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

Background and purpose: Identifying patients with inflammatory motor neuropathies (IMNs) is warranted since effective treatments are available and the prognosis of these patients differs from that of amyotrophic lateral sclerosis patients. Methods: Between January 2019 and May 2022, 102 consecutive treatment‐naïve lower motor neuron syndrome (LMNS) patients were recruited; these patients were suspected of having multifocal motor neuropathy, pure motor chronic inflammatory demyelinating polyneuropathy or amyotrophic lateral sclerosis with initial lower motor neuron presentation. Neuromuscular ultrasound (US) and nerve conduction studies (NCSs) were conducted at baseline. Relevant diagnostic investigations were performed if clinically warranted. The proposed US evidence of IMN was as follows: (i) nerve enlargement at ≥1 of the predetermined sites or (ii) absence of high intensity fasciculations in predefined muscle groups. Final diagnoses were made by experienced physicians after a prolonged follow‐up period (≥12 months). IMN patients were defined as LMNS patients who experienced convincing improvements in response to immunotherapies. IMN patients without electrodiagnostic demyelinating features were diagnosed with treatment‐responsive LMNS (TR‐LMNS). Results: In total, 16 patients were classified as IMN, including nine chronic inflammatory demyelinating polyneuropathy/multifocal motor neuropathy patients and seven TR‐LMNS patients. Six TR‐LMNS patients were identified by neuromuscular US. The sensitivity and specificity of NCSs, nerve US and muscle US were 56.3% and 100%, 43.8% and 90.7% and 68.8% and 97.7%, respectively. When these three modalities were combined, the sensitivity and specificity were 93.8% and 88.4%, respectively. Conclusion: Neuromuscular US studies are supplementary modalities to NCSs, and the combined use of these techniques might improve the identification of IMNs in LMNS patients. [ABSTRACT FROM AUTHOR]

Background: Comorbidity of Myasthenia gravis (MG) and Graves' disease (GD) in treated HIV‐infected individuals has rarely been described and little study has been done on the link between HIV‐related immune reconstitution and autoimmune diseases occurring post antiretroviral therapy. Case Presentation: Here we report on a 33‐year‐old Chinese man with HIV infection who had been virologically suppressed since 2018. The patient was diagnosed with GD and was treated in 2020. Early in 2022, he developed fluctuating weakness and fatigue involving the bilateral extraocular muscles and limbs. With a positive neostigmine test, he was considered to have MG, but showed a poor response to oral medication. After multiple failed medication attempts, a thymectomy was finally performed to resolve his symptoms. The consecutive onset of immunological events may have partially resulted from immune reconstitution after viral control. Conclusions: This is a rare case of HIV‐related immune reconstitution‐associated autoimmune disease (IRAD) with comorbidity of MG and GD which was reported initially. Cooperation with multidisciplinary teams is essential to avoid misdiagnosis and to promote the overall health of HIV‐infected patients. [ABSTRACT FROM AUTHOR]

Background and Purpose: We aim to investigate nerve enlargement patterns and their correlation with clinical subtypes and treatment response using nerve ultrasound in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Methods: Between March 2015 and December 2021, 135 CIDP patients were recruited. Nerve ultrasound and electrophysiological studies were performed on the median and ulnar nerves. The responses to intravenous immunoglobulin (IVIg) or prednisone were evaluated with the disability score. Results: There were 99 typical CIDP cases, 10 Lewis‐Sumner syndrome (LSS) cases, 15 distal acquired demyelinating symmetric neuropathy (DADS) cases, nine pure motor CIDP cases, and two pure sensory CIDP cases. Sixty (61%) typical CIDP and seven (78%) pure motor CIDP patients had moderately increased or normal cross‐sectional area (CSA), and 10 (67%) DADS and seven (70%) LSS patients had significantly increased CSA. The peripheral nerve showed a diffuse enlargement pattern in 46 (51%) typical CIDP, five (50%) LSS, three (25%) DADS, and three (33%) pure motor CIDP patients and a proximal regional enlargement pattern in 11 (12%) typical CIDP, one (10%) LSS, six (50%) DADS, and four (44%) pure motor CIDP patients. Patients with diffusely moderate enlargement patterns and those with proximal regional enlargement showed a higher response rate to glucocorticoids than to IVIg. Conclusions: Various distribution patterns of nerve enlargement existed in CIDP. Although almost all patterns could be detected in each CIDP subtype, diffusely moderate enlargement was more common in typical CIDP and LSS, while proximal regional enlargement was more common in DADS and pure motor CIDP. Different enlargement patterns might indicate different treatment responses. [ABSTRACT FROM AUTHOR]

Introduction: The aim of our study was to assess the ultrasonographic features of peripheral nerves in patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome. Method: 34 POEMS syndrome patients and 26 healthy control (HC) participants were recruited prospectively. Cross‐sectional area (CSA) was measured in nerves of limbs, trunks of brachial plexus, and cervical nerve roots Results: The CSAs were mildly enlarged at the arm segment of median nerve, elbow segment of ulnar nerve and upper trunk, moderately enlarged at the forearm segment of both median and ulnar nerve, upper trunk of brachial plexus, and C6, C7 cervical nerve roots, and markedly enlarged at the arm segment of ulnar nerve, middle and lower trunk of brachial plexus, as well as C5 cervical root. Discussion: The CSAs of upper limb nerves were larger in POEMS syndrome patients than in HCs, and the enlargements were most prominent proximally. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE: Both clinical autonomic dysfunction and involvement of autonomic nerves have been reported in a range of peripheral nerve disorders. We employed nerve ultrasound to assess the size of the vagus nerve in a serial study of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Charcot‐Marie‐Tooth type 1B (CMT1B) as compared to healthy controls (HCs). We correlated these findings with involvement of the median and ulnar nerves. METHODS: Forty‐three patients with CIDP, 8 with CMT1A, and 105 HC were prospectively recruited. The cross‐sectional areas (CSAs) of the vagus, median, and ulnar nerves were measured bilaterally. The alteration of CSA of those nerves was followed longitudinally in CIDP. RESULTS: The median (range) CSA of the vagus nerve was 2 (1‐28) mm2 in CIDP, 3 (2‐6) mm2 in CMT1A, and 1 (1‐2) mm2 in HC. The vagus nerve CSA was positively correlated with the maximum CSA of median/ulnar nerve in CIDP and CMT1A. The alteration in vagus nerve CSA was positively correlated with the alteration in mean median/ulnar nerve CSA in CIDP during follow‐up. CONCLUSIONS: The vagus nerve was involved to a similar extent as the median and ulnar nerves in CIDP and CMT1A, although no symptoms or signs of vagus nerve involvement were found. Further study should be performed to explore the clinical relevance of vagus nerve enlargement in these disorders. [ABSTRACT FROM AUTHOR]

Introduction: Detailed morphological features of the peripheral nerves could improve the diagnostic sensitivity in some polyneuropathies. In this study we aimed to establish multiple-site, cross-sectional area (CSA) reference values for peripheral nerves of upper extremities in a healthy Chinese population.Methods: One hundred eleven healthy subjects, 15 to 70 years of age, were prospectively recruited. CSA at predetermined sites of the median, ulnar, radial nerves, and brachial plexus was measured bilaterally. Ten consecutive sites were studied along the median/ulnar nerves.Results: The CSA at ten sites of the median nerve ranged from 5.59 ± 0.89 to 8.43 ± 1.30 mm2 , and for the ulnar nerve from 2.94 ± 0.57 to 5.63 ± 1.08 mm2 . Both age and gender correlated with nerve CSA at most sites.Discussion: CSA was not uniform along the length of the median and ulnar nerves. The multiple-site reference values could be helpful for investigating polyneuropathies in the Asian population. [ABSTRACT FROM AUTHOR]

Immune checkpoint inhibitors (ICIs) can cause adverse reactions in the nervous system. The incidence rate is 0.1%–12% and 80% of nervous system adverse reactions occur within the first four months of application. ICIs can cause diseases of various parts of the nervous system including central nervous system diseases such as aseptic meningitis, meningeal encephalitis, necrotizing encephalitis, brainstem encephalitis, transverse myelitis, etc., and peripheral neuropathy such as cranial nerve peripheral neuropathy, multifocal nerve root neuropathy, Guillain‐Barré syndrome, spinal nerve root neuropathy, myasthenia gravis, myopathy, etc. For these complications of the nervous system, diagnosis could be difficult. Physicians require a specific collection of nervous system symptoms and signs, combined with supplementary examinations including imaging, cerebrospinal fluid cytology, EEG or electromyography in order to exclude infection or malignant tumor before reaching a final diagnosis. With regard to treatment, ICIs should be discontinued in severe cases, and large doses of glucocorticoid or gamma globulin administered, and supportive treatment may be necessary. If severe adverse reactions of the nervous system occur, the prognosis could be poor. [ABSTRACT FROM AUTHOR]

Background: The abduction range of the little finger in the long exercise test (ET) has rarely been reported in patients with hypokalemic periodic paralysis (HypoPP) during inter-attack periods, and the diagnostic value requires clarification.Methods: The long ET was performed in 43 HypoPP patients during inter-attack periods and in 20 healthy controls (HCs). The compound muscle action potential (CMAP) and the abduction range of the little finger were recorded concurrently.Results: There were significant differences in the percent changes of the CMAP amplitudes and the abduction ranges after exercise between HypoPP patients and the HCs. The curve of percent changes in abduction ranges overlapped substantially with that of the CMAP amplitudes, and the sensitivity, specificity, and cutoff values were 0.860, 0.900, and 22.6%, respectively.Conclusions: The abduction range of the little finger can serve as a novel parameter in the long ET for the diagnosis of HypoPP during inter-attack periods. [ABSTRACT FROM AUTHOR]

Introduction: The objective of this study was to evaluate the correlation between cross-sectional area (CSA) and nerve conduction studies (NCS) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and to determine how CSA changes over time after standard treatment.Methods: Fifty-four patients with CIDP were recruited prospectively, and 21 patients were followed for more than 6 months. Ultrasonography and motor NCS were performed in the median and ulnar nerves.Results: No or weak correlation was observed between the maximum CSA and motor conduction velocity. There were segmental nerve enlargements at 61% of sites with conduction block or temporal dispersion. Among 19 patients with clinical improvement after immunotherapy, CSA decreased to normal in 5, increased in 10, and were unchanged in 4.Discussion: Different patterns of CSA and motor NCS changes after immune treatment may indicate different CIDP pathologic mechanisms. Exploration of these pathologic mechanisms could guide treatment choices in the future. Muscle Nerve, 2019. [ABSTRACT FROM AUTHOR]

Abstract: We report the retinal expression pattern of Ret, a receptor tyrosine kinase for the glial derived neurotrophic factor (GDNF) family ligands (GFLs), during development and in the adult mouse. Ret is initially expressed in retinal ganglion cells (RGCs), followed by horizontal cells (HCs) and amacrine cells (ACs), beginning with the early stages of postmitotic development. Ret expression persists in all three classes of neurons in the adult. Using RNA sequencing, immunostaining and random sparse recombination, we show that Ret is expressed in at least three distinct types of ACs, and ten types of RGCs. Using intersectional genetics, we describe the dendritic arbor morphologies of RGC types expressing Ret in combination with each of the three members of the POU4f/Brn3 family of transcription factors. Ret expression overlaps with Brn3a in 4 RGC types, with Brn3b in 5 RGC types, and with Brn3c in one RGC type, respectively. Ret+ RGCs project to the lateral geniculate nucleus (LGN), pretectal area (PTA) and superior colliculus (SC), and avoid the suprachiasmatic nucleus and accessory optic system. Brn3a+ Ret+ and Brn3c+ Ret+ RGCs project preferentially to contralateral retinorecipient areas, while Brn3b+ Ret+ RGCs shows minor ipsilateral projections to the olivary pretectal nucleus and the LGN. Our findings establish intersectional genetic approaches for the anatomic and developmental characterization of individual Ret+ RGC types. In addition, they provide necessary information for addressing the potential interplay between GDNF neurotrophic signaling and transcriptional regulation in RGC type specification. [ABSTRACT FROM AUTHOR]

Introduction: We analyzed jitter recordings made with concentric needle electrode (CNE) single-fiber electromyography (SFEMG) in Lambert-Eaton myasthenia (LEM).Methods: Fifteen subjects diagnosed with LEM were studied using CNE-SFEMG in the extensor digitorum (ED) and tibialis anterior (TA) muscles. CNE-SFEMG in the ED and TA was also used to evaluate 12 and 10 healthy controls (HCs), respectively.Results: Ten men and 5 women were diagnosed with LEM based on an increase of 100% in compound muscle action potential amplitude during 50 Hz repetitive nerve stimulation. All patients exhibited markedly greater jitter in the ED (88.8 ± 23.2 µs) and TA (92.2 ± 30.2 µs) than HCs (28.3 ± 3.4 µs and 30.9 ± 5.1 µs, respectively).Conclusions: CNE-SFEMG is sensitive for discovering abnormalities in neuromuscular transmission in LEM. Muscle Nerve 56: 253-257, 2017. [ABSTRACT FROM AUTHOR]

J. Neurochem. (2012) 122, 650-658. Abstract Mutations in Leucine-rich repeat kinase 2 ( LRRK2) are the leading causes of genetically inherited Parkinson's disease (PD) identified so far. The underlying mechanism whereby missense alterations in LRRK2 initiate neurodegeneration remains largely unclear. Mitochondrial dysfunction has been recognized to contribute to the pathogenesis of both sporadic and familial PD. The pathogenic gain-of-function mutant form of LRRK2, LRRK2 G2019S, is associated with elevated kinase activity and PD. Here we show that LRRK2 G2019S can cause defects in the morphology and dynamics of mitochondria in cortical neurons. In neurons, endogenous LRRK2 and the mitochondrial fission factor Dynamin like protein 1 (DLP1) interact with and partially co-localize with each other. DLP1 plays an essential role in LRRK2-induced mitochondrial fission. In support of this, expression of LRRK2 leads to the translocation of DLP1 from the cytosol to the mitochondria and knockdown of DLP1 expression inhibits LRRK2-induced mitochondrial fission. In addition, co-expression of LRRK2 and DLP1 induces mitochondrial clearance. Furthermore, we have found that expression of LRRK2 leads to increased reactive oxygen species levels in cells. Taken together, our results provide insights into the pathobiology of LRRK2 and suggest that LRRK2 G2019S may induce neuronal dysfunction or cell death by disturbing normal mitochondrial fission/fusion dynamics and function. [ABSTRACT FROM AUTHOR]