Muscle Activity in COPD Patients for Non-Invasive Diagnosis

This literature review analyzes the muscle activity of the diaphragm, neck, and chest wall in COPD patients for non-invasive diagnosis using EMG and MMG signal analysis. It discusses the respiratory muscle functions, muscle activity in COPD patients, and the dysfunctions of respiratory muscles. The review also highlights the importance of non-invasive diagnosis and the scope for future research in this area.

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

1LITERATURE REVIEW
DIAPHRAGM, NECK, CHEST WALL MUSCLES ACTIVITY IN COPD PATIENTS FOR
NON-INVASIVE DIAGNOSIS USING EMG AND MMG SIGNAL ANALYSIS.

2LITERATURE REVIEW
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

3LITERATURE REVIEW
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.

4LITERATURE REVIEW
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

5LITERATURE REVIEW
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

6LITERATURE REVIEW
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

7LITERATURE REVIEW
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

8LITERATURE REVIEW
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

9LITERATURE REVIEW
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

10LITERATURE REVIEW
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

11LITERATURE REVIEW
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

12LITERATURE REVIEW
sections in the diaphragm showed no injury however the length of the sarcomere is shorter. The
concept of the pathophysiology shows that shifting towards the more oxidative diaphragm fibres
are actually beneficial ad it leads to the overloaded diaphragm to be more resistant to fatigue.
The patients suffering from severe COPD normally do not develop the diaphragmatic contractile
fatigue. The main causes of the muscle dysfunctions are the interactions are the local factors and
the systematic factors. Apart from the structural changes the muscles also show oxidative stress,
damages and epigenetic changes. The cells also show signs of apoptosis and autophagy and
again an imbalance is created in between the synthesis of proteins and the breakdown
(Duiverman et al. 2017). The injury in the muscle fibres are regenerated especially in the
diaphragm muscles rather than the muscles of the neck and the chest wall muscles. The
regeneration occurs so as to prevent the loss of the mass of the muscles. The muscle cells which
are less injured or injured from normal diseases show an elevated level of the myosin chain
isoforms however patients suffering from COPD showed lower regeneration capacity than the
normal cells which are injured.
The main cause of the decrease in the functions of the muscles of the diaphragm,
neck and the chest walls.
The main cause of the decrease in the functions of the diaphragm muscles, neck muscles
or the chest wall muscles is pulmonary emphysema. This happens because of the sudden increase
in the volume of lungs. This is known as pulmonary hyperinflation. Because of this the muscles
of the muscles of the diaphragm gets shortened and flattened. However the muscles of the neck
and the chest wall rarely gets shortened. The ability to develop the contractile forces of the
muscles also gets decreased. The respiratory airways gets shortened. All the respiratory muscles
are not subjected to the local mechanical and the local metabolic factors (Smith, Chang and

13LITERATURE REVIEW
Hodges 2016). Unlike the other muscles of the body, the muscles of the diaphragm, neck and the
chest muscles are influenced more by the systematic factors like the oxidative stress and the
inflammations, depletions of the nutrients of the body and also the effect of certain drugs.
However disregarding all the causes of the hampering the respiratory muscles, the muscles show
an impairment in the properties of the functions of the muscles (Kharbanda, Ramakrishna and
Krishnan 2015). The diaphragm of the COPD patients along with the muscles of the neck and the
chest wall show an increase in the muscle strength than the respiratory muscles of the healthy
persons show. The striated muscles easily gets accustomed according with the changes in the
environment. Several authors have already discussed that the respiratory muscles originally
undergo changes in the structures and the metabolism of the muscles. The phenotypic changes
that the muscles undergo include the changes in the structural proteins like the isoforms of the
myosin heavy chains, content of the mitochondria and the capillary (Loprinzi, Sng and Walker
2017).
MMG signalling is one of the important and prominent way of measuring the
functions of the inspiratory muscles
The study of the mechanomyographic signals is one of the prominent way of the
measurement of the functional activities of the inspiratory muscles. According to Torres et al.
(2010), the researchers used the MMG signals of the muscles of the diaphragm, in order to do the
evaluation of the respiratory muscular functions of the persons suffering from COPD. In this
experiment, the researchers used the MMG signals from both the left and right hemispheres by
taking the help of two capacitive accelerometers which are placed both on the right and the left
side of the coastal wall surface (Di Marco et al. 2015). The signals of the MMG was recorded
from the right and the left hemi-diaphragm and the signal of the inspiratory pressure were

14LITERATURE REVIEW
measure when the patients suffering from COPD were carried out the inspiratory load respiratory
test. The patients who were taken in the experiment were suffering from severe COPD. A high
correlation coefficient was found between the pressure of the maximum inspiration and the
amplitude of the parameters from both the right and the left signals of the MMG. The slope of
the MMG signals were obtained when the load was increased during the respiratory test. All the
results obtained from this experiment showed that the information that are provided by the MMG
signals can be used in future for the purpose of evaluating the respiratory effort and also in
finding the efficiency of the muscles in the patients suffering from COPD (Barreiro and Gea
2015).
Literature gap
The topic of the research work is ‘diaphragm, neck, chest wall muscle activity in COPD
patients for the non-invasive diagnoses using the EMG and the MMG signal analysis’. The most
important matter of concern about this topic is that most of the researches that are done till now
are mostly on the diaphragm muscles but not on the neck muscles and the muscles of the chest
wall. Especially regarding the matters of the non-invasive treatment most of the past researches
are on the diaphragm muscles and not on the muscles of the neck and the chest muscles. So a
large literature gap is there as not much previous research works have been found regarding the
EMG and MMG signalling ad the non-invasive measures in the diagnoses of the muscles of the
diaphragm muscles, neck muscles and the chest wall muscles. COPD is one of the important
disease from which people from all over the world are suffering. So much more researches need
to be done on this diseases regarding the muscular activities of the diaphragm, neck and the chest
wall. In most of the papers found for doing this literature review the diaphragm muscles are

15LITERATURE REVIEW
considered as the main respiratory muscles, the authors rarely bothered about the neck, chest or
the abdominal muscles. Very few papers were found relevant to this research topic.
Conclusion
The chronic obstructive pulmonary diseases is one of the deadly diseases which takes the
life of many people every year. Proper diagnoses is one of the important factor not only for
COPD but for all other diseases. Most of the people die because of the unavailability of proper
treatment. The poor sections of the society rarely have money to spend on their health and they
are thus devoid of proper treatments which ultimately lead to the death of the person. After
completing this research work, much factors about the non-invasive diagnoses by using EMG
and MMG signals to measure the activities of the muscles of the diaphragm, neck and the chest
wall muscles are revealed. In some researches the muscle activity of the diaphragm muscles were
measured by the EMG and the MMG signals. After analysing the results of the EMG and the
MMG, the changes in the activity of the muscles can be identified. Much differences in the
activities of the muscles were found in the patients suffering from COPD than the healthy
persons. Tough much researches are still not done about the muscular activities of the neck and
the chest wall. The authors of the most of the articles preferred the diaphragm muscles than the
other respiratory muscles. There are many limitations regarding the research work and also much
limitations were there in the previous works. Most of the previous research works about this
topic are systematic reviews. A few related articles are there which involved the case control
methods. Chances are there for the creation of bias if systematic articles are used for doing a
research work. The result that are obtained from the articles, used for doing this work may not be
appropriate as most of the results are obtained from systematic journals. Even the research
articles that collected the data by primary collection methods did not involve accurate ways of

16LITERATURE REVIEW
deliberating the results. Even the languages that are used by some authors are not appropriate in
all respects. Much scope is there to do further research studies in this research area. It is already
proved that much research has not been done in this research area, especially in the field of the
non-invasive methods of diagnosis of the COPD patients by using the EMG and the MMG
signalling pathways. So a vast scope is there for ding future researches in this field. This
literature review will also help a lot in future for doing further analysis in this topic.

17LITERATURE REVIEW
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