Bioelectric Signals
g
Hsiao-Lung
H
i L
Chan
Ch
Dept Electrical Engineering
Chang Gung University
chanhl@mail cgu edu tw
chanhl@mail.cgu.edu.tw
Biopotential signals
From BH.Brown, Medical Physics and Biomedical Engineering, IOP Publishing Ltd, 1999.
HL Chan , EE, CGU
Biopotentials 2
HL Chan , EE, CGU
Biopotentials 3
Origin of biopotentials
Na+
Cl-
Extracellular
domain
Phospholipid
p
p bilayer
y
Intracellular
domain
K+
HL Chan , EE, CGU
Biopotentials 4
Passive channels

Selective permeable membrane
A-
Cl -
K+
Na+
Outside
(+)
Cl -
K+
Na+
Inside
(-)
HL Chan , EE, CGU
Biopotentials 5
Resting potential of a membrane premeable to one
ion (e.g. K+)
drift
Adiffusion
K+
K+
K+
K+
K+
K+
d[K  ]
J K ( diffusion )   D
dx
Cl -
Outside
(+)
Na+
Inside
(-)
Na+
Cl -
dv
d
J K ( drift )    Z [ K ]
dx

D: diffusion constant, Z: ion valence,
[K+]: ion concentration, μ: mobility,
v & -dv/dx
d /d : voltage
o age & e
electrical
ec ca field
e d ac
across
oss the
e membrane
e ba e
HL Chan , EE, CGU
Biopotentials 6
Resting potential from one ion (cont
(cont.))
d[K  ]
d
 dv
J K  J K ( diffusion )  J K ( drift )   D
 Z [ K ]
dx
dx
At equilibrium, JK = 0, the Nernst equation is derived as
RT [ K  ]o
E K  vi  v o 
ln
nF [ K  ]i
[ K  ]o
0
 0.0615 ln
(
V
)
at
37
C ((body
y temp
p erature))

[ K ]i
vi & vo : voltages outside and inside the membrane
n: valance
l
off K+
R: universal gas constant
T: absolute temperature in K
F: Faraday constant
HL Chan , EE, CGU
Biopotentials 7
Resting potential from mutliple ions

Goldman equation
At equilibrium
RT  PK [ K  ]o  PNa [ Na  ]o  PCl [Cl  ]i
ln 
E



F
P
[
K
]

P
[
Na
]

P
[
Cl
]o
i
Na
i
Cl
 K



PM : permeability coefficient of membrane for a
particular ion species M
HL Chan , EE, CGU
Biopotentials 8
Resting potential from mutliple ions
RT/F
The resting potential is -60
60 mV
HL Chan , EE, CGU
Biopotentials 9
Action potential
Na+
Na+
++++
++


+ + + Outside cell
Plasma membrane

Inside cell
++++
++
+++



K+
1
K+
Resting phase
3
Na+
N
Repolarizing phase
Na+
N



++++
++
+++
++++
++
+++

  



 
K+
Depolarizing phase
4
Membrane potential
(mV)
2
K+
2
+50
0
1
Undershoot phase
3
4
50
100
t
HL Chan , EE, CGU
Biopotentials 10
Action potential
HL Chan , EE, CGU
Biopotentials 11
Active channel: sodium
sodium-potassium
potassium pump

Remove 3 Na+ for every 2 k+
outside
K+ Na+
inside
K+ Na+
M. Bear et al, Neuroscience: exploring the
brain, Lippincott Williams & Wilkins, 2001.
HL Chan , EE, CGU
Biopotentials 12
Origins of
electromyography
HL Chan , EE, CGU
Biopotentials 13
Motor-unit firing pattern
SMUAP wave
t
y (t )   h(t   ) x( )d
0
IPI
Point process:
A series of impulse or
Dirac delta function
Inter pulse interval (IPI) >
Inter-pulse
SMUAP duration
R. Rangayyan, Biomedical Signal Analysis, John Wiely & Sons, 2002.
HL Chan , EE, CGU
Biopotentials 14
Prosthesis control using
g myoelectric
y
signal
g
(Myoelectric Control System at University of New Brunswick, Canada)
HL Chan , EE, CGU
Biopotentials 15
EMG during
g different movements
HL Chan , EE, CGU
Biopotentials 16
Cerebrum
(Frontal,Parietal,Temporal and Occipital lobes)
From JJ Carr, Introduction to Biomedical Equipment Technology, Prentice-Hall, 1998.
HL Chan , EE, CGU
Biopotentials 17
Brain
Cerebrum (大腦)
Thalamus (丘腦)
• Sensory and motor system
• Human behaviors ...
Hypothalamus (丘腦下部)
• Autonomic nervous system
• Temperature regulation
• Water and electrolyte
y balance
• Behavior response to emotion
• Endocrine control
• Sexual response ....
g
((延腦))
Medulla Oblongata
• Vital centers that regulates heart
rate, respiratory rate, blood
pressure, blood vessel, etc.
Cerebellum
C
b ll
(小腦)
• Coordinating skeletal
muscles and impulses
from cerebral cortex
M. Bear et al, Neuroscience: exploring the brain, Lippincott Williams & Wilkins, 2001.
HL Chan , EE, CGU
Biopotentials 18
Electroencephalogram (EEG)
M. Bear et al, Neuroscience: exploring the
brain, Lippincott Williams & Wilkins, 2001.
HL Chan , EE, CGU
Biopotentials 19
Biologocal neuron
HL Chan , EE, CGU
Biopotentials 20
Axon (軸突) to synapse (突觸) via neurotransmitter
HL Chan , EE, CGU
Biopotentials 21
Simplified synapse in biologocal neuron
HL Chan , EE, CGU
Biopotentials 22
Electroencephalogram (EEG) rhythms
HL Chan , EE, CGU
Biopotentials 23
EEG changes in sleep
HL Chan , EE, CGU
Biopotentials 24
EEG waveform recorded from one patient under sevoflurane
in different states
LZ complexity
awake state
intermediate
d
state
asleep state
HL Chan , EE, CGU
Biopotentials 25
Lempel-Ziv
Lempel
Ziv complexity
HL Chan , EE, CGU
Biopotentials 26
Estimation of depth of anesthesia by EEG/AEP
EEG monitoring
A dio evoked
Audio
e oked potential monitoring
monito ing
http://www.danmeter.dk/
HL Chan , EE, CGU
Biopotentials 27
EEG spikes or abnormal waveform in epilepsy
John G
G. Webster
Webster, Medical Instrumentation
Instrumentation, application and design
design, 3rd Ed.,
Ed
Houghton Mifflin, 2000.
HL Chan , EE, CGU
Biopotentials 28
EEG electrode placement
HL Chan , EE, CGU
Biopotentials 29
Multichannel EEG recodeings: NeuroscanTM
HL Chan , EE, CGU
Biopotentials 30
Monopolar measurements
HL Chan , EE, CGU
Biopotentials 31
Bipolar measuremesnts
HL Chan , EE, CGU
Biopotentials 32
Monopolar montage
Epilepsy spikes
HL Chan , EE, CGU
Biopotentials 33
Bipolar montage
Epilepsy spikes
HL Chan , EE, CGU
Biopotentials 34
Heart and electrocardiogram (ECG
(ECG, EKG)
HL Chan , EE, CGU
Biopotentials 35
Pacing rate of cardiac cells
John G. Webster, Bioinstrumentation, John Wiley & Sons, 2003.
HL Chan , EE, CGU
Biopotentials 36
Propagation of excitation pulse
Reporalization
Deporalization
R. Rangayyan, Biomedical Signal Analysis, John Wiely & Sons, 2002.
HL Chan , EE, CGU
Biopotentials 37
ECG features
R
T
P
Q S
P-R interval
R-R interval
S-T
interval
Q-T interval
R
U
QRS interval
P wave : Atrial depolarization
QRS complex : Ventricular depolarization
T wave : Ventricular repolarization
U wave : Slow repolarization of ventricular muscle
R-R : Heart period
P-R : Conduction delayy in the AV-node
Q-T, S-T : Ventricular repolarization time
HL Chan , EE, CGU
Biopotentials 38
Cardiac arrhythmia: premature ventricular
contraction (PVC)
John G. Webster, Medical Instrumentation, application and design, 3rd Ed.,
Houghton Mifflin, 2000.
HL Chan , EE, CGU
Biopotentials 39
Cardiac arrhythmia: atrioventricular block
John G.
G Webster,
Webster Medical
Instrumentation, application and design,
3rd Ed., Houghton Mifflin, 2000.
HL Chan , EE, CGU
Biopotentials 40
Cardiac arrhythmia: ventricular tachycardia (VT)、
atria flutter
John G.
G Webster,
Webster Medical
Instrumentation, application and design,
3rd Ed., Houghton Mifflin, 2000.
HL Chan , EE, CGU
Biopotentials 41
Cardiac arrhythmia: atrial Fibrillation (AF)、
ventricular fibrillation (VF)
John G. Webster, Medical
Instrumentation, application and design,
3rd Ed., Houghton Mifflin, 2000.
HL Chan , EE, CGU
Biopotentials 42
ST-segment
ST
segment elevation
John G. Webster, Medical Instrumentation, application and design, 3rd Ed., Houghton
Mifflin, 2000.
HL Chan , EE, CGU
Biopotentials 43
ST-segment
ST
segment depression (mostly in myocardial ischemia)
HL Chan , EE, CGU
Biopotentials 44
ST-segment
ST
segment elevation
HL Chan , EE, CGU
Biopotentials 45
Reference






John Enderle, Susan Blanchard, Joseph Bronzino, Introduction to
Biomedical Engineering, Academic Press, 2000.
John G. Webster, Bioinstrumentation, John Wiley & Sons, 2003.
John G. Webster, Medical Instrumentation, application and design, 3rd
Ed., Houghton Mifflin, 2000.
BH.Brown, RH.Smallwood, DC.Barber, PV.Lawford, and DR.Hose,
Medical Physics and Biomedical Engineering, IOP Publishing Ltd, 1999.
Joseph J. Carr, John M. Brown, Introduction to Biomedical Equipment
Technology, Pearson Education, 2000.
F.M. Ham, I. Kostanic, Principle of Neurocomputing for Science &
Engineering McGraw Hill,
Engineering,
Hill 2001.
2001
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Biopotentials 46