Voluntary vs Electrically Stimulated Activation in Age-Related Muscle Weakness

Clark, Brian C.; Manini, Todd M.; Wages, Nathan P.; Simon, Janet E.; Clark, Leatha A.

doi:10.1001/jamanetworkopen.2019.12052

Cited by 16 publications

(8 citation statements)

References 6 publications

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“…Previous research has shown that physical decline in the process of aging may be at least partly due to damage to the brain or nerve function, not just disorders of skeletal muscle, and the hippocampus might be involved in the regulation of human body functions ( Bland and Oddie, 2001 ; Clark et al, 2019 ). It is well known that the hippocampus is devoted to balance regulation and sensory motor integration ( Bland and Oddie, 2001 ), while the hippocampus body and anterior cingulate gyrus are involved in memory and executive function ( Mcgough et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

Deviations in Hippocampal Subregion in Older Adults With Cognitive Frailty

Wan

Lin

et al. 2021

Front. Aging Neurosci.

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BackgroundCognitive frailty is a particular state of cognitive vulnerability toward dementia with neuropathological hallmarks. The hippocampus is a complex, heterogeneous structure closely relates to the cognitive impairment in elderly which is composed of 12 subregions. Atrophy of these subregions has been implicated in a variety of neurodegenerative diseases. The aim of this study was to explore the changes in hippocampal subregions in older adults with cognitive frailty and the relationship between subregions and cognitive impairment as well as physical frailty.MethodsTwenty-six older adults with cognitive frailty and 26 matched healthy controls were included in this study. Cognitive function was evaluated by the Montreal Cognitive Assessment (MoCA) scale (Fuzhou version) and Wechsler Memory Scale-Revised Chinese version (WMS-RC), while physical frailty was tested with the Chinese version of the Edmonton Frailty Scale (EFS) and grip strength. The volume of the hippocampal subregions was measured with structural brain magnetic resonance imaging. Partial correlation analysis was carried out between the volumes of hippocampal subregions and MoCA scores, Wechsler’s Memory Quotient and physical frailty indexes.ResultsA significant volume decrease was found in six hippocampal subregions, including the bilateral presubiculum, the left parasubiculum, molecular layer of the hippocampus proper (molecular layer of the HP), and hippocampal amygdala transition area (HATA), and the right cornu ammonis subfield 1 (CA1) area, in older adults with cognitive frailty, while the proportion of brain parenchyma and total number of white matter fibers were lower than those in the healthy controls. Positive correlations were found between Wechsler’s Memory Quotient and the size of the left molecular layer of the HP and HATA and the right presubiculum. The sizes of the left presubiculum, molecular of the layer HP, and HATA and right CA1 and presubiculum were found to be positively correlated with MoCA score. The sizes of the left parasubiculum, molecular layer of the HP and HATA were found to be negatively correlated with the physical frailty index.ConclusionSignificant volume decrease occurs in hippocampal subregions of older adults with cognitive frailty, and these changes are correlated with cognitive impairment and physical frailty. Therefore, the atrophy of hippocampal subregions could participate in the pathological progression of cognitive frailty.

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Section: Introductionmentioning

confidence: 99%

Deviations in Hippocampal Subregion in Older Adults With Cognitive Frailty

Wan

Lin

et al. 2021

Front. Aging Neurosci.

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“…While declines in handgrip strength have been thought to be primarily attributed to agerelated changes in the muscular system, it has also been postulated that decreased handgrip strength is more a product of diminished neural and motor system capacity [15]. For example, during a strength capacity assessment, nervous system deficiencies may limit the amount of muscle force aging adults can generate to about half of what would be expected if the skeletal musculature were fully activated by the nervous system, primarily due to poor neuromuscular activation and motor unit recruitment [16,17]. The dysfunction observed in the neural and motor systems during aging that influence handgrip strength declines may also be linked to the incipient and progressing cognitive impairment [18].…”

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confidence: 99%

A Narrative Review of Handgrip Strength and Cognitive Functioning: Bringing a New Characteristic to Muscle Memory

Shaughnessy

Hackney

Clark

et al. 2020

JAD

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Background: Measures of handgrip strength have not only emerged as a clinically viable screening tool for determining risk for morbidity, functional disability, and early mortality, but also for helping to identify cognitive deficits. However, the phenomena that links low handgrip strength with cognitive decline remains unclear. The role of the muscular and neural systems, and their adaptations to muscle strengthening activities over the life course, may provide important information for how age-related changes to muscle mass, strength, and neural capacity influence cognition. Moreover, disentangling how handgrip strength and cognitive function are associated may help to inform healthcare providers working with aging adults and guide targeted interventions aiming to preserve muscle and cognitive functioning.Objective: To 1) highlight and summarize evidence examining the associations of handgrip strength and cognitive functioning, and 2) provide directions for future research in this area.Methods: Articles from the PubMed database were searched from November 2018-May 2019. The search term algorithm, inclusion and exclusion criteria were pre-specified by investigators.Results: Several cross-sectional and longitudinal studies have revealed that measures of handgrip strength were associated with cognitive declines regardless of age demographics and the presence of comorbidities.

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“…However, inferring information about muscle performance from voluntary contractions assumes that descending drive from the central nervous system is optimal 12,13 . While many individuals display high levels of voluntary activation, 14 this is not always the case, particularly in weaker older adults 15,16 and patients examined in clinical settings 17 . Furthermore, assessments of maximal strength during voluntary contractions assume that participants are motivated and compliant with the testing procedures 18 .…”

Section: Introductionmentioning

confidence: 99%

“…Its use provides investigators with a great deal of data. Specifically, by providing supramaximal electrical stimulation to a nerve/muscle group during a maximal effort contraction and at rest, the interpolated twitch technique can be used to parse out various voluntary and involuntary factors that may influence strength measurements 16,20,21 . Isolated measurements of involuntary torque are particularly useful in studying skeletal muscle, given that they are not reliant on voluntary effort, motivation, and central nervous system activity.…”

Section: Introductionmentioning

confidence: 99%

Is skeletal muscle echo intensity more indicative of voluntary or involuntary strength in young women?

et al. 2021

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Echo intensity has been associated with measures of muscle strength; however, associations between echo intensity and voluntary performance assume descending drive are optimal and participants are motivated. This study aimed to compare relationships between echo intensity versus involuntary and voluntary strength. Eighteen females (age = 21 ± 2 years) participated. Echo intensity was quantified from B‐mode ultrasound images obtained from the quadriceps femoris. Isometric maximal voluntary contractions (MVC) of the knee extensors were performed, and peak involuntary strength was assessed via the interpolated twitch technique. Pearson correlation coefficients evaluated relationships between corrected echo intensity, cross‐sectional area (CSA), MVC strength, and involuntary strength. A partial correlation assessed the association between corrected echo intensity versus peak involuntary torque while controlling for CSA and MVC torque. A stepwise multiple regression model was run with echo intensity as the dependent variable. Peak involuntary torque was the single best predictor of echo intensity (R = 0.580, P = .015). Importantly, involuntary and voluntary strength were not associated (r = .386, P = .126). Echo intensity was not significantly correlated with peak involuntary strength when controlling for CSA and MVC strength (r = −.474, P = .074). Echo intensity is likely more closely related to involuntary strength than voluntary strength.

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Voluntary vs Electrically Stimulated Activation in Age-Related Muscle Weakness

Abstract: This cross-sectional study compares voluntary neural activation of lower extremity muscles in clinically weak older adults vs stronger older adults.

Cited by 16 publications

References 6 publications

Deviations in Hippocampal Subregion in Older Adults With Cognitive Frailty

Deviations in Hippocampal Subregion in Older Adults With Cognitive Frailty

A Narrative Review of Handgrip Strength and Cognitive Functioning: Bringing a New Characteristic to Muscle Memory

Is skeletal muscle echo intensity more indicative of voluntary or involuntary strength in young women?

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