerve presents a significant challenge. We present a case of lateral palmar digital neuropathy of the median nerve, which was confirmed through clinical, electrophysiological, and ultrasonographic assessments. A 54-year-old woman was referred to our electrophysiology laboratory for persistent numbness and a tingling sensation on the radial side of the distal phalanx of her left second finger. She had a laceration injury on the middle phalanx of the second finger and underwent neurorrhaphy of the lateral branch of the palmar digital nerve 8 months ago. Sensory nerve conduction studies, both antidromic and orthodromic, showed low amplitude responses for the lateral branch of the palmar digital nerve. Ultrasonography revealed swelling of this nerve branch within the middle phalanx of the second finger. When patients report sensory symptoms in a specific area, it is important to evaluate for potential cutaneous nerve injuries using electrophysiological studies. Additionally, high-resolution ultrasonography is a valuable tool for investigating small cutaneous nerve lesions, even in the distal finger.

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.