A major new dimension in the problem of brain injury

Evidence that neurohormones contribute to the contralateral effects of unilateral brain injury challenges a fundamental assumption of basic neuroscience and clinical neurology.

Mode of use by mobile phone and change of time of simple audio-motor reaction for users of mobile communication. Age related features of ipsilateral and contralateral effects

By analysing the time of a simple auditory-motor reaction with mono-presentation of an audio signal, the effect of the electromagnetic radiation of a mobile phone on the human auditory system is evaluated. Regularities in the frequency of occurrence of ipsi and contralateral effects in mobile users of different age groups are obtained. This study has no analogues in either Russian or foreign publications and is currently exclusive. The purpose was to study age-related features of the severity of ipsi and contralateral effects, depending on the mode of use of the mobile phone. To record the ipsi- and contralateral effects, we used the differences in the average values of a simple auditory-motor reaction between the left and right ears with mono-presentation of the sound signal of 573 respondents of different age groups. The obtained values were compared with the control group data for each age group (491 respondents). If the difference was greater than in the control group, the ipsilateral or contralateral effect was recorded. The severity of the effect was evaluated taking into account the lateral preferences of each participant in the experiments (to which ear the mobile phone is most often held) and the mode of use of the mobile phone. Statistical processing of the results was carried out using the non-parametric Mann-Whitney test and the method of descriptive statistics: prevalence indicator (Pr) (relative frequency of manifestation of a particular attribute in the sample). The comparison of the severity of ipsi and contralateral effects for different age groups allowed us to establish the following patterns. It was found that, in general, the manifestation of the contralateral effect decreases with age, and the ipsilateral effect increases. However, this change is not linear. It is shown that the features of the manifestation of the contralateral and ipsilateral effect for each age group depend both on the time of daily use of a mobile phone and on the total duration of use of a mobile phone. We believe that when studying multidimensional input data, an individual approach is necessary. The presented results confirm the negative effect of the radiation of mobile phones on the auditory system, primarily of our younger generation. Given the special vulnerability of children to physical environmental factors and the depth of penetration of EMR MT into the brain of a child, we believe that from a radiobiological point of view, there is already a need to develop a special SanPiN (sanitary rules and norms) for all available modern low-intensity sources of electromagnetic radiation, including Wi-Fi.

The possible mechanisms of electromagnetic phone effects on the auditory system of children and adolescents

For the first time, we compared the gradients of changes in the simple auditory-motor response (SAMR) and the daily time of using a mobile phone (MP), which made it possible to describe the variants of possible changes in lateralization of effects and the frequency of their occurrence for different variants of SAMR changes. This study has no analogues neither in Russian nor in foreign publications and is currently exclusive. Objective – to determine the patterns of manifestation of contra- and ipsilateral effects, using individual changes in indicators of a simple auditory-motor response obtained as a result of longitudinal observations. The analysis of changes in the parameters of a simple auditory-motor reaction was carried out during mono-presentation of a sound signal on the left and on the right in 145 children and adolescents aged 7-14 years (470 measurements), who were under observation for 2 or more years, depending on changes in the mode of use mobile phone. Further, 48 cases were excluded (change in the lateralization of use, for example, the respondent brought the phone to both the right and the left ear, “changed” the leading ear, etc.). Three variants of changes in the mode of using MP in the longitude period (gradient of time change) were established: an increase in time (the group "less–more"), a decrease in time (group "more–less") and no changes. For each group, 4 variants of changes in the parameters of SAMR were revealed in the dynamics of observations along the longitude: decrease in SAMR indicators on the left (left ear) and increase in the right (right ear); decrease in indicators on the left and increase on the right and synchronous decrease or increase in indicators on the right and left. An assessment of the strength of the correlation was carried out (a linear Pearson correlation coefficient was used and an assessment of the statistical significance was carried out): between changes in the gradient of changes in the time of MP usage and SAMR, as well as changes in the lateralization of effects (changes in the frequency of occurrence of ipsi- and contralateral effects). The multivariance of changes in SAMR indicators and lateralization of effects was revealed depending on the mode of MP use. The proposed approach to the analysis of changes in a simple auditory-motor reaction and daily time of using a mobile phone makes it possible to suggest some mechanisms of changes in the parameters of the auditory analyzer in response to the duration of exposure to electromagnetic radiation from a mobile phone. The presence of contralateral effects of changes in SAMR parameters can serve as an assessment of the “capture” of the brain structures of children and adolescents by MP electromagnetic radiation. The results obtained once again prove the level of negative impact on the auditory system of children and adolescents. The current situation requires an immediate solution by clear regulation of the use of cellular communications by the younger generation.

Local and Contralateral Effects after the Application of Neuromuscular Electrostimulation in Lower Limbs

Neuromuscular electrostimulation (NMES) has been used mainly as a method to promote muscle strength, but its effects on improving blood flow are less well known. The aim of this study is to deepen the knowledge about the local and contralateral effects of the application of symmetric biphasic square currents on skin temperature (Tsk). An experimental pilot study was developed with a single study group consisting of 45 healthy subjects. Thermographic evaluations were recorded following the application of NMES to the anterior region of the thigh. The results showed an increase in the maximal Tsk of 0.67% in the anterior region of the thigh where the NMES was applied (p < 0.001) and an increase of 0.54% (p < 0.01) due to cross-education effects, which was higher when the NMES was applied on the dominant side (0.79%; p < 0.01). The duration of the effect was 20 min in the dominant leg and 10 min in the nondominant one. The application of a symmetrical biphasic current (8 Hz and 400 μs) creates an increase in the maximal Tsk at the local level. A temperature cross-education effect is produced, which is greater when the NMES is applied on the dominant side. This could be a useful noninvasive measurement tool in NMES treatments.

Contralateral effects of unilateral training: sparing of muscle strength and size after immobilization

The contralateral effects of unilateral strength training, known as cross-education of strength, date back well over a century. In the last decade, a limited number of studies have emerged demonstrating the preservation or “sparing” effects of cross-education during immobilization. Recently published evidence reveals that the sparing effects of cross-education show muscle site specificity and involve preservation of muscle cross-sectional area. The new research also demonstrates utility of training with eccentric contractions as a potent stimulus to preserve immobilized limb strength across multiple modes of contraction. The cumulative data in nonclinical settings suggest that cross-education can completely abolish expected declines in strength and muscle size in the range of ∼13% and ∼4%, respectively, after 3–4 weeks of immobilization of a healthy arm. The evidence hints towards the possibility that unique mechanisms may be involved in preservation effects of cross-education, as compared with those that lead to functional improvements under normal conditions. Cross-education effects after strength training appear to be larger in clinical settings, but there is still only 1 randomized clinical trial demonstrating the potential utility of cross-education in addition to standard treatment. More work is necessary in both controlled and clinical settings to understand the potential interaction of neural and muscle adaptations involved in the observed sparing effects, but there is growing evidence to advocate for the clinical utility of cross-education.