STABILOMETRIC VALUES OF HUMANS UNDER THE CONDITIONS OF FORWARD AND BACKWARD BENT POSITIONS.

Using stabilometry study the center of pressure (COP) displacement over the horizontal surface and power spectrum characteristics of postural sway in the sagittal and frontal planes (Y and X- oscillations, respectively) during an upright stance (US) and under the conditions of body bents forward and backward (BF and BB, respectively) were investigated in a group of 15 volunteers. The tests were performed under the conditions of opened and closed eyes. It was demonstrated that the power spectrum of sway depended on posture, it was greater under the conditions of body bents than during the upright stance. In all three positions blocking of optical input resulted in an increase in power spectrum as well of Y- and X-oscillations in a number of frequency bands of body sway. A significant dependence on the visual control for the mean value of COP under the conditions of bents backward was also found. Data on changes in the lateral oscillations under the conditions of body bents in the sagittal plane showed the essential role of ankle proprioceptors in the genesis of the lateral oscillations at keeping balance during standing. The comparative analysis of power spectrum characteristics of postural sway in the sagittal and frontal planes under the conditions of opened and closed eyes indicated a significant interaction between proprioceptive and visual afferentation at positions of body bents relative to upright stance.

[A model of primary open-angle glaucoma: manifestations and outcomes].

OBJECTIVE: To determine the expected duration of the disease and the age of the patients with different stages ofprimary open-angle glaucoma complicated by pseudoexfoliation syndrome (PES) and/or patients with pseudoexfoliation glaucoma (PEG). METHODS: The study protocol included data from 120 patients (50 males (41.7%), 70 females (58.3%)); 189 eyes; 102 right eyes; 87 left eyes). The first study group (28 patients, 44 eyes) comprised patients with suspected glaucoma. The second group (53 patients, 84 eyes) consisted ofpatients with early glaucoma. The third group (21 patient, 33 eyes) included patients with advanced glaucoma, the forth group (18 patients, 28 eyes) comprised patients with terminal glaucoma. Mean age of the patients at diagnosis was 61.6 (58.4; 66.9) years and 66.9 (63.4; 72.8) years at the endpoint visit in 2013. In all cases, diagnosis was made in accordance with the differential diagnostics system and confirmed by special diagnostic techniques. The database included data from 3 qualified examinations taking account of the results of tonometry and static automated perimetry. RESULTS: The mean expected age of the patients age at the onset of blindness was 75.1 years. The occurrence of the event was limited to a period of 6.1 years. Mean age at the time of possible glaucoma development was 59.58 (56.14; 64.36) years. The disease itself could develop within 3.24 (-5.38; -1.2) years prior to diagnosis. CONCLUSION: Studies for glaucoma diagnosis should be focused on the age group of 55-60 years. The degree of IOP reduction in patients with advanced glaucoma does not agree with the Russian glaucoma society recommendations which accounts for progression of the disease.

[Regional distribution of the brain steady potential level in patients with Parkinson's disease]. / Regional'noe raspredelenie urovnia postoiannogo potentsiala golovnogo mozga u bol'nykh Parkinsonizmom.

Regional distribution of the brain steady potential level (SPL) was shown to depend on the predominant clinical symptom in parkinsonian patients. Those with prevailing bradykinesia revealed a statistically significant decrease in the SPL in the frontal area as compared with the healthy subjects or the patients with prevailing tremor.

Influences of central gray matter stimulation on thalamic neuron responses to high- and low-threshold stimulation of trigeminal nerve structures.

Responses of the thalamic non-specific medial nuclei and relay ventral posteromedial nucleus neurons evoked by stimulation of the teeth pulp of A alpha and A sigma fibers of infraorbital nerve and caudal nucleus of the spinal trigeminal tract were studied in cats under thiopental-chloralose anesthesia. Three groups of neurons were revealed: low-threshold, high-threshold and convergent. In medial nuclei, 29% of neurons formed the low-threshold group, 12% made up the high-threshold group and 59% were convergent. In the ventral posteromedial nucleus 47% of neurons formed the low-threshold group, 4% made up the high-threshold group and 49% were convergent. Ninety per cent of the medial nuclei neurons and 79% of the ventral posteromedial nucleus neurons responded to stimulation of the caudal nucleus spinal trigeminal tract. The conditioning central gray matter stimulation could suppress responses of low-threshold, high-threshold and convergent neuron groups. In medial nuclei 100% of responses induced by stimulation of teeth pulp and A sigma fibers of the infraorbital nerve were completely suppressed and 86% of responses induced by stimulation of the A alpha fibers of the infraorbital nerve stimulation were also completely suppressed. In the ventral posteromedial nucleus 40% of responses induced by stimulation of teeth pulp and A sigma fibers of the infraorbital nerve were completely suppressed and 26.4% of responses induced by stimulation of the A alpha fibers of the infraorbital nerve were completely suppressed. Conditioning stimulation of the central gray matter suppressed responses evoked by stimulation of the caudal nucleus spinal trigeminal tract and in the most part neurons of the medial nuclei and neuron responses of the ventral posteromedial nucleus. The inhibitory influence of central gray matter stimulation on neuronal responses evoked by stimulation of the caudal nucleus spinal trigeminal tract shows that the central gray matter had a direct influence on the activity of thalamic neurons.

[Effect of the intensity of stimulation on the variability and interactions of various late components of the somatosensory evoked potentials in humans]. / Vliianie intensivnosti stimuliatsii na variabel'nost' i vzaimo- sviaz' nekotorykh pozdnykh komponentov somatosensornogo vyzvannogo potentsiala u cheloveka.

Human evoked potentials (EP) to paired somatosensory pain stimuli were recorded from the vertex. Amplitude of the N150 and P250 components of the second EP decreased within 600-1000 ms interstimulus interval. The depression occurred was more intensive with an increase of the first (conditioning) stimulus strength. As a rule, depression of N150 component was more pronounced. Selective averaging of EPs indicated that, when the stimulus intensity was stable, variations in the amplitudes of identical components in response to the first and second stimuli were not usually negatively correlated; positive correlation was frequently found. This can be regarded as a proof that there is no direct relation between the inhibitory after-processes in the cellular generators of the studied EP components and the degree of their previous activation. Such variations can reflect the sequence of periods of an increase and a decrease in the generator activity under conditions of stable stimulus intensity.

[Changes in late components of somatosensory evoked potentials in humans during repetitive stimulation]. / Izmeneniia pozdnykh komponentov somatosensornykh vyzvannykh potentsialov u cheloveka pri parnoi stimuliatsii.

Human evoked potentials to somatosensory stimuli of non-painful and painful intensity recorded from the vertex have been studied. The indices of variability of N150 and P250 components registered in the same subject as well as indices of interrelationship between spontaneous changes of these components decreased when stimulus intensity increased. A supposition is advanced that the role of general source responsible for generations N150 and P250 components diminished when stimulus intensity increased, accordingly participation of autonomic sources became more prominent.

[Effect of electric stimulation of auricular acupuncture points on H-reflex]. / Vliianie élektrostimuliatsii aurikuliarnykh akupunkturnykh tochek na H-refleks.

The non-nociceptive H-reflex in the musculus soleus were recorded before and after auricular electroacupuncture (AEAP) in patients with vertebrogenic pain syndrome. Changes of the H-reflex on the side of the pain syndrome were observed after ipsi- and contralateral AEAP, the latter producing effect more often. Changes of H-reflex are mainly of facilitating character (71.4%) and, rarely, of inhibitory character (14.3%). In the part of patients AEAP produced distinct facilitation of M-response.

[Modulation of the nociceptive flexor reflex by the electrostimulation of auricular acupuncture points]. / Moduliatsiia notsitseptivnogo sgibatel'nogo refleksa élektrostimuliatsiei aurikuliarnykh akupunkturnykh tochek.

Nociceptive flexor reflex (NFR) in patients with vertebrogenic lumbosacral pain syndromes was recorded before and after the ipsi- and contralateral auricular electroacupuncture (AEAP). Changes in NFR were observed after ipsi- and contralateral AEAP, each producing facilitatory and inhibitory effects on NFR. Facilitatory influence of AEAP on NFR correlated with hypalgesia, that apparently reflected recovery of the afferent input peculiarities.

[Changes in somatosensory evoked potentials in patients with vertebrogenic pain syndromes treated by electroacupuncture]. / Izmeneniia somatosensornykh vyzvannykh potentsialov u bol'nykh vertebrogennymi bolevymi sindromami pod vliianiem elektroakupunktury.

Application of electroacupuncture (EAP) of the segmental points to patients with vertebrogenic algesic syndromes decreased amplitude of N150 and P240 waves recorded from vertex to painful electrocutaneous stimulation in the region innervated by an affected root. As distinct from EAP of segmental point auricular EAP not only decreased the amplitude of late components of evoked potentials (EP), but also increased it, direction of EP changes depending on the character of sensitivity disorders. It is suggested that effect of EAP-evoked EP changes in patients with hypalgesia is determined by two oppositively acting factors: by a decrease of nociceptive afferent impulsation intensity as a result of the antinociceptive system activation and by an increase of the afferent impulsation intensity due to recovery of function of central terminals in primary sensory neurons.

[Effect of stimulation of the central gray matter of the midbrain on responses of neurons of the ventroposteromedial nucleus of the thalamus in cats]. / Vliianie stimuliatsii tsentral'nogo serogo veshchestva srednego mozga na otvety neironov ventroposteromedial'nogo iadra talamusa u koshek.

Effect of the midbrain central gray matter (CGM) stimulation on neuronal responses of the thalamic ventro-postero-medial (VPM) nucleus evoked by stimulation of the tooth pulp, A-alpha, A-delta fibres of the infraorbital nerve and caudal nucleus of the spinal trigeminal tract have been studied in cats under thiopental-chloralose anesthesia. It is shown that the CGM stimulation by a short train of stimuli evoked excitatory responses with a latency of 30 ms in part of investigated neurons. The conditioning CGM stimulation suppressed responses in neurons of "low-threshold", "convergent" and "high-threshold" groups. Responses induced by stimulation of the tooth pulp and A-delta fibres of the infraorbital nerve in 40% of neurons and by stimulation of the A-alpha fibres of the infraorbital nerve in about 26% of investigated thalamic neurons were completely suppressed. The inhibitory influence of the CGM stimulation on neuronal responses evoked by stimulation of peripheral nerves and caudal nucleus of the spinal trigeminal tract shows that the CGM influences directly the activity of thalamic neurons.

[Effect of stimulation of the central gray substance of the midbrain on neuronal responses of the thalamic medial nuclei in the cat]. / Vliianie razdrazheniia tsentral'nogo serogo veshchestva srednego mozga na otvety neironov medial'nykh iader talamusa u koshki.

Effect of the central gray matter (CGM) stimulation on neuronal responses in the thalamic nonspecific medial nuclei evoked by stimulation of the teeth pulp, A-alpha and A-sigma fibres of the infraorbital nerve and the caudal nucleus of the spinal trigeminal tract was studied in experiments on cats under thiopental-chloralose anesthesia. Stimulation of the CGM by a train of stimuli evoked excitatory responses with latency from 15 to 40 ms in a part of investigated neurons. Conditioning stimulation of the CGM led to the inhibition of responses evoked by afferent volleys in neurons of the "low-threshold", "high-threshold" and "convergent" groups. Responses evoked by stimulation of the teeth pulp and A-sigma fibres were inhibited in 100% and those evoked by stimulation of A-alpha fibres of the infraorbital nerve only in 86% of neurons. Presence of the inhibitory influence of the CGM on the thalamic neuron responses evoked both by stimulation of peripheral afferents and spinal trigeminal tract nucleus show that the CGM exerts a direct influence on the thalamic neuron activity.