A FUZZY EXPERT SYSTEM DESIGN FOR ANALYSIS OF SOUNDS

PRODUCED BY THE HUMAN BODY &

DESIGN OF AN UNIQUE ELECTRONIC STETHOSCOPE

B.HEMA KUMAR

Under the guidance of

Mr.G.BALASUBRAMANIANSenior Lecturer,

Biomedical Signal Processing

&

Instrumentation

SASTRA Deemed university

FES for heart sounds, lung sounds, intestinal sound analysis

Design of an electronic circuit to detect and amplify sounds from human body.

Comparison of electronic stethoscope with conventional stethoscope.

SOFTWARE

Twenty volunteers and twenty patients in each category (for cardiac sounds, lung sounds and intestinal sounds) randomly selected with different age, sex and clinical symptom, who were referred to the outpatient department of a major hospital.

Auscultatory findings were given to the engineer for designing a FES for each category of cases.

Fuzzy expert system design was done using fuzzy logic toolbox of MATLAB 6.1

MATERIALS AND METHODS

MATERIALS AND METHODS

HARDWARE

The electronic stethoscope was developed under the guidance of an electronic expert.

On a scale of three (1. Good 2. Better 3. Best) the doctors were asked to evaluate the overall performance of both the conventional and electronic stethoscope as per the questionnaire given to them.

STRUCTURE OF FUZZY EXPERT SYSTEM

SOUND ANALYSIS

(MAMDANI)

CONDITION

INPUT 1

INPUT 2

INPUT 3

INPUT 4

HEART SOUNDS ANALYSIS

INPUT VARIABLES

Heart sound absence or presence (HSA, HSP)

Intensity (NOR, DEC, INC)

Number of heart sounds heard (L2S, M2S)

Presence or absence of added sounds (ASP,ASA)

Character of the heard sound (NOR, ABN)

OUTPUT VARIABLE

Patient condition (CDN)

DISEASES

PERICARDIAL EFFUSION

LEFT VENTRICULAR FAILURE

AORTIC STENOSIS

MITRAL STENOSIS

SAMPLE RULE

If (HSP/A is HSP) and (INT is INC) and (CHAR is ABN) then (CDN is MS)

CDN = AORTIC STENOSIS

LUNGS SOUNDS ANALYSIS

INPUT VARIABLES

Breath sound absence or presence (BSA, BSP)

Normal vesicular or Bronchial (NORV, NORB)

Presence or absence of added sounds (ASP,ASA)

If added sounds present (rals or rhonchi) (ASRA, ASRO)

Nature of the heard sound ( tubular or cavernous ) (T, C)

OUTPUT VARIABLE

Patient condition (CDN)

DISEASES

Lung Consolidation

Lung cavity

Lung Parenchymal Disease

Lung Bronchial Disease

SAMPLE RULE

If (BSP/A is BSP) and (ASA/P is ASP) and (ASRA/RO is ASRO) then (CDN is LBD)

CDN =Lung bronchial disease

INTESTINAL SOUNDS ANALYSIS

INPUT VARIABLES

Intestine sound absence or presence (ISA, ISP)

Intensity (NOR, DEC, INC)

Duration (SD, LD)

Site of the heard sound (UA, LA)

OUTPUT VARIABLE

Patient condition (CDN)

DISEASES

PERITONITIS PERFORATION LARGE INTESTINAL OBSTRUCTION SMALL INTESTINAL OBSTRUCTION

SAMPLE RULE

If (ISA/P is ISP) and (INT is INC) and (DUR is LD) and (SITE is UA) then (CDN is SIO)

CDN = Small intestinal obstruction

PREAMPLIFIER Amplify low level signals

BUFFER AMPLIFIER Second stage of amplification

FILTER CIRCUIT To suppress whistling sound due to high feedback

MAIN AMPLIFIER TBA 810 versatile audio amplifier

1 Intensity 1 2

2 Number 1 2

3 Opening snap 1 2

4 Murmur 1 2

5 Click 1 2

1 Vesicular 1 2

2 Bronchial breath sound 1 2

3 Added sounds 1 2

1 Intensity 1 2

2 Character 1 2

The paper describes a design of a fuzzy expert system for determination of the possibility of the diagnosis of the abnormal body sounds, which can be used by the doctors with hearing impairment and by the students for learning the sounds.

Developed FES for various body sounds were compared with the clinical data given by the doctor under different clinical settings

The electronic stethoscopes scored over conventional stethoscopes by its better audibility, quality etc.

A good CS cost about Rs 125/- whereas a good ES will cost any where between 7000 to 8000 (About seventy times) whereas ours -- 1500/-

One distinct advantage of ES is its extent of audibility of sounds for in a CS only the examining doctor can hear the sound.