CHAPTER 6ELECTRONICS AND NEUROMUSCULAR APPLICATION IN DISABILITY

CONTENTINTRODUCTIONELECTRONEURAL STIMULATIONMETHODS OF ASSESSMENTMYOELECTRIC PROTHESIS CONTROLHEARING AIDS AND IMPLANTSENVIRONMENTAL ASSISTANCEOTHER ELECTRONICS APPLICATION IN REHABILITATION

INTRODUCTIONASSESSMENT=?REPLACEMENT=?ENVIRONMENT=?

INTRODUCTIONcontDisability Any restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being.(United Nations )Physical disabilitySensory disability Intellectual disabilityMental health and emotional disabilitiesDevelopmental disabilityDisabled person=?Electronic in disabilities=?

NEUROMUSCULARNeuromuscular Neuromuscular disease are those that affect the muscles and/or their nervous control.Some examples of these disorders include Parkinson, stroke and multiple sclerosis.

ELECTRONEURAL STIMULATIONElectroneural Stimulation (ES) has been used for more than 100 years in the laboratory and in the clinical setting.Purpose ;ES is designed to offer the patient a type of therapy that can increase circulation by means of the pumping action of muscles upon the vessels, while at the same time, produce mild heating with all of the benefits accrued from increased temperatures within the tissues.

ELECTRODESAn electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte or a vacuum).The interface of metallic ions in solutions with their associated metals gives an electrical potential which is called the electrode potential.Electrodes used for the measurement of bioelectric potential are known as Biopotential Electrodes.

ELECTRONEURAL STIMULATION

BIOPOTENTIAL ELECTRODESBiopotential Electrodes have metalelectrolyte interface.Types of Biopotential Electrodes;Microelectrodes.Body Surface electrodes.Needle electrodes.

ELECTRONEURAL STIMULATION

MICROELECTRODESM.E have tips small enough to penetrate a single cell and as such readings from within single cell can be obtained.Used to measure potential difference across cell membrane.Characteristic;Small enough to be placed into cell.Strong enough to penetrate cell membrane.Typical tip diameter:0.05-10 microns.M.E are two types;Metal Micropipette

ELECTRONEURAL STIMULATION

MICROELECTRODEScontMetal microelectrodes are constructed by electrolytically etching the tip of a fine tungsten or stainless steel wire to the desired size.Subsequently the wire is coated almost to the tip with insulating material.The micropipette type electrode is actually a glass micropipette with the tip of the desired size.Micropipette is filled with an electrolyte suitable with cellular fluids.

ELECTRONEURAL STIMULATION

Microelectrode with metal film on glassGlass inside metalMetal inside glass

Micropipette

ELECTRONEURAL STIMULATIONBODY SURFACE ELECTRODEThese are used to get bioelectric potentials from surface of the body and are available in different sizes and forms.Larger electrodes are generally used in ECG and smaller electrodes are suitable in EEG and EMG measurement.Types of body surface electrode;Metal plate electrodesSuction electrodesFloating electrodes

METAL PLATE ELECTRODESThe basic metal plate electrode consists of a metallic conductor in contact with the skin with a thin layer of an electrolyte gel between the metal and the skin to establish this contact.Metal commonly used include silver, gold and platinum.Used primarily for diagnostic recordings of biopotential such as ECG or EMG.Metal disk electrode with a gold surface used for EEG recordings.

ELECTRONEURAL STIMULATION

SUCTION ELECTRODEIt is used to record precordial (chest) lead of ECG, since it can be placed at a particular location and then quickly moved to the next location.It consists of a hollow, metallic, cylindrical electrode, that makes contact with the skin at its base and a rubber suction applied against the skin holds the electrode assembly in place.

ELECTRONEURAL STIMULATION

FLOATING ELECTRODEThe principle feature is that the actual metal disk is recessed in a cavity so that it does not make direct contact with the skin.The electrical contact is established through the electrolyte paste filled in the cavity.The assembly is fixed to the prepared location on the skin with a double sided, adhesive tape ring.The cavity does not move with respect to the metal disk and thus does not produce any mechanical movement of the double layer of charger.

ELECTRONEURAL STIMULATION

Metal Plate ElectrodeSuction ElectrodeMetal Disk ElectrodeFloating Electrode

NEEDLE ELECTRODEFor measure biopotentials from within the body the electrode or lead wire penetrates the skin, or they may be implanted internally and connected to an implanted electronic circuit.Usually made of stainless steel.Needle electrodes are used for acute measurements as they are uncomfortable for long term implantation such as EEG measurement.Needle electrodes are less susceptible to movement of artifacts than surface electrodes.The direct contact with the tissue or the intercellular fluids, needle electrodes have lower impedances than surface electrodes of comparable interface area.

ELECTRONEURAL STIMULATION

Needle and Wire Electrodes

METHODS OF ASSESSMENTGAIT ANALYSISAUDIOMETRYELECTRORETINOGRAPH

GAIT ANALYSISGait analysis is the systematic study of human walking.It depends on observations made by experts, together with detailed measurement of body movement, mechanics and muscle activity.In individual with condition affecting their ability to walk, such as cerebral palsy, gait analysis may be used to make detailed diagnoses and to plan optimal treatment. The observation gait begins with a general assessment, noting symmetry and smoothness of movement of the various body parts.

METHODS OF ASSESSMENT

GAIT ANALYSIScontGait Analysis is sometimes used when evaluating gait or walking problems. These problems can come from injuries, surgeries, hereditary problems & diseases. Examples are: Diabetes & neurological problems. We can therefore design shoes, orthotics or braces to help you walk better with less pain

METHODS OF ASSESSMENT

Gait cycle Visualize a patient-specific model through the gait cycle from any angle.

AUDIOMETRYAn audiometer is a machine used for evaluating hearing loss.Audiometry is the testing of hearing ability.Audiometric tests determine a subjects hearing levels with the help of an audiometer, but also measure ability to discriminate between different sound intensities, recognize pitch or distinguish speech from background noise.It is consists of an embedded hardware unit connected to a pair of headphones and a feedback button, sometimes controlled by a standard PC.

METHODS OF ASSESSMENT

Audiometry ScreeningPure tone audiometry

ELECTRORETINOGRAPHElectroretinograph measures the electrical responses of various cell types in the retina, including the photoreceptor, inner retinal cells and the ganglion cells.Electrodes are usually placed on the cornea and the skin near the eye.During a recording, the patients eyes are exposed to standardized stimuli. The electrodes measure the electrical activity of the retina in response to light. The information that comes from each electrode is transmitted to a monitor. The ERG is used for the diagnosis of various retinal diseases.

METHODS OF ASSESSMENT

A patient undergoing an electroretinogram

MYOELECTRIC PROSTHESIS CONTROLA myoelectric prosthesis uses small electric motors to power movement of the terminal device.Major disadvantages of myoelectric devices include their extremely high cost, considerable weight and need for frequent adjustment and repairs.The myoelectric hand uses a rubber cosmetic cover glove that is easily torn or stained and is expensive to replace.

MYOELECTRIC PROSTHESIS CONTROLcontMyoelectric control is used to operate electric motor-driven hands, wrist, and elbows. Surface electrodes embedded in the prosthesis socket make contact with the skin and detect and amplify muscle action potentials from voluntarily contracting muscle in the residual limb. The amplified electrical signal turns on an electric motor to provide a function (e.g., terminal device operation, wrist rotation, elbow flexion). The newest electronic control systems perform multiple functions, and allow for sequential operation of elbow motion, wrist rotation and hand motions.

MYOELECTRIC PROSTHESIS CONTROL

TYPES OF PROSTHESISCosmetic prosthetics.light and cheapa very limited degree of movement only passively grip light objectsdesigned for patients who wish to use their remaining limbs for all of the major functions

Body-powered prosthetics. allows muscles relative to the area to control the prosthetic arm through cablesallow for more degrees of freedomallows the patient to physically feel the forceonly control one movement at a time quickly cause fatigue in the user

Myoelectric externally powered prosthesis.picks up the electrical action potential in the residual muscles in the amputated limbamplifies the signal using a rechargeable 6-volt batteryuses the electric signals to power the motors operating the respective part of the armallows for a much higher degree of freedomdoes not require the patient to performed frequent strenuous muscle contractionsheavier than the conventional types and come at a much higher costthe most advanced and effective commercially available upper-limb prosthesis

MYOELECTRIC PROSTHESIS CONTROL

HEARING AIDS AND IMPLANTSA hearing aid is an electronic device that receives sound, amplifies it, and transmits this stronger sound down to the ear canal into the ear.Sound may reach the inner ear without a hearing aid, but without enough amplification the impulses reaching the brain may be weak.With a hearing aid, sound is amplified to make the weak signal more audible.The primary function of a hearing aid is to compensate for the loss sensitivity of the impaired ear.

MAIN PARTS OF HEARING AIDA microphone to convert sound to electricity.An amplifier to increase the strength of electrical signal.A loudspeaker @ receiver to turn electricity back into sound.A battery to provide the power needed by the amplifier.

The microphone picks up the sound and sends it to the amplifier, which makes the sound louder and sends it to the receiver, which sends the amplified sound into the ear canal.

HEARING AIDS AND IMPLANTS

TYPES OF HEARING AIDBODY AIDThe largest type (60 x 40 x 15 mm)Worn somewhere on the body : in a pocket, in a pouch around the neck, or on the belt.Connected via a cable containing two or three wires, to a receiver from which the amplified sound emerges.Receiver plugs into an ear mold custom made for the individuals ear canal and concha.

BEHIND THE EAR (BTE)Two piece hearing aids.Microphones, electronics and receiver are mounted in the banana shaped case.Sound is conveyed via a tube to a custom earmold.

HEARING AIDS AND IMPLANTS

TYPES OF HEARING AIDcontIN THE EAR Half concha (Half Shell)Fills only the lower half of the concha. Full concha (Full Shell)Fill the entire concha as well as about half the length of the ear canal.

IN THE CANALCompletely In the CanalFit entirely within the ear canal.Use components small enough that none of the hearing aid need protrude into the concha.

HEARING AIDS AND IMPLANTS

TYPES OF HEARING AIDcontEYEGLASS AIDThese are a combination of spectacles and one or two hearing aid.

HEARING AIDS AND IMPLANTS

ENVIRONMENTAL ASSISTANCEThe term Environmental Control (EC) is used to describe equipment that assists people with limited physical abilities access devices and equipment in their environment.The purpose of EC equipment is to provide a technical bridge which gives users independent and spontaneous control of devices.

ENVIRONMENTAL ASSISTANCEGUIDANCE SYSTEM FOR VISUALLY HANDICAPPEDCANE SYSTEMARTIFICIAL SPEECH

ENVIRONMENTAL ASSISTANCEThe Simplicity Series is a voice and switch activated Environmental Control Unit (ECU) with voice output. Through a series of simple verbal commands, or by using any compatible ability switch, a user can control his/her environment. GUIDANCE SYSTEM FOR VISUALLY HANDICAPPED

CANE SYSTEMThe blind people have been using sticks to locate the ways.With the advancement of science and technology, the facilities for the mobility for the visually impaired persons have increased.Cane is most important source of mobility.

ENVIRONMENTAL ASSISTANCE

The cane is able to detect electronic navigational aid tags and help the blind avoid obstacles and reach their destinations.

ARTIFICIAL SPEECHSpeech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware.

ENVIRONMENTAL ASSISTANCEStephen Hawking is one of the most famous people using speech synthesis to communicate

ARTIFICIAL SPEECHcontENVIRONMENTAL ASSISTANCEBlock Diagram of Natural SpeechBlock Diagram of Artificial SpeechEnergy Source(air from lung)Voiced Sound(vocal field)Unvoiced sound(turbulence)Filter(nose & mouth)Sound output(mouth)Energy Source(battery)Voiced Sound(impulse generator)Unvoiced sound(white noise generator)Filter(band pass)Sound output(loudspeaker)

OTHER ELECTRONICS APPLICATION IN REHABILITATIONCochlea ImplantAugmented hand grasp neuroprosthesis

OTHER ELECTRONICS APPLICATION IN REHABILITATION

Eye-Gaze Computer Access It allows the user to place the mouse pointer anywhere on the screen simply by looking at the desired location. "Clicking" can be done with an eye blink, or by staring

REFERENCESPhysical Therapy Aide: a worktext, Roberta C Weiss.The Biomedical Engineering Handbook, Joseph D. Bronzino.Bio Medical Electronics, O.N. Pandey and Rakesh Kumar.Gait Analysis: an introduction Vol.1, Michael Whittle.Hearing Aids, Harvey Dillon