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• Increased intraneural microvascular could be detected in patients with peripheral neuropathies using sonography. • Intraneural hypervascularization was frequently observed in patients with inflammatory neuropathies. • Superb microvascular imaging is the most sensitive technique for evaluating microvessel flow within peripheral nerves. We assessed microvessel flow within peripheral nerves using nerve sonography in patients with peripheral neuropathy. This study included consecutive patients with peripheral neuropathy who were admitted to our hospital. The patients were divided into two groups: inflammatory neuropathies for immune-mediated neuropathies, such as Guillain − Barré syndrome and chronic inflammatory demyelinating polyneuropathy, and the rest were defined as non-inflammatory neuropathies. We assessed nerve size and intraneural blood flow at four sites on each median and ulnar nerve. Blood flow was evaluated using color Doppler imaging, advanced dynamic flow (ADF), and superb microvascular imaging (SMI) techniques. Thirty-nine patients (median age, 60.0 years; 20 male) were enrolled in this study. An increase in intraneural blood flow was observed in five patients when evaluated by color Doppler, five patients by ADF, and 13 patients by SMI. An overall analysis of the three methods showed that intraneural blood flow was significantly higher in patients with inflammatory neuropathy than in those with non-inflammatory neuropathy (54.2% vs. 0%, p = 0.0005). Intraneural hypervascularization is more frequent in patients with inflammatory neuropathy than in those with non-inflammatory neuropathy. Evaluation of microvessel flow within peripheral nerves may contribute to the diagnosis of peripheral neuropathy. [ABSTRACT FROM AUTHOR]

• Common age-related cervical neuroforaminal stenoses on MRI/CT are not per se associated with nerve root enlargement on ultrasound. • Degeneration of the cervical spine is unlikely to confound the ultrasound assessment of cervical nerve roots in polyneuropathy. • Older age is associated with neuroforaminal stenosis, but is not a significant covariate of nerve root diameter in this cohort. Ultrasound can detect enlargement of cervical nerve roots, which has been described in polyneuropathies (PNP), mainly of demyelinating pathology. This study investigates whether neuroforaminal stenosis, as a common but often asymptomatic degenerative change, is associated with nerve root enlargement on ultrasound and whether neuroforaminal stenosis thus confounds cervical nerve root ultrasound findings in the diagnostic assessment of PNP. We retrospectively studied 182 patients (62 demyelinating, 71 axonal PNP; 49 without evidence of PNP) who had undergone ultrasound of the cervical nerve roots C5 and C6 and magnetic resonance or computed tomography of the cervical spine that was reviewed with respect to neuroforaminal stenoses. Patients with demyelinating PNP had larger nerve roots than those with axonal/without PNP. No significant differences in cervical nerve root diameters were found between groups with vs. without neuroforaminal stenosis. The diagnostic performance of the discrimination of PNP subtypes based on ultrasound nerve root measurements did not differ significantly when including or excluding subjects with neuroforaminal stenoses. Neuroforaminal stenosis per se does not entail relevant cervical nerve root enlargement detectable by nerve ultrasound. Ultrasound assessment of cervical nerve root size in the diagnostic evaluation of PNP is unlikely to be confounded by common degenerative changes of the cervical spine. [ABSTRACT FROM AUTHOR]

• Relapse and axonal damage were analyzed in the PATH study of subcutaneous immunoglobulin (IgPro20) in CIDP. • On placebo, non-axonal damage patients relapsed more than axonal damage patients. • IgPro20 was less effective in patients with axonal damage than those without. To assess axonal function prior to subcutaneous immunoglobulin (SCIG) therapy or placebo in relation to relapse in chronic inflammatory demyelinating polyneuropathy (CIDP) to determine whether axonal damage can predict therapy response. Relapse rates in patients from the Polyneuropathy and Treatment with Hizentra (PATH) study, where patients were treated with placebo or SCIG (IgPro20), were analyzed by baseline (post-intravenous immunoglobulin stabilization) axonal damage (≤1 mV peroneal compound muscle action potential) status. In patients with non-axonal damage, relapses were significantly higher with placebo (73.0%) than IgPro20 (0.2 g/kg: 39.1%, 0.4 g/kg: 19.2%). In patients with axonal damage, IgPro20 had no effect on relapse (placebo: 25.0%, IgPro20: 0.2 g/kg: 30.0%, 0.4 g/kg: 19.4%). Patients with axonal damage relapsed significantly less on placebo versus non-axonal damage, but they also demonstrated higher baseline disability. Axonal damage may correspond to relapse upon treatment withdrawal; patients with axonal damage relapse less, possibly reflecting poor response to immunoglobulin therapy, while non-axonal damage patients may experience more relapse, perhaps indicating better treatment response. In CIDP patients with axonal loss, immunoglobulin therapy may not be as effective. Assessing axonal damage could help guide therapy, with immunoglobulins ideally used before substantial axonal damage arises. [ABSTRACT FROM AUTHOR]

• We made reference values for nerve conduction studies with mixture model clustering. • Precise, individual reference values were based on age, sex, height and temperature. • Z-scores can be calculated to quantify the (ab)normality of a test result. Objective: to obtain locally valid reference values (RVs) from existing nerve conduction study (NCS) data. Methods: we used age, sex, height and limb temperature-based mixture model clustering (MMC) to identify normal and abnormal measurements on NCS data from two university hospitals. We compared MMC-derived RVs to published data; examined the effect of using different variables; validated MMC-derived RVs using independent data from 26 healthy control subjects and investigated their clinical applicability for the diagnosis of polyneuropathy. Results: MMC-derived RVs were similar to published RVs. Clustering can be achieved using only sex and age as variables. MMC is likely to yield reliable results with fewer abnormal than normal measurements and when the total number of measurements is at least 300. Measurements from healthy controls fell within the 95% MMC-derived prediction interval in 97.4% of cases. Conclusions: MMC can be used to obtain RVs from existing data, providing a locally valid, accurate reflection of the (ab)normality of an NCS result. Significance: MMC can be used to generate locally valid RVs for any test for which sufficient data are available. 1 All code and a test dataset have been placed online (gitlab.com/lumc/clinicalneurophysiology/ReferenceValues). 1 [ABSTRACT FROM AUTHOR]

• Excitability testing with threshold tracking was performed in 111 type 2 diabetics with and without diabetic polyneuropathy and 60 controls. • Changes in sensory and motor excitability in diabetic polyneuropathy were subtle, perhaps because of the relatively short disease duration. • There were only weak correlations between the excitability parameters and clinical scores. The aim of the present study was to gain insight into the pathophysiology of diabetic polyneuropathy (DPN) and examine the diagnostic value of sensory and motor axonal excitability testing. One hundred and eleven type 2 diabetics with and without DPN (disease duration: 6.36 ± 0.25 years) and 60 controls were included. All participants received a thorough clinical examination including Michigan Neuropathy Screening Instrument (MNSI) score, nerve conduction studies (NCS), and sensory and motor excitability tests. Patients were compared by the likelihood of neuropathy presence, ranging from no DPN (17), possible/probable DPN (46) to NCS-confirmed DPN (48). Motor excitability tests showed differences in rheobase and depolarizing threshold electrotonus measures between NCS-confirmed DPN group and controls but no changes in hyperpolarising threshold electrotonus or recovery cycle parameters. Sensory excitability showed even less changes despite pronounced sensory NCS abnormalities. There were only weak correlations between the above motor excitability parameters and clinical scores. Changes in excitability in the examined patient group were subtle, perhaps because of the relatively short disease duration. Less pronounced excitability changes than NCS suggest that axonal excitability testing is not of diagnostic value for early DPN and does not provide information on the mechanisms. [ABSTRACT FROM AUTHOR]

• Critically illness polyneuropathy/myopathy (CIN/CIM) was more prevalent in COVID-19 ICU patients with severe illness. • Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAp) levels were higher in the CIN/CIM group and GFAp correlated with motor nerve amplitudes. • COVID-19 patients who later developed CIN/CIM had significantly higher NfL and GFAp in the early phase of ICU care. The aim was to characterize the electrophysiological features and plasma biomarkers of critical illness polyneuropathy (CIN) and myopathy (CIM) in coronavirus disease 2019 (COVID-19) patients with intensive care unit acquired weakness (ICUAW). An observational ICU cohort study including adult patients admitted to the ICU at Uppsala University Hospital, Uppsala, Sweden, from March 13th to June 8th 2020. We compared the clinical, electrophysiological and plasma biomarker data between COVID-19 patients who developed CIN/CIM and those who did not. Electrophysiological characteristics were also compared between COVID-19 and non-COVID-19 ICU patients. 111 COVID-19 patients were included, 11 of whom developed CIN/CIM. Patients with CIN/CIM had more severe illness; longer ICU stay, more thromboembolic events and were more frequently treated with invasive ventilation for longer than 2 weeks. In particular CIN was more frequent among COVID-19 patients with ICUAW (50%) compared with a non-COVID-19 cohort (0%, p = 0.008). Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAp) levels were higher in the CIN/CIM group compared with those that did not develop CIN/CIM (both p = 0.001) and correlated with nerve amplitudes. CIN/CIM was more prevalent among COVID-19 ICU patients with severe illness. COVID-19 patients who later developed CIN/CIM had significantly higher NfL and GFAp in the early phase of ICU care, suggesting their potential as predictive biomarkers for CIN/CIM. [ABSTRACT FROM AUTHOR]

• In mixed fiber neuropathy PREP helps diagnosing additional A-delta fiber pathology. • PREP latencies are prolonged in patients with demyelinating neuropathies. • PREP are lost with impaired nerve conduction and reduced skin innervation. To investigate A-delta fiber pathways in patients with large, mixed, and small fiber neuropathies using pain-related evoked potentials (PREP). We prospectively examined consecutive and unselected 108 patients with neuropathies using PREP. Patients were stratified according to impaired fiber types in those with large fiber neuropathy (LFN, n = 23), mixed fiber neuropathy (MFN, n = 80), and small fiber neuropathy (SFN, n = 5). Additionally, medical history, nerve conduction studies, quantitative sensory testing (QST), and skin punch biopsy were applied. Data was compared with those of 49 healthy controls. Patients with MFN showed a distal loss of PREP (16/80, 20%) and prolonged PREP latencies after stimulation at the foot (MFN: 225.8 [135–293.6] ms, controls: 218 [135–394] ms, p < 0.05). Patients with demyelinating neuropathies had prolonged PREP latencies after stimulation at the hand (p < 0.05 each). QST showed an impairment of small and large fiber function in patients with MFN. PREP were mostly absent in patients at advanced stages of neuropathies: in 10/31 (30%) patients with no recordable sural nerve action potential (SNAP, preserved SNAP: 8/76, 10% missing) and in 4/17 (24%) patients with loss of distal epidermal innervation (preserved epidermal innervation: 7/60, 24%) PREP was not recordable. PREP peak-to-peak amplitude after stimulation at the face was lowered in patients with reduced proximal intraepidermal nerve fiber density (p < 0.02). PREP is a useful screening method for A-delta fiber pathology also in patients with simultaneous large fiber pathology. Loss of PREP indicates advance stages of nerve fiber damage. PREP may be useful as a complementary method for detection of small fiber impairment also in patients with mixed fiber neuropathy and in advanced stages. [ABSTRACT FROM AUTHOR]

• MScanFit MUNE yields detailed information on motor unit loss. • Motor involvement in diabetic neuropathy may be present as early as sensory involvement. • MScanFit MUNE provides sensitive detection of motor involvement in diabetic polyneuropathy. Detection of motor involvement in diabetic polyneuropathy (DPN) by nerve conduction studies (NCS) does not occur until there is substantial loss of motor units, because collateral reinnervation maintains compound muscle action potential (CMAP) amplitude. Motor unit number estimation (MUNE) methods may therefore be more sensitive. This study was undertaken to test whether the novel method, MScanFit MUNE (MScan) can detect motor involvement in DPN despite normal NCS. Fifty-two type-2 diabetic patients and 38 healthy controls were included. The median nerve was examined in all participants using standard NCS and a detailed CMAP scan, used for MScan. Additional lower extremity NCS in patients were used for DPN diagnosis. Of 52 diabetic patients, 21 had NCS-defined DPN while lower extremity NCS were normal in 31 patients. MScan motor unit number and size showed higher sensitivity and incidence of abnormality than motor NCS parameters, and a similar sensitivity to sensory NCS. MScan is able to detect motor axonal damage at times when collateral reinnervation limits NCS changes. MScan is a sensitive method to detect motor involvement in DPN, which our data suggests is present as early as sensory. [ABSTRACT FROM AUTHOR]

• Immune checkpoint inhibitors (ICIs) may induce immune-mediated polyneuropathy in rare cases. • ICI-related neuropathy presents as acute demyelinating polyneuropathy or axonal painful neuropathy. • Electrophysiological tests are useful in evaluation of ICI-related neuropathy. To report the electrodiagnostic features of immune checkpoint inhibitor (ICI)-related neuropathy. We retrospectively reviewed clinical presentations and electrodiagnostic features of 23 patients studied after receiving immune checkpoint inhibitors (ICIs). The presentations for electrodiagnostic evaluation included an acute neuropathy or neuromuscular junction disorder. We applied established electrodiagnostic criteria for polyneuropathy and acute demyelinating neuropathy. We identified acute demyelinating neuropathy (13 cases), axonal sensory motor neuropathy (5), pure sensory neuropathy (4) and mononeuropathy (1). 13 patients had acute demyelinating neuropathy confirmed by demonstrating demyelination in 2 or more nerves; 3 additional patients had demyelination in only one nerve. Analysis of motor nerve conduction parameters revealed demyelination involving median and ulnar nerve distal motor latencies as well as median, ulnar and peroneal nerve conduction velocities. Conduction block was found in median, ulnar and peroneal nerves. The remaining one-third patients without demyelination had acute painful axonal neuropathy. Coexisting myopathic changes (6) and neuromuscular junction dysfunction (4) were also identified. Our findings suggest that, while immune-mediated motor nerve demyelination is the primary underlying mechanism of ICI-related neuropathy, axonal painful neuropathy can also be an important presentation. Early recognition and effective intervention may reduce morbidity and permanent disability. Electrophysiological studies might be useful in the evaluation of ICI-related neuropathy. [ABSTRACT FROM AUTHOR]

Objective To reappraise the value of electrochemical skin conductance (ESC) measurement by Sudoscan® to assess the distal involvement of small autonomic fibers in familial amyloid polyneuropathy (FAP) due to various transthyretin (TTR) mutations. Methods ESC was measured at both hands and feet in 126 patients with either Val30Met (n = 65) or non-Val30Met (n = 61) TTR mutation. This series included clinically asymptomatic (n = 21) and paucisymptomatic (n = 30) patients, as well as patients with moderate (n = 37) or advanced (n = 38) TTR-FAP. Results ESC measures did not differ between patients according to the type of TTR variant and were reduced in 24% of clinically asymptomatic patients, 40% of paucisymptomatic patients, 65% of patients with moderate TTR-FAP, and 92% of patients with advanced TTR-FAP. ESC measures were found to correlate with patients' clinical status, especially assessed by the Neuropathy Impairment Score and Karnofsky Performance Status. Conclusion ESC measures well correlate with the severity of TTR-FAP and could provide early marker of the disease. Significance ESC measures appear to be relevant to evaluate distal autonomic involvement in the context of amyloidosis. [ABSTRACT FROM AUTHOR]

Objectives To explore the value of a novel sensory criterion, the ulnar ratio – defined as the SNAP amplitude of the palmar cutaneous (pUN) over that of the dorsal branch (dUN) of the ulnar nerve – as a predictor of Acute Inflammatory Demyelinating Polyneuropathy (AIDP). Methods We prospectively included 22 patients with AIDP, 20 patients with diabetic peripheral neuropathy (DPN), and 18 controls. Eligible subjects underwent nerve conduction studies including, among others, the dUN, pUN, and sural nerve. Results A sural sparing pattern was found in 72% of AIDP cases. The ulnar ratio was significantly lower in patients with AIDP compared to those with DPN or controls. The ROC curve area to discriminate AIDP (versus controls and diabetics together) was higher with the ulnar ratio and pUN compared to dUN. An ulnar ratio ≥ 0.78 seems to be the best threshold to rule out the diagnosis of AIDP, with a specificity of 100% and a sensitivity of 87%. The ulnar ratio was equally reliable in the subgroup of patients presenting within a week of symptoms onset. Conclusion The ulnar ratio is a highly sensitive and specific marker of AIDP and can help confirm the diagnosis when direct signs of demyelination are lacking. Significance Incorporating specific sensory abnormalities, such as the ulnar ratio, in the electrodiagnostic criteria of AIDP could enhance their reliability. [ABSTRACT FROM AUTHOR]

Objective The electrodiagnosis of polyneuropathy (PNP) may benefit from examination using near-nerve needle technique (NNT) and from inclusion of distal nerves. This study compared the diagnostic utility of distal nerve conduction studies (NCS) and NNT recording. Methods Bilateral NNT and surface recording of the sural nerve and surface recording of the dorsal sural and medial plantar nerves were prospectively done in 91 patients with clinically suspected PNP. Distal NCS were additionally done in 37 healthy controls. Diagnostic reference standard was the final clinical diagnosis retrieved from the patients medical records after 1–4 years. Results The clinical follow-up diagnosis confirmed PNP in 68 patients. Equally high sensitivities of the dorsal sural (72%), medial plantar (75%), and sural nerve with NNT recording (77%) were seen, while the sensitivity of conventional surface recording of the sural nerve was lower (60%). Sural NCS with both NNT and surface recording and dorsal sural NCS showed high specificities (85–95%) and positive predictive values (94–98%), while a lower specificity was seen for the medial plantar nerve (68%). Conclusion NCS of distal nerves, especially the dorsal sural nerve, have high diagnostic power equalling sural NNT recording. Significance The electrodiagnostic evaluation of patients with suspected PNP benefits from NCS of distal nerves. [ABSTRACT FROM AUTHOR]

Objective To investigate the use of nerve ultrasound in the differentiation between Charcot–Marie Tooth hereditary neuropathy (CMT1) and chronic inflammatory demyelinating polyradiculoneuropathies (CIDP), multifocal motor neuropathy (MMN) and multifocal acquired demyelinating sensory and motor neuropathies (MADSAM). Methods Ultrasound/electrophysiology of predefined nerves was performed in CMT1a/b, immunoneuropathies, and healthy controls. Ultrasound pattern sum score (UPSS, sum of the amount of 12 predefined measurement points), homogeneity score (HS) and regional nerve enlargement index (RNEI) in ulnar, median, and tibial nerve were used for evaluation of morphology. Results 13 CMT1, 27 CIDP, 10 MADSAM, 12 MMN, and 23 controls were included. Significant enlargement was shown in all neuropathies compared to the controls, ( p < 0.001), however the amount of enlargement as evaluated by the UPSS was most prominent in CMT compared to the others (median UPSS 18 vs. 11/8.5/5 in CIDP/MADSAM/MMN, p < 0.001). Homogeneous enlargement was significantly more often seen in CMT (67%, HS 6 vs. 2–3 in immune-mediated PNP, p < 0.001), while in CIDP the enlargement was regional, homogeneous or inhomogeneous with equal contribution. In MMN and MADSAM regional enlargement (48%/40%) next to normal segments (∼20%) predominated (RNEI in MMN = 2, in MADSAM = 1 vs. 0 in the others). CSAs were inversely correlated with motor conduction velocity. Conclusion Ultrasound, quantified by UPSS, HS, and RNEI facilitates a reliable and reproducible differentiation of immunoneuropathies and hereditary neuropathies by the use of boundary values. Significance By the use of quantitative scores, ultrasound differentiation of demyelinating neuropathies is operationalized and ameliorated compared to CSA measurements only. [ABSTRACT FROM AUTHOR]

Objective Transthyretin familial amyloid polyneuropathy (TTR-FAP) is an axonal sensory-motor and autonomic neuropathy. Reliable quantification of sudomotor function could prove essential in the diagnosis and early treatment management. We aim to assess the diagnostic value of a new sudomotor test ( Sudoscan ) in TTR-FAP. Methods One hundred and thirty-three TTR-FAP Val30Met carriers, divided in asymptomatic and symptomatic stage 1, were compared with 37 healthy controls. We analyzed the right sural sensory nerve action potential (SNAP), the plantar sympathetic skin response (SSR) and the electrochemical skin conductance (ESC) measured by Sudoscan in both hands and feet. Results All neurophysiological measures were significantly worse in the symptomatic group. However, feet ESC was the only test distinguishing symptomatic patients with autonomic dysfunction from those without autonomic dysfunction, and both groups from asymptomatic subjects and healthy controls. Feet ESC was a significant independent predictor for the presence of symptoms and autonomic failure, after adjusting for demographic characteristics, sural SNAP and SSR amplitudes ( p < 0.05). Feet ESC showed 76% sensitivity and 85% specificity for detection of dysautonomia. Conclusion Feet ESC is a sensitive test to assess early autonomic dysfunction in TTR-FAP subjects. This investigation should be considered for routine assessment in this population. Significance Abnormal feet responses on Sudoscan support early diagnosis in TTR-FAP. [ABSTRACT FROM AUTHOR]

Objective: This study quantifies functioning axons and reinnervation by applying two methods multiple point stimulation (MPS) MUNE, and motor unit number index (MUNIX), in patients with acute- and chronic inflammatory demyelinating polyneuropathy (AIDP, CIDP). Methods: Nineteen patients with inflammatory demyelinating polyneuropathy (eleven AIDP and eight CIDP) were prospectively included. MPS MUNE and MUNIX examinations on the thenar muscle group by stimulating the median nerve were applied on all patients. Motor unit size was calculated as single motor unit potential (sMUP) and motor unit size index (MUSIX). The results were compared with twenty healthy subjects. Results: In AIDP patients mean MPS MUNE (106) and MUNIX (80) were lower than control MPS MUNE (329) and MUNIX (215) (p < 0.001). In CIDP patients both MPS MUNE (88) and MUNIX (67) were lower than controls (p < 0.001). In CIDP patients sMUP (63) and MUSIX (90) were higher than control sMUP (35) and MUSIX (58) (p < 0.05 and p < 0.01). When AIDP and CIDP groups were combined the sensitivity for MPS MUNE and MUNIX were 89.5% and 68.4%, respectively. Conclusions: Decreased MPS MUNE and MUNIX suggest presence of axonal loss or loss of functioning axons in AIDP and CIDP. Increased motor unit size in CIDP patients indicates compensatory reinnervation. Moreover, both MPS MUNE and MUNIX can discriminate between disease versus non-disease. [ABSTRACT FROM AUTHOR]

Objective To investigate the cutaneous silent period (CSP), a spinal inhibitory reflex mainly mediated by A-delta fibres, in demyelinating and axonal polyneuropathy (PNP) and evaluate whether CSP parameters differ between patients with and without neuropathic pain. Methods Eighty-four patients with demyelinating PNP, 178 patients with axonal PNP and 265 controls underwent clinical examination, DN4 questionnaire, standard nerve conduction study, motor-root stimulation and CSP recordings from abductor digiti minimi. We calculated the afferent conduction time of CSP (a-CSP time) with the formula: CSP latency − root motor evoked potential latency. Results In the demyelinating PNP group the a-CSP time was significantly longer; in the axonal PNP group, CSP duration was shorter than the demyelinating group ( p = 0.010) and controls ( p = 0.001). CSP parameters were not different between patients with and without neuropathic pain. Conclusions The abnormality of a-CSP time in the demyelinating PNP group suggests the crucial role of A-delta fibres in the mechanism of CSP; the shorter CSP duration in the axonal PNP group supports the strong influence of the number of axons on this parameter. Our study suggests that neuropathic pain could be related to pathophysiological mechanisms differing from mere A-delta fibre loss. Significance CSP evaluation is effective in detecting A-delta fibre dysfunction in axonal as well as demyelinating PNP. [ABSTRACT FROM AUTHOR]

Objective The duration of the distal compound muscle action potential (DCMAP) is a useful index to detect demyelination in the distal nerve segments. However in published electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP), the cut-off values of DCMAP duration are defined using an EMG low frequency filter of only 20 Hz. We aimed to provide widely-available reference data using several low cut filters. Methods In 13 Japanese and European tertiary centers, DCMAP duration data using 2, 5, 10, and 20 Hz low frequency filters were prospectively collected from 147 normal controls, 59 patients with typical CIDP, and 100 with diabetic polyneuropathy. Optimal cut-off values were calculated with receiver-operating characteristic curves, offering 100% specificity versus normal controls. Results The higher low frequency filter was associated with significantly shorter DCMAP duration in all groups. For CIDP diagnosis, the calculated cut-off values had a sensitivity ranging from 51% to 66%, and a specificity versus diabetic neuropathy from 96% to 98%. Conclusions Our results show that DCMAP duration is largely dependent on low frequency filter settings, but is a useful index for CIDP diagnosis when the cut-off values are properly determined at each filter setting. Significance Our data provide the systematic reference values of DCMAP duration for CIDP diagnosis available for most EMG laboratories. [ABSTRACT FROM AUTHOR]

Introduction. Guillain-Barre Syndrome (GBS) is an autoimmune disease with acute ascending paralysis of the limb. Intravenous Immunoglobulin (IVIG) and plasmapharesis are still the effective treatment for GBS. In some cases, recurrence and treatment related fluctuation (TRF) of GBS can occur. TRF is defined as improvement in the GBS disability scale of at least one grade after completion of therapy followed by a worsening of the disability scale of at least one grade within the first 2 months after disease onset. Meanwhile, recurrence of GBS is defined as two or more episodes that fulfilled the criteria for GBS, with either a minimum interval greater than 4 months between episodes if the patient did not recover completely or greater than 2 months when there was a complete or near complete recovery after the previous episode. Results. A 47-year-old male with acute ascending paralysis accompanied with paresthesia in his leg. EMG result showed moderate axonal demyelinating motor sensory polyneuropathy (AMSAN) and diagnosed with GBS AMSAN type. He had plasmapharesis 2 times and his condition was improved (GBS Disability scale from 4 before plasmapharesis and became 3 after treatment). One month after onset, he complained his condition became worse again (GBS Disability scale 4). We assessed this condition as TRF. We conducted plasmapharesis again but only 2 times, because of limitation in national health insurance claim. Patient was discharged from hospital with no improvement. He routinely underwent physiotherapy and not on any pharmacotherapy. His condition improved in six months. Conclusion. We assumed that TRF in this patient was caused by inadequacy of plasmapharesis. This problem arises because of high cost of plasmapharesis while the national health insurance does not cover all serial plasmapharesis. [ABSTRACT FROM AUTHOR]

Introduction. Guillain-Barré syndrome (GBS) is the commonest cause of acute flaccid paralysis. However, clinicians should not miss the other causes of acute flaccid paralysis which may mimic GBS. Results. We present 3 cases of flaccid areflexic paralysis which presented acute/subacutely resembling GBS. Case 1: A 29-year-old lady presented with 2-week history of bilateral lower limb weakness with left hip pain for 3 years. Investigations revealed hypercalcaemia, hypophosphataemia, elevated ALP, vitamin D deficiency, hyperparathyroidism with right parathyroid adenoma from parathyroid ultrasonography and scintigraphy. She had plasma exchange for presumed GBS, but her lower limb weakness worsened and progressed to involve upper limbs and facial muscles. Her weakness improved after parathyroidectomy and the diagnosis was revised to hyperparathyroidism-related polyneuropathy. Case 2: A 28-year- old lady with underlying epilepsy and intellectual disability presented with progressive weakness of extremities over 3 weeks after prolonged fasting. Her weakness did not improve after treatment with immunoglobulin for GBS. Investigations showed positive urine porphobilinogen and raised urine delta-aminolaevulinic acid. A diagnosis of acute intermittent porphyria was considered most likely and her weakness improved after continuous glucose loading. Case 3: A 52-year-old lady who had bariatric surgery presented with bilateral lower limb weakness over 4 weeks after recurrent bouts of vomiting and excessive weight loss. Investigations revealed vitamin D deficiency, hypoalbuminaemia, hyperhomocysteinemia, low folate and low normal serum thiamine. As her weakness continued to progress, a diagnosis of acute nutritional neuropathy was considered more likely. Her weakness improved following multivitamins replacement. All 3 patients had normal CSF analysis except Case 1 who showed cyto-albuminologic dissociation. Sensorimotor axonal polyneuropathy was the electrodiagnosis demonstrated in all the cases. Conclusion. Clinicians should have high index of suspicion when treating acute flaccid paralysis with progressive disease and null response to immunotherapy as the neurology is reversible with treatment of the underlying cause. [ABSTRACT FROM AUTHOR]

Introduction. Critical Illness Polyneuropathy (CIP) is a frequent complication of critical illness, acutely and primarily affecting the motor and sensory axons. CIP delays weaning from mechanical ventilation, increases the length of stay at the intensive care unit, compromises rehabilitation and may result in a lifelong loss of function and in a reduction in quality of life. Greater than 50% of patients mechanically ventilated for more than 7 days will develop electrophysiological abnormalities with 25-33% developing clinically overt weakness. Until recently, no therapeutic measures had been proven to affect its incidence, and apart from supportive treatment. Results. A 52-year-old chinese lady presented to ED with shortness of breath due to SIRS et. causa pneumonia was consulted to neurology department because of loss of conciousness. After being intubated, patient awakened within stable condition. On neurological examination, there were bilateral ptosis, bilateral ophthalmoplegia, flaccid over all extremities, decrease of tendon reflexes and sensory were intact. There were leukocytosis and respiratory acidosis on laboratory findings. Chest X-ray noticed bilateral minimal pleural effusion and cardiomegaly. Bronchoscopy and Thorax CT-scan found inflammation. Abdominal ultrasound and head CT scan were within normal limits. Lumbar puncture was not done due to rejection from the family. On EDX findings, NCS found axonal loss pattern in motor and sensory, RNS was within normal limits and needle EMG findings noted distal pattern of decreased recruitment with denervation. After 18 months being hospitalised in ICU and using mechanical ventilator, the patient died. Conclusion. There is no direct treatment for CIP. CIP results in substantial morbidity, mortality, costs and could likely be improved with earlier diagnosis and more timely intervention. To achieve this goal, however, more awareness on the part of medical establishment is needed, as well as further research into the causes of treatments for CIP. [ABSTRACT FROM AUTHOR]

Introduction. What is well known: Myasthenia gravis presents with ocular, bulbar and proximal limb weakness. What is less known: Myasthenia gravis can rarely present with predominant distal weakness of hand muscles. Myasthenia gravis (MG) is an immune mediated, post-synaptic neuromuscular transmission disorder, presenting with predominant ocular, bulbar and/or proximal fluctuating weakness and fatiguability. Distal and asymmetric onset of symptoms in MG is rare and could lead to delay in diagnosis especially when fatiguability or fluctuation is not clearly reported as a prominent initial symptom - as seen in our patients. Results. We report 3 cases of distal MG who presented with predominant distal asymmetric hand weakness. Their clinically diagnoses for referral to the electrodiagnostic (EDx) laboratory were chronic inflammatory demyelinating polyneuropathy, C8T1 motor radiculopathy and multifocal motor neuropathy. It was in the EDx laboratory that the diagnosis of MG was suspected in these patients. Since the routine EDx tests were normal in all 3 patients - a repetitive nerve stimulation test (RNST) was done - which was positive in the affected muscles and hence a diagnosis of distal MG made (This is the protocol followed in our laboratory). These patients were then found to have high serum levels of antibodies to acetylcholine receptors - confirming the diagnosis of MG. RNST is not routinely done in all patients sent for electrodiagnostic testing and none of these patients had a reference for the same – however using a protocol based method of EDx testing, leading to the diagnosis of a treatable condition. Conclusion. Electrodiagnosticians need to be aware of this presentation of MG and follow protocols or else the diagnosis could be missed. [ABSTRACT FROM AUTHOR]