Cortical representations of muscles can be probed non‑invasively using transcranial magnetic stimulation (TMS) motor mapping. TMS mapping can be applied both in research and clinical settings to assess motor cortex reorganization under the influence of various factors, to clarify pathophysiological mechanisms of motor system damage in various diseases, and to develop novel biomarkers of this damage. The article discusses the main methodological aspects of TMS motor mapping: choosing stimulation intensity and interstimulus interval, using of grid, neuronavigation and robotic systems, determining of a target muscle, etc. Special attention is paid to the cortical motor representation parameters such as the “hot spot” and center of gravity localization, area, etc. and their reproducibility under various mapping protocols. A review of publications on the use of TMS motor mapping application in brain tumors, stroke and amyotrophic lateral sclerosis is presented. The most significant practical impact of TMS motor mapping of the cortex is seen in brain tumors when used for presurgical localization of eloquent motor areas, as it is associated with the improvement of functional outcomes and progression‑free survival.

Restless legs syndrome (RLS) is a neurological, sensorimotor disorder. It is characterized by the uncomfortable and unpleasant sensations in the legs which begin or worsen during periods of rest, primarily in the evening or night, and are relieved by movement. Central iron deficiency plays a vital role in the pathogenesis of RLS. There is evidence that chronic inflammation is an additional risk factor for RLS. Anemia is the most common complication and extraintestinal manifestation of inflammatory bowel disease, therefore the prevalence of RLS in these patients is a problem of great interest. In addition, inflammatory bowel disease patients’ sleep disturbances directly influence the disease’s clinical course and can be the preclinical marker of exacerbation. It is essential for clinicians to be aware of RLS as a possible reason for sleep disturbance and as a factor that negatively affects the quality of life in inflammatory bowel disease patients.

While compression neuropathies of the nerves of the lower limbs are not a common pathology, peroneal nerve neuropathy is the most common of them. Peroneal nerve compression most commonly occurs at or around the head of the fibula, but can also occur in the lower leg, ankle, or foot. Neurophysiological and neuroimaging methods are effective in diagnosing peroneal nerve compression and determining the type of damage. The first line of therapy is lifestyle modification, avoidance of compressive postures, ankle joint orthotics, treatment of knee joint instability when detected, kinesiotherapy. An important role in the correction of symptoms is played using anticholinesterase drugs, the effectiveness of which in diseases of peripheral nervous system has been shown in a number of domestic studies. If conservative treatment fails, surgical treatment is recommended. The diagnosis of peroneal neuropathy is associated with a good prognosis and most patients experience complete recovery of nerve function.

Background. Spinal muscular atrophy (SMA) associated with chromosome 5q is an autosomal recessive neuromuscular disease caused by a mutation in the SMN1 gene. Adult forms of SMA are relatively rarer and associated with significant diagnostic difficulties and pronounced delay in diagnosis. The available pathogenetic therapy for SMA has the greatest effect with an earlier start of treatment, so timely diagnosis of the disease significantly improves the overall prognosis.
Aim. To evaluate the features of diagnosis of the adult SMA and summarize the first experience of such diagnosis in Russian patients.
Materials and methods. We analyzed the archived medical records of 50 adult patients with SMA consulted at the Research Center of Neurology (Moscow).
Results. The data of patients with SMA type 2 (n = 26), SMA type 3 (n = 21), SMA type 4 (n = 3) were analyzed. The delay time for diagnosis in SMA type 2 is 35 (0–270) months, with SMA types 3 and 4 – 108 (0–408) months. The diagnosis of SMA was the first diagnosis in SMA type 2 in 69 % of cases, in SMA types 3 and 4 in 29 % of cases. The most common first diagnosis in patients with SMA is myopathy, accounting for 52 % of all misdiagnosed cases. A small percentage of the use of needle electromyography in the diagnostic process was noted (1/3 of cases); in cases of its use, this did not accelerate the correct diagnosis. Creatine phosphokinase activity is often elevated in patients with SMA types 3 and 4 compared with SMA type 2 (p <0.05).
Conclusions. To reduce the delay in the correct diagnosis of SMA and earlier initiation of pathogenetic therapy, it is necessary to increase the awareness of specialists about the features of diagnosis the disease and focus on alternative erroneous diagnoses, among which adult patients with SMA may “hide”. The key to confirming the diagnosis is DNA testing.

Background. As motor neuron disease (MND) and myasthenia gravis (MG) progress, the respiratory muscles are involved in the pathological process with the development of respiratory failure, which is one of the main causes of death. Respiratory disorders due to weakness and pathological muscle fatigue are often diagnosed with a delay, which is associated with the moderation of changes in the early stages of the disease. The ultrasound examination is one of the additional methods for diagnosing dysfunction of the respiratory muscles, however, the lack of methodological recommendations leads to the heterogeneity of diagnostic data.
Aim. To identify subclinical signs of impaired function of the respiratory muscles in the early stages of the development of MND and MG using ultrasound.
Results. Ultrasonography was performed in 19 (44 %) patients with MND and 24 (56 %) with MG; the comparison group consisted of 35 healthy volunteers. Diagnostics was carried out with application of an Philips HD11 XE device (Philips, USA), using a linear transducer with a frequency of 5–12 MHz and a convex transducer of 2–5 MHz. Compared with the control, patients with MND showed a statistically significant decrease in the following parameters: diaphragm thickness, diaphragm movement amplitude, intercostal spaces, kidney right and left respiratory mobility during calm and deep breathing, and the diaphragm thickening coefficient on the left (U, р <0.05). Patients with MG showed a statistically significant decrease in the amplitude of diaphragm movement during deep breathing on the right, the size of the intercostal spaces during deep breathing on the left, and the coefficient of diaphragm thickening on the left (U, p <0.05).
Conclusions. The obtained data reflect the presence of functional and structural changes in the respiratory muscles, caused by their weakness. Ultrasound signs of dysfunction of the respiratory muscles were established, indicating the presence of pathological fatigue and/or weakness of the respiratory muscles, which may indicate either developing or developed respiratory failure. Ultrasound is a non‑invasive, inexpensive and safe diagnostic method and can be a good and convenient way to detect dysfunction of the respiratory muscles, and in some cases can be an additional diagnostic method (for example, when correct spirometry is difficult to perform due to the presence of bulbar disorders in MND and MG).

Mitochondrial neurogastrointestinal encephalomyopathy is an extremely rare (1–9:1 000 000, Orphanet, 2021) multisystem genetic disease caused by mutations in the TYMP gene encoding the enzyme thymidine phosphorylase.
The article presents the data of a thirteen‑year survey on 40‑year‑old patient D. with clinical manifestations of mitochondrial neurogastrointestinal encephalomyopathy syndrome associated with the previously undescribed missense mutation c.1301G>T (p.Gly434Val) of the TYMP gene. Detailed clinical picture (gastrointestinal dysfunction, cachexia, blepharoptosis, ophthalmoparesis, peripheral polyneuropathy and leukoaraiosis), electroneuromyography data (demyelination with secondary axonopathy), high blood serum level of dihydrothymine together with normal levels of thymidine and deoxyuridine made it possible to verify the diagnosis. Histopathological examination revealed atrophy of the longitudinal (outer) muscle layer of the small and large intestines and a significant decrease in the number of CD117+ cells (telocytes), signs of damage to the striated skeletal muscles of a mixed nature with a predominance of the myogenic pattern, as well the destruction of the myelin sheaths of peripheral nerves. Histochemical examination did not reveal “ragged red fibers” characteristic of mitochondrial pathology. Transmission electron microscopy demonstrated the presence of megalomitochondria in the myocardium.

Differential diagnosis of inflammatory myopathies with hereditary muscular dystrophies accompanied by a secondary inflammatory process is a time‑consuming clinical and pathomorphological task. In particular, false diagnosis of polymyositis in patients with dysferlinopathy reaches 25 % of cases.
A 40‑year‑old female patient with a limb‑girdle phenotype of dysferlinopathy, initially diagnosed as polymyositis, is presented. The reasons that led to the erroneous diagnosis were: sporadic case; subacute onset; proximal muscle weakness; myalgia, which stopped on the glucocorticosteroid therapy; high levels of creatine phosphokinase (up to 17 times); the presence of lymphocytic‑macrophage infiltrate in the muscle biopsy and the absence of magnetic resonance imaging data in primary examination of the patient.
The refractoriness of clinical and laboratory signs to complex immunosuppressive therapy was the reason for revising the muscle biopsy with typing of the inflammatory infiltrate. The predominantly unexpressed perivascular infiltrate was characterized by the predominance of macrophages and, to a lesser extent, CD4+, which indicated the secondary nature of the inflammation in the muscle observed in some hereditary muscular dystrophies. When conducting an immunohistochemical reaction, the absence of the dysferlin protein in the sarcoplasmic membrane was revealed.
Whole‑exome sequencing (NGS) revealed a mutation in exon 39 of the DYSF gene (p.Gln1428Ter) in the heterozygous state, which leads to the appearance of a stop codon and premature termination of protein translation. MLPA method registered 3 copies of exons 18, 19, 20, 22, 24 of the DYSF gene.
Thus, this clinical example reflects the main methodological errors and possible effects of immunosuppressive therapy in patients with dysferlinopathy.

Aromatic L‑amino acid decarboxylase (AADC) deficiency is rare autosomal recessive neurometabolic disorder. It caused by generalized combined deficiency of serotonin, dopamine, norepinephrine and adrenaline. This disorder is characterized by muscular hypotonia, motor development delay, oculogyric crises and impairment of the autonomic nervous system.
Laboratory diagnostic of AADC deficiency in Russian Federation includes determination of the concentration of 3‑O‑methyldophamine in dried blood spots by tandem mass spectrometry and molecular analysis of the DDC gene by Sanger sequencing or next generation sequencing.
Therapy of AADC deficiency includes combination of drugs which increase the formation of dopamine, inhibit its reuptake and increase the residual activity of the enzyme. The first‑line drugs are selective dopamine agonists, monoamine oxidase inhibitors of type B and vitamin B6 supplements.
We present the case of management and treatment of patients with AADC deficiency. The patient’s condition was improved by using of combination therapy with pyridoxal‑5‑phosphate, pramipexole and selegiline. Significant positive dynamics was achieved on pyridoxal‑5‑phosphate therapy for the first time.