Age-related slowing of movement as basal ganglia dysfunction

Abstract

Attributions of age-related deficits in motor function to structural changes are compromised once the elderly exhibit lower error rates. This is because performance decrements observed in older adults are attributed to inferred strategic preferences for accuracy over speed. To understand genuine age differences in performance, we argue in the following theoretical paper that research needs to resolve methodological shortcomings and account for them within theoretical models of aging. Accounts of aging need to directly manipulate or control strategic differences in performance while assessing structural deficits. When this is done, age-related changes in motor control resemble the intermittencies of control seen in basal ganglia disorders. Given homologous circuitry in the basal ganglia, such observations could generalize to age-related changes in cognitive and emotional processes.Keywords Aging . Slowing of performance . Strategy . Basal ganglia . Performance operating characteristics Psychomotor function is a major contributor to the independence of older adults. Unfortunately, accounts of psychomotor change with age are complicated by difficulties in unequivocally addressing age-related change. Although gerontologists may wish to identify real structural deficits that can account for the behavior of older adults, the ability to address these deficits is limited by the ability to draw inferences from observable behaviors in the light of potential strategic variation [13,14,15,19,31,75]. By structural changes, we mean physiological changes associated with brain structures, in this case, the basal ganglia and its associated functional circuitry (e.g., see [39], for a discussion of structural and functional basal ganglia changes associated with aging).Such difficulties then cause problems in the tractability of models of age-related deficits, and even when specific behaviors are readily observable, there may be problems of generalizability when extrapolating to other domains.Models are possible, but there are problems of testability. This is because performance differences may simply reflect a strategic preference for accuracy over speed. As there is a tendency for differences in strategy to be inferred from performance decrements, this undermines any attributions of age-related changes in performance to structural changes. For there to be progress in the understanding of genuine age differences in performance, accounts of aging need to address strategic differences in performance while assessing structural deficits. This theoretical paper therefore seeks to address these problems by incorporating strategic variation into accounts of age-related changes in performance, delineating means whereby this can be addressed theoretically. By means of a discussion of empirical research, this paper demonstrates how strategic differences can be managed through the use of performance operating characteristics. Such solutions are therefore tractable and testable. Studies that control strategy reveal that the psychomot...

Alterations of local functional connectivity in lifespan: A resting‐state fMRI study

“…For example, the FCs between DMN and FPN/attentional networks were increased in lifespan due to the dedifferentiation process of aging brain, occurrence of aging for late neurodevelopmental stages, and a compensatory for cognitive decline (Grady et al., 2016; Zhai & Li, 2019; Zonneveld et al., 2019). Meanwhile, the BGN was thought to be related to motor learning functions and the increased FC within BGN might suggest as a compensatory role of dysfunctions of motor learning, especially in Parkinson's disease‐related research (Lyman, Anguera, & Terman, 2011; Saling & Phillips, 2008). Furthermore, it was also found that the homologous basal ganglia circuitry was related to cognition and emotion (Saling & Phillips, 2008) and an increased FC within it might compensate high‐order cognition (Siman‐Tov, 2016).…”

“…Meanwhile, the BGN was thought to be related to motor learning functions and the increased FC within BGN might suggest as a compensatory role of dysfunctions of motor learning, especially in Parkinson's disease‐related research (Lyman, Anguera, & Terman, 2011; Saling & Phillips, 2008). Furthermore, it was also found that the homologous basal ganglia circuitry was related to cognition and emotion (Saling & Phillips, 2008) and an increased FC within it might compensate high‐order cognition (Siman‐Tov, 2016). In lifespan, the BGN might play a compensatory role to balance the dysfunction of other functional networks.…”

Bradykinesia in dystonic hand tremor: kinematic analysis and clinical rating

“…Age-related changes in the human brain’s functioning fundamentally affect the motor system, causing increased reaction time, low ability to control movements, and difficulties in learning new motor skills ( Frolov et al, 2020 ). The performance decrements observed in older adults are also attributed to inferred strategic preferences for accuracy over speed ( Saling and Phillips, 2008 ).…”

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