Bio-Medical Signal Analysis (Both normal and Abnormal)

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Outline:

Origin, Characteristics and analysis of heart sound & their ECG Waves (Both normal and abnormal)

Analysis of EEG (Both normal and abnormal)

Analysis of EMG (Both normal and abnormal)

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Origin, Characteristics and Analysis of Heart Sound & their ECG Waveforms

(Both Normal and Abnormal)

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Heart SoundAuscultation:

The Technique of listening to the sound produced by the organs and vessels of the body is called “Auscultation”.

In this technique, physician learn to recognize sounds or change in sounds that he can associate with various type of disorders. This technique is used to obtain information by listening the sound of hearts, lungs etc.

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Cause of Sound:

The principle cause of sound in the heart seems to be the vibration set up in the blood inside the heart due to sudden closure the valves.(Remember, opening a valve does not cause sound)

Instrument used:

The heart sound can be heard by physician through his stethoscope actually occur at the time of closure of major valves in the heart.

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Characteristics of Heart Sound:

There are four heart sounds SI, S2, S3 & S4.

Two heart sound are audible with stethoscope S1 & S2 (Lub - Dub).

S3 & S4 are not audible with stethoscope Under normal conditions because they are low frequency sounds.

Ventricular Systole is between First and second Heart sound.

Ventricular diastole is between Second and First heart sounds.

Analysis of Heart SoundFirst heart sound (S1)• It is produced due to the closure of Atrioventricular valves

(Mitral & Tricuspid)• It occurs at the beginning of the systole and sounds like LUB• Frequency:50-60 Hz• Time: 0.15 sec

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Second heart sound (S2)• It is produced due to the closure of Semilunar valves (Aortic &

Pulmonary)• It occurs at the end of the systole and sounds like DUB• Frequency:80-90 Hz [ High pitch ]• Time: 0.12 sec• It is short and sharp

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Third heart sound (S3)• It occurs at the beginning of one third part of next Diastole.• Cause of third heart sound – Rush of blood from Atria to

Ventricle during rapid filling phase of Cardiac Cycle. It causes vibration in the blood

• Frequency:20-30 Hz• Time: 0.1 sec

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Fourth heart sound (S4) or Atrial Sound

• It occurs at the last one third of Diastole (just before S1)• Cause of Fourth heart sound – Due to Atrial contraction which causes

rapid flow of blood from Atria to noncompliant Ventricle and vibration in the blood.

• Frequency: < 20 HzNote:• Third and Fourth heart sound are low pitched sounds therefore not

audible normally with stethoscope• S3 may be heard in children and young adults but usually pathological

in old age 10

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Heart Murmurs• Murmurs are abnormal sounds produced due to abnormal

flow of blood [turbulent blood flow] through abnormal heart valves e.g.. Stenosis or incompetence.

• Stenosis means narrow or stiff, valve that does not open completely.

• Incompetent means valve which does not close properly and remains open.

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13Comparison of Laminar and Turbulent Flow

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Demonstrations: Heart Sounds & Murmurs Normal Heart Sound : ` Murmurs and their Audio Examples Aortic Stenosis (Early) : Aortic Stenosis (Late) : Mitral Regurgitation : Pulmonic Stenosis : Aortic Insufficiency : Mitral Stenosis : Benign Murmur : Atrial Septal Defect : Ventriculat Septal Defect : Patent Ductus Arterious :

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Extra Heart Sounds:

Split S2 :

S3 :

S4 :

Rubs

Pericardial Rub (2 Component) :

Preicardial Rub (3 Component) :

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Waveforms

Normal Heart ECG

Aortic Stenosis

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Hypertrophies

Mitral Regurgitation

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Mitral Stenosis

Ventricular Tachycardia

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Analysis of EEG (Both normal and abnormal)

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severe epileptic seizure

epilepsy

22Alpha Coma

23Abnormal Slow Waves

24RMTD

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Analysis of EMG (Both normal and abnormal)

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(D) Myotonic discharges in a patient with dystrophia myotonica. There is a characteristic waxing and waning in frequency

(C)Fasciculations in the tongue in a patient with amyotrophic lateral sclerosis. The single discharges are irregular and occur on a background of ongoing EMG activity caused by poor relaxation

(B)Single, doublet, triplet, and multiplet motor unit neuromyotonic discharges. Bursts of discharge are irregular in frequency and the intra-burst frequency of discharge is up to 200 Hz.

(A)Fibrillations (*) and positive sharp waves (**) in an acutely denervated hand muscle

Abnormal Spontaneous Activity.

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Figure 4.11: Motor unit potentials from normal dorsal interosseus muscle during progressively more powerful contractions. In the interference pattern(c), individual units can no longer be clearly distinguished.(d) Interference pattern during very strong muscular contraction. Time scale is 10 ms per dot. (From J. A. R. Lenman and A. E. Ritchie. Clinical Electromyography. 2nd ed. . Philadelphia: Lippincott. 1977 : reproduced by permission of the authors.)

Conclusion As we have seen in the previous slides, Bio-medical signal analysis and Bio-

medical Image Processing are useful in detecting the various abnormalities in human body.

Sound Analysis is also helpful in detecting the type of abnormality in organs like in heart sound Analysis(14,15) or Auscultation.

On the basis of ECG also we can also analysis the type of abnormality like blockage of valves or increase in size of tissues or organ or abnormal variation in Blood Pressure/ Volume etc.(16,17,18)

With the help of EEG and EMG analysis, we are able to identify which part of Brain/muscle is not working properly .

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Further.....Electroneurogram (ENG):

The ENG is the electrical signal observed as a stimulus and the associated nerve action potential propagate over the length of a nerve.

Electrogastrogram (EGG):The electrical activity of the stomach consists of the rhythmic waves of depolarization and repolarization of its constituent smooth muscle cells.

Phonocardiogram (PCG):PCG is a vibration or sound signal related to the contractile activity of the cardiohemic system(the heart and blood together) and represent the recording of the heart sound signal.

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Carotid Pulse Signal (CPS):It is a recording of the pressure signal recorded over the carotid artery as it passes near the surface of the body at the neck.

Vibromyogram (VMG):The VMG is the direct mechanical manifestation of the contraction of a skeletal muscle. It records the muscle sound / vibration during movement with the help of micrometers / accelerometers.

Electrooculogram: This is used to record the retina movement.

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Reference “Biomedical Signal Analysis” by Rangaraj M. Rangayyan EOG by Hema L. Ramkumar or follow the link: http://

eyewiki.aao.org/Electrooculogram Various case Studies of ECG, EMG , EEG are taken from the following

links: AnaesthesiaUK : http://www.frca.co.uk/ American Heart Association or go to the link :

http://circ.ahajournals.org/ Computational Research Laboratory or go to the link:

http://cialab.ee.washington.edu/research/seizure Neuro Development Centre .Go to the link:

http://www.ns2.salamander-group.com/uploads/pics/eeg_traces. Heart Sound are taken from the database of University of Washington or

click on the following link: http://depts.washington.edu/physdx/heart/demo.html

http://en.wikipedia.org/wiki/Myopathy http://en.wikipedia.org/wiki/Peripheral_neuropathy

http://en.wikipedia.org/wiki/Neuropathy_(disambiguation)

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