scholarly journals Psychophysiological responses to manual lifting of unknown loads

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247442
Author(s):  
Tamer M. Khalaf ◽  
Mohamed Z. Ramadan ◽  
Adham E. Ragab ◽  
Mohammed H. Alhaag ◽  
Khalil A. AlSharabi
Keyword(s):  
Nervous Activity ◽  
Maximum Voluntary Contraction ◽  
Low Frequency ◽  
Voluntary Contraction ◽  
Erector Spinae ◽  
Coding System ◽  
Manual Lifting ◽  
Actual Weight ◽  
Low Frequency Power ◽  
Frequency Power

Background The handling of unknown weights, which is common in daily routines either at work or during leisure time, is suspected to be highly associated with the incidence of low back pain (LBP). Objectives To investigate the effects of knowledge and magnitude of a load (to be lifted) on brain responses, autonomic nervous activity, and trapezius and erector spinae muscle activity. Methods A randomized, within-subjects experiment involving manual lifting was conducted, wherein 10 participants lifted three different weights (1.1, 5, and 15 kg) under two conditions: either having or not having prior knowledge of the weight to be lifted. Results The results revealed that the lifting of unknown weights caused increased average heart rate and percentage of maximum voluntary contraction (%MVC) but decreased average inter-beat interval, very-low-frequency power, low-frequency power, and low-frequency/high-frequency ratio. Regardless of the weight magnitude, lifting of unknown weights was associated with smaller theta activities in the power spectrum density (PSD) of the central region, smaller alpha activities in the PSD of the frontal region, and smaller beta activities in the PSDs of both the frontal and central regions. Moreover, smaller alpha and beta activities in the PSD of the parietal region were associated only with lifting of unknown lightweights. Conclusions Uncertainty regarding the weight to be lifted could be considered as a stress-adding variable that may increase the required physical demand to be sustained during manual lifting tasks. The findings of this study stress the importance of eliminating uncertainty associated with handling unknown weights, such as in the cases of handling patients and dispatching luggage. This can be achieved through preliminary self-sensing of the load to be lifted, or the cautious disclosure of the actual weight of manually lifted objects, for example, through clear labeling and/or a coding system.

scholarly journals Development of a trunk motor paradigm for use in neuroimaging

2020 ◽  
Vol 11 (1) ◽  
pp. 193-200
Author(s):  
Elizabeth Saunders ◽  
Brian C. Clark ◽  
Leatha A. Clark ◽  
Dustin R. Grooms
Keyword(s):  
Motor Control ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Erector Spinae ◽  
Head Motion ◽  
Low Back ◽  
Cyclic Contraction ◽  
Cyclic Contractions ◽  
Measurement Units ◽  
Healthy Participants

AbstractThe purpose of this study was to quantify head motion between isometric erector spinae (ES) contraction strategies, paradigms, and intensities in the development of a neuroimaging protocol for the study of neural activity associated with trunk motor control in individuals with low back pain. Ten healthy participants completed two contraction strategies; (1) a supine upper spine (US) press and (2) a supine lower extremity (LE) press. Each contraction strategy was performed at electromyographic (EMG) contraction intensities of 30, 40, 50, and 60% of an individually determined maximum voluntary contraction (MVC) (±10% range for each respective intensity) with real-time, EMG biofeedback. A cyclic contraction paradigm was performed at 30% of MVC with US and LE contraction strategies. Inertial measurement units (IMUs) quantified head motion to determine the viability of each paradigm for neuroimaging. US vs LE hold contractions induced no differences in head motion. Hold contractions elicited significantly less head motion relative to cyclic contractions. Contraction intensity increased head motion in a linear fashion with 30% MVC having the least head motion and 60% the highest. The LE hold contraction strategy, below 50% MVC, was found to be the most viable trunk motor control neuroimaging paradigm.

scholarly journals Toward asleep DBS: cortico-basal ganglia spectral and coherence activity during interleaved propofol/ketamine sedation mimics NREM/REM sleep activity

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jing Guang ◽  
Halen Baker ◽  
Orilia Ben-Yishay Nizri ◽  
Shimon Firman ◽  
Uri Werner-Reiss ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Rem Sleep ◽  
Standard Procedure ◽  
Low Frequency ◽  
Nrem Sleep ◽  
Sleep Cycle ◽  
Advanced Parkinson’S Disease ◽  
Low Frequency Power ◽  
The Brain ◽  
Frequency Power

AbstractDeep brain stimulation (DBS) is currently a standard procedure for advanced Parkinson’s disease. Many centers employ awake physiological navigation and stimulation assessment to optimize DBS localization and outcome. To enable DBS under sedation, asleep DBS, we characterized the cortico-basal ganglia neuronal network of two nonhuman primates under propofol, ketamine, and interleaved propofol-ketamine (IPK) sedation. Further, we compared these sedation states in the healthy and Parkinsonian condition to those of healthy sleep. Ketamine increases high-frequency power and synchronization while propofol increases low-frequency power and synchronization in polysomnography and neuronal activity recordings. Thus, ketamine does not mask the low-frequency oscillations used for physiological navigation toward the basal ganglia DBS targets. The brain spectral state under ketamine and propofol mimicked rapid eye movement (REM) and Non-REM (NREM) sleep activity, respectively, and the IPK protocol resembles the NREM-REM sleep cycle. These promising results are a meaningful step toward asleep DBS with nondistorted physiological navigation.

Cortical low‐frequency power correlates with behavioral impairment in animal model of focal limbic seizures

Epilepsia ◽  
2021 ◽  
Author(s):  
Abhijeet Gummadavelli ◽  
Reese Martin ◽  
Derek Goshay ◽  
Lim‐Anna Sieu ◽  
Jingwen Xu ◽  
...  
Keyword(s):  
Animal Model ◽  
Low Frequency ◽  
Behavioral Impairment ◽  
Limbic Seizures ◽  
Low Frequency Power ◽  
Frequency Power

Low-frequency heating of doublets

1981 ◽  
Vol 25 (1) ◽  
pp. 133-143 ◽  
Author(s):  
T. H. Jensen ◽  
F. W. McClain ◽  
H. Grad
Keyword(s):  
Physical Model ◽  
Linear Theory ◽  
Low Frequency ◽  
Plasma Temperature ◽  
Auxiliary Heating ◽  
Power Sources ◽  
Axisymmetric Mode ◽  
Low Frequency Power ◽  
Frequency Power ◽  
Frequency Heating

Heating of a doublet plasma by driving an axisymmetric mode at low frequency may be an attractive means for auxiliary heating. The attractiveness of the method stems from (1) the low technology required for low-frequency power sources, (2) the fact that the field-shaping coils required for doublets may also be used as the antennae for transmitting the power, (3) the possibility of transmitting the power through a resistive vacuum wall, (4) the insensitivity to the plasma temperature and density and (5) the relative simplicity of the physical model. The utility of the concept depends on the existence of a special axisymmetric eigenmode in the resistive M.HD approximation which is used. This mode has nodes through the elliptic axes of the doublet equilibrium and an antinode at the hyperbolic axis. It is remarkable that the dissipation per cycle of this mode remains large at low plasma resistivity. This paper describes a linear theory for such heating.

Preeclamptic pregnancy is associated with increased sympathetic and decreased parasympathetic control of HR

2000 ◽  
Vol 278 (4) ◽  
pp. H1269-H1273 ◽  
Author(s):  
Cheryl C. H. Yang ◽  
Te-Chang Chao ◽  
Terry B. J. Kuo ◽  
Chang-Sheng Yin ◽  
Hsing I. Chen
Keyword(s):  
Heart Rate ◽  
Low Frequency ◽  
Normal Pregnancy ◽  
Frequency Domain Analysis ◽  
Natural Logarithm ◽  
Sympathetic Regulation ◽  
History Of ◽  
Low Frequency Power ◽  
Normalized Units ◽  
Frequency Power

Previous work from our laboratory using heart rate variability (HRV) has demonstrated that women before menopause have a more dominant parasympathetic and less effective sympathetic regulations of heart rate compared with men. Because it is still not clear whether normal or preeclamptic pregnancy coincides with alternations in the autonomic functions, we evaluated the changes of HRV in 17 nonpregnant, 17 normotensive pregnant, and 11 preeclamptic women who were clinically diagnosed without history of diabetic neuropathy, cardiac arrhythmia, and other cardiovascular diseases. Frequency-domain analysis of short-term, stationary R-R intervals was performed to evaluate the total variance, low-frequency power (LF; 0.04–0.15 Hz), high-frequency power (HF; 0.15–0.40 Hz), ratio of LF to HF (LF/HF), and LF in normalized units (LF%). Natural logarithm transformation was applied to variance, LF, HF, and LF/HF for the adjustment of the skewness of distribution. We found that the normal pregnant group had a lower R-R value and HF but had a higher LF/HF and LF% compared with the nonpregnant group. The preeclamptic group had lower HF but higher LF/HF compared with either the normal pregnant or nonpregnant group. Our results suggest that normal pregnancy is associated with a facilitation of sympathetic regulation and an attenuation of parasympathetic influence of heart rate, and such alterations are enhanced in preeclamptic pregnancy.

scholarly journals In search of Universal Cortical Power Changes Linked to NMDA-Antagonist based Anesthetic Induced Reductions in Consciousness

2019 ◽  
Author(s):  
Andria Pelentritou ◽  
Levin Kuhlmann ◽  
John Cormack ◽  
Steven Mcguigan ◽  
Will Woods ◽  
...  
Keyword(s):  
Spectral Power ◽  
Low Frequency ◽  
Nmda Antagonist ◽  
Alpha Power ◽  
Source Imaging ◽  
Source Power ◽  
Gamma Range ◽  
Anesthetic Agents ◽  
Low Frequency Power ◽  
Frequency Power

B. AbstractBackground.Despite their intriguing nature, investigations of the neurophysiology of N-methyl-D-aspartate (NMDA)-antagonists Xenon (Xe) and nitrous oxide (N2O) are limited and have revealed inconsistent frequency-dependent alterations, in spectral power and functional connectivity. Discrepancies are likely due to using low resolution electroencephalography restricted to sensor level changes, concomitant anesthetic agent administration and dosage. Our intention was to describe the effects of equivalent stepwise levels of Xe and N2O administration on oscillatory source power using a crossover design, to explore universal mechanisms of NMDA-based anesthesia.Methods.22 healthy males participated in a study of simultaneous magnetoencephalography and electroencephalography recordings. In separate sessions, equivalent subanesthetic doses of gaseous anesthetic agents N2O and Xe (0.25, 0.50, 0.75 equi MAC-awake) and 1.30 MAC-awake Xe (for Loss of Responsiveness) were administered. Source power in various frequency bands was computed and statistically assessed relative to a conscious baseline.Results.Delta (l-4Hz) and theta (4-8Hz) band power was significantly increased at the highest Xe concentration (42%, 1.30 MAC-awake) relative to baseline for both magnetoencephalography and electroencephalography source power (p<0.005). A reduction in frontal alpha (8-13 Hz) power was observed upon N2O administration, and shown to be stronger than equivalent Xe dosage reductions (p=0.005). Higher frequency activity increases were observed in magnetoencephalographic but not encephalographic signals for N2O alone with occipital low gamma (30-49Hz) and widespread high gamma (51-99Hz) rise in source power.Conclusions.Magnetoencephalography source imaging revealed unequivocal and widespread power changes in dissociative anesthesia, which were divergent to source electroencephalography. Loss of Responsiveness anesthesia at 42% Xe (1.30 MAC-awake) demonstrated, similar to inductive agents, low frequency power increases in frontal delta and global theta. N2O sedation yielded a rise in high frequency power in the gamma range which was primarily occipital for lower gamma bandwidth (3049 Hz) and substantially decreased alpha power, particularly in frontal regions.Clinical trial number and Registry URLNot applicable.Prior PresentationsPelentritou Andria, Kuhlmann Levin; Lee Heonsoo; Cormack John; Mcguigan Steven; Woods Will; Sleigh Jamie; Lee UnCheol; Muthukumaraswamy Suresh; Liley David. Searching For Universal Cortical Power Changes Linked To Anesthetic Induced Reductions In Consciousness. The Science of Consciousness April 4th2018. Tucson, Arizona, USA.Summary StatementNot applicable.

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