Changes in corticomotor excitability of the calf muscles during postural tasks

The estimation of the body’s center of mass (CoM) trajectory is typically obtained using force platforms, or optoelectronic systems (OS), bounding the assessment inside a laboratory setting. The use of magneto-inertial measurement units (MIMUs) allows for more ecological evaluations, and previous studies proposed methods based on either a single sensor or a sensors’ network. In this study, we compared the accuracy of two methods based on MIMUs. Body CoM was estimated during six postural tasks performed by 15 healthy subjects, using data collected by a single sensor on the pelvis (Strapdown Integration Method, SDI), and seven sensors on the pelvis and lower limbs (Biomechanical Model, BM). The accuracy of the two methods was compared in terms of RMSE and estimation of posturographic parameters, using an OS as reference. The RMSE of the SDI was lower in tasks with little or no oscillations, while the BM outperformed in tasks with greater CoM displacement. Moreover, higher correlation coefficients were obtained between the posturographic parameters obtained with the BM and the OS. Our findings showed that the estimation of CoM displacement based on MIMU was reasonably accurate, and the use of the inertial sensors network methods should be preferred to estimate the kinematic parameters.

Download Full-text

Association between Oxygen Consumption and Surface Electromyographic Amplitude and Its Variation within Individual Calf Muscles during Walking at Various Speeds

Sensors ◽

10.3390/s21051748 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1748

Author(s):

Kohei Watanabe ◽

Shideh Narouei

Keyword(s):

Oxygen Consumption ◽

Spatial Variation ◽

Metabolic Response ◽

Correlation Coefficients ◽

Surface Emg ◽

Medial Gastrocnemius ◽

Whole Body ◽

Young Males ◽

Emg Amplitude ◽

Calf Muscles

Surface electromyography (EMG) has been used to estimate muscle work and physiological burden of the whole body during human movements. However, there are spatial variations in surface EMG responses within individual muscles. The aim of this study was to investigate the relation between oxygen consumption and surface EMG responses of lower leg muscles during walking at various speeds and to quantify its spatial variation within an individual muscle. Nine young males walked on a treadmill at four speeds: preferred minus 1 km/h, preferred, preferred plus 1 km/h, and preferred plus 2 km/h, and the metabolic response was measured based on the expired gas. High-density surface EMG of the tibialis anterior (TA), medial gastrocnemius (MG), lateral gastrocnemius, and soleus muscles was performed using 64 two-dimensional electrode grids. Correlation coefficients between oxygen consumption and the surface EMG amplitude were calculated across the gait speeds for each channel in the electrode grid and for individual muscles. Mean correlation coefficients across electrodes were 0.69–0.87 for the four individual muscles, and the spatial variation of correlation between the surface EMG amplitude and oxygen consumption within an electrode grid was significantly greater in MG muscle than in TA muscle (Quartile deviations: 0.24 for MG and 0.02 for TA, p < 0.05). These results suggest that the physiological burden of the whole body during gait at various speeds can be estimated from the surface EMG amplitude of calf muscles, but we need to note its spatial distribution within the MG muscle.

Download Full-text

Modulation of intracortical inhibition during physically performed and mentally simulated balance tasks

European Journal of Applied Physiology ◽

10.1007/s00421-020-04577-1 ◽

2021 ◽

Vol 121 (5) ◽

pp. 1379-1388

Author(s):

A. Mouthon ◽

J. Ruffieux ◽

W. Taube

Keyword(s):

Motor Evoked Potentials ◽

Action Observation ◽

Short Interval ◽

Intracortical Inhibition ◽

Mental Simulation ◽

Task Execution ◽

Postural Tasks ◽

Execution Condition ◽

The One ◽

Postural Task

Abstract Purpose Action observation (AO) during motor imagery (MI), so-called AO + MI, has been proposed as a new form of non-physical training, but the neural mechanisms involved remains largely unknown. Therefore, this study aimed to explore whether there were similarities in the modulation of short-interval intracortical inhibition (SICI) during execution and mental simulation of postural tasks, and if there was a difference in modulation of SICI between AO + MI and AO alone. Method 21 young adults (mean ± SD = 24 ± 6.3 years) were asked to either passively observe (AO) or imagine while observing (AO + MI) or physically perform a stable and an unstable standing task, while motor evoked potentials and SICI were assessed in the soleus muscle. Result SICI results showed a modulation by condition (F2,40 = 6.42, p = 0.009) with less SICI in the execution condition compared to the AO + MI (p = 0.009) and AO (p = 0.002) condition. Moreover, switching from the stable to the unstable stance condition reduced significantly SICI (F1,20 = 8.34, p = 0.009) during both, physically performed (− 38.5%; p = 0.03) and mentally simulated balance (− 10%, p < 0.001, AO + MI and AO taken together). Conclusion The data demonstrate that SICI is reduced when switching from a stable to a more unstable standing task during both real task execution and mental simulation. Therefore, our results strengthen and further support the existence of similarities between executed and mentally simulated actions by showing that not only corticospinal excitability is similarly modulated but also SICI. This proposes that the activity of the inhibitory cortical network during mental simulation of balance tasks resembles the one during physical postural task execution.

Download Full-text

Does pericentral mu-rhythm “power” corticomotor excitability? – a matter of EEG perspective

Brain Stimulation ◽

10.1016/j.brs.2021.03.017 ◽

2021 ◽

Author(s):

Anke Ninija Karabanov ◽

Kristoffer Hougaard Madsen ◽

Lærke Gebser Krohne ◽

Hartwig Roman Siebner

Keyword(s):

Mu Rhythm ◽

Corticomotor Excitability

Download Full-text

Are attentional instruction and feedback type affect on learning of postural and supra-postural tasks?

Neurological Sciences ◽

10.1007/s10072-020-04278-9 ◽

2020 ◽

Vol 41 (7) ◽

pp. 1773-1779

Author(s):

Amir Shams ◽

Parvaneh Shamsipour Dehkordi ◽

Farshid Tahmasbi ◽

Mandana Sangari

Keyword(s):

Feedback Type ◽

Postural Tasks

Download Full-text

Correlating cognition and cortical excitability with pain in fibromyalgia: a case control study

Advances in Rheumatology ◽

10.1186/s42358-021-00163-x ◽

2021 ◽

Vol 61 (1) ◽

Author(s):

Vikas Kumar Tiwari ◽

Srishti Nanda ◽

Suvercha Arya ◽

Uma Kumar ◽

Ratna Sharma ◽

...

Keyword(s):

Reaction Time ◽

Sleep Quality ◽

Daytime Sleepiness ◽

Case Control Study ◽

Color Word ◽

Case Control ◽

Corticomotor Excitability ◽

Word Task ◽

Control Study

Abstract Background Fibromyalgia is a chronic pain disorder characterized by widespread musculoskeletal symptoms, primarily attributed to sensitization of somatosensory system carrying pain. Few reports have investigated the impact of fibromyalgia symptoms on cognition, corticomotor excitability, sleepiness, and the sleep quality — all of which can deteriorate the quality of life in fibromyalgia. However, the existing reports are underpowered and have conflicting directions of findings, limiting their generalizability. Therefore, the present study was designed to compare measures of cognition, corticomotor excitability, sleepiness, and sleep quality using standardized instruments in the recruited patients of fibromyalgia with pain-free controls. Methods Diagnosed cases of fibromyalgia were recruited from the Rheumatology department for the cross-sectional, case-control study. Cognition (Mini-Mental State Examination, Stroop color-word task), corticomotor excitability (Resting motor threshold, Motor evoked potential amplitude), daytime sleepiness (Epworth sleepiness scale), and sleep quality (Pittsburgh sleep quality index) were studied according to the standard procedure. Results Thirty-four patients of fibromyalgia and 30 pain-free controls were recruited for the study. Patients of fibromyalgia showed decreased cognitive scores (p = 0.05), lowered accuracy in Stroop color-word task (for color: 0.02, for word: 0.01), and prolonged reaction time (< 0.01, < 0.01). Excessive daytime sleepiness in patients were found (< 0.01) and worsened sleep quality (< 0.01) were found. Parameters of corticomotor excitability were comparable between patients of fibromyalgia and pain-free controls. Conclusions Patients of fibromyalgia made more errors, had significantly increased reaction time for cognitive tasks, marked daytime sleepiness, and impaired quality of sleep. Future treatment strategies may include cognitive deficits and sleep disturbances as an integral part of fibromyalgia management.

Download Full-text