Postural Steadiness and Ankle Force Variability in Peripheral Neuropathy

Paxton, Roger; Feldman-Kothe, Caitlin E.; Trabert, Megan K.; Hitchcock, Leah N.; Reiser, Raoul F.; Tracy, Brian

doi:10.1123/mc.2014-0072

Cited by 5 publications

(6 citation statements)

References 44 publications

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“…These findings agree with our similarly-designed studies in larger muscle groups such as the elbow flexors, knee extensors, ankle dorsiflexors, and ankle plantarflexors (Tracy et al, 2007 ; Welsh et al, 2007 ; Paxton et al, 2015 ). For example, in a study of the knee extensors that produced results very similar to the present work (Tracy et al, 2007 ), we showed that the normalized amplitude of force fluctuations during low force isometric contractions was 38% greater for older adults only when high gain visual force feedback was provided, compared with no visual feedback.…”

Section: Discussionsupporting

confidence: 91%

“…Furthermore, in our other study of the knee extensors in a similarly-aged subject sample, there was a 38% increase in the CV of force for older adults but no change for young adults during visual feedback compared with no visual feedback (Welsh et al, 2007 ). Also, in our recent study of dorsiflexors and plantarflexors of healthy older adults (mean age 73 years) and older peripheral neuropathy patients (mean age 75 years), we observed significant 1.3-fold to 2-fold increases in the CV of force during low-force isometric contractions when high gain visual feedback was provided (Paxton et al, 2015 ). The changes in young adults (mean age 23 years) were not significant for the dorsiflexors (11% increase, p = 0.22) or relatively small for plantarflexors (28% increase, p = 0.05).…”

Section: Discussionmentioning

confidence: 74%

“…The gain of visual feedback can be a significant determinant of the variability of force for older adults (Sosnoff and Newell, 2006b ; Tracy, 2009 ; Kennedy and Christou, 2011 ; Fox et al, 2013 ; Baweja et al, 2015 ). Accordingly, we performed studies in which young and older adults performed low force isometric contractions that were presented with either relatively high gain visual force feedback, or with no visual feedback (Tracy et al, 2007 ; Tracy, 2007b , 2009 ; Welsh et al, 2007 ; Paxton et al, 2015 ). In widely differing muscle groups (knee extensors, elbow flexors, ankle dorsiflexors, ankle plantarflexors), the older adults exhibited greater force variability compared with young adults only with visual feedback, with minimal age differences observed in the absence of visual feedback.…”

Section: Introductionmentioning

confidence: 99%

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Visuomotor Correction is a Robust Contributor to Force Variability During Index Finger Abduction by Older Adults

Tracy

Hitchcock

Welsh

et al. 2015

Front. Aging Neurosci.

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We examined aging-related differences in the contribution of visuomotor correction to force fluctuations during index finger abduction via the analysis of two datasets from similar subjects. Study (1) Young (N = 27, 23 ± 8 years) and older adults (N = 14, 72 ± 9 years) underwent assessment of maximum voluntary contraction force (MVC) and force steadiness during constant-force (CF) index finger abduction (2.5, 30, 65% MVC). For each trial, visual feedback of the force (VIS) was provided for 8–10 s and removed for 8–10 s (NOVIS). Visual gain of the force feedback at 2.5% MVC was high; 12- and 26-fold greater than the 30 and 65% MVC targets. Mean force, standard deviation (SD) of force, and coefficient of variation (CV) of force was calculated for detrended (<0.5 Hz drift removed) VIS and NOVIS data segments. Study (2) A similar group of 14 older adults performed discrete, randomly-ordered VIS or NOVIS trials at low target forces (1–3% MVC) and high visual gain. Study (1) For young adults the CV of force was similar between VIS and NOVIS for the 2.5% (4.8 vs. 4.3%), 30% (3.2 vs. 3.2%) and 65% (3.5 vs. 4.2%) target forces. In contrast, for older adults the CV of force was greater for VIS than NOVIS for 2.5% MVC (6.6 vs. 4.2%, p < 0.001), but not for the 30% (2.4 vs. 2.4%) and 65% (3.1 vs. 3.3%) target forces. At 2.5% MVC, the increase in CV of force for VIS compared with NOVIS was significantly greater (age × visual condition p = 0.008) for older than young adults. Study (2) Similarly, for older adults performing discrete, randomly ordered trials the CV of force was greater for VIS than NOVIS (6.04 vs. 3.81%, p = 0.01). When visual force feedback was a dominant source of information at low forces, normalized force variability was ~58% greater for older adults, but only 11% greater for young adults. The significant effect of visual feedback for older adults was not dependent on the order of presentation of visual conditions. The results indicate that impaired processing of visuomotor information underlies the greater motor variability observed in older adults during lab-based isometric contractions of a hand muscle.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Visuomotor Correction is a Robust Contributor to Force Variability During Index Finger Abduction by Older Adults

Tracy

Hitchcock

Welsh

et al. 2015

Front. Aging Neurosci.

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“…Significant correlations of lower extremity muscle strength to postural stability were detected in both groups, which is consistent with some previous studies ( 7 , 10 ) and inconsistent with another one ( 38 ), in which there was no correlation of ankle strength to postural stability was detected. However, only static postural stability was tested in their study, and postural control included static balance and dynamic balance ( 9 ).…”

Section: Discussionsupporting

confidence: 85%

Balancing sensory inputs: somatosensory reweighting from proprioception to tactile sensation in maintaining postural stability among older adults with sensory deficits

Ziyin

Wang

Sun

et al. 2023

Front. Public Health

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BackgroundSensory deficits increase the risk of falls among older adults. The purpose of this study was to investigate the correlations of lower extremity muscle strength, proprioception, and tactile sensation to postural stability among older adults with and without sensory deficits, to understand the contribution of each factor to postural stability, and to explore sensory reweighting among the two populations.MethodsA total of 103 participants were recruited and divided into two older adult groups with (female = 24, male = 26, age = 69.1 ± 3.15 years, height = 162.72 ± 6.94 cm, body mass = 64.05 ± 9.82 kg) and without sensory deficits (female = 26, male = 27, age = 70.02 ± 4.9 years, height = 163.76 ± 7.60 cm, body mass = 65.83 ± 10.31 kg), based on whether a 5.07 Semmes–Weinstein monofilament could be detected at foot soles. Their Berg Balance Scale (BBS), lower extremity muscle strength, proprioception, and tactile sensation were tested and compared between the two groups. Pearson's or Spearman's correlations were used to explore the relationships between the BBS and each variable. Factor analysis and multivariate linear regression were used to verify the degrees of correlation between the generated factors and the postural stability.ResultsLow BBS (p = 0.003, η2 = 0.088) scores and higher proprioception thresholds (knee flexion: p = 0.015, η2 = 0.059; knee extension: p = 0.011, η2 = 0.065; ankle plantarflexion: p = 0.006, η2 = 0.075; ankle dorsiflexion: p = 0.001, η2 = 0.106) were detected among older adults with sensory deficits compared with those without sensory deficits. Lower extremity muscle strength (ankle plantarflexion: r = 0.342, p = 0.002; hip abduction: r = 0.303, p = 0.041) and proprioception (knee flexion: r = −0.419, p = 0.004; knee extension: r = −0.292, p = 0.049; ankle plantarflexion: r = −0.450, p = 0.002; ankle dorsiflexion: r = −0.441, p = 0.002) were correlated with BBS among older adults without sensory deficits, while lower extremity muscle strength (ankle plantarflexion: r = 0.501, p<0.001; hip abduction: r = 0.302, p = 0.041) and tactile sensation (great toe: r = −0.388, p = 0.008; 5th metatarsal: r = −0.301, p = 0.042) were correlated with BBS among older adults with sensory deficits.ConclusionOlder adults with sensory deficits have poorer proprioception and postural stability. Somatosensory reweighting occurs from proprioception to tactile sensation among older adults with sensory deficits in maintaining postural stability.

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“…No or minimal age-related difference was observed for tasks performed in the absence of visual feedback. However, the age-related and vision-dependent increased force variability was mainly reported for large muscle groups (Tracy, 2007 ; Tracy et al, 2007 ; Welsh et al, 2007 ; Paxton et al, 2015 ). Here, Tracy et al showed age-related increase in force variability under high-gain visual feedback for an intrinsic muscle of the hand.…”

mentioning

confidence: 99%