Quantitative Mechanical Properties of the Relaxed Biceps and Triceps Brachii Muscles in Patients with Subacute Stroke: A Reliability Study of the Myoton-3 Myometer

Abstract

<jats:p><jats:italic>Objective</jats:italic>. Test-retest reliability of the myotonometer was investigated in patients with subacute stroke.<jats:italic>Methods</jats:italic>. Twelve patients with substroke (3 to 9 months poststroke) were examined in standardized testing position twice, 60 minutes apart, with the Myoton-3 myometer to measure tone, elasticity, and stiffness of relaxed bilateral biceps and triceps brachii muscles. Intrarater reliability of muscle properties was determined using intraclass correlation coefficient (ICC), the standard error of measurement (SEM), and the minimal detectable change (MDC).<jats:italic>Results</jats:italic>. Intrarater reliability of muscle properties of bilateral biceps and triceps brachii muscles were good (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>ICCs</mml:mtext><mml:mo>=</mml:mo><mml:mn>0.79</mml:mn></mml:math>–0.96) except for unaffected biceps tone (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>ICC</mml:mtext><mml:mo>=</mml:mo><mml:mn>0.72</mml:mn></mml:math>). The SEM and MDC of bilateral biceps and triceps brachii muscles indicated small measurement error (SEM%<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>&lt;</mml:mo><mml:mn>10</mml:mn></mml:math>%, MDC%<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>&lt;</mml:mo><mml:mn>25</mml:mn></mml:math>%).<jats:italic>Conclusion</jats:italic>. The Myoton-3 myometer is a reliable tool for quantifying muscle tone, elasticity, and stiffness of the biceps and triceps brachii in patients with subacute stroke.</jats:p>

Parameters Representing Muscle Tone, Elasticity and Stiffness of Biceps Brachii in Healthy Older Males: Symmetry and Within-Session Reliability Using the MyotonPRO

“…For instance, in some older participants, the middle of BB muscle belly lay more medially and distally than in younger participants, making precision of the muscle belly difficult to ensure, and resultant deviation of testing site from the measurement protocol outlined above. The studies on stroke patients mentioned above used palpation to locate the muscle belly and found good reliability [16,17], so it may not be necessary to be as precise as in the present protocol for locating the testing site. However, the reliability on different days was not assessed in the studies on stroke patients, only for sessions 30 minutes apart [16,17], so the variability over time, when muscle characteristics and recording conditions can change and influence reliability, has yet to be studied.…”

“…These two earlier studies also examined betweenday reliability of testing rectus femoris in young (ICC 3,1: 0.81-0.87) [14] and older (0.77-0.82) [13] males. Studies using earlier Myoton prototypes have reported high-to-very-high test re-test reliability for sessions 30 minutes apart in stroke populations [16,17]. In 61 chronic stroke patients studied using the Myoton-3, ICCs ranged from 0.82 to 0.95 and measurements of biceps had more stability and less variability between the two sessions than the other muscles studied, which were deltoid, triceps brachii, extensor digitorum, flexor carpi radialis and flexor carpi ulnaris [17].…”

“…When compared with TMG, the Myoton-3 device was more reliable on repeated testing and more valid for detecting changes in muscle parameters at different muscle lengths [20]. The within day (sessions 30 minutes apart) intra-rater reliability of the Myoton-3 in BB in a small group of stroke patients (n=12) produced fair to good ICCs for both the affected side (ICC: 0.54-0.99) and poor to good for the non-affected sides (ICC 0.25-0.98) [16]. A larger study of 62 stroke patients, testing 60 minutes apart, found excellent ICCs for BB and triceps in both limbs (ICC 0.79-0.96) apart from BB tone in the unaffected limb (ICC=0.72) [17].…”

“…New measures of muscular properties are being developed, offering an in vivo, objective, clinical, non-invasive alternative to subjective assessments. These include tensiomyography or TMG, which uses electrical stimulation to elicit muscle oscillations to measure contraction time and muscle displacement [7]; various devices that measure tissue stiffness, such as muscle 'hardness' meters [8], myotonometry, which compresses (≥ 1 ≤ 2 seconds) the muscle to record tissue displacement [9,10], and a mechano-acoustic indentor system that records tissue displacement to measure non-linear elastic properties [11]; and the recently introduced Myoton technology, which elicits mechanically induced oscillations [12][13][14][15][16][17][18][19][20][21]. The different technologies have their relative advantages.…”

“…Although the basic principle of testing remains the same, some differences are detailed in the Methods section. Myoton technology has been examined for the assessment of muscle in neurological conditions, including Parkinson's disease [15] and stroke [16,17]. The technology is potentially useful for aiding assessment of muscle dysfunction and monitoring the effects of treatment on muscle tone and rigidity (elasticity), which are important impairments in the case of stroke and Parkinson's disease respectively.…”