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Motor unit

Mehmet Cemal Kahya, Oğuz Sebik, Kemal S Türker
Painful stimulation of the hand results in an inhibitory response in the hand muscles known as the cutaneous silent period (CSP). In this study, we employed probability- and frequency-based analysis methods to examine the CSP induced by laser stimuli. Subjects were asked to contract their first dorsal interosseous muscle so that selected motor units discharged at a rate of about 8Hz. Laser pulses were delivered to the palm of the hand, and reflex responses were recorded. The stimuli generated CSP in all test subjects...
October 14, 2016: Journal of Electromyography and Kinesiology
Suhitha Veeravelli, Bijan Najafi, Ivan Marin, Fernando Blumenkron, Shannon Smith, Stephen A Klotz
Approximately 1.2 million people in the United States live with HIV infection. Medical advancements have increased the life expectancy and this cohort is aging. HIV-positive individuals have a high incidence of frailty (~20%) characterized by depression and sedentary behavior. Exercise would be healthy, but due to the frail status of many HIV-positive individuals, conventional exercise is too taxing. The aim of this study was to evaluate the effectiveness and acceptability of a novel game-based training program (exergame) in ameliorating some aspects of frailty in HIV-infected individuals...
October 6, 2016: Journal of Visualized Experiments: JoVE
Faisal R Jahangiri, Sami Al Eissa, Samir Sayegh, Fahad Al Helal, Shomoukh A Al-Sharif, Monerah M Annaim, Sheryar Muhammad, Tanweer Aziz
A 16-year-old male patient with Ehler-Danlos syndrome (EDS) and a back deformity since birth presented with severe kyphoscoliosis. The patient was neurologically intact but had respiratory and cardiac insufficiencies. A two-stage vertebral column resection (VCR) at T9-T10 with multiple level fusion with multimodality intraoperative neurophysiological monitoring (IONM) was planned.  During the first stage, pedicle screws were placed at multiple spinal levels above and below the VCR level. Upper and lower somatosensory evoked potentials (SSEP), transcranial electrical motor evoked potentials (TCeMEP), and electromyography were monitored continuously and showed no significant changes...
August 31, 2016: Curēus
Janna M Gottwald, Sheila Achermann, Carin Marciszko, Marcus Lindskog, Gustaf Gredebäck
The importance of executive functioning for later life outcomes, along with its potential to be positively affected by intervention programs, motivates the need to find early markers of executive functioning. In this study, 18-month-olds performed three executive-function tasks-involving simple inhibition, working memory, and more complex inhibition-and a motion-capture task assessing prospective motor control during reaching. We demonstrated that prospective motor control, as measured by the peak velocity of the first movement unit, is related to infants' performance on simple-inhibition and working memory tasks...
October 7, 2016: Psychological Science
Sanath Allampati, Kevin D Mullen
Hepatic Encephalopathy (HE) is a complex neuropsychiatric syndrome associated with decompensated liver disease. The spectrum of disease ranges from trivial abnormalities in complex decision making and prolonged reaction time to coma in its most severe form1. The very initial stages, recently termed covert Hepatic Encephalopathy (CHE), can only be diagnosed with the help of neuropsychiatric testing while the later and more severe forms, termed overt Hepatic Encephalopathy (OHE), can be diagnosed clinically. Severity of HE is graded based on West Haven Criteria and please refer to table 1 for more details2...
October 20, 2016: Minerva Gastroenterologica e Dietologica
Khader A Almhdawi, Virgil G Mathiowetz, Matthew White, Robert C delMas
There is a need for more effective rehabilitation methods for individuals post-stroke. Occupational Therapy Task-Oriented (TO) approach has not been evaluated in a randomized clinical trial. The purpose of this study was to evaluate functional and impairment efficacies of TO approach on the more-affected Upper Extremity (UE) of persons post-stroke. A randomized single-blinded cross-over trial recruited 20 participants post-stroke (mean chronicity = 62 months) who demonstrated at least 10° active more-affected shoulder flexion and abduction and elbow flexion-extension...
October 20, 2016: Occupational Therapy International
Athanasios Papathanasiou, Ioannis Markakis
Guillain-Barré syndrome (GBS) is mainly classified into acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). Although diagnosis of GBS requires progressive weakness and universal areflexia or hyporeflexia, cases of GBS with preserved or increased deep tendon reflexes (DTRs) have been increasingly recognized. We report three cases of GBS, presenting at a single unit in six months. Our first case presented with pure sensory symptoms. The second case had nonspecific generalized weakness, while the third presented with typical ascending weakness...
2016: Case Reports in Emergency Medicine
Nathan D Crosby, John J Janik, Warren M Grill
Kilohertz-frequency spinal cord stimulation (KHF-SCS) is a potential paresthesia-free treatment for chronic pain. However, the effects of KHF-SCS on spinal dorsal column (DC) axons and its mechanisms of action remain unknown. The objectives of this study were to quantify activation and conduction block of DC axons by KHF-SCS across a range of kHz frequencies (1, 5, 10, or 20 kHz) and waveforms (biphasic pulses or sinusoids). Custom platinum electrodes delivered SCS to the T10/T11 DCs of anesthetized male Sprague-Dawley rats...
October 19, 2016: Journal of Neurophysiology
Anne Synnes, Thuy Mai Luu, Diane Moddemann, Paige Church, David Lee, Michael Vincer, Marilyn Ballantyne, Annette Majnemer, Dianne Creighton, Junmin Yang, Reginald Sauve, Saroj Saigal, Prakesh Shah, Shoo K Lee
OBJECTIVES: Identify determinants of neurodevelopmental outcome in preterm children. METHODS: Prospective national cohort study of children born between 2009 and 2011 at <29 weeks gestational age, admitted to one of 28 Canadian neonatal intensive care units and assessed at a Canadian Neonatal Follow-up Network site at 21 months corrected age for cerebral palsy (CP), visual, hearing and developmental status using the Bayley Scales of Infant and Toddler Development-Third Edition (Bayley-III)...
October 6, 2016: Archives of Disease in Childhood. Fetal and Neonatal Edition
Thashi Chang, Bethan Lang, Angela Vincent
BACKGROUND: Stiff person syndrome is a highly disabling, progressive autoimmune disorder of the central nervous system characterized by muscle rigidity and spasms. Stiff person syndrome is rare, but is believed to be under diagnosed with only 14 cases been reported among a 1.7 billion population in South Asia. We report the first authenticated case from Sri Lanka. CASE PRESENTATION: A 55-year-old Sri Lankan female presented with difficulty in walking and recurrent falls due to progressive muscular rigidity in her lower limbs and trunk with superimposed muscle spasms that occurred in response to unexpected noise, startle or emotional upset...
October 18, 2016: BMC Research Notes
Cory M Smith, Terry J Housh, Nathaniel D M Jenkins, Ethan C Hill, Kristen C Cochrane, Amelia A Miramonti, Richard J Schmidt, Glen O Johnson
The purposes of the present study were to apply a unique method for the identification of the time course of changes in neuromuscular responses and to infer the motor unit activation strategies used to maintain force during a fatiguing, intermittent isometric workbout. Eleven men performed 50, 6 s intermittent isometric muscle actions of the leg extensors, each separated by 2 s of rest at 60% maximal voluntary isometric contraction (MVIC). Electromyographic (EMG) and mechanomyographic (MMG) amplitude (root mean square; RMS) and frequency (mean power frequency; MPF) were obtained from the vastus lateralis (VL) every 5 of the 50 repetitions and normalized as a percent of the initial repetition...
October 18, 2016: Physiological Measurement
Yasuhide Yoshitake, Hiroaki Kanehisa, Minoru Shinohara
PURPOSE: The purpose of this study was to determine the modulation of common low-frequency oscillations in pools of motor units across antagonistic muscles due to the difference in the activation level of pools of spinal motor neurons and the presence of neuromuscular fatigue during intended co-contraction. METHODS: Ten healthy young men (21.8 ± 1.5 yr) performed intended steady co-contractions of elbow flexors and extensors at maximal and a submaximal (10% of maximal electromyogram, EMG) effort...
October 6, 2016: Medicine and Science in Sports and Exercise
Deydre S Teyhen, Scott W Shaffer, Robert J Butler, Stephen L Goffar, Kyle B Kiesel, Daniel I Rhon, Robert E Boyles, Daniel J McMillian, Jared N Williamson, Phillip J Plisky
: Performance on movement tests helps to predict injury risk in a variety of physically active populations. Understanding baseline measures for normal is an important first step. OBJECTIVES: Determine differences in physical performance assessments and describe normative values for these tests based on military unit type. METHODS: Assessment of power, balance, mobility, motor control, and performance on the Army Physical Fitness Test were assessed in a cohort of 1,466 soldiers...
October 2016: Military Medicine
Priti Bandi, Diana Silver, Tod Mijanovich, James Macinko
BACKGROUND: In the past 40 years, a variety of factors might have impacted motor vehicle (MV) fatality trends in the US, including public health policies, engineering innovations, trauma care improvements, etc. These factors varied in their timing across states/localities, and many were targeted at particular population subgroups. In order to identify and quantify differential rates of change over time and differences in trend patterns between population subgroups, this study employed a novel analytic method to assess temporal trends in MV fatalities between 1968 and 2010, by age group and sex...
December 2015: Injury Epidemiology
Victor Puac-Polanco, Katherine M Keyes, Guohua Li
BACKGROUND: Motorcyclists are known to be at substantially higher risk per mile traveled of dying from crashes than car occupants. In 2014, motorcycling made up less than 1 % of person-miles traveled but 13 % of the total mortality from motor-vehicle crashes in the United States. We assessed the cohort effect of the baby-boomers (i.e., those born between 1946 and 1964) in motorcycle crash mortality from 1975 to 2014 in the United States. METHODS: Using mortality data for motorcycle occupants from the Fatality Analysis Reporting System, we performed an age-period-cohort analysis using the multiphase method and the intrinsic estimator method...
December 2016: Injury Epidemiology
Regan W Bergmark, Emily Gliklich, Rong Guo, Richard E Gliklich
BACKGROUND: Texting while driving and other cell-phone reading and writing activities are high-risk activities associated with motor vehicle collisions and mortality. This paper describes the development and preliminary evaluation of the Distracted Driving Survey (DDS) and score. METHODS: Survey questions were developed by a research team using semi-structured interviews, pilot-tested, and evaluated in young drivers for validity and reliability. Questions focused on texting while driving and use of email, social media, and maps on cellular phones with specific questions about the driving speeds at which these activities are performed...
December 2016: Injury Epidemiology
Damien Benis, Olivier David, Brigitte Piallat, Astrid Kibleur, Laurent Goetz, Manik Bhattacharjee, Valérie Fraix, Eric Seigneuret, Paul Krack, Stéphan Chabardès, Julien Bastin
The subthalamic nucleus (STN) plays a critical role during action inhibition, perhaps by acting like a fast brake on the motor system when inappropriate responses have to be rapidly suppressed. However, the mechanisms involving the STN during motor inhibition are still unclear, particularly because of a relative lack of single-cell responses reported in this structure in humans. In this study, we used extracellular microelectrode recordings during deep brain stimulation surgery in patients with Parkinson's disease (PD) to study STN neurophysiological correlates of inhibitory control during a stop signal task...
September 21, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Andrea Becerra-Calixto, Gloria Patricia Cardona-Gómez
Cerebral ischemia is a cerebrovascular episode that generates a high incidence of death and physical and mental disabilities worldwide. Excitotoxicity, release of free radicals, and exacerbated immune response cause serious complications in motor and cognitive areas during both short and long time frames post-ischemia. CDK5 is a kinase that is widely involved in the functions of neurons and astrocytes, and its over-activation is implicated in neurodegenerative processes. In this study, we evaluated the brain parenchymal response to the transplantation of CDK5-knockdown astrocytes into the somatosensory cortex after ischemia in rats...
October 15, 2016: Molecular Neurobiology
Luca Mesin, Davide Dardanello, Alberto Rainoldi, Gennaro Boccia
During fatiguing contractions, many adjustments in motor units behaviour occur: decrease in muscle fibre conduction velocity; increase in motor units synchronisation; modulation of motor units firing rate; increase in variability of motor units inter-spike interval. We simulated the influence of all these adjustments on synthetic EMG signals in isometric/isotonic conditions. The fractal dimension of the EMG signal was found mainly influenced by motor units firing behaviour, being affected by both firing rate and synchronisation level, and least affected by muscle fibre conduction velocity...
October 12, 2016: Medical Engineering & Physics
Alberto M Saibene, Elena Zambrelli, Carlotta Pipolo, Alberto Maccari, Giovanni Felisati, Elena Felisati, Francesca Furia, Aglaia Vignoli, Maria Paola Canevini, Enrico Alfonsi
Vagus nerve stimulation (VNS) is a useful tool for drug-resistant epilepsy, but it induces known laryngeal side effects, with a significant role on patients' quality of life. VNS patients may show persistent left vocal fold (LVF) palsy at rest and/or recurrent LVF adduction during stimulation. This study aims at electromyographically evaluating laryngeal muscles abnormalities in VNS patients. We compared endoscopic laryngeal evaluation data in six VNS patients with laryngeal muscle electromyography (LMEMG) carried out on the thyroarytenoid, cricothyroid, posterior cricoarytenoid, and cricopharyngeal muscles...
October 13, 2016: European Archives of Oto-rhino-laryngology
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