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Motor Conduction Time (motor + conduction_time)

Distribution by Scientific Domains
Medical Sciences100%

Kinds of Motor Conduction Time

  • central motor conduction time
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    Selected Abstracts

    Altered Motor Cortex Excitability to Magnetic Stimulation in Alcohol Withdrawal Syndrome

    ALCOHOLISM, Issue 4 2010
    Raffaele Nardone
    Background:, Alcohol addiction is a complex brain disease caused by alterations in crucial neurotransmitter systems, including gamma-aminobutyric acid (GABA) and glutamate. These disturbances could be revealed by changes in cortical excitability parameters, as assessed by transcranial magnetic stimulation (TMS). This study was aimed to further investigate the complex pathophysiology of alcohol withdrawal syndrome (AWS). Methods:, Motor cortex excitability was examined in 13 subjects with AWS in a mild predelirial state, in 12 chronic alcoholics and in 15 age-matched control subjects, using a range of TMS protocols. Central motor conduction time, resting and active motor threshold, duration of the cortical silent period, short latency intracortical inhibition (SICI), and intracortical facilitation (ICF) to paired TMS were examined. Results:, Intracortical facilitation was significantly increased in the AWS patients when compared with the chronic alcoholics and the control subjects. The other TMS parameters did not differ significantly from the controls. Administration of a single oral dose of the glutamatergic antagonist riluzole in a subgroup of 8 patients significantly reduced ICF; motor threshold and SICI were not affected by riluzole. Conclusion:, Transcranial magnetic stimulation shows a selective increase in intracortical facilitation after ethanol withdrawal. Our findings support the theory that altered glutamatergic receptor function plays an important role in the pathogenesis of human alcohol withdrawal. This study provides further physiological evidence that antiglutamatergic approaches represent an efficacious alternative for treating alcohol withdrawal symptoms. [source]

    Sensitivity of electrophysiological tests for upper and lower motor neuron dysfunction in ALS: A six-month longitudinal study

    MUSCLE AND NERVE, Issue 2 2010
    Mamede de Carvalho MD
    Abstract By following a group of amyotrophic lateral sclerosis (ALS) patients longitudinally using lower motor neuron (LMN) and upper motor neuron (UMN) markers of dysfunction it may be possible to better understand the functional relationships between these motor systems in this disease. We used neurophysiological techniques to follow UMN and LMN dysfunction in a group of 28 patients with ALS, in comparison with the ALS functional rating scale (ALS-FRS) score and the forced vital capacity (FVC). We used motor unit number estimation (MUNE), compound muscle action potential (CMAP) amplitude, and the Neurophysiological Index (NI) to quantify the LMN disorder, and transcranial motor stimulation to study cortical motor threshold, motor-evoked response amplitude, central motor conduction time, and cortical silent period (CSP). The patients were studied shortly after diagnosis and then 6 months later, using both abductor digiti minimi muscles (ADM); ADM strength was initially >MRC 3 (Medical Research Council, UK). The NI and MUNE changed more than any other variable. CSP increased by about 30%, a change more marked than the slight increase observed in the cortical motor threshold (9%). The normal increase of CSP after acute muscle fatigue was preserved during disease progression. The CSP increase correlated with the MUNE rate of decay but not to the NI reduction, perhaps because NI includes F-wave frequency in itscalculation. There was no definite correlation between UMN and LMNdysfunction or progression, but there was a link between CSP and LMN changes in ALS. The CSP may be a useful variable in following UMN dysfunction in clinical practice and in clinical trials. Muscle Nerve, 2010 [source]

    Clinical electrophysiological characterization of the acquired neuromyotonia phenotype of autoimmune peripheral nerve hyperexcitability

    MUSCLE AND NERVE, Issue 6 2006
    Paul Maddison MD
    Abstract Acquired autoimmune neuromyotonia is regarded as part of the spectrum of peripheral nerve hyperexcitability disorders. We aimed to use clinical neurophysiological measurements to study the extent, distribution, and characteristics of spontaneous motor unit potentials in 11 patients with acquired neuromyotonia. Investigations revealed that most spontaneous discharges recorded were motor unit, or partial motor unit potentials of normal size. Bursts of motor unit potentials arose more commonly from distal portions of the peripheral nerve and had abnormal absolute and relative refractory periods. Spontaneous discharges in some patients occurred in semirhythmic bursts in certain muscles. No patient had neurophysiological abnormalities detectable in first-order neurons of the central nervous system when using transcranial magnetic stimulation to estimate the threshold for corticomotor excitation and determine central motor conduction time. Only patients with coexistent myasthenia gravis had neurophysiologically detectable defects in neuromuscular transmission. The pathogenic region of abnormality in peripheral nerve hyperexcitability disorders therefore seems to lie within the terminal branches of peripheral motor nerves. Muscle Nerve, 2006 [source]

    Development of the corticospinal system and hand motor function: central conduction times and motor performance tests

    DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 4 2000
    U M Fietzek
    Maturation of the corticospinal (CS) tract and hand motor function provide paradigms for central nervous system development. In this study, involving 112 participants (aged from 0.2 to 30 years), we evaluated central motor conduction times (CMCT) obtained with transcranial magnetic stimulation (TMS) during preinnervation conditions of facilitation and relaxation. Auditory reaction time, velocity of a ballistic movement of the arm, finger tapping, diadochokinesis, and fine motor visuomanual tracking were also examined. The maturation profiles for every parameter were calculated. CMCTs for the different preinnervation conditions reached adult values at different times and this could be explained by maturation of excitability at the cortical and spinal level. A stable phase for CMCTs and reaction time was reached during childhood. Parameters which measured motor speed and skill indicated that the development of these continued into adulthood. The maturation of the fast CS tract seems to be completed before the acquisition of the related motor performance has been accomplished. In conclusion, we could demonstrate that data from several neurophysiological methods can be combined and used to study the maturation of the function of the nervous system. This approach could allow appraisal of pathological conditions that show parallels with omissions or lack of developmental progress. [source]