Aging causes a reorganization of cortical and spinal control of posture

Papegaaij, Selma; Taube, Wolfgang; Baudry, Stéphane; Otten, Egbert; Hortobágyi, Tibor

doi:10.3389/fnagi.2014.00028

Cited by 156 publications

(156 citation statements)

References 154 publications

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“…Other responsible factors were not directly determined but may be explained by age and disease-associated impairments. The selective atrophy of type II fibres with advancing age may partly explain poorer performance at high speeds 24 . Interestingly, muscles biopsies from persons with PD have shown increased type-I fibres and decreased type-II 25 .…”

Section: Discussionmentioning

confidence: 99%

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Work and power reduced in L-dopa naïve patients in the early-stages of Parkinson’s disease

Lima

Cardoso

Teixeira-Salmela

et al. 2016

Arq. Neuro-Psiquiatr.

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Parkinson's disease (PD) is a neuro-degenerative disease in which the progressions of the symptoms are associated with progressive loss of strength and power, which leads to deterioration of physical abilities 1,2 . Studies that employed measures of peak torque have observed muscular deficits in individuals at various stages of PD, mainly in the intermediate and advanced phases 3,4 . Usually, these individuals demonstrated bilateral motor impairments, which are associated with deficits in balance and gait and may contribute to immobility and poorer functional performance 5 .Recently, studies have found that in the early stages, individuals with PD already demonstrate cognitive decline 6 , impaired planning 7 , altered dynamic postural control 8 , and functional losses when compared to those without the disease 9 . In addition to these impairments, it is possible that muscle deficits may also contribute to the functional losses. However, few studies have investigated muscular performance in individuals in the early stages of PD. Bridgewater and Sharpe 10 showed decreases in trunk extensor torque during the early-stages of PD, which could contribute to the flexed posture observed in the advanced stages. Koller and Kase 11 observed decreases in the maximal isotonic knee strength of individuals in the early stages of the disease; however, the hip and ankle muscular groups were not assessed. Furthermore, several studies have AbstrACtStudies which have investigated muscular performance during the initial stages of Parkinson´s disease (PD) without L-dopa treatments were not found. Objective: to assess whether muscular performance, work and power, of the trunk and lower limbs in L-dopa naïve patients in the early stages of PD was lower than those of healthy subjects and to compare muscular performance between the lower limbs. Method: Ten subjects with PD, Hoehn and Yahr (HY) I-II, L-dopa naïve and 10 subjects in the control group were assessed with the isokinetic dynamometer. Results: ANOVAs revealed that work and power measures of the trunk, hip, knee, and ankle muscular groups were lower in PD compared with the control group (p < 0.05). There were no significant differences in muscular performance between the lower limbs. Conclusion:The results suggested the use of specific exercises, as rehabilitation strategies, to improve the ability to produce work and power with this population.Keywords: Parkinson's disease; muscle strength; Muscle strength dynamometer; rehabilitation; physical therapy speciality. resumo Estudos que investigaram o desempenho muscular durante os estágios iniciais da doença de Parkinson (DP), sem tratamento com L-dopa não foram encontrados. Objetivo: Avaliar se o desempenho muscular, por meio de medidas de trabalho e potência, do tronco e dos membros inferiores em pacientes sem o uso de L-dopa nas fases iniciais da DP é menor do que o de indivíduos saudáveis e comparar o desempenho muscular entre os membros inferiores. Método: Dez indivíduos com DP, Hoehn and Yahr (HY) I-II, sem L-dopa e 10 indiv...

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Section: Discussionmentioning

confidence: 99%

“…In the ankle, age induces neural changes as decline of 39% in estimated motor unit number in the tibial anterior. However, this can be compensated by collateral reinnervation of muscle fibers and larger size of the remaining motor untis 24 . So, this could contribute to a better ankle performance compared to the hip.…”

Section: Discussionmentioning

confidence: 99%

Work and power reduced in L-dopa naïve patients in the early-stages of Parkinson’s disease

Lima

Cardoso

Teixeira-Salmela

et al. 2016

Arq. Neuro-Psiquiatr.

View full text Add to dashboard Cite

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“…However, it remains elusive if the motor cortical control differs between voluntary and postural contractions and if age affects this control (Papegaaij et al, 2014a).…”

Section: Introductionmentioning

confidence: 99%

Postural challenge affects motor cortical activity in young and old adults

Papegaaij

Taube

Keeken

et al. 2016

Experimental Gerontology

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When humans voluntarily activate a muscle, intracortical inhibition decreases. Such a decrease also occurs in the presence of a postural challenge and more so with increasing age. Here, we examined age-related changes in motor cortical activity during postural and non-postural contractions with varying levels of postural challenge. Fourteen young (age 22) and twelve old adults (age 70) performed three conditions: (1) voluntary contraction of the soleus muscle in sitting and (2) leaning forward while standing with and (3) without being supported. Subthreshold transcranial magnetic stimulation was applied to the soleus motor area suppressing ongoing EMG, as an index of motor cortical activity. The area of EMG suppression was~60% smaller (p b 0.05) in unsupported vs. supported leaning and sitting, with no difference between these latter two conditions (p N 0.05). Even though in absolute terms young compared with old adults leaned farther (p = 0.018), there was no age effect or an age by condition interaction in EMG suppression. Leaning closer to the maximum without support correlated with less EMG suppression (rho = −0.44, p = 0.034). We conclude that the critical factor in modulating motor cortical activity was postural challenge and not contraction aim or posture. Age did not affect the motor control strategy as quantified by the modulation of motor cortical activity, but the modulation appeared at a lower task difficulty with increasing age.

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“…But it remains possible that adaptations in the spinal cord in older adults may have compensated for reductions in cortical adaptations. However, evidence suggests that neuroplasticity at the level of the spinal cord is reduced in older adults (see Papegaaij et al, 2014 for review), which argues against this possibility. This study was the first to measure training-induced changes in corticospinal excitability and behavioural performance bilaterally in young and older adults at multiple time points post training.…”

Section: Cross-limb Transfer Of a Simple Motor Skill Is Maintained Inmentioning

confidence: 99%

“…Moreover, plasticity within the spinal cord appears to be reduced with advancing age (see Papegaaij, 2014 for review). Therefore, any contribution of spinal adaptations to corticospinal plasticity is likely to be attenuated in older adults.…”

Section: Why Was Corticospinal Plasticity Not Reduced In the Target Hmentioning

confidence: 99%

Is plasticity in the human motor cortices altered in healthy older adults?

Dickins¹

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Neuroplasticity refers to the ability of the brain to alter its structure and function in response to the demands of its environment. Substantial evidence from studies in non-human animals suggests that neuroplasticity at the synaptic level is reduced in the aged brain. In humans, ageing is associated with cognitive and motor decline and some experimental evidence using non-invasive brain stimulation and motor training suggests that neuroplasticity is reduced in the motor cortex. It is also evident, however, that there is variability in age-related decline of motor performance and neuroplasticity across individuals. In the studies investigating neuroplasticity, little consideration has been given to changes occurring outside the targeted region, for example in homotopic regions of the contralateral hemisphere. This is an important limitation, as neuroimaging studies suggest that older adults exhibit more widespread activity both within and across the cerebral hemispheres, relative to young adults, when performing the same motor task. This finding suggests that additional neural populations may be recruited in older adults to assist in learning new motor skills. The aim of this thesis then, was to investigate whether the manifestation of neuroplasticity across the cerebral hemispheres is altered in older adults. To achieve this, three different protocols using skilled training or non-invasive brain stimulation were employed to experimentally induce neuroplasticity primarily in the primary motor cortex (M1). These protocols have been shown to induce changes with characteristics that resemble long-term potentiation (LTP) and long-term depression (LTD) in animal models, which is the candidate mechanism for synaptic plasticity. In each study neuroplasticity effects were probed by measuring changes in corticospinal excitability in bilateral coritcospinal pathways (corticospinal plasticity) using single-pulse transcranial magnetic stimulation (TMS) and motor-evoked potentials (MEPs).In the first study young and older participants were trained on a simple and complex motor task.The degree to which performance improvement transferred from the trained to the untrained hand and the extent to which this reflected changes in the distribution of corticospinal plasticity across the hemispheres were assessed. Both groups demonstrated performance improvements in the trained and untrained hand, although performance improvement in the trained hand was smaller in older adults. The percentage transfer from the trained to the untrained hand was comparable between young and older adults. Importantly, after training on the simple task, corticospinal excitability increased bilaterally in both young and older adults, a similar trend was also observed with the complex task. This result indicates that corticospinal plasticity, its manifestation in bilateral corticospinal pathways, and its relation to behavioural performance was comparable between young and older adults.iii In a second study, intermittent theta burst stimulation (iT...

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Aging causes a reorganization of cortical and spinal control of posture

Cited by 156 publications

References 154 publications

Work and power reduced in L-dopa naïve patients in the early-stages of Parkinson’s disease

Work and power reduced in L-dopa naïve patients in the early-stages of Parkinson’s disease

Postural challenge affects motor cortical activity in young and old adults

Is plasticity in the human motor cortices altered in healthy older adults?

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