Michal Šimera 2013. What is lecture about? ⇒ Measurement of electric biological signal ⇒ Measurement of non-electric biological signal ⇒ Processing of.

Michal Šimera2013

Biocybernetics – cybernetics systems,Model and modelling,

Theory of an information, Systems theory

What is lecture about? ⇒ Measurement of electric biological signal⇒ Measurement of non-electric biological signal⇒ Processing of electrical signals⇒ Display devices⇒ Computers, principle of function ...⇒ Use of computers in medical practice⇒ Transmission of information, signal, coding⇒ Regulating system

Lecture symbol

⇒ good to know for the exam

Please enjoy the lecture

CyberneticsThe term cybernetics stems from Ancient Greek (kybernētēs, meaning steersman) arouse as independent science orientation after World War II.

The originator of cybernetics is an american mathematician Norbert Wiener (1894-1964).

Cybernetics is a transdisciplinary approach for exploring regulatory systems, their structures and properties. Cybernetics is relevant to the study of systems, such as mechanical, physical, biological, cognitive and social systems.

Systematic application of theoretical knowledge from mathematics, chemistry, physics in study of biological systems ⇒ Biocybernetics.

So what is the meaning of Biocybernetics?Biocybernetics plays a major role in systems biology, seeking to integrate different levels of information to understand how biological systems function.

Medical cybernetics applies the concepts of cybernetics to medical research and practice

... development of new materials for medicine micro and nano-technology ⇒

development of new diagnostic tools and methods ⇒

⇐ development of new diagnostic softwares, simulations ...

Interactions

The organism continually interacts with the surroundings and with other systems ⇒ it uses an INFORMATION

organism perceives signals arriving from the external world and processes the information of these signals.

change of a statea response

Theory of an information⇒ Information is a sequence of symbols that can be interpreted as a message which express state and behavior of subject

⇒ Information is created during description of subject state and its behavior

Types of information:

analog – human body perceives an information through receptors (sound, light, pressure, temperature)

digital - progression of 1 and 0, which carrier an information about a sound or an image...(e.g.: 10100101101111)

1 Bit is a basic unit of an information

Information transmission

SOURCE ofinformation

TransmitterCHANNEL

NOISE

ReceiverUSER

The signals are transmitted to the receiver through a channel

Signals may comprise noise, which may distort the original meaning of the information.

Code is a rule for converting a piece of information (for example, a letter, word, phrase, or gesture) into another form or representation

The sensory pathways provide information on stimulus type, intensity, and location.

Information (action potentials) are coded by frequency not by amplitude

PRIMARY SENSORY CODING

Example: increased stimulus intensity an increased action potential

frequency in a single afferent nerve fiber.

Actionpotential

Pressure

Information source the sound arriving at the ears

Coding

the hair cells of the organ of Corti

Þ during the movement of Basilar membrane, the mechanical vibration of the hair cells is transformed into a generator potential and the action potential of the fibres of the auditory nerve. Both potentials result in microphone potential.

Channel Þ the fibres of the auditory nerve and

the information is carried by action potential signals

Receiver a brain

Genetic information

Genetic information is transported in 3 levels, while each level is regulated

DNA → RNA → a protein

⇒ Genetic information is written in primary structure of a DNA (RNA) molecule

⇒ DNA determines a protein structure

There are 2 different „alphabets“:

1. Nucleic acid – 4 letters C, G, A, T (U)2. Amino acid – 20 letters

Biological signal = carrier of information

Are generated in life organism ⇒ Biosignal is an information about body apparatus activity and their relations with the surrounding

Biosignals are created: ⇒ by vital manifestation of organism (during functioning of organs – heart, brain ....)

⇒ by stimulus from external space (interaction of organism with: electrical current, magnetic field, ionizing radiation ... (CT, MRI, SONO, X-ray ...)

Biologicals signals created by vital manifestation

Type of manifestation Type of sampling Diagnostic tool

Mechanical manifestation- movement- speed- pressure

mechanoelectrical transducer

spirometryfonocardiographyapexcardiography (heart apex beat) hrotu)tonometry (eye pressure)ergometry

Temperature manifestation- body temperature- Surface temperature- IR radiation

thermometerliquid crystalIR detectorcalorimeter

thermometrycontact thermographytermovision

Active electric properties (AP) electrodes ECG, EMG, EEG, ERG

Magnetical manifestation Quantum magnetometer MCG, MMG, MEG

Internal enviromental factors- pH- pO2- pCO2

electrodes Monitoring of internal enviroment

Biologicals signals created by stimulus from external space

Quantity Type of modulation Displaying tool Diagnostic tool

Röntgen radiation reduce the amount of X-rays photographic plates photographic film digital detector

sciagraphysciascopy

Nuclear radiation photons emission positrons emission scintillation detector

gama cameraSPECTPET

Visible light reflection and refraction of light

an eyecamera

endoscopyvideoendoscopy

Ultrasound reflectionchange in frequency piezoelectric senzor ultrasonography

doppler

Electrical current electrical conductancestimulation electrodes reopletysmography

chronaximetry

Electromagnetic field resonance measurement coils MRI

Method Frequency band Voltage

Elektrocardiography 0,5 - 250 Hz 0,5 - 4 mV

Elektroencefalography 0,5 - 100 Hz 5 - 300 V

Elektromyography 1,5 - 10 000 Hz 0,1 - 5 mV

Elektrogastrography 0 - 1 Hz 10 - 100 V

Electroneurography 1 - 10 000 Hz 0,01 - 3 mV

Blood pressure 0,05 - 50 Hz

Pressure in urinary bladder 0 - 10 Hz

Blood flowing 0,05 - 20 Hz

Fonocardiography 15 - 2000 Hz

Psychogalvanic reflex 0,01 - 1 Hz

Respiratory rate 0,03 - 1 Hz

Biological signals

according to their physical entity are divided into

ELECTRICAL SIGNALS ⇒ generated as a result of electrical actions, which are happened in plasma cell mambraneECG, EEG, EMG, ENG....

NON-ELECTRICAL SIGNALS ⇒ movements, deflections, pressure, voltage, volume or floving changese.g.:Expenditure of the heart - blood volume ejected by the heart muscle for some instant of time (normal value is 5,5 l·min-1 )

electrical

non-electrical

For recording of electrical signals electrodes are used

Polarized electrodes ⇒ they have a changeable electrode potential during of el. current flowingElectrodes are made for high-grade metals such as Au, Ag, Cu

⇒ do not react with tissue Non-polarized electrodes ⇒ - they have a stable electrode potential Silver-chlorine electrode (Ag-AgCl)

Types of electrodes:

Macroelectrodes

⇒ surface – A sticker that is attached to the skin to measure or cause electrical activity in the tissue under it

⇒ needle - puncture needle for EMG recording

Microelectrodes

⇒ is an extremely small electrode with a tip which is capable of being inserted into the wall of a single cell without causing damage.

⇒ for processing a non-electrical signals transducers are usedTransducers convert non-electrical signals to electrical current or

voltage waveforms,Blood pressure measurement:

catheter – pressure senzor - electromanometer

Transducers :

CapacitiveInductivePiezoelectric ...

ArterySaline filled catheter

Pressure transducer

The inductive transducer

The capacitive transducer

variable capacitance

The capacitive transducer: the instruments using capacitance transducers - the capacitance changes due to changes in the input quantity (that is to be measured.)

The inductive transducer: the changes in the air gap results in changes of the circuit inductance

The oldest biosensor ever...

CO CO

An allusion to caged canaries (birds) that mining workers would carry down into the mine tunnels with them. If dangerous gases such as methane or carbon monoxide leaked into the mine, the

gases would kill the canary before killing the miners, thus providing a warning to exit the tunnels immediately.

Biosignals are too weak for direct registration Amplitude amplification is needed.⇒

The term amplifier describes an electronic device, whose task is to increase amplitude of the floating electrical signal, in order to

conservation of other characteristics (frequency range)

Processing of biological signals

⇒ Frequency characteristics (what frequences signal contains)

⇒ Spectral analysis:signal processing, an algorithm that estimates the strength of different frequency components (the power spectrum) of a time-domain signal

⇒ Frequency mapping

Colour reprezentation of various frequences depending on time

Telemetry (Medical Telemetry)Wireless data transfer

In medicine- EEG- ECG- EMG- Blood pressure- pH - pO2- Blood Glucose level- RR- Temperature- ...

In sport- distance- speed- Body balance- HR ...

Inside of cathode tube in oscilloscope:

1. Deflection voltage electrodes 2. Electron gun 3. Electron beam4. Focusing coil 5. Phosphor-coated inner side of the screen

Display devices - OSCILLOSCOPE

Uses:Monitoring vital functions: ECG, EEG..

Oscillospcope is a type of electronic test instrument that allows observation of constantly varying signal voltages, usually as a two-dimensional graph of one or more electrical potential differences using the vertical or y axis, plotted as a function of time (horizontal ‑or x axis). This way, many types of signals can be converted to voltages and displayed.‑Oscilloscopes are used to observe the change of an electrical signal over time, such that voltage and time describe a shape which is continuously graphed against a calibrated scale.

Analog oscilloscopeAnalog signal is displayed on a

phosphor-coated inner side of the screen

Digital oscilloscopeAnalog signal is digitalized (101001)

and displayed on LCD

Electroencefalogram (EEG)to distinguish epileptic seizures

from other types of spells, such as psychogenic non-epileptic seizures, syncope (fainting), sub-cortical movement disorders and migraine variants.

to differentiate "organic" encephalopathy or delirium from primary psychiatric syndromes such as catatonia

to serve as an adjunct test of brain death

to prognosticate, in certain instances, in patients with coma

Electromyogram (EMG)

An EMG may be used to evaluate a variety of problems, including the following:

Nerve damage from compression by a disk in the neck or the back

Nerve compression from carpal tunnel syndrome

Neuromuscular diseases such as amyotrophic lateral sclerosis (ALS), poliomyelitis, myasthenia gravis and muscular dystrophy

Peripheral neuropathy caused by such conditions as diabetes, pernicious anemia and heavy metal toxicity

Bioimpedance signalsbioimpedance applicationsinclude e.g.: Skin water content Body fat content Impedance imaging (tomography) Body composition (training,

nutrition) Impedance Cardiography (ICG) Cardiac Output monitoring Ablation monitoring Blood volume Meat quality assessment Tissue ischemia monitoring CO2 catheter transducer Single cell counting and

characterisation Fingerprint sensors

bioimpedance is a term used to describe the response of a living organism to an externally applied electric current. It is a measurement of the opposition to the flow of that electric current through the tissues, the opposite of electrical conductivity.

scanned voltage amplitude depends on tissue impedance, through which is the current passing (it depends on their composition, voltage, congestion)

Bioimpedance signals

Bioacoustical signals

A lot of physiological phenomena are involved in sound generation

Phonocardiogram provides real time visual display of patient heart and lung sounds

Biomagnetic signal

local ion current involved in magnetic field creation during depolarization and repolarization of neurons and muscle cells (brain, heart, lung)

contactless measurement

low intensities up to decade of pT (e.g.: brain 10-13 pT; heart 10-10 pT)

Fetal magnetocardiography (f-MCG) is a non-invase technique in which the magnetic field caused by electrical activity within the fetal heart is measured.

the peak magnetic field of the fetal heart is about about 3pT (= 3×10-12 T),

Magneto-cardiogram of the Fetal Heart

Mechanical manifestation of biological systems:

movements, deflections, pressure, voltage, volume or flowing changes Blood pressure Expenditure of the heart – blood volume ejected by the heart (normal value is 5,5 l·min-1 )

Biomechanical signals

Biochemical signal

Scheme of a glucose sensor. Glucose is oxidized into gluconolactone at the membrane and O 2 is consumed. H 2 O 2 is produced at the same time. Both O 2 and H 2 O 2 can be measured by the electrode.

Systems theoryAccording to relationship of a living object with outside enviroment are systems divided into:

⇒ isolated system is a system without any external exchange – neither matter nor energy can enter or exit (truly isolated systems cannot exist in nature)⇒ closed system which can exchange energy with its surroundings but not matter⇒ open system which can exchange both matter and energy (a cell)

According to system behavior in time are systems divided into:static (no change in time) and dynamic (changeable system in time)

A cell is a dynamic and open system

Biological systems are coordinated and regulated

system control:

A result of a system regulation a Homeostasis

e.g.: regulation of a temperature, hormones level, blood pressure, pH, level of blood glucose, ...

Each type of control is based on the transmission of information

⇒ without a feedback⇒ with a feedbackPOSITIVE

NEGATIVE

⇒ control without feedback no information reaches the controlling unit (centre) from the controlled unit.

Output signal does not react upon the control centre

Example: the adaptation of an organism to its environment ⇒ the sensation of warmth, cold

Negative feedback

⇒ Negative feedback is a process that happens when the system needs to slow down or completely stop a physiological process⇒ Negative feedback helps to maintain stability in a system in spite of external changes ⇒ homeostasis.

Examples: ⇒ sweating, regulation of the blood pressure, pH value or hormonal regulation

A negative feedback loop and how it regulates body temperature

two antagonistic mechanisms:

Shivering is induced when the body temperatures falls to low, and it gradually subsides as the temperature rises.

Sweating occurs when the body temperature is too high, and it diminishes as the temperature falls.

⇒ Positive feedback is the opposite of negative feedback ⇒ it stimulates a fysiological process

Positive feedback is a cyclic process that can continue to amplify the body response to a stimulus

Examples:⇒ fast autoexcitation of elements of endocrine and nervous systems (stress response)⇒ growth, and development of organs

A positive feedback

Positive feedback control of blood clotting

number of individuals which are running

general panic

+

+

FLOCK BEHAVIOR

Model and modelling⇒ modelling is a method of study of system

properties, structure and behavior⇒ modelling is based on a change of original to similar object (model)

⇒ simulation is a process generated by model (computer simulation)

MODEL = is a simplified representation of a reality

Knowledge from model study are useful in human medicine where a research of some diseases is complicated or

impossible

⇒ a model can be alive:

e.g.: laboratory animals (a rat, a rabbit...)

micro-organisms (a virus, a bacteria, yeasts, mould)

⇒ a model can be lifeless:e.g.: a model of chemical structure,3D computer ...

Models & Simulators at JLF UKHarvey - cardiopulmonary auscultation simulatorIt enables an auscultation of 30 cardiological findings and adequate respiratory murmurs with very high fidelity

MetiMan Prehospital whole-body patient simulatorcomputer-controlled simulator with complete patient monitor (designed for pre-hospital care)

HARDWARE

A motherboard (the mainboard or system board) is a printed circuit board found in all modern computers which holds many of the crucial components of the system, such as the central processing unit and memory, and provides connectors for other peripherals. CPU (central processing unit) is the hardware within a computer system which carries out the instructions of a computer program by performing the basic arithmetical, logical, and input/output operations of the system

Video Card is an expansion card which generates a feed of output images to a display.

HDD (hard drive) is a block-based data storage device used for storing and retrieving digital information

DVD ROM (digital versatile disc or digital video disc) is a technology of writing and reading

DVD - DVD uses 650 nm wavelength laser diode light (CD 780 nm)

Blu-ray DVD uses a wavelength of 405 nm (capacity 50 GB)

Power Supply is a switch-mode power supply that converts AC power from the mains supply, to several DC voltages (from 230V to 12V)

RAM: (Random Access Memory) is a form of computer data storage. A random-access device allows stored data to be accessed in very nearly the same amount of time for any storage location, so data can be accessed quickly in any random order (read and write)

ROM: (Read-Only Memory) is a permanent (or read-only) random-access memory

SOFTWARE

Software is a collection of computer programs and related data that provides the instructions for telling a computer what to do and how to do it.

Software is divided into a system and application software

Computers in medicine

⇒ Administrationmedical records, drugs prescription history, medical reports, research articles …

⇒ DiagnosisMedical imaging:CT, X-ray, MRI, Ultra soundpre-operative planning...

⇒ Computer assisted surgery (uses 2D and 3D images)powerful and accurate tools for planning and performing a variety of surgical procedures(DaVinci)

⇒ Monitoringpostoperative monitoring,medication dosing, emergency alarm in case of acute downgrade of patient`s medical state

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