SNAP Amplitude Research Articles

Longitudinal artificial intelligence-based deep learning models for diagnosis and prediction of the future occurrence of polyneuropathy in diabetes and prediabetes

ObjectiveThe objective of this study was to develop artificial intelligence-based deep learning models and assess their potential utility and accuracy in diagnosing and predicting the future occurrence of diabetic distal sensorimotor polyneuropathy (DSPN) among individuals with type 2 diabetes mellitus (T2DM) and prediabetes. MethodsIn 394 patients (T2DM=300, Prediabetes=94), we developed a DSPN diagnostic and predictive model using Random Forest (RF)-based variable selection techniques, specifically incorporating the combined capabilities of the Clinical Toronto Neuropathy Score (TCNS) and nerve conduction study (NCS) to identify relevant variables. These important variables were then integrated into a deep learning framework comprising Convolutional Neural Networks (CNNs) and Long Short-Term Memory (LSTM) networks. To evaluate temporal predictive efficacy, patients were assessed at enrollment and one-year follow-up. ResultsRF-based variable selection identified key factors for diagnosing DSPN. Numbness scores, sensory test results (vibration), reflexes (knee, ankle), sural nerve attributes (sensory nerve action potential [SNAP] amplitude, nerve conduction velocity [NCV], latency), and peroneal/tibial motor NCV were candidate variables at baseline and over one year. Tibial compound motor action potential amplitudes were used for initial diagnosis, and ulnar SNAP amplitude for subsequent diagnoses. CNNs and LSTMs achieved impressive AUC values of 0.98 for DSPN diagnosis prediction, and 0.93 and 0.89 respectively for predicting the future occurrence of DSPN. RF techniques combined with two deep learning algorithms exhibited outstanding performance in diagnosing and predicting the future occurrence of DSPN. These algorithms have the potential to serve as surrogate measures, aiding clinicians in accurate diagnosis and future prediction of DSPN.

Upper-limb dysfunction in cancer survivors with chemotherapy-induced peripheral neurotoxicity

IntroductionUpper-limb symptoms are often reported in the context of chemotherapy-induced peripheral neurotoxicity (CIPN), but objective quantification of functional deficits is often lacking. We examined and compared a range of neurophysiological and functional assessments of the upper-limb in the assessment of CIPN severity. MethodsCross-sectional assessment of neurotoxic chemotherapy-treated patients was undertaken using patient-reported and clinically-graded CIPN measures. Upper-limb functional assessments comprised of assessing fine motor skills, sensory perception, and neurophysiological measures of the median nerve. Group comparisons between participants who reported absence or presence of upper-limb functional deficits were investigated. Results60 participants who were 11.5 (IQR = 4.0–26.0) months post-neurotoxic chemotherapy treatment reported CIPN. 65% (n = 39) reported upper-limb CIPN symptoms. Reduction in fine motor skills, sensory perception and median nerve SNAP amplitudes were associated with higher CIPN severity. Participants who self-reported presence of upper-limb functional deficits had worse CIPN severity across all measures, compared to participants who reported no upper-limb functional deficits. ConclusionsParticipants who reported upper-limb symptoms and functional deficits had worse CIPN severity and quality-of-life. There is a high burden of upper-limb dysfunction long after neurotoxic chemotherapy treatment cessation. Focus on research into supportive care and rehabilitation options to improve upper-limb function is warranted to improve patient quality-of-life.

Natural evolution of idiopathic carpal tunnel syndrome with respect to wrist and hand anthropometry: A prospective cohort study

ObjectiveA greater wrist depth/width ratio and wrist depth/palm length ratio are known risk factors for carpal tunnel syndrome. We hypothesized that these parameters might also predict progression in patients who were not surgically treated. MethodsSeventy-eight patients with moderately severe idiopathic carpal tunnel syndrome of at least 10 months duration at recruitment, who declined surgical treatment and steroid injection, underwent repeated neurophysiological assessments after 3 years. A > 10% increase in median SNAP latency was taken as evidence of significant deterioration. ResultsPatients with a wrist ratio ≥ 0.72 showed a statistically significant deterioration in SNAP latency from 5.46 (SD 2.09) to 7.16 (SD 1.56) ms and in SNAP amplitude from 30.19 (SD 13.8) to 16.62 (SD 14.42) µv. For those with a wrist-to-palm ratio ≥ 0.42, SNAP latency deteriorated from 5.27 (SD 1.21) to 7.1 (SD 1.52) ms, and amplitude from 32.78 (SD 13.76) to 19.45 (SD 16.62) µv. Patients with lower ratios did not show significant changes in any neurophysiological parameter. The relative risk of significant deterioration in SNAP latency in patients with a wrist ratio ≥ 0.72 was 2.04 (95% CI 1.27–3.27). ConclusionIn untreated idiopathic carpal tunnel syndrome, patients with larger wrist and wrist-to-palm ratios are more likely to show neurophysiological progression.

Diagnostic Relevance of Electromyographic Values and their Role in Forecasting the Conservative Treatment in Patients with Carpal Tunnel Syndrome

Summary. Instrumental investigation and electromyography (EMG), one of the most widespread and informative of its methods, still remains widely used for differentiated diagnostics with any other disorder, compressive-ishemic focal neuropathy (CIFN) of the median nerve (MN) ) at the level of the carpal tunnel (CT) diagnosis verification and determination of the severity of damage to the MN. The clinical diagnosis of this pathologyis better know as carpal tunnel syndrome (CTS). Objective: To study the diagnostic relevance of electromyographic values in the Ukrainian population of CTS patients and their role in forecasting the efficiency of conservative treatment of this disorder.
 Materials and methods: 128 patients (204 extremities) with the clinical signs of CTS, who formed the Main Group (MG) underwent electromyography (EMG). The mean age of the patients was 58.2±12.5 years old; among them were 105 (82 %) women and 23 (18 %) men; 77 persons with a bilateral and 51 with a unilateral process. The control group (CG) included 30 volunteers (54 extremities) without any claims and signs of neurological symptoms. The mean age was 45.1±7.8 years old; among them were 23 (77.6%) women and 7 (23,3%) men. To determine the EMG predictors of the effectiveness of clinical outcomes after paraneural corticosteroid injection (PCI) 58 extremities MG were examined.For the EMG examination, we used the «Viking Quest» machine by Nicollet, the USA. Applying relevant methods, we investigated the following: median motor distal latency (DMLm) and CMAP of M. abductor pollicis brevis (APB); median sensory distal onset (MOL-D2), median sensory distal peak latency (MPL-D2), median SNAP amplitude digit 2, median sensory conduction velocity between wrist and digit 2 (mSNCV); difference in median sensory onset latency (digit 1) (MSL-D1) to radial sensory onset latency (digit 1) (RSL-D1) – MD1-RD1; difference in median nerve distal motor latency (2nd lumbrical)to the ulnar nerve distal motor latency (2nd interossei) – 2LI-DML; interrelation of the amplitudes of CMAP APB obtained by the stimulation of the MN on the level of the lower third of forearm to the amplitude of CMAP APB – on the level of the lower third of a palm (wrist to palm amplitude ratio); the sensory ulnar nerve conduction velocity (uSNCV).
 Results: The analysis of mean values of the core EMG values has demonstrated the significant differences between MG and CG, with different directions of changes, typical of the CTS. Relying on the data collected while studying people from the CG (the discovered referential and abnormal values) and the ROC analysis, we have established the sensitivity and specificity of EMG values: DMLm – 73.5% and 96.3%; MPL-D2 – 81.9% and 100%; mSNCV– 93.9% and 100%; MD1-RD1 – 62.5% and 100%; MSL-D1– 83.3% and 96.9%; 2LI-DML – 88.2% and 100%, respectively (AUC=0,91-0.96). Based on the results of the ROC analysis, determined that the most prognostically significant EMG predictor of clinical outcome after PCI was median SNAP amplitude digit 2 (sensitivity 90,9% and specificity 92%, AUC=0,95.
 Conclusions: The EMG is the objective and informative method to diagnose CIFN of the MN at the level of the CT, severity of nerve damage in CTS patients and predicting of clinical outcome after PCI.

Neuropathy as the Initial Manifestation of Leprosy in an Older Patient (P3-10.004)

<h3>Objective:</h3> To consider Leprosy in the differential diagnosis of an older patient who presents with demyelinating polyneuropathy. <h3>Background:</h3> 70-year-old Bangladeshi Man with Diabetes Mellitus presents with two years of distal right arm numbness, right hand weakness, intermittent bilateral feet numbness, and prior blisters on the dorsolateral fingers. Neurologic exam revealed right arm distal&gt;proximal weakness, absent vibration in toes, decreased sensation to pinprick below the right elbow and bilateral ankles, and loss of proprioception of bilateral hallux. During initial skin evaluation no lesions were noted. <h3>Design/Methods:</h3> NA <h3>Results:</h3> Serology was unremarkable including ESR/CRP. EMG/NCS consistent with moderate sensorimotor demyelinating polyneuropathy and possible superimposed right lower trunk brachial plexopathy. MRI C-spine and brachial plexus were unrevealing. Due to EMG results and persistent symptoms Lewis Sumner Syndrome was considered. Ganglioside panel, celiac panel, and CSF studies were normal. On 3-year follow up, the patient developed worsening weakness and blisters of the left hand, and atrophy of the right hand. Dermatologic exam showed left hand hyperkeratotic plaques, right arm subcutaneous nodules, and hypopigmented patches on the trunk. Biopsy of a hypopigmented patch was negative for AFB. Repeat EMG/NCS showed decreased CMAP and SNAP amplitudes compared to the prior study in bilateral arms with continued ongoing denervation. Left medial antebrachial nerve biopsy confirmed Mycobacterium leprae. <h3>Conclusions:</h3> Leprosy is an infectious disease involving the skin, peripheral nerves, mucosal surface of the respiratory tract and eyes. Early diagnosis and treatment are essential to reduce the likelihood of disability as it is often irreversible and requires lifelong care. When leprosy occurs exclusively in neuropathic syndromes and at an older age, diagnosis can be difficult. Current classification systems rely heavily on skin manifestations, and diagnosis at the time of only peripheral nerve involvement can become challenging. As information accumulates on various neurological disorders in leprosy, it becomes increasingly clear that treatment paradigms should evolve. <b>Disclosure:</b> Dr. Sharma has nothing to disclose. Dr. Monohan has nothing to disclose. Dr. Anziska has nothing to disclose. Dr. Jacoby has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Jacoby has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Argenx. Dr. Jacoby has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for N/A. The institution of Dr. Jacoby has received research support from ABPN.

Median to ulnar nerve comparison on diagnosis of carpal tunnel syndrome in patients with diabetic polyneuropathy - A neurophysiological study.

<p style="text-align: justify;"><strong>Background and purpose </strong>&ndash; To analyze the utility of median nerve (MN) to ulnar nerve (UN) comparative parameters on the diagnosis of carpal tunnel syndrome (CTS) in diabetic patients with distal symmetrical sensorimotor polyneuropathy (DSMPNP). <br><br><strong>Methods</strong> &ndash; Patients who were referred to our electroneuromyography laboratory within the last two years were included. We compared the diagnostic accuracy values of traditional MN conduction parameters, and the MN-to-UN comparative tests on electrodiagnosis of CTS between the patients with DSMPNP involving the nerves of upper and lower extremities (UEI-positive group), and the ones without the involvement of upper extremities (UEI-negative group). <br><br><strong>Results</strong> &ndash; There were 64 upper extremities in the UEI-positive group and 70 patients in the UEI-negative group. The most accurate traditional parameter was MN distal motor latency (DML) with a diagnostic accuracy of 70.2% whereas the most accurate comparative technique was the second lumbricalinterosseous DML difference (2L-INT DMLD) with an accuracy of 81.3%. (p=0.03). In addition, when compared diagnostic accuracy values of MN parameters with their corresponding comparative parameters in the UEI-positive group which carries the major diagnostic challenges for detecting co-morbid CTS, MN to UN minimum F wave latency (mFWL) difference, SNAP amplitude ratio on the ring finger (RF), and 2L-INT DMLD had higher accuracy values than MN mFWL, MN SNAP amplitude on RF, and MN DML on lumbrical muscle, respectively (p&lt;0.05 for all comparisons). <br><br><strong>Conclusion</strong> &ndash; MN to UN comparative studies have high accuracy values in electrodiagnosis of CTS in DSMPNP. In particular, 2L-INT DMLD could be helpful to overcome the diagnostic difficulty in the presence of UEI as an additional conduction technique.</p>.

O.10 First-in-human intrathecal gene transfer study for giant axonal neuropathy: Preliminary review of long-term efficacy and safety

Giant axonal neuropathy (GAN) is a rare and fatal pediatric neurodegenerative disorder affecting the central and peripheral nervous system. Recessive variants in the <i>GAN</i> gene cause dysfunction of gigaxonin, a cytoskeletal regulatory protein, leading to progressive sensorimotor and optic neuropathy, CNS involvement and respiratory failure with death by the second to third decade of life. We are conducting a first-in-human intrathecal (IT) AAV9-mediated gene transfer trial for GAN (NCT02362438). This is an ongoing single site, phase I, non-randomized, open label dose escalation trial with lead-in and GAN natural history data serving for comparison. Fourteen GAN participants ages 6 years to 14 years old have received a single IT dose of scAAV9-JeT-GANopt (ranging from 3.5x10¹³ vector genomes (vg) to 3.5x10¹⁴ vg total dose) with concomitant immunomodulation protocols. Safety is the primary outcome measure with follow-up data spanning 24-72 months post gene transfer. Secondary outcome measures include the motor function measure (MFM)-32, nerve conduction studies, and nerve pathology. Here we review safety and immunologic findings related to dose, genotype, baseline AAV9 seropositivity, and the use of T-cell immune modulation. We present preliminary efficacy results on change in MFM-32 at one year post gene transfer compared to lead-in and our GAN natural history data as well as MFM-32 trajectories in long-term follow-up. Neurophysiologic (CMAP and SNAP amplitude) and nerve pathology findings are also reviewed. This study highlights the overall safety and feasibility of an intrathecal route of AAV9 based gene transfer and demonstrates the ability of IT gene transfer to positively modify the expected rate of decline and progression in GAN. Importantly, this study serves as proof of concept for IT gene transfer with targeted immune modulation as a successful strategy for gene replacement in disorders affecting the central and peripheral nervous system.

Sural Sensory Nerve Action Potential: A Study in Healthy Indian Subjects at Tertiary Care Center of North-West India.

This study was done to obtain the reference data for the sural SNAP amplitude and latency at distances of 14, 12, and 10 cm from the active recording electrode in Indian healthy subjects for different age groups. Two hundred forty-four healthy subjects (18-80 years) were included in this cross-sectional study. Subjects were divided into six groups according to age. Sural SNAP was recorded antidromically stimulating at three sites (14, 12, and 10 cm from the recording electrode). The quantitative variables were expressed as Mean ± SD/Median (IQR) and compared using t test/ANOVA. Transformed data for amplitude were analyzed with the use of paired t test. P < 0.05 was considered statistically significant. SPSS version 20.0 software was used for statistical analysis. Mean age of included subjects was 43.28 years. Maximum leg girth was at 14 cm. Analysis showed a significant difference in the leg girth at all three sites (P < 0.001). Sural SNAP latency at each stimulating site was compared in different age groups, no significant difference was found between groups (P = 0.19). Maximum amplitude was in the 18-30-years age group and amplitude was minimum in the 71-80-years age group (4.34 and 2.79, respectively). The difference in the amplitude recorded in the different age groups was found to be statistically different (P < 0.001). The difference in the amplitude recorded at each site was found to be statistically different (P < 0.001). This is the first study with a large sample size (244 subjects) to provide age-stratified reference data for SNAP in the Indian population by using three sites of stimulation at distances of 14, 12, and 10 cm from the recording electrode. This study shows that sural SNAP amplitude varies with the age of the subject and distance from stimulation.

Polyneuropathy In Obstructive Sleep Apnea Patients

Aim: Hypoxemia due to obstructive sleep apnea (OSA) is thought to cause peripheral nerve damage. A case-control study was conducted to test the accuracy of this phenomenon. Material and Methods: The patient group consisted of 45 patients with OSA who had an apnea-hypopnea index (AHI) score of &gt;10 and were newly diagnosed with OSA and control group consisted of 37 individuals who did not have OSA. Sensory and motor nerve conduction investigations were performed on both the upper and right lower extremity Mann-Whitney U, chi square and independent sample T tests were carried out. Results: Both groups had the same average age of 46. The mean body mass index (BMI) in patients with OSA was 31.81; the average AHI was 55.17; the periodic leg movements in sleep (PLMS) was 30.71; the T90 value was 74.23; the lowest saturation was 37; the average saturation value was 72.97. The other nerves' sensory and motor distal latency lengths were more prolonged than the control group, except the ulnar nerve. The averages of the left median, ulnar, and right peroneal motor nerves’ compound motor action potential (CMAP) amplitude were lower in individuals with OSA than in the control group. Compared to the control group, patients with OSA had slower right tibial nerve motor conduction velocity. The mean snap amplitude of bilateral median and left ulnar sensory nerve were higher in patients with OSA. Conclusion: OSA-induced hypoxia may have an impact on peripheral nerve damage.

Correlation of nerve conduction study parameters with thyroid hormone in newly diagnosed hypothyroid patients

Background: Thyroid hormones act on many organs including central and peripheral nervous system for maintaining metabolic homeostasis. Entrapment neuropathies are most common in hypothyroidism. Nerve conduction parameters are impaired even in newly diagnosed cases of hypothyroid. Aims and Objectives: This study aims to study the correlation between thyroid hormone and nerve conduction study (NCS) parameters in newly diagnosed hypothyroid patients. Materials and Methods: This cross-sectional, descriptive study included newly diagnosed hypothyroid patients (n=30; age: 31.96±9.12). In all subjects, NCS was performed in median, ulnar, tibial motor nerve and median, ulnar, sural sensory nerve using Nihon Kohden machine in Neurophysiology lab 2, B. P. Koirala Institute of Health Science. Thyroid function test (TFT) was analyzed by ELISA. The association between thyroid hormone and NCS parameters was done using Pearson’s correlation. Results: In NCS sensory parameters; SNAP amplitude of the left sural nerve showed significant positive correlation with t3 (lt; r=0.451, P=0.012). Among motor parameters, distal latency of left median nerve showed significant negative correlation with t3 whereas nerve conduction velocity of the left median nerve showed positive correlation with t3. In rest of the nerve, the association between NCS parameters and TFT (t3, t4, and TSH) parameters did not show any significant changes. Conclusion: Our study reveals that in newly diagnosed cases of hypothyroidism, nerve impairment occurs in which the left side is affected much earlier than right side and further its severity can be correlated with level of T3 rather than TSH.

FV 10. Nerve conduction studies in CIDP at first diagnosis and during disease course: a cross-sectional study in a large cohort of patients

Background. Nerve conduction studies represent the gold standard in the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) and play a central role in the EFNS/PNS criteria. However, the highly extensive examination protocol of those criteria and the question how to further monitor are relevant problems in daily medical practice. Hence, the aim of this cross-sectional study is to establish a practical and applicable strategy a) conducting the EFNS/PNS criteria and b) monitoring disease related disability in a large cohort of CIDP patients. Methods. As part of a prospective cohort study, we conducted a bilateral neurographic examination of the median nerve (mot.+sens.), ulnar nerve (mot.+sens.), radial nerve (sens.), tibial nerve (mot.), peroneal nerve (mot.+sens.), and sural nerve (sens.) in 95 CIDP patients. The EFNS/PNS criteria were applied on the collected neurographic data and compared with the INCAT overall disability sum score (INCAT-ODSS) and INCAT sensory score (ISS) to quantify disease disabilities. Results. In total, 95 CIDP patients (f:m 1:3.32; mean age 59±12y; 52% atypical CIDP; mean disease duration 74±60 months) were recruited, thereof 25 at initial diagnosis. All patients fulfilled the electrophysiological EFNS/PNS diagnosis criteria for CIDP. At initial diagnosis, the median nerve met the single parameters of the EFNS/PNS criteria most frequently with 72%, followed by the tibial nerve with 66%, ulnar nerve with 46%, and peroneal nerve with 22%. In total, the criterion of prolonged distal cMAP duration was met most frequently (32%), followed by an abnormal temporal dispersion (16%) and absence of F-waves (13%). However, we identified axonal damage as the parameter related with clinical disability ( p < 0.001), not demyelination. Thus, distal cMAP and sNAP amplitudes could be identified as predictive markers of disability, especially in the upper limbs (related to INCAT-ODSS: ulnar nerve: R2 = 0.219; median nerve: R2 = 0.099; peroneal nerve: R2 = 0.044; tibial nerve: R2 = 0.034; related to ISS: ulnar nerve: R2 = 0.118; radial nerve: R2 = 0.112; sural nerve: R2 = 0.096; peroneal nerve: R2 = 0.084; median nerve: R2 = 0.082). The neurographic parameters of the upper limbs might relate to a greater extent to the total disability than those of the lower limbs, since nerves of the lower limbs have already shown extensive axonal damage (71% of distal cMAP amplitudes of the peroneal nerve and 45% of the tibial nerve <1 mV). Conclusions. Although the majority of CIDP patients reveal symptoms predominant of the legs, the examination of the upper limbs has proven to be essential for both initial diagnosis and disease monitoring, underlining CIDP as a systemic disease. Especially the determination of the distal cMAP duration was a sensitive parameter in the detection of CIDP. The total disability is largely determined by the degree of axonal damage. Therefore, neuroprotection should have an important additional role in the CIDP therapy in the future.

P-PN025. Peculiarities of differential diagnosis and treatment of upper limb tunnel neuropathies

Introduction . It is well-known that numbness in hands is associated with peripheral nerves compression or “tunnel neuropathies” (TN). According to numerous authors, TN account for up to 40% of all neurological diseases. However, TN diagnosing in outpatients is practically uncommon. Methods . 597 cases of hand numbness were selected on analysis of 2495 outpatient records in two remote ambulatories during 2016-2017, with the share of TN being 0.7% of all initial diagnoses. 92 patients with mild to moderate TN symptoms were included in the study, and divided into main (n=50) and control (n=42) groups. Both groups received B vitamins and thioctic acid as baseline medications. Ipidacrine (Ipigrix by Grindex, Latvia) was added in the main group: 15 mg I.M. q.d. for a week and 20 mg p.o. q.d. for 3 more weeks. Thorough clinical and ENMG examinations were carried out before and after treatment. Results . All initial diagnoses were associated with cervical osteochondrosis, including radiculopathy, lacking any signs of its objectification. The Kruskal-Wallis test revealed sample homogeneity regardless of the diagnoses, and no statistically significant inter-group differences by clinical or ENMG markers of TN were originally detected. A 4-week follow-up analysis compared with the baseline results demonstrated that the control group had a positive trend, but no significant differences before and after treatment. Meanwhile, in the main group, additionally receiving ipidacrine, there was a statistically confirmed improvement of hypoesthesia, paresthesia, provocative test results, SNAP amplitudes and conduction time within carpal and pronator TN, as well as CMAPs in the cubital TN (p<0.05). Conclusion . The study describes typical “diagnostic masks” of TN, traditionally associated with osteochondrosis, the role of which in the occurrence of hand numbness is greatly exaggerated. Furthermore, the results suggest the efficacy of a short course of ipidacrine in the complex treatment of patients with mild and moderate TN.

Skin biopsy and quantitative sensory assessment in an Italian cohort of ATTRv patients with polyneuropathy and asymptomatic carriers: possible evidence of early non-length dependent denervation.

Study of intraepidermal nerve fiber density (IENFD) by skin biopsy represents a promising tool in the evaluation of patients with ATTRv polyneuropathy (ATTRv-PN). Herein, we retrospectively analyze intraepidermal innervation and quantitative sensory test (QST) data from an Italian cohort of Italian ATTRv-PN patients and asymptomatic carriers aimed to provide insights into early nerve pathological and functional changes in this disease. IENFD and QST data of 14 ATTRv-PN patients and 14 asymptomatic carriers were retrospectively analyzed together with clinical and paraclinical data such as disease stage and severity, neuropathic pain scales, and sural SNAP amplitude. Given an estimated time to the predicted age of onset of symptomatic disease of 20.27 + / - 7.9years, small nerve fiber loss seems to be unexpectedly early in carriers. Moreover, carriers showed skin denervation at the proximal (thigh) site, suggesting a non-length-dependent neuropathic process. IENFD at ankle correlated with disease severity and other paraclinical variables such as sural nerve potential amplitude and QST parameters. Patients at earlier stages of the disease did not show significant differences in ankle IENFD compared with asymptomatic carriers, but significant differences in terms of QST parameters, small fiber neuropathy symptoms, and neuropathic pain. Skin biopsy can disclose an early non-length-dependent small fiber loss in ATTRv-PN and, together with QST, could provide a useful insight disease onset and progression.

Asymptomatic Median Neuropathy in Patients with Diabetic Polyneuropathy

Aim: This study aims to investigate whether asymptomatic median neuropathy (AMN) in patients with diabetic peripheral polyneuropathy (DPNP) is a result of polyneuropathic involvement of median nerve (MN) or its true entrapment. Subjects and Methods: We determined the grades of the Michigan severity scale and the rates of peripheral nerve conduction abnormalities in study subgroups, including patients with carpal tunnel syndrome (CTS), AMN, and normal MN conductions to highlight if the severity of polyneuropathic involvement was different between them. In addition, the results of conventional and comparative nerve conduction studies (NCSs) were compared between these study subgroups. Results: Distributions of Michigan grades and rates of abnormalities in peroneal and sural NCSs were similar between the subgroups (P &gt; 0.05 for all analyses). Abnormality rates of ulnar NCSs were higher in the AMN group than in the other groups, whereas those of comparative transcarpal NCSs were higher in the CTS group. The mean distal sensory latency (DSL) and motor latency (DML) of MN were longer, sensory conduction velocity (SCV) was slower in the CTS group than AMN group, whereas MN motor conduction velocity (MCV) was slower, UN DSL was longer, SCV was slower, SNAP amplitude was smaller, DML was longer, and MCV were slower in the AMN group (P &lt; 0.05 for all analyses). Discussion: Our findings reveal that grade of polyneuropathic involvement is more prominent in AMN, whereas transcarpal MN conduction delay is greater in CTS. The results of the study suggest that the prominence of polyneuropathic impairment in addition to a lesser degree of MN sheet compression obscures the clinical signs in patients with diabetes with AMN.

Electrodiagnostic (EDX) Predictors of Sensory Neuropathy in Primary Hypothyroidism and its Association with Age and Body Mass Index (BMI): A Cross Sectional Study

Background: Sensory neuropathy occurs in hypothyroidism often early as compared to motor. Involvement of median and sural nerve is reported earliest in literature. There is controversial electrophysiological data with respect to predictors of neuropathy and its association with age and body mass index. Objectives: Present study was aimed to find out EDX predictors of sensory neuropathy and its association with age and BMI in primary hypothyroidism patients. Materials and Method: Total 28 out of 39 hypothyroid cases referred to clinical neurophysiology laboratory were selected for analysis. These cases satisfied the biochemical and EDX criteria. Percentages of abnormalities in different variables of nerve conduction study were calculated. Also coefficient of correlation between age, BMI and different variables evaluated for association between them if any. Results: Study population was having age range from 23-75 years, 15 female and 13 male. Female preponderance was observed. Correlation between Age, BMI and different variables of NCV were statistically not significant. Sensory conduction velocity was most common abnormality observed (49%), followed by SNAP amplitude (42%) and onset latency (25%). Conclusion: We concluded that age and BMI have no effect on occurrence of neuropathy in primary hypothyroidism. Sensory Conduction velocity was most common predictor of sensory neuropathy in these cases.

Topiramate prevents oxaliplatin-related axonal hyperexcitability and oxaliplatin induced peripheral neurotoxicity.

Oxaliplatin (OHP) Induced Peripheral Neurotoxicity (OIPN) is one of the dose-limiting toxicities of the drug and these adverse effects limit cancer therapy with L-OHP, used for colorectal cancer treatment. Acute neurotoxicity consists of symptoms that are the hallmarks of a transient axonal hyperexcitability; chronic neurotoxicity has a clinical picture compatible with a length-dependent sensory neuropathy. Acute OIPN pathogenesis has been linked to sodium voltage-operated channels (Na + VOC) dysfunction and it has been advocated as a possible predisposing factor to chronic neurotoxicity.We tested if topiramate (TPM), a well-known Na + VOC modulator, was able to modify acute as well as chronic OIPN. The project was divided into two parts. In Experiment 1 we tested by means of Nerve Excitability Testing (NET) a cohort of female Wistar rats to assess TPM effects after a single OHP administration (5 mg/kg, iv). In Experiment 2 we assessed TPM effects after chronic OHP treatment (5 mg/kg, 2qw4ws, iv) using NET, nerve conduction studies (NCS), behavioral tests and neuropathology (caudal nerve morphometry and morphology and Intraepidermal Nerve Fiber [IENF] density). In Experiment 1 TPM was able to prevent OHP effects on Na + VOC: OHP treatment induced a highly significant reduction of the sensory nerve's threshold, during the superexcitability period (p-value = 0.008), whereas TPM co-administration prevented this effect. In Experiment 2 we verified that TPM was able to prevent not only acute phenomena, but also to completely prevent chronic OIPN. This latter observation was supported by a multimodal approach: in fact, only OHP group showed altered findings compared to CTRL group at a neurophysiological (proximal caudal nerve sensory nerve action potential [SNAP] amplitude, p-value = 0.001; distal caudal nerve SNAP amplitude, p-value<0.001, distal caudal nerve sensory conduction velocity, p-value = 0.04), behavioral (mechanical threshold, p-value 0.003) and neuropathological levels (caudal nerve fibers density, p-value 0.001; IENF density, p-value <0.001).Our data show that TPM is a promising drug to prevent both acute and chronic OIPN. These findings have a high translational potential, since they were obtained using outcome measures that match clinical practice and TPM is already approved for clinical use being free from detrimental interaction with OHP anticancer properties.

Glycemic Control and Clinico-Electrophysiological Severity of Diabetic Polyneuropathy

Background: Diabetic polyneuropathy (DPN) has a significant positive correlation with poor glycemic&#x0D; control (HbA1c ≥7%). The clinical, biochemical and electrophysiological parameters of DPN in Bangladeshi citizens have not yet been explored elaborately&#x0D; Objective: The purpose of the study was to detect and categorize status of glycemic control of Bangladeshi people and to analyze its impact on clinical severity of DPN using Toronto Clinical Scoring System (TCSS) and electrophysiological severity by modified Michigan diabetic neuropathy score (MDNS).&#x0D; Methodology: This observational study was carried out on diabetic patients having probable DPN by purposive sampling, attending Neurology OPD of Dhaka Medical College Hospital, Dhaka, Bangladesh and Bangladesh Institute of Research &amp; Rehabilitation in Diabetes, Endocrine &amp; Metabolic Disorder (BIRDEM) Hospital, Dhaka, Bangladesh from July 2014 to June 2016. Clinical parameters were recorded and DPN was graded as “no neuropathy”, “mild”, “moderate” and “severe” neuropathy by the Toronto Clinical Scoring System (TCSS). A standard nerve conduction study was performed on each patient and electrophysiological grading according to modified Michigan diabetic neuropathy score (MDNS) was done. Diabetic status of patients was classified into “controlled” (HbA1c &lt;7.0%) and “uncontrolled” (HbA1c ≥7.0%) groups and HbA1c level and the clinical &amp; electrophysiological severity scores were compared and were analyzed.&#x0D; Results: Mean age of the patients was 57.2±9.37 years. 51.0% cases were males and 49% cases were females. The mean HbA1c in the study population was 7.6±0.94% and 56.0% patients had HbA1c≥ 7% .Motor nerve conduction studies revealed that both CMAP amplitudes and MNCV in the ulnar, peroneal and tibial nerves were reduced significantly in patients of uncontrolled (HbA1c≥7%) DM (p&lt;0.001). Sensory nerve conduction studies revealed significant reduction in SNAP amplitudes of median and ulnar sensory and sural nerves in the uncontrolled group (p&lt;0.001). Electrophysiologically, 65.43% patients had mixed sensory-motor neuropathy (p&lt;0.00001). Clinically severe DPN patients were higher (45.2%) within the uncontrolled (HbA1C ≥7%) group (p&lt;0.00001). Similarly, severity in electrophysiological grading was more in patients with uncontrolled DM (48.8%) (p&lt;0.00001).&#x0D; Conclusions: Neuropathic severity, either clinically or electrophysiologically, was associated with higher values of HbA1c.&#x0D; Journal of National Institute of Neurosciences Bangladesh, 2019;5(2): 177-184

Clinical-neurophysiological correlations in chronic inflammatory demyelinating polyradiculoneuropathy patients treated with subcutaneous immunoglobulin.

Despite the well-described clinical efficacy of long-term subcutaneous immunoglobulin (LT-SCIg) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients, the neurophysiological effects of SCIg have been followed only for a short time and were not correlated with clinical parameters. Fourteen CIDP patients were evaluated at baseline and after LT-SCIg administration for 24 to 48 months. Nerve conduction studies were performed and clinical features were assessed for: (a) overall strength, by Medical Research Council sum score; (b) sensory function, by Inflammatory Neuropathy Cause And Treatment score; (c) disability, by Rasch-built overall disability scale; (d) quality of life (QoL), by the EuroQol Visual Analog Scale. LT-SCIg treatment improved clinical and neurophysiological features, preserving strength and improving sensory deficits, disability, and QoL. Clinical scores correlated with the amplitude of distal motor action (dCMAP) and sensory nerve action (SNAP) potentials. LT-SCIg treatment demonstrates efficacy in maintaining and continuing clinical improvement at 24 to 48 months after start of treatment. dCMAP and SNAP amplitudes represent useful prognostic factors for functional outcome.

P39-S Multimodal evoked potentials in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

Background The central nervous system in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is involved in about 5% of patients. The aim of the study was the assessment of the prevalence of central sensory impairment, and its reliance on peripheral nerve damage in patients with CIDP. Materials and methods The study group consisted of 24 patients with mean age of 60.7, who fulfilled the diagnostic criteria of typical form of CIDP at the time of multimodal (visual - VEP, brainstem auditory - BAEP, somatosensory SEP) evoked potentials (EPs) study. Each patient underwent a neurological examination, as well as a CT/MRI scan of the head. The evoked potentials was conducted according to the International Federation of Clinical Neurophysiology (IFCN) guidelines. Results Mean latency of most components of EP were considerably prolonged in patients compared to the control group. Negative correlations of SNAP amplitudes and sensory conduction velocities in peripheral nerves were obtained for I-V and III-V inter-latencies BAEP, for N20, P16, P22 SEP and the central conduction time TT for all sensory fibers of the left upper limb nerves. Conclusions Correlations of SNAP and EP parameters indicate subclinical damage to the central sensory pathways. The CIDP pathomechanism is still unclear and needs further research.

Ultrasonographic and electrophysiologic evaluation of median and ulnar nerves in chronic stroke patients with upper extremity spasticity

Objective: To evaluate the upper extremity nerves of stroke patients morphologically and electrophysiologically and to determine whether there is a relationship between clinical evaluations, ultrasonographic measurements, and electrodiagnostic findings.Methods: This cross-sectional study included 30 chronic stroke patients. After recording demographical data, clinical, ultrasonographic, and electrophysiological evaluations were performed. Clinical evaluations included Brunnstrom Recovery Stages (BRS), Fugl-Meyer Assessment (FMA), Modified Ashworth Scale (MAS), Motricity index (MI), Functional Independence Measurement (FIM), and Functional Ambulation Scale (FAS). For ultrasonographic measurements, median and ulnar nerves were scanned. Median and ulnar nerve conduction studies were performed bilaterally.Results: Mean ages of the patients were 62.2 ± 13.0 years (range 24–84 years; 22 males, 8 females). There was no significant difference in median/ulnar nerve ultrasonographic measurements between paretic and non-paretic sides (p > .05), whereas median nerve motor conduction velocity was significantly slower and median nerve F-wave latency was prolonged on the paretic side (p < .05). The median and ulnar nerve compound motor action potential (CMAP) amplitudes of paretic sides were positively correlated with lower extremity BRS and FAS scores. Median CMAP amplitudes were also positively correlated with FIM scores and ulnar CMAP amplitudes were positively correlated with motricity scores. Moreover, on the paretic side, there were positive correlations of median SNAP amplitudes with FIM and FAS scores (p < .05).Conclusions: Our results showed electrophysiological changes in peripheral nerves on the paretic upper extremities, however, no morphological change was determined. Further studies with larger number of patients and longer follow-up periods are needed to clarify the effect of stroke and spasticity on the peripheral nervous system.