Engineering, 2013, 5, 90-93
http://dx.doi.org/10.4236/eng.2013.510B018 Published Online October 2013 (http://www.scirp.org/journal/eng)
Copyright © 2013 SciRes. ENG
Regulation of E lectroacupu ncture on Gastric Myoelectrial
Activities: Monitered by Ele ctrogastrogram s
1Research Center of Biomedical Engineering, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
2Shenzhen Key Laboratory for Minimal Invasive Medical Technologies, Shenzhen, China
Received December 2012
It is reported that acupuncture on some acupoints can enhance the regularity of gastric myoelectrical activities, which
can be observed from the electrogastrograms (EEGs). In this paper, the electroacupuncture (EA) treatments were per-
formed on subjects with slight gastric disorders and the EEGs were monitored in the mean while. The EEGs features of
baseline, during and after EA treatments were analyzed. The results show that the EA treatments do enhance the regu-
larity of EEGs. And a highly possible pattern for EA to attain the enhancement is to regulate the pacemaker quantity
and propagation of slow waves rather than regulating the amplitude of slow waves.
Keywords: Acupuncture; Electroacupuncture; Gastric Disorder; Electrogastrog rams; Gastric Myoelectrial Activity
Being practiced in China for tens of centuries, acupunc-
ture now is accepted to treat some kinds of diseases in
both East and West. Especially, in recent decades, acu-
puncture is becoming a popular non-medication therapy
for the patients with functional gastrointestinal disorders
(FGIDs), which has the prevalence as high as 40% - 70%
in general population. The electroacupuncture (EA) and
cutaneous electrical stimulation on acupoint are applied
and reported as effective as the traditional manual acu-
puncture in the recent decades [1-3]. The acupoints Zu-
sanli (Stomach-36, ST36, at the lower limb) and Neiguan
(Pericardium-6, PC-6, at the wrist) are the most com-
monly used points in treating FGIDs. Ouyang  and
Takahashi  reviewed the research on applications and
mechanisms of acupuncture for the treatment of FGIDs
respectively. The efficiency of acupuncture on FGIDs is
certified, but its mechanism still remains unc lear .
As a noninvasive measurement of gastric function,
electrogastrograms (EGGs) gain much attention in diag-
nose and treatment of gastric disorders in recent decades.
EGGs are measurements of the gastric myoelectrical ac-
tivities, which are composed of rhythmic slow waves and
spikes. EEGs usually refer to the surface measurements
by placing electrodes on the abdominal skin. As recor ded
cutaneously, the EGGs present a weighted summation of
the electrical activities of var ious regions of the stomach.
Studies have shown that the cutaneous electrodes can
only pick up the rhythm of the slow waves but not that of
the spikes. The normal frequency of slow waves in hu-
man is about 3 cycles per minute (3 cpm or 0.05 Hz).
The slow waves of 2.4 - 3.7 cpm are defined as normal
slow waves, and less than 2.4 cpm as bradygastria, more
than 3.7 as tachygastria [6-8].
It is reported that acupuncture on some acupoints can
enhance the regularity of gastric myoelectrical activities
[1,3-5]. It can be observed from the EEGs. The percen-
tage of normal slow waves is increased significantly
during acupuncture and after acup uncture is increased
slightly or similar to the baseline .
In order to obtain more information from EEGs, some
new methods and parameters were proposed [9-11]. In
this paper, EEGs were monitored before, during and after
acupuncture treatments on subjects with gastric disorder s.
The features of EEGs were studied and compared. The
efficiency of acupuncture on regulating gastric myoelec-
trical activities were certified once more, and a possible
pattern of the regulation can be derived.
2. Materials and Methods
Eleven volunteer subjects with slight gastric disorder or
discomfort participated in this study, including 2 males
and 9 females, aged from 23 to 61 (average 37.5). All
subjects were fasted for more than 10 hours before the
2.2. EEG Measurement
To obtain the EEG data, five Ag/AgCl electrodes were
Copyright © 2013 SciRes. ENG
placed on the abdomen, including four active electrodes,
and one reference electrode. The first active electrodes
was positioned 45 degree upper left of the midpoint be-
tween the umbilicus and the xiphoid process with an in-
terval of 2 - 3 cm, the last active electrode was positioned
1 - 3 cm right to the midpoint mentioned above. The other
two were placed between them with proper distance. The
reference electrode was positioned on the right ribs with
the same height of the first electrode. Four-channel EGG
signals were derived with sample frequency of 4 Hz by a
multichannel physiological signal recorder (RM6280C
Chengdu Instrument Factory, Chengdu, China) by con-
necting each active electrode to the reference electrode.
2.3. Electroacupuncture Experim en t
Electroacupuncture (EA) was performed on acupoints
Zusanli (ST36) on both legs. The acupuncture needles
were inserted into Zusanli points firstly. When the sub-
jects get the sense of “Deqi”, the needles were connected
to an electrical acupuncture instrument (HANS LH-
202H). The 2-Hz squared pulse was delivered. The cur-
rent of pulse was gently increased from 1mA until the
subject can feel it, then the current kept with such suita-
ble intensity during the EA experiment.
EGGs were recorded before (baseline), during and after
the EA experiment for at least 20 minutes respectively.
2.4. Data Processing and Analysis
After preprocessed by low-pass filter, The EGG raw data
were fed into an adaptive filter  and extracted by the
method of independent component analysis with refer-
ence (ICA-R) . The output data were denoised and can
represent the slow waves of the gastric myoelectrical
The following parameters are analyzed (see Figures
1) The dominant frequencies (DFs) over whole data
2) The instability coefficients (ICs) of subsection DFs
3) The time percentages (TPs) and relative power per-
centages (R-PPs) of normal slow waves, they pr esent the
proportions of normal slow waves in time duration and
power respectively .
4) The time-p ower percentages map of normal slow
waves, which is plotted by TPs of normal slow wav es on
the horizontal axis and R-PPs on the vertical. From the
map, it can be derived that the amplitudes of normal slow
waves are higher or lower than those of abnormal slow
waves (bradygastria or tachygastria). If the power in unit
time or amplitude of different kinds of slow waves is
(normal, bradygastria or tachygastria) close to each other,
TPs and R-PPs should be close, and the point in Time-
Figure 1. DFs of baseline, duri ng EA and after EA. The box
presents the median and the standard deviation; the whisker
presents the maximum and minimum; the symbol ‘+’ pre-
sents the mean value.
Figure 2. DFs over whole data of each subject.
Figure 3. TPs and R-PPs of normal slow waves. (a) TP of
normal slow waves; (b) R-PP of normal slow waves. The
symbols are the same as Figure 1.
Figure 4. ICs of subsection DFs. (a) ICs of all subsec tio n DF s;
(b) ICs of subsection DFs within the normal range. The
symbols are the same as Figure 1 .
Power map of normal slow waves should be near the
diagonal. If the amplitude of normal slow waves is higher
than that of abnormal slow waves, the point should be
above of the diagona l, vice versa .
Copyright © 2013 SciRes. ENG
Figure 5. Time-power percentages map of normal slow
3.1. DFs over Whole Data
The distributions and statistic boxes of DFs over whole
data are shown in Figure 1, and for each subjects in
Figure 2. The box presents the median and the standard
deviation; the whisker presents the maximu m and mini-
mum ; the symbol “+” presents the mean value. The DFs
are raised slightly during EA than b aseline. But the re are
no significant differences between each two sections.
3.2. TPs and R-PPs of Normal Slow Waves
The results of TPs and R-PPs of normal slow waves are
shown in Figure 3. Compared with baseline, the TPs and
R-PPs of normal slow waves increase both during and
after EA. It means that the regularity of EGG slow waves
or the regularity of gastric myoelectrical activities are
enhanced by EA, and the effect works on both time dur a-
tion and power proportions can sustain at least 20 mi-
nutes after the EA.
3.3. ICs of All Subsection DFs and of Subsections
DFs within the Normal Range
The ICs of all subsection DFs including normal slow
waves, tachygastria and bradygastria are analyzed (Fig-
ure 4(a)). The ICs during and after EA are much lower
than baseline, which means the DFs of subsections were
more stable under the regulation of EA, and the effect
can sustain at least 20 minutes after the EA. That is in
accord with the results of TPs and R-PPs of normal slow
Particularly, the subsection DFs only of normal slow
waves were analyzed to see if the acupuncture affects the
regularity of normal slow waves (Figure 4( b)). The re-
sult show that the stability of subsections DFs of normal
slow waves are not increased by EA, which means the
EA does not make the normal slow waves “more regular”.
Hence, it may be derived that the EA enhances the regu-
larity of EGGs by making the abnormal slow waves (ta-
chygastria and bradygastria) “more regular” and tending
to be normal.
3.4. Time-Power Percenta ges Map of Normal
The time-power percentages map of normal slow waves
of baseline, during EA section and after EA section is
shown in Figure 5. Compared with baseline, the points
of during and after EA section are centralized to the di-
agonal obviously. It means that both duration and power
are regulated, and the amplitudes of normal slow waves
and abnormal slow waves tend to be equal to each other
during and after the EA treatment.
4. Conclusions and Discussion
In this paper, the EA treatments were performed on sub-
jects with slight gastric disorders and the EEGs were
monitored before, during and after the EA treatments.
Besides the commonly used dominant frequencies, insta-
bility coefficients of subsection dominant frequencies
and time percentages of normal slow waves, we intro-
duced relative power percentages of normal slow waves
and time-power percentages map.
It is certified that acupuncture can enhance the regu-
larities of gastric myoelectrical activities, as in the cur-
rent paper. Assuming there are several possible ways for
acupuncture to attain the enhancement, a) by inhibiting
the generation of abnormal slow waves, so that the ab-
normal pacemakers are reduced or converted to normal;
b) by decreasing the amplitude of abnormal slow waves
or increasing that of normal ones; c) by decreasing the
propagation range of abnormal slow waves or extend that
of normal ones. The assumption b) has been disproved
by Result D Time-power percentages map of normal
slow waves, which tells us the amplitudes of normal slow
waves and abnormal slow waves tend to be equal to each
other during and after the EA treatments. Hence, a possi-
ble pattern is that the EA treatments regulate the pace-
maker quantity and propagation of slow waves rather
than regulating the amplitude of slow waves to attain the
regularity enhancement of EEGs.
The generation and propagation details of gastric
myoelectrical activities seem difficult to be figured out
by the surface recorded EEGs which essentially are con-
volutional results of loca l gastric myoelectrical activities.
The multichannel intraluminal (serosal or mucosal) re-
cordings of gastric myoelectrical activities could be
much more accurate in localization of myoelectrical ac-
tivities and with the potential in research on generation
and propagation of myoelectrical activities.
Copyright © 2013 SciRes. ENG
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