This study was conducted to examine the effect of chronic low dose organic solvent exposures in the industries towards then neurobehavioral functions of workers subjective symptoms on neurobehavioral function as well as a visual reaction time test (Flicker test) were administered to 94 exposed and 162 unexposed workers in a oil refinery and some other auto-repair shops. The results obtained were as follows: 1. Symptom complaints were higher and Flicker test values were lower in exposed workers than in unexposed workers. 2. Flicker values were inversely correlated with urinary Hippuric acid concentration in exposed workers (r=-0.26, p<0.05). 3. Flicker values were inversely correlated with subjective symptom score (r=-0.15, p<0.05). Low Flicker value were also related with some subjective symptoms such as "Dimmed vision", "Nightmare", "weakness on extremity" in workers as a whole. While symptoms of "Dimmed vision", "Nightmare" only observed among exposed workers.
Reaction Time

This study aims to investigate visual tracking task of Koreans to the various visual stimuli by measuring the horizontal saccadic reaction times. The measuring system consists of eye monitor using infra-red reflection technique, oscillographic recorder and forehead-chin fixation devices. The visual stimuli generated by target function generator displayed simple-step, pulsestep and double-step stimulus patterns. The results revealed that the sacoadic reaction time showed no significant changes between the size of target displacement within horizontal 20 degrees. Furthermore, no significant changes between the particular direction of stimulus could be found. The nominal value of reaction time was 259 +/- 25 msec.
Reaction Time

Background: In the classical psychological refractory period (PRP) paradigm, two stimuli are presented in brief succession, and participants are asked to make separate speeded responses to both stimuli. Due to a central cognitive bottleneck, responses to the second stimulus are delayed, especially at short stimulus-onset asynchrony (SOA) between the two stimuli. Although the mechanisms of dual-task interference in the classical PRP paradigm have been extensively investigated, specific mechanisms underlying the cross-modal PRP paradigm are not well understood. In particular, it remains unknown whether the dominance of vision over audition manifests in the cross-modal PRP tasks. The present study aimed to investigate whether the visual dominance effect manifests in the cross-modal PRP paradigm. Methods: We adapted the classical PRP paradigm by manipulating the order of a visual and an auditory task: the visual task could either precede the auditory task or vice versa, at either short or long SOAs. Twenty-five healthy participants took part in Experiment 1, and thirty-three new participants took part in Experiment 2. Reaction time and accuracy data were calculated and further analyzed by repeated-measures analysis of variance. Results: The results showed that visual precedence in the Visual-Auditory condition caused larger impairments to the subsequent auditory processing than vice versa in the Auditory-Visual condition: a larger delay of second response was revealed in the Visual-Auditory condition (135 ± 10 ms) than the Auditory-Visual condition (88 ± 9 ms). This effect was found only at the short SOAs under the existence of the central bottleneck, but not at the long SOAs. Moreover, this effect occurred both when the single visual and the single auditory task were of equal difficulty in Experiment 1 and when the single auditory task was more difficult than the single visual task in Experiment 2. Conclusion Results of the two experiments suggested that the visual dominance effect occurred under the central bottleneck of cognitive processing.
Acoustic Stimulation ; Adolescent ; Adult ; Attention ; Auditory Perception ; Female ; Humans ; Male ; Photic Stimulation ; Reaction Time ; Refractory Period, Psychological ; Young Adult

15 parkinsonian patients with mainly unilateral symptoms (right side 10, left side 5) were studied in a decision reaction time (DRT) experiment in which the performance of the more affected hand was compared with that of the less affected hand. Decision time (DT) was longer in the more affected hand, however, the movement time (MT) did not differ between the two hands. In conclusion, slowness of movement in complex reaction response in Parkinsonian patients may be attributable to the defect of premovement central neural processing related to motor planning.
Hand ; Humans ; Reaction Time

OBJECTIVES: This study was conducted to examine the effect of blood mercury on neurobehavioral performance in Korean elementary school students. METHODS: We measured the blood mercury concentration in 1,077 elementary school students from Seoul, Busan, Daegu and Gwangju, then the students underwent computerized neurobehavioral test. RESULTS: The mean concentration of blood mercury of study subjects was 2.10 microg/L. An increased blood mercury was associated with an increased reaction time in digit addition and symbol digit. CONCLUSIONS: The blood mercury concentration of study subjects was very high compared to findings in a foreign country. We found several associations between blood mercury level and neurobehavioral performance.
Humans ; Reaction Time

To compare between the Worth 4-dot test(W4D) with polarized 4-dot test(P4D), we examined the interpretable response rate, response time, age of test failure, false positive rate and negative rate of reporting fusion in 133 patients older than 3 years of age. The interpretable response rate for W4D was 91% and for P4D 93.2%. The mean response times were 20.9 seconds for W4D versus 16.9 seconds for the P4D, the difference being statistically significant(p<0.05). The age of test failure for W4D was 4.8 years old and for P4D 3.8 years old. The false positive rate of reporting fusion for W4D was 4.5% and for P4D 8.8%. The false negative rate for W4D was 37.5%, while for P4D was 15.2%, the difference being statistically significant(p<0.05). In conclusion, the P4D was found to be less dissociative test by allowing more natural environment, and was easier, more rapid interpretable test. Therefore, the P4D may provide a more accurate assessment of a patients sensory status.
Humans ; Reaction Time

OBJECTIVE: To assess the clinical usefulness of computer- assisted line bisection task for the patients with sensory- attentional visuospatial neglect. METHOD: Forty patients with unilateral hemispheric stroke (25 right, 15 left) and 15 normal age-matched subjects participated in this study. Computer-assisted line bisection task (CALBT) was designed using modified Milner landmark test to assess the sensory-attentional aspect of visuospatial neglect. Accuracy of response and reaction time for the transected lines, and response rate for the bisected lines were measured. Correlation between the results of CALBT and conventional line bisection test and Albert test was evaluated. RESULTS: In patients with right hemispheric lesion, results of CALBT demonstrated shifting of attention to the right hemifield and neglect of the stimulus in the left hemifield. In contrast, patients with left hemispheric lesion showed significantly decreased attention to the right hemifield and shifting of attention to the left hemifield. Performances of CALBT correlated with the line bisection test, but not with the Albert test. CONCLUSION: Computed assisted line bisection task can be used for the quantitative assessment of the sensory attentional aspect of visuospatial attention in patients with unilateral neglect.
Humans ; Reaction Time ; Stroke

OBJECTIVES: The purpose of this study was to compare two subtypes of attention-deficit hyperactivity disorder (ADHD) and controls in their attention using ADHD diagnostic system(ADS), a kind of continuous performance test. METHODS: Subjects of this study were 8 children with ADHD-predominantly inattentive type, 28 children with ADHDcombined type and 20 control children. Ages ranged from 5 to 14 years. The Korean Educational Development Institute version of the Wechsler Intelligence Scale for Children(KEDI-WISC) and the ADS were administered to all subjects to provide measures of intelligence and attention. RESULTS: Significant differences were found in the ADS variables for the three groups. When compared with controls, the ADHD-predominantly inattentive type children scored significantly higher on the omission error at middle stage and later stage and ADHD-combined type children scored significantly higher on the omission error and reaction time at later stage. When compared with the other two groups, the ADHD-combined type children scored significantly higher on the commission error at all three stages. CONCLUSION: Our results suggest that the two subtypes of ADHD have different features in attention deficit. And there was a possibility that commission error is available variable to show cognitive characteristics of ADHD-combined type than any other ADS variables. Further studies are needed to evaluate this finding.
Child ; Humans ; Intelligence ; Reaction Time

No abstract available.
Real-Time Polymerase Chain Reaction*

An experimental investigation was conducted to explore visual reaction time and visual anticipation time between athletes and non-athletes. These visual perceptual skills form the base for cognitive processes required by the brain to respond instantaneously to a stimulus. A total of 228 adolescents, equally distributed between athletes and non-athletes, aged 13 to 16 years (mean age 14.69 ± 0.99 years) were examined. The visual reaction time and visual anticipation time were measured using a Lafayette Reaction Timer (Model 63035) and Bassin Anticipation Timer (Model 35575) respectively. The visual reaction time results revealed that athletes have faster reaction time scores as compared to non-athletes, whereas with visual anticipation time, athletes had fewer errors and a higher consistency compared to non-athletes. There was, however, no interaction between gender and sports participation noted for both these visual perceptual skills. These research findings indicate that gender was not an obstacle in sports participation, therefore not limiting the potential to excel in sports performance. Knowledge gained from these research findings will benefit the sports industry, specifically in athletic and sports training as well as provide a basis for the identification of an individual’s potential in their sports.
athletes ; non-athletes ; sports ; visual anticipation time ; visual reaction time