University Literature Review: COPD, Respiratory Muscles, EMG/MMG

This literature review examines the activity of the diaphragm, neck, and chest wall muscles in patients with Chronic Obstructive Pulmonary Disease (COPD), focusing on non-invasive diagnostic methods using Electromyography (EMG) and Mechanomyography (MMG) signal analysis. The review synthesizes existing research to explore respiratory muscle function and dysfunction in COPD, including the impact of the disease on muscle activity and the limitations of current diagnostic approaches. It investigates the causes of respiratory muscle dysfunction, the role of EMG and MMG in assessing muscle activity, and identifies gaps in current research. The review also discusses the importance of understanding respiratory muscle activity for effective COPD diagnosis and treatment, highlighting the potential for future research in this area. The findings suggest that the use of EMG and MMG could be valuable for understanding the dysfunctions of muscles and nerves.

Running head: LITERATURE REVIEW
LITERATURE REVIEW
Name of the Student
Name of the University
Author note

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DIAPHRAGM, NECK, CHEST WALL MUSCLES ACTIVITY IN COPD PATIENTS FOR
NON-INVASIVE DIAGNOSIS USING EMG AND MMG SIGNAL ANALYSIS.

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Table of Contents
Abstract............................................................................................................................................3
Introduction......................................................................................................................................4
Literature review..............................................................................................................................5
Respiratory muscle functions involving diaphragm, neck and chest wall muscles and
activation of COPD......................................................................................................................5
The muscle activity of the neck and the abdominal region in patients suffering from COPD....7
Assessment of the diaphragm muscles of COPD patients...........................................................8
The dysfunctions of the muscle fibres of the respiratory muscles including the diaphragm
muscles, neck muscles and the chest wall muscles...................................................................10
The main cause of the decrease in the functions of the muscles of the diaphragm, neck and the
chest walls..................................................................................................................................12
MMG signalling is one of the important and prominent way of measuring the functions of the
inspiratory muscles....................................................................................................................13
Literature gap.............................................................................................................................13
Conclusion.....................................................................................................................................14
Reference.......................................................................................................................................16

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Abstract
The aim of this research work is to analyse the muscle activity of the diaphragm, neck and the
chest wall in the COPD patients for the non-invasive diagnoses using the EMF and the MMG
signal analyses. This is a literature review which has been done by analysing different articles
from the past research works that are done on this topic. Few research articles were found which
included the studies about the diaphragm muscles, neck muscles as well as the chest wall
muscles. The reasons for the dysfunction of the respiratory muscles are discussed in this
literature review. The diagnosis of COPD is the first aspect of starting the treatment procedures
and thus analysis of the respiratory muscle activity will help in further analysis of the disease and
will help in the treatment of the disease. Important information regarding diseases are included in
the literature review. Most of the information that are given are about the muscular activities of
the diaphragm and it contains less information about the neck muscle and the chest wall muscle.
The non-invasive diagnoses using the EMG and MMG signal analysis has described the
activities of the muscles clearly. Till now not much research work has been done on this topic
and it provides a large scope for doing much research work in future.

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Introduction
A medical procedure is known as non-invasive when no break has been made in the skin
and no contact is there with the mucosa or any break in the skin. The range of non-invasive
procedures actually vary a lot. Since many years, the physicians are involving many non-
invasive treatment methods which are based on the physical parameters of the functions of the
body for the purpose of assessing the health of the person and the diseases. The Chronic
Obstructive Pulmonary disease is one of the major cause of death of large number of people
throughout the world. The main cause of this disease is smoking but sometimes the
environmental pollution also serves as major important causes of the lung diseases (El et al.
2017). The earlier stage of COPD is asthma and this disease is progressive but the exacerbation
and the severity of the disease can be controlled by following by methods like cessation of
smoking, managing the infections carefully. One of the major problems that the patients with
COPD are suffering is the intolerance of exercises. Though this disease is mainly characterised
by reduction in the capacity of the maximal respiratory flow. However in single and double lung
transplant, the exercise capacity has improved after the surgery. The patients suffering from
COPD are suffering from muscle dysfunction. If the deterioration of the exercise capability
increases with increase in exercise capability then, the muscle function will also be effected.
So, the increase in the muscle dysfunction needs to be reduced and the significant factors which
are involved in the muscle dysfunction needs to be identified. The loss of the functions of the
muscles of patients suffering from COPD have become a common phenomenon. This also leads
to the weaknesses of the neck muscles, diaphragm and the chest muscle walls (Stockley and
Stockley 2016). The muscle atrophy happens when a disbalance is created between protein
synthesis and the degradation shifts to the next protein breakdown. The intramuscular weakness

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of the patients suffering from COPD has become one of the matter s of major clinical relevance.
The research problem is diaphragm, neck and chest wall activity in COPD patients for non-
invasive diagnoses using EMG and MMG signals. The research question is whether the
respiratory muscle activity can be analysed by non-invasive measures or not and there is a huge
literature gap of this question with availing literatures. This study is really important in the
context of the diagnoses of the COPD patients. This study has much scope for research in future.
The thesis statement is the activity of the respiratory muscles can be measured by EMG and
MMG signalling. This report contains a detail literature review of the thesis statement involving
some related sub-points also. The main findings of this literature review is to know in details
about the theses statement and to know the past researches done on this. The results of the test of
EMG reveals the dysfunctions of muscles and nerves. This process involves the usage of
electrodes which records the electrical activity of the muscles. The mechanomyography is
another way for the examination of the characteristics of the muscles including the functions of
muscles, the control of the muscles, the signal processing, the physiological exercises and the
medical rehabilitation (McKenzie et al. 2009).
Literature review
Respiratory muscle functions involving diaphragm, neck and chest wall muscles and
activation of COPD
The functions of the respiratory muscles are different from all other muscles because this
muscle work throughout the life starting from the birth till the death of the person. The
diaphragm is the most important muscle also during when the person sleeps and this muscle has
the capacity to resist fatigue more than all other muscles. The functions of the respiratory

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muscles are compromised in the patients suffering from COPD. The resistive loads and the
elastic loads upon the muscle increases, the effective compliance also gets reduced as
inequalities in the constants of time happen (El et al. 2017). Reduction in the ability of the walls
of the chest happens and the tension length of the respiratory muscles gets reduced. Because of
this reason the driving in the respiratory muscles gets increased in the patients suffering from
COPD. Different methods were used for the purpose of driving the respiratory rates of the
patients suffering from COPD. Abnormalities in the exchanges of gases, increased in loads,
impaired chest wall mechanics are the poor indicators of the drive. In some previous research
articles it has been found that diaphragmatic EMG were high in patients suffering from COPD
rather than those who are not suffering from COPD, however the early oesophageal recordings
showed large changes in the amplitudes of EMG along with changes in the volume of lung and
the configurations of the thoracic cavity (Ottenheijm, Heunks and Dekhuijzen 2008) The total
number of motor units which are active can be derived by ding the combination of the results
derived from the increase in the firing frequency and the esophageal recordings of the EMG and
normally this value comes much higher in comparison to normal persons. The mechanics and the
geometry of the chest wall and the diaphragm also gets altered. The diaphragm functions well as
a generator of volume at the time of rest in patients suffering from COPD, it is compromise at
the time of doing exercises. The main reason for this is that a little reserve capacity is there for
the shortening of diaphragm at the end of the respiration (Stockley and Stockley 2016).
When the diaphragm of the person do not work properly, the start using other muscles of
the body like the muscles of the neck, the muscles of the shoulders and the muscles of the back
for the purpose of doing the activities of contraction and expansion of the chests. However all
these muscles do not provide the compensation fully for the weak diaphragm muscles. The

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patients who are suffering from higher COPD and hyperinflation show the phenomenon of in-
drawing of the lower muscles of the costal margin at the time of tidal breathing (Sanders et al.
2016). The muscles of the inter-coastal regions are rarely studied than the muscles of the
diaphragm region because of their complex relationships of the anatomical and geometric
structures. The hyperinflation of the COPD causes the reduction of the flow and pressure
generation capability of the diaphragm. This is again compensated by the increase in the neural
drive, adaptations in the walls of the chest and the also in the shape of the diaphragm for the
purpose of the accommodation of the increase in volume. Adaptations in the fibres of the
muscles are also done for the purpose of the preservation of the endurance and the strength
(Estenne, Derom and De Troyer 1998).
The muscle activity of the neck and the abdominal region in patients suffering from
COPD
Most of the patients suffering from COPD need not use the sternocleidomastoid muscles
when the person are breathing at rest. In contrasting with the patients who are not suffering from
COPD, the persons who are suffering from COPD also do the contraction of the abdominal
muscles in the resting conditions. Some also use the rib muscles for the purpose of breathing
during the resting conditions. The pattern of the activation of the respiratory muscles of the
patients suffering from COPD is relatively uniform and it is completely independent of the
nature of the disease from which the patient is suffering (McKenzie et al. 2009). It has been
proved experimentally that the patients are having a rapid and shallow breathing pattern than
those who are not suffering from COPD. According to the EMG data obtained, at the time when
the patients are at resting conditions, mostly patients show phasic activities of the inhibitory
scalene muscles. The EMG records show that the activity starts along with the start of the

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inspiration, it involves the motor units also and then reach at the end of the inspiration. However
at the same time it has also been proved that all patients who are suffering from COPD do not
show EMG results (Sarlabous et al. 2015). The abdominal muscle activities are also tested
during different experiments in which it was found that the rectus abdominis and the external
oblique muscles are mostly silent throughout the electrical signalling. However, the intermittent
phasic expiratory is found in the muscles of the rectus abdominis (Gea et al. 2015). Invariable
phasic expiratory activity has also been reported in some patients in the transverse abdominis.
Previous different EMG studies have showed that a huge difference exists in the procedures of
recruitment of the scalene and sternocleidomastoid muscle cells in humans. Previous researches
show that normal people who are not suffering from COPD mostly use the scalene muscles than
the sternocleidomastoid muscles at the time of respiration. The scalene muscles are also the most
active muscles in the healthy persons (Cè, Rampichini and Esposito 2015). It is proved that the
threshold for the activation of the sternocleidomastoid muscles is much more than the scalene
muscles. However experiments were done in the patients suffering from severe COPD to
measure the inspiratory activities in the scalene muscles at the resting phase of breathing and the
result showed that most of the patients who are involved in the experiment showed high
inspiratory activities in the scalene muscles but not in the srernocleidomastoid muscles. It is also
proved that the normal human beings do not use the muscles of the anterolateral walls of the
abdominal region during the tome of resting. When the persons who are healthy increase the
ventilation, recruitment of the transverse abdominis occurs (Jin et al. 2017). Many patients
having severe exacerbation of COPD shows contraction of the transverse abdominis in the
isolated manner at the time of expiration, this contraction do not have much impact on the
expiratory flow of air as they are at rest. Studies have established that patients the pattern of the

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muscles of the respiratory organs at the time of resting in patients suffering from thoracic
scoliosis in severe conditions is quite similar to that conditions shown by the patients suffering
from chronic obstructive pulmonary diseases (Lozano-García et al. 2018).
Assessment of the diaphragm muscles of COPD patients
El et al. (2017) in their research paper did the diaphragmatic assessments in the patients
suffering from severe COPD. The diaphragm has to be studied properly in order to properly
assess the patients suffering from severe COPD. According to the authors, ultrasonography can
be done for assessing the site, the structure and also the motions of the diaphragm, assessment of
the expiration rate, measuring the thickness and also in the diagnoses of the paralysed
diaphragm. For the purpose of the conduction of the experiments 10 mild stable COPD patients
were involved, 10 moderate stable patients having mild of the disease, 10 severe stable patients
having severe disease and 10 severe stable patients were involved (Chen and Hsiao 2018). The
patients were included in such a way that all of them showed medical history of COPD and at the
same time the control were taken in such a way considering the age and the sex. Patients having
diseases which effect directly to the diaphragm are excluded from participating from ant
experiments. Persons suffering from other chest diseases like asthma and patients who has
undergone recent surgery in the abdomen or in the thoracic region. Spirometry test was done for
checking the pulmonary test functions. To identify the diaphragmatic motion it is required to do
the ultrasonography of the patients at the time of breathing. The diaphragmatic excursion in the
supine position is far greater than in the sitting position or in the standing position (Marcus et al.
2015). The left hemidiaphragm is more difficult to visualize due to the presence of the spleen but
the right hemidiaphragm can be viewed. A transducer should be there for the purpose of viewing
the thickness of the diaphragm at the zone of the apposition. From this experiment it is seen that

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in the patients suffering from COPD a loss in the fat free mass is reported and the muscles also
showed much alterations in the mass, area and thickness of the diaphragm (Chen and Hsiao
2018). The ultrasonography is mainly done for the purpose of the evaluation of the thickness of
the diaphragm at variables of lung volumes. In the patients suffering from COPD, a non-invasive
evaluation of the diaphragmatic functions is an effective way for evaluating how severe the
disease is. It has been found that the maximal inspiratory pressure and the maximal expiratory
pressure were lower in the patients suffering from COPD than in the patients who were not
suffering from COPD (Finsterer and Drory 2016) When the malnutrition were combined with
pulmonary over infection then the muscle becomes more weak and this even lead to the
reduction in the ability of the respiratory muscles to make pressure over the tidal breathing. From
this experiment it can be seen that that MIP and MEP are the only non-invasive accurate
measures for the purpose of assessing the diaphragmatic functions. The diaphragm muscles are
the most important respiratory muscles and in any cases when a person suffers from chronic
obstructive pulmonary diseases the first diagnoses of the patient involves measuring the size and
the thickness of the diaphragm (Eddy 2015).
The dysfunctions of the muscle fibres of the respiratory muscles including the
diaphragm muscles, neck muscles and the chest wall muscles
Most of the previous studies about the weakness of the inspiratory muscles deals with the
diaphragm muscles mostly and do not give much preference to the other muscles. This is because
the diaphragm is the principle muscle for respiration. The trans-diaphragmatic pressure in the
patient suffering from COPD is lower than the normal healthy patients. The diaphragm
shortening has been reported because of the hyperinflation however not such incidences about
the shortening of the neck muscles or the chest wall muscles have been reported (Kang, Jeong

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and Choi 2016). Shifting of the fibre muscles have been reported from the diaphragm muscles
but not in the neck muscles or in the chest wall muscles. The chest wall and the neck muscles
seem to be less effected than the diaphragm muscles. According Coen et al. (2007), several
molecular changes and the cellular changes occur in the diaphragm muscles than the neck and
the chest wall muscles in patients suffering from COPD. The proportion of muscle fibres which
are slow fatigue resistant increases where as those fibres who are fast fatigue resistant decreases.
It is also mentioned by the authors that the oxidative capacity of the muscle of the diaphragm
increases than the neck muscles or the chest muscles. As the COPD progresses, the electron
chain functions of the diaphragm muscles also gets increased. In vivo, the diaphragm do not give
maximum isometric contractions rather it gets shortened against a submaximal load (Adami et
al. 2017). Recent studies show that at a particular calcium concentration, the force generated in
relation to the maximum force is lower in the patients suffering from COPD than the healthy
persons. The dysfunction of the muscles contribute to the prognosis of the disease. Patients
suffering from moderate COPD normally do not face the problems of diaphragm atrophy
(Estrada Petrocelli 2016). These patients even do not show atrophy of the neck muscles and the
chest muscles. The atrophy of the striated muscles can be due to increased proteolysis or
reduction in the synthesis of proteins though few resources are available on the effects of the
disease COPD on the protein synthesis of diaphragm muscles, neck muscles and the chest wall
muscles. Recent studies have reported the activation of the proteolytic pathways in the
diaphragm of patients suffering from COPD, but nothing like that has been reported regarding
the activation of the proteolytic pathways in the neck muscles and in the chest wall muscles.
Previous studies have also showed that the main injury at the time of COPD occurs in the
diaphragm muscles only and not in the other muscles. According to Coen et al. (2007), the cross