Electrical Bioimpedance Analysis for Evaluating the Effect of Pelotherapy on the Human Skin: Methodology and Experiments.

BACKGROUND: Pelotherapy is the traditional procedure of applying curative muds on the skin's surface-shown to have a positive effect on the human body and cure illnesses. The effect of pelotherapy is complex, functioning through several mechanisms, and depends on the skin's functional condition. The current research objective was to develop a methodology and electrodes to assess the passage of the chemical and biologically active compounds of curative mud through human skin by performing electrical bioimpedance (EBI) analysis. METHODS: The methodology included local area mud pack and simultaneous tap water compress application on the forearms with the comparison to the measurements of the dry skin. A custom-designed small-area gold-plated electrode on a rigid printed circuit board, in a tetrapolar configuration, was designed. A pilot study experiment with ten volunteers was performed. RESULTS: Our results indicated the presence of an effect of pelotherapy, manifested by the varying electrical properties of the skin. Distinguishable difference in the measured real part of impedance (R) emerged, showing a very strong correlation between the dry and tap-water-treated skin (r = 0.941), while a poor correlation between the dry and mud-pack-treated skin (r = 0.166) appeared. The findings emerged exclusively in the frequency interval of 10 kHz …1 MHz and only for R. CONCLUSIONS: EBI provides a promising tool for monitoring the variations in the electrical properties of the skin, including the skin barrier. We foresee developing smart devices for promoting the exploitation of spa therapies.

The therapeutic effect of Värska mud and Värska mineral water baths on the overuse pain and muscle tension syndromes in the working age population.

The effects of bath therapy are complex and result from a unique interaction between the aquatic environment and the human body functions. The effect of bath therapy depends on both water temperature and chemical additives (mineral substances and humic substances). Värska Resort Centre, in south-eastern Estonia, uses for the balneotherapy the local curative mud and mineral water. The aim of the study was to evaluate and compare the effects of Värska's local mud bath and mineral water bath on moderate musculoskeletal pains in working-age people. The study involved 64 working-age subjects: within two weeks, 32 of them received five general mineral water baths, and another 32 received five general curative mud baths. Pain was assessed with the Nordic Musculosceletal Questionnaire, and muscle tension was measured with a myotonometer in m. erector spinae and m. trapezius. Measurements were performed three times: before the start of the study, immediately after the last procedure, and 2-3 weeks after the last procedure. Both the Värska curative mud bath and the Värska mineral water bath showed a positive effect on musculoskeletal pain and muscle tension. Both procedures can be recommended as drug-free interventions for mild to moderate musculoskeletal pain syndrome and muscle tensions, in both prevention and treatment.

Prevention of MSDs and psychological stress at computer-equipped workplaces / Prevención de trastornos musculo-esqueléticos y estrés psicológico en los lugares de trabajo equipados con computadores

Introduction: The human body responds to stress-factors through four systems - central nervous, autonomic nervous, endocrine and immune - which are constantly interacting as a complex network. The main stress-factor at the computer-equipped workplaces is a poorly designed workplace, specifically the positioning of equipment on and around the workstation. The number of occupational diseases among office workers is the specific indicator of influencing of existing hazards and risk factors on the worker in the work environment. Objective: To find out the health disturbances and to make the suggestions for health promotion for computer workers. Methods: Over 400 computer workers' working conditions were measured with subsequent measuring equipment; the fatigue of muscles was measured with myometer; the investigation of the workers' opinion on working conditions based on Nordic, Work ability index (WAI) and Kiva questionnaire was carried out. The workers were divided into different groups by the age (A: under 40 years and B: over 40 years). This paper investigates the satisfaction of computer workers with their working conditions. Results: According to the results of Nordic and WAI questionnaires, musculoskeletal disorders (MSDs) were observed by 53.6%; the cardiovascular disturbances by 20.4% and visual disturbances by 16.7% of the respondents in group A (under 40 years). In group B, MSDs were observed by 50.1%; cardiovascular disorders by 45.7% and visual disturbances by 23.2% of the respondents (over 40 years). Muscle and joint complaints were reported only by 19.7% of workers. The majority of the respondents declared the existence of two or more local pain points. Neck, shoulder, wrist and back pain were registered as the main complaints. Conclusions: The results of measurements of physical workplaces revealed that in some offices there are deficiencies in lighting, problems with stuffy air (high CO2 value) and low relative humidity value on cold season. As muscle strain is often coming from the static posture, it may be influenced also by the psycho-emotional stress at workplace. The questionnaires, objective methods and environmental measurements are useful to plan prevention and early rehabilitation before the disability appears.

Introducción: El cuerpo humano responde a los factores estresantes a través de cuatro sistemas - nervioso central, autónomo, endocrino e inmune- los cuales están constantemente interactuando como una red compleja. Los factores estresantes principales en los lugares de trabajo equipados con computadores son lugares de trabajo pobremente diseñados, específicamente el posicionamiento de los equipos en y alrededor de los puestos de trabajo. El número de enfermedades ocupacionales en los trabajadores de oficina es el indicador específico de la influencia de los peligros existentes y factores de riesgo sobre trabajador en el ambiente de trabajo. Objetivo: Encontrar los problemas en salud y realizar sugerencias para la promoción en salud para trabajadores con computadores. Materiales y métodos: Más de 400 condiciones en trabajadores con computadores fueron medidas con el equipo de medición pertinente; la fatiga muscular fue medida con el miometro, la opinión de los trabajadores sobre las condiciones de trabajo fueron registradas por medio de Nordic, el índice de habilidad de trabajo (WAI por sus siglas en ingles) y el cuestionario Kiva. Los trabajadores fueron divididos en diferentes grupos por edad (A: menores de 40 años y B: mayores de 40 años). En este artículo se investiga la satisfacción de los trabajadores de computadores con su condición de trabajo. Resultados: De acuerdo con los resultado de los cuestionarios Nordic y WAI, los trastornos musculo-esqueléticos (TME) fueron observadas en el 53.6%; los problemas cardiovasculares en un 20.4% y los problemas visuales en un 16.7% de los encuestados del grupo A (menores de 40 años). En grupo B, los TME fueron observados en un 50.1%; los problemas cardiovasculares en un 45.7% y los problemas visuales en un 23.2% de los encuestados (mayores de 40 años). Las quejas musculares y articulares fueron reportados solo en el 19.7% de los trabajadores. La mayoría de los encuestados reportaron la existencia de dos o más puntos locales de dolor. Los dolores de cuello, hombros, muñeca y espalda fueron registrados como las principales quejas. Conclusiones: Los resultados de las mediciones de los lugares de trabajo físicos revelaron que en algunas oficinas hay deficiencias en la iluminación, problemas con la contaminación del aire (altos niveles de CO²) y el bajo valor de la humedad relativa en la estación fría. La tensión muscular es a menudo a causa de la postura estática, esta puede estar influenciada también por el estrés psico-emocional en lugar de trabajo. Los cuestionarios, métodos objetivos y mediciones ambientales son útiles para planificar la prevención y la rehabilitación temprana antes de que aparezca la discapacidad.

Higuchi's fractal dimension for analysis of the effect of external periodic stressor on electrical oscillations in the brain.

This study addresses application of Higuchi's fractal dimension (FD) as a measure to evaluate the effect of external periodic stressor on electrical oscillations in the brain. Modulated microwave radiation was applied as a weak periodic stressor with strongly inhomogeneous distribution inside the brain. Experiments were performed on a group of 14 volunteers. Ten cycles (1 min on, 1 min off) of 450-MHz microwave radiation modulated at 40 Hz were applied. Higuchi's FD was calculated in eight symmetric electroencephalographic (EEG) channels located in frontal, temporal, parietal, and occipital areas. FD values averaged over a group detected a small (1-2%) but statistically significant increase with exposure in all EEG channels. FD increased for 12, decreased for one, and was constant for one subject. FD showed the most remarkable effect in temporal and parietal regions of the left hemisphere where the microwave field was maximal. Changes of FD in these regions of the right hemisphere were much higher than expected in accordance with the field distribution. Correlation of FD between different EEG channels was high and retained its value in exposed conditions. Spreading of disturbance between different brain areas is supposed to be crucial for the effect of exposure on the electrical oscillations in the brain.

Electroencephalographic spectral asymmetry index for detection of depression.

This study is aimed to compare sensitivity of different electroencephalographic (EEG) indicators for detection of depression. The novel EEG spectral asymmetry index (SASI) was introduced based on balance between the powers of two special EEG frequency bands selected lower and higher of the EEG spectrum maximum and excluding the central frequency from the calculations. The efficiency of the SASI was compared to the traditional EEG inter-hemispheric asymmetry and coherence methods. EEG recordings were carried out on groups of depressive and healthy subjects of 18 female volunteers each. The resting eight-channel EEG was recorded during 30 min. The SASI calculated in an arbitrary EEG channel differentiated clearly between the depressive and healthy group (p < 0.005). Correlation between SASI and Hamilton Depression Rating Scale score was 0.7. The EEG inter-hemispheric asymmetry and coherence revealed some trends, but no significant differences between the groups of healthy controls and patients with depressive disorder.

Effect of low frequency modulated microwave exposure on human EEG: individual sensitivity.

The aim of this study was to evaluate the effect of modulated microwave exposure on human EEG of individual subjects. The experiments were carried out on four different groups of healthy volunteers. The 450 MHz microwave radiation modulated at 7 Hz (first group, 19 subjects), 14 and 21 Hz (second group, 13 subjects), 40 and 70 Hz (third group, 15 subjects), 217 and 1000 Hz (fourth group, 19 subjects) frequencies was applied. The field power density at the scalp was 0.16 mW/cm(2). The calculated spatial peak SAR averaged over 1 g was 0.303 W/kg. Ten cycles of the exposure (1 min off and 1 min on) at fixed modulation frequencies were applied. All subjects completed the experimental protocols with exposure and sham. The exposed and sham-exposed subjects were randomly assigned. A computer also randomly assigned the succession of modulation frequencies. Our results showed that microwave exposure increased the EEG energy. Relative changes in the EEG beta1 power in P3-P4 channels were selected for evaluation of individual sensitivity. The rate of subjects significantly affected is similar in all groups except for the 1000 Hz group: in first group 3 subjects (16%) at 7 Hz modulation; in second group 4 subjects (31%) at 14 Hz modulation and 3 subjects (23%) at 21 Hz modulation; in third group 3 subjects (20%) at 40 Hz and 2 subjects (13%) at 70 Hz modulation; in fourth group 3 subjects (16%) at 217 Hz and 0 subjects at 1000 Hz modulation frequency.

Effect of 7, 14 and 21 Hz modulated 450 MHz microwave radiation on human electroencephalographic rhythms.

PURPOSE: The aim of this study was to evaluate the effect of microwaves modulated at different frequencies on human electroencephalographic (EEG) rhythms. MATERIALS AND METHODS: Thirteen healthy volunteers were exposed to microwaves (450 MHz) pulse-modulated at frequencies of 7, 14 and 21 Hz. The field power density at the scalp was 0.16 mW/cm2. Our experimental protocol consisted of two five-cycle (1 min on and 1 min off) series of exposures at fixed modulation frequencies. A relative change in the EEG power with and without exposure was used as a quantitative measure. EEG frequencies recorded in the theta (4-6.8 Hz), alpha (8-13 Hz), betal (15-20 Hz), and beta2 (22-38 Hz) bands were analyzed. RESULTS: Modulated microwaves caused an increase in the average EEG alpha (17%) and beta (7%) power but the theta rhythm remained unaffected. Increases in the EEG alpha and beta power were statistically significant during the first half-period of the exposure interval (30 s) at the modulation frequencies of 14 and 21 Hz. Differences were found in individual sensitivity to exposure. Increases in the EEG beta power appeared statistically significant in the case of four subjects. CONCLUSIONS: Our findings suggest that the effect of the 450 MHz microwave radiation modulated at 7, 14 and 21 Hz varies depending on the modulation frequency. The microwave exposure modulated at 14 and 21 Hz enhanced the EEG power in the alpha and beta frequency bands, whereas no enhancement occurred during exposure to the modulation frequency of 7 Hz.

Adaptation of human brain bioelectrical activity to low-level microwave.

The experiments of adaptation of the human brain bioelectrical activity were carried out on a group of 14 healthy volunteers exposed to 450 MHz microwave radiation modulated at 40 Hz frequencies. The field power density at the scalp was 0.16 mW/cm(2). Results of the study indicate that adaptation effect of human brain to low-level microwave exposure is evident. The initial increase of EEG power was compensated and even overcompensated. The adaptation phenomena were obvious in EEG alpha and beta rhythms..

Assessment of potential hazards during the process of house building in Estonia.

The aim of this study was to evaluate new working conditions in the construction industry in Estonia. Three construction sites were investigated: a dwelling house at the stage of renovation, a warehouse at the stage of excavation and preparation work, and a hotel, where we examined the working conditions of the finishers. Microclimate: air temperature, relative humidity and air velocity were determined at every workplace. Full-shift personal exposure measurements of dust and gas exposure were performed among 97 construction workers in breathing zone air. The concentration of lead in the air was analysed by AAS. Vapours of benzene, styrene and toluene concentrations were determined by gas chromatography. The noise level was measured with the help of the sound-level meter at every workplace. All microclimatic indices were sometimes below or above exposure standards for indoor work. High levels of airborne dust and increased concentrations of lead were observed during repair work. Low concentrations of organic solvents in the air were determined when using paints and some synthetic substances. The noise level exceeded the permitted limit when an excavator and powerful electric appliances were used. A questionnaire determined the prevalence of subjectively experienced musculoskeletal strain in 30% of workers. The working conditions in the construction industry in Estonia are approaching European level. However, it is necessary to improve working conditions permanently by the use of new harmless materials, personal protective equipment, and through influencing worker health by permanent education and medical watch. We consider that questionnaires are very important in the control of the work environment, in subjective health assessments, and as a source of useful proposals to improve working conditions.

Integration of differences in EEG analysis reveals changes in human EEG caused by microwave.

Three different methods in combination with integration of differences in signals were applied for EEG analysis to distinguish changes in EEG caused by microwave: S-parameter, power spectral density and length distribution of low variability periods. The experiments on the effect of modulated low-level microwaves on human EEG were carried out on four different groups of healthy volunteers exposed to 450 MHz microwave radiation modulated with 7 Hz, 14 Hz, 21 Hz, 40 Hz, 70 Hz, 217 or 1000 Hz frequencies. The field power density at the scalp was 0.16 mW/cm2. The EEG analysis performed for individuals with three different methods showed that statistically significant changes occur in the EEG rhythms energy and dynamics between 12% and 30% of subjects.

Changes in human EEG caused by low level modulated microwave stimulation.

This study focuses on the effect of low level microwave radiation on human EEG alpha and theta rhythms. During the experiment, 20 healthy volunteers were exposed to a 450 MHz microwaves with 7 Hz on-off modulation. The field power density at the scalp was 0.16 mW/cm2. Signals from the following EEG channels were used: FP1, FP2, P3, P4, T3, T4, O1, and O2. The experimental protocol consisted of one cycle of short term photic and ten cycles of the repetitive microwave stimulation. The changes caused by photic as well as microwave stimulation were more regular on the alpha rhythm. In the majority of cases, photic stimulation caused changes in the EEG energy level in the occipital and microwave stimulation in the frontal region. Our experimental results demonstrated that microwave stimulation effects became apparent, starting from the third stimulation cycle. Changes varied strongly from subject to subject. Therefore, photic and microwave exposure did not cause statistically significant changes in the EEG activity level for the whole group. For some subjects, clear tendencies of changes in microwave on-off cycles were noticeable.