This study investigated age-related changes of how visual information affects control of body sway in community-dwelling older adults. The subjects were 637 older adults (263 males, 374 females) aged 67 to 91 years living in Nangai Village in Japan. The subjects, with shoes on, stood stationary and upright on a force platform with their feet together (Romberg stance) for 20 seconds with eyes open and eyes closed, respectively. Body sway length and body sway area were calculated as magnitude of body sway. The four parameters used to examine the effect of visual information on postural control were calculated. They were body sway length difference, body sway area difference, body sway length ratio, and body sway area ratio.The body sway length ratio and the body sway area ratio did not change with advancing age. The body sway length difference and body sway area difference changed with age. They increased with age from age 67 to 79, and then they decreased beyond 80 years of age. Measurements of all of the four parameters in the male subjects were significantly higher than those in the female subjects.
Four-year longitudinal changes in walking ability were examined in 510 older adults in a rural community in Japan. The participants walked on an 11-m walkway at their preferred and maximum speeds, and velocity, step length, step rate, and walk ratio (step length/step rate) were measured. Physical performance, including muscle strength, balance, and manual skill, was examined concur rently. An age-related decline in all variables except for step rate was confirmed in the longitudinal as well as cross-sectional data. The longitudinal decline accelerated for participants in their seventies and over, as compared to those in their sixties. Grip strength, balance, and manual speed, measured at the baseline, predicted relative changes in walking velocity over four years. The risk of mortality and instrumental ADL decline in four years were also predicted by maximum walking velocity at the baseline. These results suggest that the walking test has discriminant and predictive validities for assessing the physical functioning of community-dwelling older adults.
Spatial working memory (SWM) involves both simultaneous and sequential encoding, but the differences in their neural correlates are unclear. We investigated the differences in prefrontal cortex activity related to these SWM encoding types. We also examined the patterns of brain activity influencing individual visuospatial abilities (VSA). We conducted SWM tasks with two different conditions, sequential and simultaneous encoding, and examined hemodynamic activity in 39 healthy adults using near-infrared spectroscopy. The bilateral dorsolateral prefrontal cortex was activated more strongly in the sequential condition compared with the simultaneous condition. This suggests that prefrontal cortex activity underlying SWM is modulated by the type of encoding. We also found that individuals with high VSA showed weaker activation in the right-dorsolateral prefrontal cortex compared with those with lower VSA during the simultaneous condition. This hypoactivation is thought to reflect neural efficiency in the individuals with high ability. These findings are expected to lead to a better understanding of neural substrates for SWM.
In this cross-sectional study, differences in interference control, one component of executive function, were investigated among three age groups, 15 early childhood (7- to 8-yr.-olds), 25 middle childhood (9- to 12-yr.-olds), and 20 young adults (21- to 30-yr.-olds). Participants were administered a computer version of the Stroop color–word test with an oral response; correct responses, response time (RT), and the interference ratio were examined. The data indicated that (1) most of the participants showed no errors in word reading, color-naming, and incongruent color-naming tasks; (2) in word-reading and color-naming tasks, RT for 7- to 8-yr.-olds was longer than that for 9- to 12-yr.-olds, while RT of 9- to 12-yr.-olds and young adults were comparable; (3) in an incongruent color-naming task, RT for 7- to 8-yr.-olds was longer than RT for 9- to 12-yr.-olds, which was longer than RT for young adults; and (4) the interference ratio was higher in 7- to 8-yr.-olds than in 9- to 12-yr.-olds, which was higher than in young adults. These results suggested the difference in interference control between early and middle childhood reported on the go/no-go task and the stop-signal procedure would be observed in the Stroop color–word paradigm as well. The utility of this modified Stroop color–word test for those with intellectual and developmental disabilities was discussed.
This study was conducted to investigate the factors of one foot balancing and beam-walking in persons with intellectual disabilities (ID). There were 181 subjects with ID (male, 126; female, 55; 14 persons with autism; 22 with Down's Syndrome (DS)). One foot balancing was measured with eyes open and with eyes closed. In the beam-walking test, the subjects were asked to walk on five types of beam 3 meters in length. A stepwise multiple regression analysis was used to analyze the results. The dependent variables were the one foot balancing score (sec) with eyes open and with eyes closed and the beam-walking score (from 0 to 5), and the independents were sex, age, height (cm), weight (kg), IQ, presence/absence of autism, and presence/absence of DS. The results were as follows: (1) The one foot balancing with eyes open only related to IQ. Persons with a higher IQ showed a higher score in all the three balance tests than those with a lower IQ. The one foot balancing with eyes closed correlated with IQ and presence/absence of autism. Autistic subjects stood longer than persons with other IDs. The beam walking correlated with IQ, presence/absence of autism, and presence/absence of DS. Autistic subjects attained a higher score than subjects with other IDs, and DS subjects had lower scores. These characteristics of balance in subjects with ID are discussed in terms of executive function, motor dysfunction, and compensatory strategies.
For two paper–pencil versions of inhibitory tasks that require no reading skill, this study investigated the performance of young adults with no disability. Experiment 1 examined performance on same–different tasks by 42 participants. Three conditions were administered, all of which used geometric shapes: the same (no interference) condition, which asked each participant to check the same items as the target stimuli; the different(interference) condition, which asked to check the different items from the target stimuli while inhibiting the prepotent tendency of checking the same; and the motor condition, which measured motor speed. Results showed the highest performance in the motor condition and the lowest in the different condition. Experiment 2 examined performances of 43 participants on the flanker task, which asked participants to check the same arrow as the target placed in the middle of five arrows in line. Four conditions were administered: the same (no interference) condition, in which all five arrows pointed to the same direction; the different (interference) condition, in which the four arrows flanking the target pointed to the opposite direction against it; the partially different(interference) condition, in which one of the four arrows flanking pointed to the opposite direction; and the motor condition, which measured motor speed. Results showed the highest performance for the motor condition and the lowest for the different and partially different conditions, among which the differences were not significant. These results suggest that the two inhibitory tasks developed in this study are easy to administer and useful for people with little or no reading ability. Results demonstrate that the same–different task might be more inhibitory–demanding than the flanker task.
This study investigated 21 children with ASD to ascertain the effects of verbalization to others on cognitive planning in children with ASD. The Tower of Hanoi (ToH) test was administered in two conditions: solo and duo. Participants performed the ToH test using the normal method in the solo condition. In the duo condition, a participant was not allowed to touch the ToH apparatus, but was allowed to communicate about the procedure verbally to complete the ToH test. In children with ASD in this study, performance of the duo condition was not different from the solo condition. However, individual differences in the performance of the duo condition were observed. Participants were classifiable into three groups based on their performance. The results show that the roles of verbalization on cognitive planning in children with ASD are not homogeneous.
