Electrically induced mechanomyograms reflect inspiratory muscle strength in young or elderly subjects

Shogo Watanabe; Ippei Nojima; Yuuna Agarie; Tatsunori Watanabe; Shinichi Fukuhara; Takeshi Fujinaga; Hisao Oka

doi:10.1016/j.resinv.2016.06.001

Electrically induced mechanomyograms reflect inspiratory muscle strength in young or elderly subjects

Respir Investig. 2016 Nov;54(6):436-444. doi: 10.1016/j.resinv.2016.06.001. Epub 2016 Aug 8.

Authors

Shogo Watanabe¹, Ippei Nojima², Yuuna Agarie³, Tatsunori Watanabe⁴, Shinichi Fukuhara⁵, Takeshi Fujinaga⁶, Hisao Oka⁷

Affiliations

¹ Department of Medical Technology, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan. Electronic address: watanabe1224@okayama-u.ac.jp.
² Department of Physical and Occupational Therapy, Nagoya University Graduate School of Medicine, 1-1-20, Daiko-Minami, Higashi-ku, Nagoya, Aichi, Japan. Electronic address: nojima@met.nagoya-u.ac.jp.
³ Department of Rehabilitation Science, Nagoya University School of Health Sciences, 1-1-20, Daiko-Minami, Higashi-ku, Nagoya, Aichi, Japan. Electronic address: korottokoron@gmail.com.
⁴ Department of Physical and Occupational Therapy, Nagoya University Graduate School of Medicine, 1-1-20, Daiko-Minami, Higashi-ku, Nagoya, Aichi, Japan. Electronic address: watanabe.tatsunori@h.mbox.nagoya-u.ac.jp.
⁵ Department of Medical Technology, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan; Department of Medical Engineering, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama, Japan. Electronic address: fukuhara@mw.kawasaki-m.ac.jp.
⁶ Department of Medical Technology, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan. Electronic address: takety0525@s.okayama-u.ac.jp.
⁷ Department of Medical Technology, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan. Electronic address: hoka@okayama-u.ac.jp.

PMID: 27886855
DOI: 10.1016/j.resinv.2016.06.001

Abstract

Background: Respiratory muscle strength has been used as a tool for evaluating respiratory rehabilitation in chronic obstructive pulmonary disease. However, mouth pressure measurement evaluated by maximum expiratory mouth pressure (PEmax) or inspiratory mouth pressure (PImax) offers an indirect method for measuring respiratory muscle strength. We demonstrated the evaluation of diaphragm contractility using a mechanomyogram (MMG), which is the mechanical signal generated by the motion of the diaphragm induced by the electric stimulation of the phrenic nerve.

Methods: Study participants were 21 young and 20 elderly subjects with no symptoms of respiratory disease. The elderly subjects were divided into non-smoker or smoker groups. The smoker group was defined as subjects having a Brinkman Index of greater than 300. We measured basic spirometric parameters, mouth pressure (PEmax, PImax), and diaphragmatic MMG.

Results: Diaphragmatic MMG showed more clear contrast between young subjects and elderly non-smoker or smoker subjects than the conventional method for respiratory muscle contraction (PEmax, PImax). In addition, the diaphragmatic MMG strongly correlated with inspiratory muscle strength.

Conclusions: Diaphragmatic MMG may reflect diaphragmatic contractility more directly and sensitively than the conventional method.

Keywords: Electric stimulation; Mechanomyogram; Respiratory muscle strength; Smoking.

MeSH terms

Adult
Aged
Aged, 80 and over
Diaphragm / physiology*
Diaphragm / physiopathology*
Electric Stimulation
Humans
Mouth / physiology
Mouth / physiopathology
Muscle Contraction
Muscle Strength*
Myography*
Phrenic Nerve / physiology
Pressure
Pulmonary Disease, Chronic Obstructive / physiopathology*
Pulmonary Disease, Chronic Obstructive / rehabilitation
Smoking
Young Adult