Background. One of the key distinctions between multifocal motor neuropathy (MMN) and multifocal variant of chronic inflammatory demyelinating polyradiculoneuropathy (mCIDP) lies in the presence or absence of sensory deficits. Nevertheless, existing literature suggests that MMN can also involve sensory fibers of peripheral nerves, complicating the differential diagnosis of MMN and mCIDP, which remains a relevant issue.

Aim. To evaluate the profile and intensity of objective sensory deficits and autonomic dysfunction in MMN and mCIDP, as well as to identify differential diagnostic markers.

Materials and methods. Out of 65 patients followed up in the study, 30 were diagnosed with MMN and 35 were diagnosed with mCIDP. A retrospective analysis of clinical and epidemiological characteristics was carried out. The evaluation encompassed clinical assessments of sensory symptoms (including on the NTSS-9 scale), assessments of the severity of autonomic dysfunction using the COMPASS-31 questionnaire, and neurophysiological multimodal sensory testing (including electroneuromyography, computer pallesthesiometry, and short-latency auditory evoked potentials).

Results. Patients with mCIDP were significantly more likely to have subjective (according to the NTSS-9 and COMPASS-31 scales) and objective (according to clinical examination) sensory deficits and autonomic dysfunction (p <0.05). A third of patients with MMN reported sensory complaints, yet there was no objective evidence of impaired pain sensitivity. Changes in vibration sensitivity were equally prevalent during clinical assessment in both groups (p >0.05). Electroneuromyography studies revealed significantly lower amplitudes of hand sensory nerve action potentials in the mCIDP group compared to MMN patients (p <0.05). At the same time, a third of patients with MMN with a previous history of disease of 13 [10.0; 16.0] years also had low amplitudes of hand sensory nerve action potentials. The mean value of the autonomic reaction threshold, as well as the cutaneous vibration perception threshold were significantly higher in mCIDP compared to MMN (p <0.05) when examining the hands.

Conclusion. Differential diagnosis of MMN and mCIDP at the onset and in early disease (under 5 years) poses no challenges. However, it has been shown that a third of patients with MMN in the long-term catamnesis of the disease have some kind of sensory impairment, which may complicate the differential diagnosis with mCIDP. In such cases, employing computer pallesthesiography to measure vibration perception threshold can aid in clarifying the diagnosis and determining optimal treatment strategies.

Background. The development of neuropathic pain in chemotherapy‑induced polyneuropathy, is one of the complications of chemotherapy (CT). Especially often it develops after treatment with platinum and taxane drugs. The lesion of thin fibers is an important component of the painful form of polyneuropathy. Since electroneuromyographic examination does not confirm the lesion of thin nerve fibers, this diagnosis is often difficult to confirm in clinical practice, based mainly on subjective assessment of complaints, sensitivity, and the use of questionnaires. Skin biopsy is a validated method for determining intraepidermal nerve fiber density and can be considered for the diagnosis of distal sensory neuropathy, especially small fiber neuropathy. Given the difficulty in assessing small fiber damage, the prevalence and pathophysiology of small fiber neuropathy in cancer patients remain poorly understood.

Aim. To evaluate the changes in the number of thin fibers in patients with chemotherapy‑induced polyneuropathy and oncological diseases of the gastrointestinal tract (GIT) and pelvic organs (PO), as well as to analyze the relationship of fiber density with clinical and neurophysiological parameters and neuropathic pain syndrome.

Materials and methods. The study included 34 patients over 18 years old, divided equally into two groups: the first group – patients with GIT organs cancer, in which oxaliplatin was the main drug; the second group – patients with PO cancer, in which paclitaxel/docetaxel was the main drug. Patients were examined before and after CT. Exclusion criteria were the presence in the history of complaints that allowed suspecting pathologic conditions potentially capable of causing peripheral nerve damage. All patients underwent electroneuromyography with SRAR index calculation and skin biopsy, as well as assessment of neuropathic pain using scales (National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0, Visual Analogue Scale) and questionnaires (Douleur Neuropathique en 4 Questions, Small fiber neuropathy – symptoms inventory questionnaire). Statistical processing was performed using the GraphPad Prism 8.0.1 program package. Quantitative variables were evaluated using the Kolmogorov–Smirnov test. Correlation analysis between intraepidermal nerve fiber density clinical scales and neurophysiological data was evaluated using Spearman coefficient.

Results. 31 patients (14 patients with GIT organs cancer, 17 patients with PO cancer) completed the full cycle of examination before and after СT, 3 patients with GIT organs cancer dropped out of the study due to death. The mean age was 58.0 ± 11.5 years (23–70 years), of which elderly patients (over 60 years old) were 16 (51 %). Wilcoxon signed rank test for pairs showed a significant difference between intraepidermal nerve fiber density in the group of patients with GIT organs cancer before and after CT (p = 0.02), and no significant difference in patients with PO cancer before and after CT (p = 0.37). Statistically significant differences in the amplitude of the sensory potential (S‑response) of the superficial peroneal nerve in patients with PO cancer (p p = 0.0002) and of the calf nerve in patients with PO cancer (p = 0.0001) and GIT organs cancer (p = 0.0017) before and after CT were obtained. Also, SRAR index before and after CT showed a significant difference for both PO (p = 0.0017) and GIT organs cancer (p = 0.0245). Spearman correlation analysis found no significant correlations between intraepidermal nerve fiber density density and the results of electroneuromyography as well as major scales.

Conclusion. Small fiber neuropathy is part of mixed sensory neuropathy in patients with chemotherapy‑induced polyneuropathy and occurs more often with the use of oxaliplatin in patients with GIT organs cancer. Identification of patients with pain symptoms and the presence of small fiber neuropathy in the future will help develop an individual approach to the management of this group of patients, and the wider use of skin biopsy techniques will help in the study of reinnervation processes, which is especially important in the development of new therapeutic targets aimed at eliminating nerve damage.

Background. Excessive evaporation of the tear film can lead to damage to the corneal nerve fibers and cause the occurrence of chronic neuropathic pain that mimics dryness. Laser confocal microscopy of the cornea allows you to record morphological changes in the nerve fibers of the cornea and can be a diagnostic tool for finding the substrate of neuropathic pain.

Aim. To study and compare the structural changes of corneal nerve fibers in patients with burning eye syndrome and dry eye disease.

Materials and methods. 54 patients (108 eyes) aged 20–35 years were examined: 17 patients (34 eyes) with a verified diagnosis of mild and moderate dry eye disease were the first group, 17 patients (34 eyes) with burning eye syndrome were the second group. The third group (control) consisted of 20 volunteers (40 eyes) of the same age, who did not have any somatic and eye diseases. The criterion for exclusion from the study was the presence of clinical signs of blepharitis and dysfunction of the meibomian glands in patients and individuals of the control group. In all patients, the number of blinking movements and the completeness of eyelid closure were determined, the Norn test and the Schirmer I test were performed. For an objective assessment of corneal nerve fibers, laser confocal microscopy of the cornea was used on a Heidelberg Retina Tomograph III device with a rostock corneal module.

Results. The lowest values of the anisotropy coefficient of the corneal nerve fibers directivity were recorded in the group of patients with burning eye syndrome (2.605), which indicates the greatest changes in the structure of the nerve fiber in this group. There was no significant negative correlation between the value of the Norn sample, the number of blinking movements, and the value of the anisotropy coefficient of the corneal nerve fibers orientation in the group of patients with burning eye syndrome (r = –0.45, p = 0.07 and r = –0.45, p = 0.07). There was a statistically significant (p >0.05) increase in the number of inflammatory Langerhans cells, the length and density of their processes in the groups of burning eye syndrome and dry eye disease compared with the group of healthy volunteers.

Conclusion. The method of laser confocal microscopy of the cornea can be used to detect changes in corneal nerve fibers associated with the occurrence of neuropathic pain syndrome.

A description of the clinical and genetic characteristics of four Russian patients with Schaaf–Yang syndrome, caused by previously described and newly identified nucleotide variants in MAGEL2 gene, is presented. It was shown that the most severe clinical manifestations were found in a patient with the new identified variant c.1828C>T (p.Gln610Ter), while in a patient with a new nucleotide variant c.1609C>T (p.Gln537Ter) the manifestations of the disease were moderate. Considering the significant similarity of the clinical manifestations of Schaaf–Yang syndrome with Prader–Willi syndrome, the criteria for their differential diagnosis are outlined, the use of which will help optimize the process of molecular genetic analysis aimed at finding the etiologic factor.

Duchenne muscular dystrophy is one of the most common inherited muscular dystrophies. The cause of this disease with an X‑linked recessive type of inheritance is mutations of the DMD gene, leading to the absence of the dystrophin protein this gene encodes or its impaired function. Loss of dystrophin leads to severe degenerative processes in patients, especially in muscle tissue, with impaired muscle function, loss of ability to move independently, respiratory failure, cardiomyopathies, etc.

More than 160 years have passed since the work of Guillaume‑Benjamin‑Armand Duchenne in the 19^th century. Despite the efforts of many researchers who have developed various therapeutic approaches designed to alleviate the condition of patients if not cure it, few of them have significantly changed the course of the disease. Different approaches related to specific therapy of ischemia and fibrosis in affected muscles, correction of hormonal regulation of muscle tissue growth, therapeutic methods aimed at preventing damaged myocytes from excessive accumulation of calcium ions, which enhance proteolytic processes, suppression of oxidative stress in muscles, etc. have not yet shown high effectiveness both independently and in combination with glucocorticoids. The introduction of corticosteroid drugs made it possible to slow down disease development, but the average survival still does not exceed 30–40 years and patients spend many of them in a wheelchair. At the same time, the patients’ quality of life can be additionally diminished due to the common corticosteroids’ side effects.

The term “acute flaccid myelitis” is used to describe a condition characterized by acute flaccid paralysis of the limb, as well as damage to the motor neurons of the spinal cord. The absence of specific treatment, severe neurological deficit that persists in 75–95 % of patients in the long term indicates its severity.

The aim of the work is to describe acute flaccid myelitis in children, modern methods of treatment, and estimate the effectiveness of nerve transfers for restoration of the upper limb function.

The search for publications was carried out in the PubMed/MEDLINE, Google Scholar databases from 2003 to 2022, and data from the US Centers for Disease Control and Prevention (https://www.cdc.gov) were used. There were analyzed surgical treatments of 57 children with paresis of the upper extremities due to AFM (105 nerve transfers). Restoration of shoulder function (neurotization of n. axillaris, n. suprascapularis) was performed in 57 (54.3 %) patients, elbow flexion (neurotization of n. musculocutaneus) in 37 (35.2 %), elbow extension in 9 (8.5 %) (neurotization of the branch of n. radialis to m. triceps brachii), fingers flexion in 1 (1 %) (neurotization of the n. interosseus anterior branch), fingers extension in 1 (1 %) (neurotization of n. interosseus posterior).

The review demonstrated the effectiveness of nerve transfers in children with paresis of the upper extremities due to acute flaccid myelitis who were operated up to 1 year from the onset of the disease.

Over the past decade magnetic resonance imaging is being increasingly used in revealing pathological changes in peripheral nervous system due to a number of technical innovations and growth of diagnostical strength, and, therefore, due to initiation of research of several magnetic resonance imaging methods which allow to perform quantitative assessment of peripheral nerves. Among them, diffusion tensor magnetic resonance imaging which gives an opportunity to investigate microstructural changes in nerves tissue by water diffusion evaluation should be mentioned first. T2‑relaxometry and magnetization transfer ratio studies allow assessing macromolecular integrity of peripheral nerves elements. Chemical shift‑based fat fraction evaluation in peripheral nerves and corresponding muscles is also of great scientific interest both for diagnostic and therapy effect monitoring purposes. Manuscript presents brief description of above‑ mentioned methods, as well as recent results and perspectives of their application for peripheral nerves evaluation, supplemented with own illustrations of experimental observations.

Spinal muscular atrophy (SMA) is a hereditary, autosomal recessive disease that debuts at different ages. Neurological symptoms are progressive and lead to significant limitation of life activity and reduced life expectancy. Currently, there are several drugs for the pathogenetical treatment of SMA. This article reflects the evolution of clinicians’ views on the treatment of patients with SMA as scientific evidence from clinical trials and experience in managing patients in real‑world clinical practice accumulates. The biggest debate is about the treatment of patients with 4 copies of the SMN2 gene. An analysis of the “SMA Families” patient registry database was carried out; data on two patients with 4 copies of the SMN2 gene with early onset of the disease were presented.