Somayeh Hafezi; Mohammadreza Doustan; Esmaeel Saemi
Abstract
. Introduction: The present study aimed to investigate the effect of anodal and cathodal brain tDCS and stimulus-response asynchrony on the backward-compatibility effect (BCE) in conditions of acute mental fatigue.Methods: The participants were 39 boys (20 to 24 years old). The instruments included ...
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. Introduction: The present study aimed to investigate the effect of anodal and cathodal brain tDCS and stimulus-response asynchrony on the backward-compatibility effect (BCE) in conditions of acute mental fatigue.Methods: The participants were 39 boys (20 to 24 years old). The instruments included the informed consent form, the Edinburgh handedness questionnaire, the dual reaction time instrument, the Stroop software, the visual analog scale to evaluate fatigue severity (VAS-F), and the tDCS device. The participants in the pre-test were tested in two conditions of non-fatigue and mental fatigue with a dual reaction time instrument. The tests consisted of two three-choice visual stimulus-response (letters and colors) with ten different stimulus onset asynchronies (SOAs). Then the subjects were randomly assigned to three Anodal, Cathodal, and Sham stimulation groups. The intervention consisted of four consecutive 20-minute sessions of tDCS stimulation on the DLPFC area. One day and four days after the last stimulation session, the tests were repeated. For inferential data analysis, Mixed Model ANOVA and One-way ANOVA tests were used at a significance level of 0.05.Results: The results showed that there is a difference between different SOAs in response time to the first stimulus (RT1) which is a representation of backward adaptation, and at lower SOAs, the RT1 is shorter. Also, there is a difference in RT1 at low SOAs between fatigued and non-fatigued conditions. However, the effect of cathodal and anodal tDCS on RT1 was very small.Conclusion: In general, the results showed that at least some central aspects related to the response can be processed in parallel. Fatigue also affects this parallel processing.
Kambiz Nouri; Seyede Nahid Shetab Booshehri; Mohammadreza Doustan
Abstract
Given the importance of preparation to respond to two stimuli in different sport conditions, the aim of this study was to investigate the effect of foreperiod and time intervals between two stimuli on psychological refractory period (PRP) in athletes. This study was semi-experimental with a within-group ...
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Given the importance of preparation to respond to two stimuli in different sport conditions, the aim of this study was to investigate the effect of foreperiod and time intervals between two stimuli on psychological refractory period (PRP) in athletes. This study was semi-experimental with a within-group design and fundamental-applied in terms of objectives. 50 male athlete students of Shahid Chamran University of Ahvaz (age range 22.47±1.45 years) were selected by convenience sampling method. A five-core processor ASUS notebook, Edinburgh Handedness Questionnaire, software and hardware to measure the psychological refractory period were used in this study. Participants responded to two visual (selective) stimuli that were presented with short time intervals as quickly as possible. Tests were conducted in dual tasks and single tasks in foreperiods of 1,2,4,8 s and time intervals of 100, 250, 500, 800 ms randomly. The data were analyzed using mean, standard deviation, within group analysis of variance at significance level (P<0.05). The results showed that the effects of foreperiod and the stimuli intervals were significant. The foreperiod of 1s and interval of 100 ms had the most psychological refractory period and foreperiod of 8s and interval of 800 ms had the lowest psychological refractory period. This study showed that the pattern of psychological refractory period was affected by experimental manipulation of the preparation processes when recognizing the stages of information processing. Contrary to the common belief that preparation time operates on premotor processes, in the present study preparation time operates on late motion processes and confirms the existence of processing bottlenecks in dual tasks
Hamideh Jahanbakhsh; Mehdi Sohrabi; Aireza Saberi Kakhki; Ezzat Khodashenas
Abstract
The aim of this study was to investigate the effect of a selected balance training program under dual and single-task conditions on working memory of children with developmental coordination disorder. The research method was semi-experimental and a pre-test-post-test- follow-up design with a control ...
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The aim of this study was to investigate the effect of a selected balance training program under dual and single-task conditions on working memory of children with developmental coordination disorder. The research method was semi-experimental and a pre-test-post-test- follow-up design with a control group. In this study, 39 boys with DCD were selected by the available sampling method and randomly assigned to three groups: Dual-task training (n=13), single-task training (n=13), and control (n=13). The two experimental groups performed a selected training program with two different conditions for 8 weeks. All subjects were evaluated in three stages of pre-test, post-test and follow-up test (two months after post-test) by the Corsi block-tapping test (working memory test). Data analysis using ANOVA with the repeated measure as well as one-way ANCOVA showed that in the post-test, working memory in dual-task group was superior to both single and control groups (P <0.05). Also, a significant difference was observed from pre-test to post-test in all experimental groups except the single task group in the extended block index and the control group. In the follow-up test, this superior was maintained only in the overall score index and the overall effort. Also, the single-task group was superior to the control group in the post-test (P <0.05). Due to the importance of executive function, using this selected exercise program to improve working memory can be a useful tool and is suggested for this group of children.
Hesam Iranmanesh; Elahe Arab Ameri; Ahmad Farrokhi; Hamideh Iranmanesh
Abstract
The aim of this study was to compare the effects of three types of balancetraining: single task, dual task under fixed priority instructional set (Fp) and dualtask under a variable priority instructional set (Vp) on the balance of the elderly.The participants were 36 elderly over 65 years old from Kerman ...
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The aim of this study was to compare the effects of three types of balancetraining: single task, dual task under fixed priority instructional set (Fp) and dualtask under a variable priority instructional set (Vp) on the balance of the elderly.The participants were 36 elderly over 65 years old from Kerman province whowere randomly divided into three groups (each 12 subjects) based on Burg pretestscores. The groups included single task, dual task under fixed priority and dualtask under variable priority. Experimental groups received 45 minutes of trainingsession, 3 sessions a week for 4 weeks. For data analysis, ANCOVA andBonferroni post hoc test were used at (P≤0.05). The results showed that asignificant difference between single task and dual task under fixed priority groupsand also between single task and dual task under variable priority (P=0.008 andP=0.000 respectively). There was no significant difference between dual task underfixed priority and variable priority groups (P=0.149). In addition, the results inTug test under dual task condition showed a significant difference between singletask and dual task under fixed priority groups and also between single task anddual task under variable priority groups and also between dual task under fixedand variable priority groups (P=0.035, P=0.033, P=0.000 respectively). Theresults showed that single and dual task balance training improved balanceperformance in the elderly but those who had training under dual taskoutperformed under single and dual task conditions.
Alireza Farsi; Behrooz Abdoli; Maryam Kaviyani
Volume 3, Issue 1 , June 2011, , Pages 43-55
Abstract
The aim of this study was to compare the effects of cognitive-attentional and cognitive-motor load on the performance of bimanual coordination skill. 31 female students (mean age 25+2 years) from Shahid Beheshti University attending were selected voluntarily and divided randomly into three groups: single ...
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The aim of this study was to compare the effects of cognitive-attentional and cognitive-motor load on the performance of bimanual coordination skill. 31 female students (mean age 25+2 years) from Shahid Beheshti University attending were selected voluntarily and divided randomly into three groups: single group (N=11), cognitive group (N=10) and cognitive-motor group (N=10). Single group participants performed bimanual coordination single task. Cognitive group participants performed bimanual coordination task simultaneously with number countdown task, and cognitive – motor participants performed bimanual coordination task simultaneously with feet reaction time task. Two hand coordination of Vienna test system was used to assess the performance of bimanual coordination task. One – way ANOVA and Tukey post hoc test were used to analyze data. Statistical significance level was p
