Chondrodystrophic myotonia characterized by generalized myotonic myopathy, masklike face, skeletal dysplasia, contracture of joints,
growth retardation and bone maturation delay. Two types have been defined by the age of manifestation of the symptoms: the severe neonatal form, sometimes called type 2 (Stuve–Wiedemann syndrome), and the classical form (Schwartz–Jampel syndrome) with late infantile or childhood manifestation. Therapy targets electrical stabilization of the muscle membrane. Successful therapies include anticonvulsants and antiarrhythmic drugs.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune peripheral neuropathy that affects both adults and children. The basis for the paper is the analysis of 5 cases of CIDP in children (3 girls and 2 boys) aged 5 to 17 years, followed up for 3 to 6 years. The types of its clinical picture and electromyographic changes at different disease stages are considered in detail. The course of the disease is traced during therapy with corticosteroids and intravenous human immunoglobulin and plasmapheresis. The results of the authors’ observations are compared with those of investigations conducted by other authors. The consideration of the diagnosis of CIDP and its treatment options focuses on that the international standards must be necessarily met to minimize errors in its differential diagnosis and management of these patients, and to make the prognosis for the disease.

Ultrastructural analysis of 7 biopsies from m.palmaris longus and m.deltoideus in patients with confirmed polymyositis revealed alteration
and degeneration of muscle fibers and anomalies of neuro-muscular junction (NMJ). The NMJ abnormalities and following denervation of
muscle fibers in polymyositis start with subsynaptic damages. The occurance of regeneration features in muscle fibers at any stage is characteristic for PM.

The previous studies have data concerning surgery and diagnostic methods of cervical spondylotic myelopathy (CSM). The aim of this case was to study the on‑line assessment of the functions of corticospinal and somatosensory pathways changed due to surgical decompression of cervical spinal cord. Our study included 11 patients (6 men and 5 women, mean age 59,3 ± 9,2 years old) with MRI‑confirmed cervical spine stenosis (CSS). All of them had intraoperative neurophysiological monitoring standing for transcranial electric stimulation (TES) and recording of the median nerve somatosensory evoked potentials (SEP). Investigations were performed before and 10–15 minutes after surgical spinal cord decompression. The obtained data provides additional information about the spinal cord pathways functional status and it is a reliable predictor of neurological outcome.

The clinical case of hereditary neuropathy with liability to pressure palsies (HNPP) confirmed the results of DNA diagnostics is described. Clinical and electrophysiological features of the course of HNPP in adolescent is analyzed. Many various illnesses require exclusion in case of the foot extensor paresis.