Aging and longitudinal change in perceptual-motor skill acquisition in healthy adults

Prevention of slip-related backward balance loss: the effect of session intensity and frequency on long-term retention

OBJECTIVE

To examine the effects of session intensity (number of slip exposures) and frequency on the retention of acquired adaptation for prevention of backward balance loss after repeated-slip training.

DESIGN

A 4-group, randomized, and controlled study.

SETTING

Biomechanics research laboratory.

PARTICIPANTS

Healthy young subjects (N=46; 21 men).

INTERVENTIONS

Twenty-four subjects experienced a high-intensity session of 24 repeated right-side slips; 12 received additional single-slip sessions at a frequency of 1 week, 2 weeks, and 1 month, whereas the rest got no ancillary training. Another 24 subjects received a low-intensity initial session of a single slip; 12 received the same high-frequency ancillary training, whereas the rest got none. All groups were retested with a single slip 4 months after the first session.

MAIN OUTCOME MEASURES

The incidence of backward balance loss, gait stability, and limb support.

RESULTS

The high-intensity groups, irrespective of ancillary training, displayed similar improvements in all 3 outcome measures. Remarkably, the low-intensity group receiving ancillary training also significantly improved in all measures, with retention comparable to that observed in the other 2 groups. A single-slip exposure without ancillary sessions was insufficient to yield a longer-term effect.

CONCLUSIONS

Frequent ancillary sessions may be unnecessary for slip-related fall prevention up to 4 months if the initial session intensity is sufficient. Furthermore, the minimum of a single slip may be as effective if the subject is exposed to frequent ancillary sessions.

Effects of sensorimotor adaptation training on functional mobility in older adults

The goal of this study was to determine if prolonged exposure to perceptual-motor mismatch increased adaptability and retention of balance in older adults. Sixteen adults, aged 66 to 81 years, were randomized to one of two groups: either the control group (n=8) or the experimental group (n=8). Both groups first completed six trials of walking an obstacle course. Participants then trained twice a week for 4 weeks. In the training, the control group walked on a treadmill for 20 minutes while viewing a static visual scene and the experimental group walked on a treadmill for 20 minutes while viewing a rotating visual scene that provided a perceptual-motor mismatch. Following training, both groups were post-tested on the obstacle course. The experimental group moved faster through the obstacle course with fewer penalties. This training effect was retained for 4 weeks. Exposure to perceptual-motor mismatch induced an adaptive training effect that improved balance and locomotor control in older adults.

Motor-skill learning in older adults—a review of studies on age-related differences

This paper reviews research on motor-skill learning across the life span with particular emphasis on older age. For this purpose, studies that focus on age-related differences in fine and gross motor skills and studies that analyze the further refinement of known skills as well as learning of unknown motor skills are summarized. The reviewed studies suggest that although motor performance tends to decline in old age, learning capabilities remain intact, and older adults are able to achieve considerable performance gains. The extent to which the learning capability varies with age, however, has to be considered very carefully. While most studies revealed that performance gains in fine motor tasks are diminished in older adults, results for gross-motor-skill learning are more contradictory. Additionally, there is considerable agreement on the finding that age-related learning differences are statistically more robust in complex tasks, whereas in low-complexity tasks, the learning of younger and older adults is very similar. This applies to fine and gross motor skills. Relative age differences seem to become enlarged when effortful resources are required for motor performance. Thus, the decline in motor learning that accompanies aging is task specific and not absolute.

The Model Human Processor and the older adult: parameter estimation and validation within a mobile phone task

The authors estimate weighted mean values for nine information processing parameters for older adults using the Card, Moran, and Newell (1983) Model Human Processor model. The authors validate a subset of these parameters by modeling two mobile phone tasks using two different phones and comparing model predictions to a sample of younger (N = 20; M-sub(age) = 20) and older (N = 20; M-sub(age) = 69) adults. Older adult models fit keystroke-level performance at the aggregate grain of analysis extremely well (R = 0.99) and produced equivalent fits to previously validated younger adult models. Critical path analyses highlighted points of poor design as a function of cognitive workload, hardware/software design, and user characteristics. The findings demonstrate that estimated older adult information processing parameters are valid for modeling purposes, can help designers understand age-related performance using existing interfaces, and may support the development of age-sensitive technologies.

Fragmented pictures revisited: long-term changes in repetition priming, relation to skill learning, and the role of cognitive resources

BACKGROUND

Whereas age-related declines in declarative memory have been demonstrated in multiple cross-sectional and longitudinal studies, the effect of age on non-declarative manifestations of memory, such as repetition priming and perceptual skill learning, are less clear. The common assumption, based on cross-sectional studies, is that these processes are only mildly (if at all) affected by age.

OBJECTIVE

To investigate long-term changes in repetition priming and age-related differences in identification of fragmented pictures in a 5-year longitudinal design.

METHOD

Healthy adults (age 28-82 years) viewed drawings of objects presented in descending order of fragmentation. The identification threshold (IT) was the highest fragmentation level at which the object was correctly named. After a short interval, old pictures were presented again along with a set of similar but novel pictures. Five years later the participants repeated the experiment.

RESULTS

At baseline and 5-year follow-up alike, one repeated exposure improved IT for old (priming) and new (skill acquisition) pictures. However, long-term retention of priming gains was observed only in young adults. Working memory explained a significant proportion of variance in within-occasion priming, long-term priming, and skill learning.

CONCLUSION

Contrary to cross-sectional results, this longitudinal study suggests perceptual repetition priming is not an age-invariant phenomenon and advanced age and reduced availability of cognitive resources may contribute to its decline.

Regional white matter and neuropsychological functioning across the adult lifespan

BACKGROUND

The current study utilized magnetic resonance imaging (MRI) to more fully elucidate the relationship among age, regional white matter, and neuropsychological functioning.

METHODS

One hundred ninety-nine neurologically healthy adults received MRI and standardized neuropsychological assessment. MR images were spatially normalized and segmented by tissue type; relative white matter values in each of the four cerebral lobes in each hemisphere were computed. Subjects were divided into Younger (ages 21-30), Middle (ages 31-54), and Older (ages 55-79) age groups.

RESULTS

The Older group had significantly less overall relative white matter than the Middle group, who had significantly less overall relative white matter than the Younger participants (F (2, 193) = 5.42, p = 0.005). Differences in frontal lobe white matter were of largest magnitude, followed by temporal lobe (F (6, 579) = 3.32, p = 0.003). Age and frontal and temporal lobe white matter were primarily associated with performance on neuropsychological tests of executive functioning and memory. Mediational analysis suggested that frontal lobe white matter mediated the relationship between age and performance on tasks of executive functioning and memory.

CONCLUSIONS

The results confirm age-associated decline in frontal and temporal white matter, and age-related cognitive decline in several domains. Decline in neuropsychological functioning is, in part, mediated by a relative age-related reduction in frontal white matter.

Motor plasticity in a juggling task in older adults-a developmental study

OBJECTIVE

to examine the plasticity of motor performance in old age. Older adults were instructed and trained in a juggling task and their performances were compared, first, within the group of older adults and, second, with the performances of children, youths and younger adults.

SUBJECTS

older adults, children, youths and younger adults (n = 1,206, range 6-89 years).

METHODS

participants were asked to learn a juggling task. Performance was tested before semantic instruction (pre-test 1), after semantic instruction (pre-test 2) and after 6 days of juggling practice (post-test). None of the participants had prior experiences in juggling. Results were analysed using repeated measure analysis of variance (ANOVA).

RESULTS

older adults showed a clear improvement in juggling performance after instruction and after six training sessions. On average, they reached performances comparable with those of children aged between 10 and 14 years, and with those of younger adults aged between 30 and 59 years. Only youths and younger adults aged between 15 and 29 years showed significantly higher performances at baseline, after instruction and after training.

CONCLUSIONS

older adults exhibit high reserve capacity, that is, a potential for learning 'new' motor skills.