title: Electrically induced mechanomyograms reflect inspiratory muscle strength in young or elderly subjects.
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.
authors.affiliation: 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.
authors.forename: Shogo
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: 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.
authors.forename: Ippei
authors.initials: I
authors.lastname: Nojima
authors.affiliation: 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.
authors.forename: Yuuna
authors.initials: Y
authors.lastname: Agarie
authors.affiliation: 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.
authors.forename: Tatsunori
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: 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.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Fukuhara
authors.affiliation: 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.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujinaga
authors.affiliation: 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.
authors.forename: Hisao
authors.initials: H
authors.lastname: Oka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003964:Diaphragm / Q000502:physiology* / Q000503:physiopathology*; D004558:Electric Stimulation; D006801:Humans; D009055:Mouth / Q000502:physiology / Q000503:physiopathology; D009119:Muscle Contraction; D053580:Muscle Strength; D009213:Myography; D010791:Phrenic Nerve / Q000502:physiology; D011312:Pressure; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000534:rehabilitation; D012907:Smoking; D055815:Young Adult
keywords: Electric stimulation; Mechanomyogram; Respiratory muscle strength; Smoking