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Method to measure tone of axial and proximal muscle.

Abstract

The control of tonic muscular activity remains poorly understood. While abnormal tone is commonly assessed clinically by measuring the passive resistance of relaxed limbs, no systems are available to study tonic muscle control in a natural, active state of antigravity support. We have developed a device (Twister) to study tonic regulation of axial and proximal muscles during active postural maintenance (i.e. postural tone). Twister rotates axial body regions relative to each other about the vertical axis during stance, so as to twist the neck, trunk or hip regions. This twisting imposes length changes on axial muscles without changing the body's relationship to gravity. Because Twister does not provide postural support, tone must be regulated to counteract gravitational torques. We quantify this tonic regulation by the restive torque to twisting, which reflects the state of all muscles undergoing length changes, as well as by electromyography of relevant muscles. Because tone is characterized by long-lasting low-level muscle activity, tonic control is studied with slow movements that produce "tonic" changes in muscle length, without evoking fast "phasic" responses. Twister can be reconfigured to study various aspects of muscle tone, such as co-contraction, tonic modulation to postural changes, tonic interactions across body segments, as well as perceptual thresholds to slow axial rotation. Twister can also be used to provide a quantitative measurement of the effects of disease on axial and proximal postural tone and assess the efficacy of intervention.

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  • Authors+Show Affiliations

    ,

    Department of Biomedical Engineering, Oregon Health and Science University, USA.

    , ,

    Source

    MeSH

    Humans
    Muscle Tonus
    Muscle, Skeletal
    Myography
    Posture
    Weight-Bearing

    Pub Type(s)

    Journal Article
    Research Support, N.I.H., Extramural
    Video-Audio Media

    Language

    eng

    PubMed ID

    22214974

    Citation

    TY - JOUR T1 - Method to measure tone of axial and proximal muscle. AU - Gurfinkel,Victor S, AU - Cacciatore,Timothy W, AU - Cordo,Paul J, AU - Horak,Fay B, Y1 - 2011/12/14/ PY - 2012/1/5/entrez PY - 2012/1/5/pubmed PY - 2012/2/18/medline SP - EP - JF - Journal of visualized experiments : JoVE JO - J Vis Exp IS - 58 N2 - The control of tonic muscular activity remains poorly understood. While abnormal tone is commonly assessed clinically by measuring the passive resistance of relaxed limbs, no systems are available to study tonic muscle control in a natural, active state of antigravity support. We have developed a device (Twister) to study tonic regulation of axial and proximal muscles during active postural maintenance (i.e. postural tone). Twister rotates axial body regions relative to each other about the vertical axis during stance, so as to twist the neck, trunk or hip regions. This twisting imposes length changes on axial muscles without changing the body's relationship to gravity. Because Twister does not provide postural support, tone must be regulated to counteract gravitational torques. We quantify this tonic regulation by the restive torque to twisting, which reflects the state of all muscles undergoing length changes, as well as by electromyography of relevant muscles. Because tone is characterized by long-lasting low-level muscle activity, tonic control is studied with slow movements that produce "tonic" changes in muscle length, without evoking fast "phasic" responses. Twister can be reconfigured to study various aspects of muscle tone, such as co-contraction, tonic modulation to postural changes, tonic interactions across body segments, as well as perceptual thresholds to slow axial rotation. Twister can also be used to provide a quantitative measurement of the effects of disease on axial and proximal postural tone and assess the efficacy of intervention. SN - 1940-087X UR - https://www.unboundmedicine.com/medline/citation/22214974/Method_to_measure_tone_of_axial_and_proximal_muscle_ L2 - http://dx.doi.org/10.3791/3677 ER -