2024-09

Applied Neuropsychology: Child

Objectives Mental chronometry is the scientific study of cognitive processing speed measured by reaction time (RT), which is the elapsed time between the onset of a stimulus and an individual’s response. This study aims at measuring the RT among young children with autism spectrum disorders (ASD) and comparing it with normal (typically developing) children. Methods 60 ASD children were selected from different ASD centers, and 60 normal children were selected from different kindergartens for participation in this study. Participants were aged 3–6 years old. The RT was measured using the Fitlight trainer device. The findings were statistically evaluated using independent t-tests and ANOVA tests. Result Significant differences (p < 0.0001) were found between both groups in all tasks, and ASD children demonstrated slower RT compared to the normal group. The RT measured through three senses (visual, auditory, and touch) for ASD and normal were 3.64 ± 2.16, 13.19 ± 2.41(trial), 1835.23 ± 757.95, 697.12 ± 87.83 (second), and 1550.89 ± 499.76, 752.67 ± 124.02 (second) respectively. Conclusion The evaluated RT showed significant impairment in RT among ASD in comparison to normal children and this was true for the three senses. The Fitlight trainer could be used to assess RT and stimulus-response among ASD children in various cognitive tasks. Similar studies, involving larger samples from different areas and involving other sense organs, are indicated to confirm the results.

2024-08

Sensors (Issue : 16) (Volume : 24)

Abstract: Electrodermal activity (EDA) is a widely used psychophysiological measurement in laboratory-based studies. In recent times, these measurements have seen a transfer from the laboratory to wearable devices due to the simplicity of EDA measurement as well as modern electronics. However, proper conditions for EDA measurement are recommended once wearable devices are used, and the ambient conditions may influence such measurements. It is not completely known how different types of ambient noise impact EDA measurement and how this translates to wearable EDA measurement. Therefore, this study explored the effects of various noise disturbances on the generation of EDA responses using a system for the simultaneous recording of all measures of EDA, i.e., skin conductance responses (SCRs), skin susceptance responses (SSRs), and skin potential responses (SPRs), at the same skin site. The SCRs, SSRs, and SPRs due to five types of noise stimuli at different sound pressure levels (70, 75, 80, 85, and 90 dB) were measured from 40 participants. The obtained results showed that EDA responses were generated at all levels and that the EDA response magnitudes were significantly (p < 0.001) influenced by the increasing noise levels. Different types of environmental noise may elicit EDA responses and influence wearable recordings outside the laboratory, where such noises are more likely than in standardized laboratory tests. Depending on the application, it is recommended to prevent these types of unwanted variation, presenting a challenge for the quality of wearable EDA measurement in real-world conditions. Future developments to shorten the quality gap between standardized laboratory-based and wearable EDA measurements may include adding microphone sensors and algorithms to detect, classify, and process the noise-related EDA.

2024-07

Science Journal of University of Zakho (Issue : 3) (Volume : 12)

Once the pandemic started, there were no clues regarding overall COVID-19 infections. There are no studies that demonstrate the effects of COVID-19 on skin surface pH, moisture, sebum, and temperature in terms of gender differences and body mass index (BMI) among infected people. The goal of this study was to investigate some of the skin biophysical scores of patients infected with COVID-19 and evaluate the impact of gender differences and the body mass index on them. Skin surface sebum, pH, temperature, and hydration (moisture), were measured in 30 COVID-19 patients using employing non-invasive portable devices. Insignificant effects of gender differences and BMI on skin biophysical properties were observed. In addition, females showed higher skin biophysical characteristics than males. Moreover, obese patients had higher skin biophysical parameter values than normal-weight patients. However, all the study results were statistically insignificant (p > 0.05). Further investigations are required to recognize other skin biophysical parameters such as transepidermal water loss and elasticity that may aid in the early identification of skin damage in COVID-19 patients.

2024-03

Science Journal of University of Zakho (Issue : 1) (Volume : 12)

Electrodermal activity (EDA) represents changes in the electrical properties of the skin due to the opening of sweat pores and sweat secretion. EDA responses are classified into specific and nonspecific responses. Nonspecific EDA responses (NS.EDRs) are EDA responses without external stimuli or motor activity and are shown to be a good measure of psychophysiological states and traits. Studies investigating NSEDRs are rare, especially on responses, which occur following specific responses at resting periods. This study aimed to investigate variations in NS.EDRs (in terms of frequency and amplitude) at a sequence of resting periods (pre and post of various stimuli). NS.EDRs parameters were recorded from 20 subjects simultaneously in the same skin area. They were computed at resting periods before and following specific responses due to five external stimuli. The study results indicated that there were differences in the frequency and amplitude of NS.EDRs recorded at different resting periods. Additionally, the frequency of NS.EDRs obtained before stimuli were more than those detected at other resting periods, whereas amplitudes of NS.EDRs following sound stimulus were higher than those computed before and after other stimuli; however, these results were statistically nonsignificant (p>0.05). This study suggests that nonspecific skin potential responses (NS.SPRs) are very sensitive to capture variations in the frequency and amplitude of NS.EDRs, whereas nonspecific skin susceptance responses (NS.SSRs) are the least sensitive compared to nonspecific skin conductance responses (NS.SCRs) and NS.SPRs. NS.EDRs may be an important indicator for tracking arousal, emotional behavior, psychophysiological variables, and goal-directed thinking in clinical applications due to their sensitivity to such responses.

2024-02

Journal of electrical bioimpedance (Issue : 1) (Volume : 15)

Moisturizers are cosmetic compounds designed to increase the moisture content of the skin. There are many types of these products in the market making it difficult for consumers to select the most effective moisturizer according to their age and gender. Hence, the aim of this study was to evaluate the effects of different moisturizers on skin hydration as well as to figure out any dependencies of the effects of these products on age or gender-related differences. We investigated the short-term moisturizing effects of five different skin moisturizers on 60 participants by using a low frequency electrical instrument. Skin surface susceptance was recorded and compared before and after the application of moisturizers. Statistically significant differences were observed in the moisturizing effect among different types of products. However, with respect to gender and age differences, there were insignificant differences in the effects of the moisturizers. Results of this study suggest that some types of moisturizers that exist in the markets are not as effective as required, which calls for a further evaluation of the moisturizers before entering markets and offering them for sale. In addition, findings suggest that gender or age differences are perhaps not important to consider in the application of moisturizers.

2024-02

International Biological & Biomedical Journal (Issue : 3) (Volume : 9)

Psychological stress can play a crucial role in detrimental physiological and functional consequences on the skin. Psychological stress cannot be monitored directly, hence in this study, we tried to monitor stress via recording some biophysical parameters of the skin (skin moisture, skin sebum (oil), and skin temperature) and compared to stress levels assessed based on Perceived Stress Scale. Skin biophysical parameters were recorded from 20 subjects, which experienced three different psychological stress levels. The answers to the Perceived Stress Scale questionnaire were used to assess the subject's stress levels. Skin moisture, sebum, and temperature were reduced as a function of psychological stress levels. However, statistically, no significant differences were observed among the three levels of stress. This study illustrated that different psychological stress levels led to a reduction in biophysical parameters of the skin. These findings suggest that the skin parameters might be used as a method for monitoring psychological stress.

2023-09

Sensor (Issue : 19) (Volume : 23)

Electrodermal activity (EDA) usually relates to variations in the electrical properties of palmar or plantar skin sites. EDA responses, namely skin conductance responses (SCRs), skin potential responses (SPRs) and skin susceptance responses (SSRs) are shown to be sensitive indexes of sympathetic nervous system activation and are studied in many research projects. However, the association between EDA responses and the five basic human senses has not been investigated yet. Our study aimed to explore the relationship between the three EDA responses (SCRs, SSRs and SPRs) and the five basic human senses. These three EDA responses were measured simultaneously at the same skin site on each of the 38 volunteers. The tested five senses were sight, hearing, touch, taste and smell. The results showed that the different tested senses led to different degrees of EDA responses due to activation of the sympathetic nervous system and corresponding secretion of sweat. Although a controlled study on the degree of EDA as a function of the strength of each stimulus was not performed, we noted that the largest EDA responses were typically associated with the smell sense test. We conclude that EDA responses could be utilized as measures for examining the sensitivity of the human senses. Hence, EDA devices may have important roles in sensory systems for future clinical applications.

2023-07

Fresenius Environmental Bulletin (Issue : 7) (Volume : 32)

Using sunscreens with a different sun protection factor (SPF) has been advocated by many health care practitioners as a means to protect the skin from damage caused by ultraviolet (UV) radiation from sunlight. There is a need to better understand the changes that occur in the skin's Biophysical parameters following the application of sunscreen products. The main objective of this study was to know the influence of sunscreen with various SPF on some skin biophysical parameters. In the present study, we investigated the effects of sunscreen on skin moisture, oil, and pH in 20 subjects. Skin conditions such as moisture, oil, and pH were measured and compared before and after the application of sunscreen. Statistically significant differences were observed in skin moisture and pH. There were also inter-individual differences but, with respect to gender differences, only skin pH was significantly different. According to the study results, applying sunscreen with SPF 50 on the skin was found to have a better profile of biophysical parameters than the sunscreens of low SPFs. Therefore, it can be concluded that a chemical sunscreen with SPF 50 is probably the optimal level to protect the skin from the damage of exposure to the sun's UV rays

2023-07

THE JOURNAL OF THE INTERNATIONAL ORGANIZATION FOR MEDICAL PHYSICS (Issue : 1) (Volume : 11)

Monitoring radiation exposure to patients experiencing CT is an ongoing concern to the scientific community. Using SSDE is more feasible than CTDIvol for setting reference levels for diagnostics. The negligence of volume in CTDIvol makes it challenging to check the reasonableness of its values when comparing thin or obese patients, so CTDIvol must be compared with SSDE to inspect the reasonableness of the CTDIvol value output by the scanner. The aim of this research is to efficiently estimate the SSDE index of a the chest and abdominal CT scans.

2022-08

Eastern Journal of Medicine (Issue : 3) (Volume : 27)

Recent development in technology and the release of powerful techniques among them virtual reality can help investigate various aspects of life. With 3D virtual reality technology, the influences of acceleration stress on arterial oxygen saturat ion (SpO2) and heart rate (HR) can be predicted. This study explored the correlations among acceleration stress, HR and SpO 2. HR and SpO2 were recorded from 20 healthy subjects (10 males and 10 females) during relaxation and positive and negative acceleration stress. They were university and secondary school students with the mean age (21.71± 2.54 yrs.) for university and (12.2± 1.1 yrs.) for secondary students. It was found that, both HR and SpO2 are changed with acceleration stress, but that the change was not statistically significant (p>0.05). Males have lower HR and higher SpO2 than females, and adults have lower HR and higher SpO2 than children. Findings of the study suggest that acceleration stress, at least within the range studied in the present study, could produce effects on the HR and SpO2. Future studies could aim to better categorize stress levels in virtual reality for thrill Seekers based on more psychological variables.

2022-07

Physiological Measurement (Issue : 6) (Volume : 43)

Objective. Electrodermal Activity (EDA) is a reliable indicator for variations in the skin electrical properties attributed to sympathetic nerve system activity. EDA recordings can be influenced by various internal and external factors including environmental ones. Ambient temperature can be considered as one of the possible factors which might influence EDA recordings. Hence, this study aimed to precisely investigate influence of ambient temperature on tonic and phasic EDA components by employing a new EDA measurement technique, which depends on simultaneously recording of several EDA parameters. Approach. Tonic and phasic EDA components during three different ambient temperature levels were recorded from 36 healthy participants. In addition, for evoking electrodermal responses, participants were exposed to cognitive, visual and breathing external stimuli. Main results. Significant effects of temperature on tonic skin conductance (SC), skin susceptance (SS) and skin potential (SP) were obtained, whereas such significant effects were not observed with phasic SC, SS and SP. Tonic EDA parameters were increased as a function of temperature, but changes in phasic component were fluctuating. Significance. This should mean that, keeping recording of tonic EDA component in normal room temperature is highly crucial, but for recording or analysis of phasic component it is not important as they are more robust in this context. This is important in applications of EDA instruments, particularly in wearable devices where environmental temperature typically cannot be controlled

2022-05

Journal of Electrical Bioimpedance (Issue : 1) (Volume : 13)

The coronavirus epidemic 2019 is spreading all over the world now. Several parameters are used to monitor the status of hospitalized patients; however, monitoring variations in biophysical properties of the skin has not been investigated yet. In this preliminary study, we seek to monitor skin biophysical parameters among coronavirus patients for three days in a row. Skin moisture, pH, sebum, and temperature during the three days were monitored in 30 coronavirus patients by using non-invasive portable instruments. Skin biophysical parameters were increased on the third day of monitoring compared to the first one. In addition, the increase in both skin moisture and temperature were statistically significant. According to the results of this preliminary study, skin biophysical parameters changed (increased) during the specified period in which the patients were monitored. However, changes in skin sebum content and pH were not significant. These skin parameters need to be further investigated until we know their indication ability for the health condition of coronavirus patients in clinical applications.

2022-02

Biomedical Human Kinetics (Issue : 1) (Volume : 14)

Study aim: The COVID-19 pandemic has unhinged the lives of people across the globe, in particular, university students who are home-schooling. No study has investigated the influence of specific parameters on reaction time (RT) among university students during the COVID-19 pandemic. The current study aims to describe the relationship between RT and parameters (types of stimuli, handedness, and gender differences) that may affect its values during the COVID-19 pandemic. Material and methods: RT of 60 volunteers to visual and auditory stimuli were recorded using the drop ruler method. RT was compared within-subject with respect to handedness and type of stimulus, and between subjects with regards to gender. Results: Although a small difference between RT reported as a function of hands and gender was observed, these results were statistically insignificant. However, females had a significant shorter RT to visual than the auditory stimulus. Conclusions: Findings showed that no significant differences were obtained between all comparisons made, except between females RT to visual stimulus and auditory stimulus. This can be attributed to the high level of stress and anxiety that may occur among students due to the COVID-19, which is the most prevalent and dangerous topic for university students, especially female students.

2021-11

International Journal of Online and Biomedical Engineering (Issue : 12) (Volume : 17)

Continues wearing gloves is a crucial problem among health care workers treating patients with coronavirus (COVID-19) infection that may cause skin complications. In the present study, the skin conductance (SC), skin potential (SP) and skin susceptance (SS) were used to identify the effects of long-term wearing gloves among health care workers managing COVID-19. The experimental procedure was repeated 30 times on three subjects recruited as volunteers to wear gloves for 4 hours. The baseline of parameters SC, SP, and SS were recorded at normal conditions without wearing the glove at zero time (To). The parameters were again recorded in the cases of glove-wearing with and without zinc oxide ointment (ZnO) for the same period. Noticeable differences were found in each of SC, SP and SS for subjects who wore gloves when compared to the baseline for 4 h. Results also showed significant differences in each of SP and SS during the same period with applying ZnO comparing to wearing gloves without applying ZnO. The results show that skin hydration is significantly improved by using ZnO and changing gloves at least every four hours of continuous wearing is recommended. However, due to the small sample size and the specific study population, the results cannot be generalized to all ages of health workers.

2020-12

Skin Research and Technology (Issue : 1) (Volume : 27)

Background/aim: The skin conductance responses (SCRs) are a well-accepted indicator of physiological arousal for both research purposes and clinical approaches. The shape of SCRs is analyzed by various features. However, the estimation of how much (in %) one feature can explain another is still an open issue. The aim of this study was to assess whether variation in one SCR feature predicts changes in other features. Methods: Skin conductance (SC) was measured during relaxation and mental stress in 40 subjects. SCRs were induced by three external stimuli, which were deep breath, a mental arithmetic, task and a visual task. Results: The findings of this study showed that about 55% (R2 = 0.55) of the variation in the half recovery time (SCRs_rec 50%) can be explained by the rise time (SCRs_ris), whereas variation in amplitude of the skin conductance responses (SCRs_amp) and the skin conductance level (SCL) is independent and cannot be explained by the other features, as R2 values obtained from all analyses among these SCR features in average were lower 0.19. Conclusions: The study results suggest that the two timing phases (SCRs_rec and SCRs_ris) are not completely independent from each other, although they might be governed by different sweating mechanisms (secretion and reabsorption). However, SCRs_amp and SCL were independent. These findings can help in choosing the optimal set of features of an automated system for processing EDA, which reflect the alterations in the activation level generated during an emotional episode.

2020-05

Journal of Biological Physics (Issue : 2) (Volume : 46)

Electrodermal activity (EDA) measurements are influenced by various factors. Age related psychological and physiological changes may be considered as one of the possible factors which may influence EDA measurements. In order to properly investigate the effects of such factors on EDA, techniques of precisely and simultaneously recording more than one EDA parameter are recommended. This study aims to explore the impact of age-related differences on EDA components through employing a new measuring technique, which is composed of a small front-end electronic box, DAQ card, and a laptop running LabVIEW software. It is dependent on the simultaneous recording of three EDA parameters: skin conductance (SC), skin potential (SP), and skin susceptance (SS) at the same skin site. EDA components as results of breathing, mathematical tasks, and image stimuli were recorded from 60 healthy participants simultaneously at the same skin site. They were categorized by age into young adults (ages 18–25), middle-aged adults (ages 30–40), and old adults (ages 50–70) years. It was found that skin potential responses (SPRs), and skin conductance level (SCL) (p < 0.001), were significantly decreased due to aging, but changes in other EDA parameters were nonsignificant (p > 0.05). Moreover, both tonic and phasic SS were the least affected and found to be more robust than SC and SP with respect to aging. The study suggests that it is important to take age into account in research studies where the mean aim of the study is to compare EDA parameters; however, in the meantime, the results from our small number and specific study population cannot be generalized to clinical applications.

2020-03

Science Journal of University of Zakho (Issue : 1) (Volume : 8)

Electrodermal activity (EDA) is a well-established psychophysiological measurement for research and clinical approaches. Males and females often display different physiological responses to stimuli, which can be detected by EDA recordings. Using a new method to measure skin conductance (SC), skin potential (SP) and skin susceptance (SS) simultaneously at the same electrode, these differences were investigated. SC, SP, and SS were recorded from 60 participants during relaxation and stress. It was found that both tonic and phasic EDA parameters indicated gender differences. In addition, female displayed greater tonic and phasic EDA parameters (except for skin potential responses (SPRs)) than males under both relaxation and conditions of stimulation (stress). However, these results were not statistically significant (p > 0.05). This suggests that it is perhaps important to consider gender or at least note type of gender in EDA researches, but this cannot be generalized to clinical approaches.

2019-12

Journal of Electrical Bioimpedance (Issue : 1) (Volume : 10)

Spontaneous fluctuations in electrodermal responses are known as nonspecific electrodermal responses (NS.EDRs). The use of NS.EDRs as a tool in applied psychophysiological research has resulted in a variety of publications. NS.EDRs are examined separately as associated with the (as a biomarker of) levels of anxiety. The aim of this study was to compare changes (in terms of amplitude, frequency and time components) in NS.EDRs at two different (pre and post of an external stimulus) resting phases. NS.EDRs (nonspecific skin conductance responses (NS.SCRs), nonspecific skin potential responses (NS.SPRs), and nonspecific skin susceptance responses (NS.SSRs)) were recorded from 50 apparently healthy volunteers simultaneously at the same skin area. They were scored as NS.SCRs and NS.SSRs for changes greater than 0.02 μS and NS.SPRs greater than 0.02 mV. It was found that NS.EDRs, in particular NS.SCRs and NS.SPRs, were significantly changed in the second resting period, following the specific stimulus. More specifically, the amplitude of NS.EDRs were significantly decreased for NS.SCRs (p<0.001) and for NS.SPRs (p<0.005), but NS.SSRs remained stable. Moreover, the rise time of NS.SCRs was decreased in the second resting time. Furthermore, the frequency of responses was also changed. The computed NS.EDRs, in particular NS.SCRs and NS.SPRs could be of psychological interest and be used to study the electrodermal responses in detail. NS.SSRs were found to be robust with respect to nonspecific stimuli at various relaxation periods and their role was found to be less important in analysis of NS.EDRs in comparison to NS.SCRs and NS.SPRs at low frequency (20 Hz AC current). This should be considered in analysis of NS.EDRs. The computed NS.EDRs, especially NS.SCRs and NS.SPRs may be used as a useful measure of arousal due to their fast response and sensitivity to nonspecific stimuli and may also be used in assessment of individual differences.

2019-12

Journal of Electrical Bioimpedance (Issue : 1) (Volume : 10)

A circuit is presented that enables measurement of skin electrical conductance, susceptance, and potential simultaneously beneath the same monopolar electrode. Example measurements are shown to confirm the function of the circuit. The measurements are also in accordance with earlier findings that changes in skin conductance and potential do not always correspond and hence contain unique information.

2018-11

Journal of Electrical Bioimpedance (Issue : 1) (Volume : 9)

Accurate assessment of experienced pain is a well-known problem in the clinical practices. Therefore, a proper method for pain detection is highly desirable. Electrodermal activity (EDA) is known as a measure of the sympathetic nervous system activity, which changes during various mental stresses. As pain causes mental stress, EDA measures may reflect the felt pain. This study aims to evaluate changes in skin conductance responses (SCRs), skin potential responses (SPRs), and skin susceptance responses (SSRs) simultaneously as a result of sequences of electrical (painful) stimuli with different intensities. EDA responses as results of painful stimuli were recorded from 40 healthy volunteers. The stimuli with three different intensities were produced by using an electrical stimulator. EDA responses significantly changed (increased) with respect to the intensity of the stimuli. Both SCRs and SSRs showed linear relationship with the painful stimuli. It was found that the EDA responses, particularly SCRs (p < 0.001) and SSRs (p = 0.001) were linearly affected by the intensity of the painful stimuli. EDA responses, in particular SCRs, may be used as a useful indicator for assessment of experienced pain in clinical settings.

2018-09

Skin Pharmacology and Physiology (Issue : 6) (Volume : 31)

Background/Aim: Electrodermal activity (EDA) is a widely used measure in psychophysiological research, and its use in wearable devices has grown in recent times. It is recommended to have proper conditions for EDA measurement, and skin hydration is one factor that has a significant influence. It is, however, not known to what extent the ambient humidity influences the recording. This study explored the influence of relative humidity (RH) on EDA levels, and also the responses using a new technique for simultaneous recording of all measures of EDA: skin conductance (SC), skin susceptance (SS), and skin potential (SP) at the same skin site. Methods: A total of 10 healthy subjects were exposed to environments of low and high RH while EDA measures were recorded, including cognitive, visual and breathing stimuli for evoking electrodermal responses of different origin. EDA levels and responses were compared between the two humidity levels for all stimuli and all EDA measures. Results: It was found that EDA levels, in particular for SC and SS, were significantly increased during high humidity exposure, but that the change in EDA responses (SC, SS, and SP) was not statistically significant ( p > 0.05, paired t test). Conclusion: This suggests that ambient humidity influences the recording of EDA levels and is important to consider when these parameters are used, but is not important in the recording or analysis of EDA responses.

2018-08

Second International Conference of Natural Sciences (Issue : 1) (Volume : 2)

Electrodermal activity (EDA) is a sensitive measure of sympathetic nervous system activity. It is used to describe changes in the skin electrical properties. This review aimed to show advantages of simultaneously recordings EDA parameters at the same skin site over other recordings. The literature databases Science Web, Google Scholar was searched using terms ‘electrodermal activity’, ‘sequentially recording’, ‘simultaneously recording’, ‘skin conductance’, ‘skin potential’, and ‘skin susceptance’. Articles that include sequentially and/or simultaneously recording EDA parameters were analyzed. The review presents a description of the oldest and current methods used for recording EDA parameters and an explanation of the newest techniques used in EDA researches. Although sequentially recordings are predominant and wide spread, much effort have been made to simultaneously record skin conductance (SC) and skin potential (SP), and recently researchers realized capability of simultaneously recording SC, SP, and skin susceptance (SS) at the same skin site. The advantage of simultaneous over the sequence measurements is that the latter must be manually time realigned when measured by different instruments which means time consuming. Although the simultaneous measurements are used exclusively for research purposes at this stage, this may open horizons in the modern trends of psychophysiology applications in the near future.

2017-08

Skin Research and Technology (Issue : 1) (Volume : 24)

Background/aim: Presently, electrodermal activity (EDA) is the preferred term for changes in electrical properties of the skin. Change in the skin conductance responses (SCRs) and skin potential responses (SPRs) due to external stimuli have previously been investigated in a number of studies, but very little for skin susceptance responses (SSRs) recorded simultaneously at the same skin site. This study aimed to investigate the association between the three parameters of EDA, skin conductance (SC), skin potential (SP), and skin susceptance (SS) responses generated by different types of psychological stimuli. Methods: SCRs, SPRs, and SSRs were recorded from 20 healthy test subjects simultaneously at the same skin area. EDA responses were induced by five different external stimuli, which were shown in the form of PowerPoint slides on a PC monitor that situated in front of participants. Results: All stimuli evoked EDA responses, but with significantly different magnitudes, dependent on stimulus type. Both SC and SP waveforms yielded positive responses with respect to the stimuli; however, SS showed negative response and its role was found to be significant at low frequency (20 Hz). Conclusions: This study illustrated that different discrete stimuli showed different passive and active electrodermal responses at the same skin site. SCRs, SPRs, and SSRs were dependent on the stimulus type, and the highest response was associated with the sound stimulus, which can be attributed to orienting response or startle reflex. In addition, it was found that the SSRs have a significant contribution at 20 Hz. In spite of a high correlation found between average amplitude values of SCRs and SSRs, no significant association was seen between average amplitudes values of SPRs and SSRs, and between SCRs and SPRs.

2015-04

Journal of Modern Physics (Issue : 5) (Volume : 6)

During operating of the X-ray machines, if the protection of X-ray rooms is insufficient, not only the patient but also clinical staffs as well as public are exposed to high X-ray dosage and they are affected from X-ray related to the dose level. In the present survey, by testing the radiological leakage and scatter from X-rays machines in radiology departments of 7 randomly selected hospitals in Duhok governorate, the effects dose of X-ray to the both control panel area and the patients waiting or visiting area who are located near the radiography room, were measured. The dose was recorded for a range of peak kilovoltage (kVp) and mAs values to find efficiency of shielding materials (barriers) of radiography rooms for different X-rays level. The measurements were performed at one meter above the ground surface which was the same height of X-rays tube by using Gamma Scout dosimeter. From the measurement results, it was seen that the most hospitals barriers (doors and walls) were not appropriate to the standards except 2 hospitals. The maximum effective doses were measured in uncontrolled area of Khazer hospital which was 82.48 ± 0.73 mSv·yr−1 that was much more than the reference dose limits and in controlled area of Haval Banda Zaroka hospital which was 12.98 ± 0.16 mSv·yr−1. In result, the knowledge about the radiation dose affecting the radiologists and public in the selected hospitals was obtained, and by informing the radiologists and the hospitals managements, the necessary regulations would be planned.

2015-02

Medical Physics (Issue : 2) (Volume : 42)

Purpose: This study explores the possibility of using lead to cover part of the radiation therapy facility maze walls in order to absorb low energy photons and reduce the total dose at the maze entrance of radiation therapy rooms. Methods: Experiments and Monte Carlo simulations were utilized to establish the possibility of using high-Z materials to cover the concrete walls of the maze in order to reduce the dose of the scattered photons at the maze entrance. The dose of the backscattered photons from a concrete wall was measured for various scattering angles. The dose was also calculated by the FLUKA and EGSnrc Monte Carlo codes. The FLUKA codewas also used to simulate an existing radiotherapy room to study the effect of multiple scattering when adding lead to cover the concrete walls of the maze. Monoenergetic photons were used to represent the main components of the x ray spectrum up to 10 MV. Results: It was observed that when the concrete wall was covered with just 2 mm of lead, the measured dose rate at all backscattering angles was reduced by 20% for photons of energy comparable to Co-60 emissions and 70% for Cs-137 emissions. The simulations with FLUKA and EGS showed that the reduction in the dose was potentially even higher when lead was added. One explanation for the reduction is the increased absorption of backscattered photons due to the photoelectric interaction in lead. The results also showed that adding 2 mm lead to the concrete walls and floor of the maze reduced the dose at the maze entrance by up to 90%. Conclusions: This novel proposal of covering part or the entire maze walls with a few millimeters of lead would have a direct implication for the design of radiation therapy facilities and would assist in upgrading the design of some mazes, especially those in facilities with limited space where the maze length cannot be extended to sufficiently reduce the dose.

2014-12

Science Journal of University of Zakho (Issue : 2) (Volume : 2)

The aim of this study was to introduce a method to reduce the dose of the backscattered photons from a linear accelerator at the maze entrance of a radiotherapy room (RR). For this purpose a typical RR was designed and simulated using FLUKA Monte Carlo Code (version 2011.2b.1). The maze of a RR was the main focus for the study. Its walls including, floor and ceiling were lined with thin sheets of lead and stainless steel of 2 mm and 4 mm thicknesses respectively to find the most effective material and thickness for dose reducing. It was found that 2 mm lead sheet was able to reduce the dose at the maze entrance by more than 60 % and 4 mm 70 %. Whereas, 2 mm of stainless steel was able to reduce about 30% of the dose and 4 mm was able to reduce about 35%.