Background. Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy in children, that occurs between one and three years of age. DMD is caused by pathogenic and likely pathogenic variants in the DMD gene, which lead to a deficit of various isoforms of the dystrophin protein, the main protein of the muscle cytoskeleton. Drugs aimed at slowing the progression of the disease are being actively developed around the world. One of the perspective approaches to pathogenetic therapy is therapy using exon skipping. As a result of this treatment, the reading frame is restored due to the exon skipping enabling the production of truncated dystrophin.

Aim. To evaluate the applicability of exon skipping therapy in Russian patients with DMD.

Materials and methods. The applicability of therapy aimed at exon skipping was analyzed for a sample of 1519 patients admitted to the laboratory of DNA diagnostics of the Research Centre for Medical Genetics with a referral diagnosis of Duchenne/Becker muscular dystrophy from October 1, 2018 to September 1, 2023.

Results. As a result of the study and analysis of the spectrum of mutations in the DMD gene among patients with DMD in the Russian Federation, the theoretical applicability of exon skipping therapy was assessed: for 29.3 % of patients this approach to treatment is applicable. The proportions of patients for whom existing exon skipping therapies are available were also estimated. In total, skipping of frequent exons 51, 53, 45 is applicable for 14.6 % of patients. Conclusion. One of the effective and accessible types of therapy for DMD is exon skipping. This type of therapy is mutation-specific. In this regard, the assessment of applicability will allow us to estimate the proportion of patients for whom a particular exon skipping will be available.

Background. Most modern bioprostheses use two sensors located on the flexor and extensor muscles of the hand and fingers to register muscle activity, which severely limits the functionality of the device and complicates switching between grips. One of the solutions to this problem is to use an array of more sensors to recognize different grips using a neural network.

Aim. To evaluate the possibility in principle of using an array of 8 sensors for recognizing different grips.

Materials and methods. Research was conducted on 23 healthy volunteers, whose surface myograms were recorded at 13 different grips. An array of surface-type electroneuromyographic sensors (n = 8) with bipolar electrodes and electroneuromyographic signal amplification factor of 2000 times, myograph and software are of own development were used as a technical base for the research.

Results. For most subjects, the differences in the investigated parameters when comparing grips with each other reached thousands of percent, especially when comparing the product of frequency and mean amplitude. In some pairs the differences were less significant and amounted to less than 400 %. The proportion of pairs with reliable differences varies from subject to subject when comparing the product of frequency and mean amplitude and ranges from 71 to 98 %. The average value for the whole group is 87 %. When comparing frequency only, the variation ranges from 67 to 93 %, with an average of 78 %.

Conclusion. For most subjects, the majority of grips are confidently differentiated from each other. Due to pronounced individual peculiarities, the decision to use this or that parameter to control the bioprosthesis for a definite person is individual and should be made after a thorough neurophysiological research. Some people will require training in order to develop a new motor stereotype.

The scratch-collapse test was proposed in 2008 to detect the level of compression of the ulnar and median nerves in tunnel lesions. Further study of this phenomenon has shown that weakness of the shoulder external rotators occurs in nerve lesions at other levels as well. The scratch-collapse test was studied in 155 patients (mean age 45 years) with unilateral reflex cervical-elbow syndrome, with complaints of different localization. The scratch-collapse test was positive in all patients on the affected side. The localization of the trigger zone depended on the patient’s complaints and was established experimentally. Short-term kneading of the trapezius muscle or voluntary contraction of the forearm muscles on the side of the lesion was used to prove the reflex nature of the cervico-elbow syndrome, resulting in complete recovery of triceps or extensor strength of the first and third finger. In the course of the study, suppression of the scratch-collapse test in reflex cervico-elbow syndrome with proprioceptive stimulation was found. In confirmed carpal tunnel and cubital tunnel syndromes, the phenomenon of suppression of the scratch-collapse test was also observed in response to proprioceptive stimulation. The scratch-collapse test and reflex cervical-elbow syndrome have a common mechanism of occurrence, which is based on the protective reaction of the body in the form of a nociceptive shortening reflex. The scratch-collapse test at skin irritation over the site of nerve injury can be considered as a subthreshold physiologic nociceptive reflex. Based on the theory of prognostic action of the nociceptive system, cervicolumbar reflex syndrome is a pathologic nociceptive reflex. Scratchcollapse test suppression phenomenon and recovery of muscle strength in reflexive cervical-elbow syndrome after shortterm kneading of the trapezius muscle are the result of activation of the antinociceptive system in response to proprioceptive stimulation. This suppression phenomenon can be used for the treatment of reflex cervical lockjaw syndrome.

Background. Grasping objects with the hand is one of the most common movements in everyday life. It requires training involving the cognitive processes of goal selection and motor planning.

Aim. To investigate the effect of object rotation on motor planning using an experiment where participants moved abstract objects that sometimes required rotation, and movement was assessed using a kinematic analysis system. We hypothesized that reaction times and movements would be longer for tasks with rotation.

Materials and methods. Sixteen subjects participated in the study (11 females and 5 males), mean age – 23.375 ± 2.277 years. Participants were required to perform a task of moving 4 abstract objects onto corresponding platforms with their right hand, while periodically rotating the object by 90°, 180°, or 270°. The motion tracking system monitored the movement of trackers located on the subject’s right thumb and index finger, on the subject’s right wrist, and on the object and the subject’s special glasses.

Results. To assess the effect of object rotation on motor planning, the data were grouped according to the angle of rotation. A one-factor analysis of variance with repeated measures was used. The results showed statistically significant differences:

• total movement time as a function of turning angle: F(3.45) = 5.014, p = 0.004;
• time to reach the grasping target: F(3.45) = 61.79, p = 0.001;
• object motion time: F(3.45) = 14.641, p = 0.001;
• time to reach maximum capture aperture: F(3.45) = 8.559, p = 0.001.

Conclusion. Overall, our results support the hypothesis that object rotation during movement affects both the preparation and execution of the movement itself. The planning and executing the movement with the object rotated 180° was easier and faster than with 90° and 270° rotations. The testing allows distinguishing the stages of planning and preparation of the movement from the execution of the movement itself. Using this approach in patients with central nervous system lesions helps to assess and monitor the state of motor function, which is important for monitoring the recovery process.

Background. Existing registries of patients with spinal muscular atrophy (SMA) 5q serve as a valuable source of information on identified patients. Information on the characteristics of Russian patients with SMA 5q and the therapy administered in real clinical practice is currently limited.

Aim. To describe a cohort of Russian patients with a confirmed diagnosis of SMA 5q and to evaluate patient routing data in real clinical practice settings in Russia.

Materials and methods. The present study was a descriptive non-interventional retrospective cohort study in patients diagnosed with SMA 5q who were enrolled in the Russian patient registry between January 1, 2020 and March 31, 2023. Study participants who met the inclusion criteria were automatically identified in the integrated database of the SMA 5q patient registry. Data were uploaded into validated electronic charts, verified and analyzed using descriptive statistics methods. Results. As of March 31, 2023, the Russian SMA registry contained information on 1408 patients from all federal districts and obtained epidemiological, sociodemographic and clinical characteristics of patients, as well as routes to diagnosis and treatment regimens for patients. The median time from disease onset to confirmed diagnosis was 3 months in patients with SMA type 1, 9 months in patients with SMA type 2, 20 months in patients with SMA type 3 and 68 months in patients with SMA type 4. The median time from confirmed diagnosis to the start of disease-modifying therapy was 0.5 months in SMA patients identified by neonatal screening, 21 months in patients with SMA type 1, 59 months in patients with SMA type 2, 47 months in patients with SMA type 3 and 87 months in patients with SMA type 4.

Conclusion. This retrospective analysis was carried out in order to identify recent approaches to the diagnosis and treatment of SMA used in real-world clinical practice in Russia. The identified parameters (duration from the disease onset to confirmed diagnosis, duration from the confirmed diagnosis to disease-modifying therapy initiation) indicate that more widespread use of newborn screening and more rapid treatment initiation are unmet needs for SMA patients in Russia.

In the last decade, pathogenetic methods for the treatment of spinal muscular atrophy 5q have been developed. These include increased expression of the SMN2 gene, correction of SMN2 splicing, or reexpression of the SMN1 gene. Despite the comprehension of the genetic causes of the disease and the existence of therapies, it is still not completely known which molecular mechanisms in SMN protein deficiency lead to the degeneration of motor neurons. Understanding the molecular pathways involved in the loss of motor neurons may help develop new therapeutic strategies. The article presents genetic and biochemical data that reveal the molecular mechanisms of neurodegeneration in spinal muscular atrophy 5q.

Dystrophinopathies are a spectrum of X-linked muscular disorders associated with pathogenic/likely pathogenic variants in the dystrophin gene (DMD). Typically, the condition develops in males, but cases of symptom manifestation have also been described in females. The review presents contemporary data on the manifestations of dystrophinopathies in women with pathogenic variants in the DMD gene, discussing the reasons for the varying degrees of symptom expression in carrier women with pathogenic/ likely pathogenic variants. It discusses the importance of mutation screening in the DMD gene for women presenting with muscular dystrophy symptoms and investigating carrier status in relatives of patients with Duchenne/Becker muscular dystrophy.

Steroid myopathy is a common drug-induced non-inflammatory myopathy that affects patients requiring long-term glucocorticoid treatment for various autoimmune, inflammatory and oncological diseases. According to the neurology clinical practice guidelines, non-fluorinated glucocorticoids are the first-line pathogen-directed therapy for a number of dysimmune neuromuscular disorders, including myasthenia gravis. Long-term high-dose steroid treatment regime for myasthenia gravis leads to both acute and chronic development of glucocorticoids-induced proximal muscle weakness and atrophy. Steroid myopathy, along with other undesirable side effects of glucocorticoids therapy, impact health-related quality of life, patient satisfaction and adherence to treatment. Hence, further studies are required to expand our knowledge of clinical evaluation, diagnostic testing and prevention approaches for glucocorticoids-induced myopathy. The aim of this literature review is to analyze existing data on pathogenesis, diagnostic tools and treatment strategies for steroid myopathy.

Duchenne muscular dystrophy is a severe genetic disease caused by mutations in the dystrophin gene (DMD), which lead to a significant decrease or complete absence of the protein of the same name in muscle fibers. The disease manifests itself in boys from the age of 2–5 years in the form of progressive muscular weakness, cardiomyopathy and respiratory failure. As a result of progression, patients lose the ability to move by adolescence and die in the third decade from cardiopulmonary complications. However, timely pathogenetic therapy for Duchenne muscular dystrophy can prolong the life of patients and improve its quality. In this regard, early diagnosis of the disease and early initiation of pathogenetic therapy are very important.

The article describes two clinical cases of the disease in siblings with onset at 2 years of age and different ages of diagnosis. Pathogenetic therapy in the first case made it possible to prolong the patient’s outpatient stay and improve the quality of life, and early diagnosis and initiation of pathogenetic therapy in the second case avoided disease progression and contributed to the development of new motor skills. The presented clinical case demonstrates the need for early diagnosis of the disease even before the onset of clinical manifestations.