Relationship between chopstick manipulation and cross-sectional shape in the developmental stages from infancy to early school age.

Motor development was investigated in 114 children aged 4-9 years, and the effects of different cross-sectional shapes of chopsticks (octagonal, square, and triangular) on manipulation ability were examined. Children's chopstick manipulation was found to be related to the developmental stage and their way of holding them. Manipulation was enhanced when they transmitted the optimal force to the tips when closing, the bottom chopstick was stabilized when opening, and the upper chopstick was encouraged to rotate moderately. In addition, opening chopsticks is more difficult than closing them. Square chopsticks increase the force of the tips, whereas octagonal chopsticks encourage more rotation of the upper chopstick, indicating that differences in the ability to manipulate chopsticks during development affect the preference for cross-sectional shapes. We plan to examine the effectiveness of chopsticks with different cross-sectional shapes of the upper and bottom chopsticks by focusing on the opening operation.

The effect of different visual stimuli on reaction times: a performance comparison of young and middle-aged people.

[Purpose] Here, we evaluated the reaction times of young and middle-aged people in different tasks. [Participants and Methods] The study included 23 young and 28 middle-aged volunteers. Their reaction times were measured in three tasks featuring different symbols (arrow and figure symbols) and spatial attributes (left, right, and ipsilateral choices). [Results] No significant inter-group differences in the reaction times were found for the simple reaction time task. In the choice reaction time and go/no-go reaction time tasks, the middle-aged participants demonstrated significantly slower reaction times. When the correct response was congruous with the direction of an arrow stimulus, the reaction times were shortened significantly among the middle-aged participants. In the go/no-go reaction time task, the reactions were delayed due to an inhibition of responses to upcoming stimuli. [Conclusion] The slower reaction time of the middle-aged participants in the choice reaction time task suggested that their responses were guided by the arrow stimulus to a greater extent compared to that of the younger participants. In the go/no-go reaction time task, the reaction times may have been slower in middle-aged participants because of a non-response possibility, which meant that participants had to first check the stimulus before deciding whether to respond.

Quantitative evaluation of handwriting: factors that affect pen operating skills.

[Purpose] The purpose of this study was to present control data on writing pressure, the amount of weight on the upper limb, joint angle, and the area of overlap from the sample in graphic tracing tasks, and to extract factors that affect pen-operating skills. [Participants and Methods] The participants included 35 healthy volunteers who performed 1-inch graphic tracing and writing. The measurements were recorded under two conditions as follows: strong and weak writing pressure tasks, and fast and careful writing speed tasks. [Results] In the writing pressure task, increase in pen pressure was accompanied by increase in hand pressure; however, the forearm pressure did not change. In the writing speed task, no significant difference in pressure was observed, except for a slight difference in writing pressure. The degree of variation in pen pressure and areas of overlap were greater in the fast task than in the careful task. Two multiple regression models revealed the contributing factors to pen-operating skills, both showing that the degree of variation in pen pressure was significantly involved. [Conclusion] The multiple regression analysis results showed that pen-operating skills can likely be evaluated, where the degree of variation in writing pressure is an index for deciding the effect of treatment intervention.