Biomedical subjects

Florian Schmiedek

Publications and source records attributed to Florian Schmiedek.

4 recordsLinked to original sources

PubMed2006

Dual-tasking postural control: aging and the effects of cognitive demand in conjunction with focus of attention.

Postural control in everyday life is generally accompanied by posture-unrelated cognitive activity. Thus, mild forms of dual-tasking postural control are the norm rather than the exception. Based on this consideration and available evidence, we propose and empirically examined, in young and old adults, a non-monotonic, U-shaped relation between the efficacy of postural control and concurrent cognitive demands that reflect opposing trends of the effects of attention focus and attentional resource competition. When instructed to perform an easy cognitive task that presumably shifted the focus of attention away from posture control, the center of body pressure (COP) excursions decreased both in young and older adults relative to a single-task baseline where the focus of attention was explicitly directed towards the postural control task itself. However, when performing more demanding cognitive tasks, older adults showed increased COP displacements, in line with the predicted U-shape function, whereas young adults did not. We outline mechanisms linking postural control to cognitive demand and suggest routes for future investigation.

Adult↗

PubMed2004

Toward an alternative representation for disentangling age-associated differences in general and specific cognitive abilities.

Much of cognitive aging research concerns whether age-associated differences in various cognitive performances can be accounted for by general explanatory constructs or whether several specific processes are involved. Structural equation models have been proposed to disentangle general and specific age-associated differences in cognitive performance. This article demonstrates that existing methods that employ stepwise procedures run the risk of biasing results toward general resource accounts. An alternative model representation (i.e., the nested factor model) is proposed that affords simultaneous estimation of general and specific effects and is applied to data from the Berlin Aging Study. Using the nested factor model allowed the authors to detect that specific group factors explained 25% of the age-associated variance in addition to the general factor.

Adult↗

PubMedDate not supplied

Age is not necessarily aging: another step towards understanding the "clocks" that time aging.

Hofer and Sliwinski raise a critical concern regarding a popular practice in aging research of inferring associations among aging changes of different processes from correlations based on cross-sectional age differences. It is shown analytically that cross-sectional information drawn from age-heterogeneous samples is not suitable for answering questions about the interdependence between aging changes. While in general we agree with the problem pointed out by Hofer and Sliwinski, the two aims of this commentary are: (1) to highlight links between the specific concern and two long-standing issues confronting life-span researchers and (2) to introduce alternative approaches that are currently underutilized in gerontological research. We elaborate general issues with respect to challenges in inferring aging changes from age differences and using age as a proxy for aging. We show that several other sources of variance independent of rates of change, such as cohort- and mortality-related selection effects, are confounded in age-heterogeneous designs. We suggest general considerations for developing more explicit theories of cognitive aging in the future. Alternative research methods and paradigms for studying the causes and mechanisms of the aging mind at different time scales and levels are also highlighted. The role of chronological age in aging research is rather "superficial". To understand the underlying processes and mechanisms of cognitive aging, classical process-oriented, rather than solely age-oriented, theoretical conceptions need to be reconsidered and reified with new methodological and empirical advances. Concerted gerontological research endeavors utilizing recent progresses made in statistical analyses of dynamic processes and in cognitive and computational neurosciences that may lead to fruitful breakthroughs.

Aged↗

PubMedDate not supplied

Aging and attenuated processing robustness. Evidence from cognitive and sensorimotor functioning.

BACKGROUND: Within-person, across-time variations in processes and performance are intrinsic to all aspects of human functioning. OBJECTIVE: This article starts with a brief taxonomy of intraindividual dynamics. There are adaptive as well as non-adaptive types of intraindividual variations that unfold with different degrees of reversibility on different time scales and involve either single, or systems of, functions. METHODS: Empirical findings regarding aging and a specific type of intraindividual variation, namely attenuated processing robustness, are then presented with respect to cognitive and sensorimotor functioning. RESULTS: In both domains of functioning, old adults exhibit less robust functioning with a greater amount of week-to-week, day-to-day, or trial-by-trial fluctuations in their cognitive, walking, and postural control performances. CONCLUSION: Currently, the causes for the attenuation of processing robustness in cognitive and sensorimotor functioning are not well understood. Neurocomputational models are useful tools for exploring the tripartite relationships between the aging of neural information-processing fidelity, and cognitive, and sensorimotor processes.

Aging↗