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Audiology by Mind Map: Audiology

1. Outer Ear

1.1. Pinna/Auricle

1.1.1. Directs sound

1.1.2. What most people associate with ear

1.1.3. Important Landmarks Helix Scaphoid Fossa Concha Tragus Ear lobe Vestigial muscles

1.1.4. Composition and Functions Most prominent but least useful Made entirely of cartilage Covered in skin Localized sound to EAC

1.1.5. Landmarks Superior crus of the antihelix Triangular fossa Inferior crus of the antihelix Crus of the helix Tragus Blocks background noise External acoustic meatus Antitragus Helix Scapha Antihelical fold Antihelix Concha cavum Concha cymba Lobule

1.1.6. Disorders of the Auricle Microtia Shrunken Auricle Anotia Auricle is not present whatsoever Individual may have cancer Abuse Otoplasty And Pinnaplasty Keloids Keloids come back Scar Tissue Usually procured from piercings Tumours Painless, slowly growing, solid tumour that distorts the auricle and destroys normal architecture Resembles cauliflower ear Cauliflower ear The sign of warrior Repeated blows to the head Permanent deformity Blood clots Perichondrium Perichondritis of the Auricle Auricular Hematomas Psoriasis Bifid Earlobe

1.2. External auditory meatus

1.2.1. One inch long

1.2.2. Ear canal

1.2.3. Elliptical in shape

1.3. Tympanic Membrane

1.3.1. Semi-transparent and vibrates

2. Middle Ear

2.1. Ossicles

2.1.1. Stapes Stirrups

2.1.2. Malleus Hammer

2.1.3. Incus Anvil

2.2. Stapedius Muscle

2.3. Mechanical Responsibility of processing sound into cochlea

2.4. Tympanic Cavity Proper

2.4.1. Resembles a drum

2.4.2. Oxygen constantly being absorbed In membrane

2.4.3. Barotrauma Rupture of tympanic membrane Pain

2.4.4. Pressure must be equalized for good TM mobility Tympanic membrane must have equal pressure on both sides of it for most optimal compliance Discomfort

2.4.5. Mucous membrane lined; open/vents to the Eustachian tube

2.4.6. Cavity filled with air at atmospheric pressure "O" pressure differential

2.4.7. Stapedius muscle is innervated by facial nerve

2.4.8. Tensor tympani innervated by

2.4.9. Branch of the facial nerve Corta tympani nerve Taste Anterior 2/3rd of tongue Delicate structure issues? Infections

2.5. Eustachian Tube

2.5.1. Vents middle ear to nasopharynx

2.5.2. Provides the middle ear with Air ventilation/Oxygen

2.5.3. Opens and closes to keep air pressure equal during yawning, swallowing, chewing, taking, flying or excessive pressure from the nose

2.5.4. Permit drainage of normal and diseased middle ear secretions

2.5.5. 36mm in length half as long in children

2.5.6. Lined with a layer of scilia Used to move things along

2.5.7. Underlying tissue is bone in the upper 1/3rd

2.6. Epitympanic space

2.6.1. Roof of middle ear is a thin layer of bone which separates the middle ear from the brain

2.6.2. Opening in posterior wall of recess that connects with the tympanic antrum (sinus). This antrum connects with air cells of the mastoid portion of temporal Opens in to thin small honeycomb structure

2.6.3. Malleus and Incus poke up into Epitympanic space

2.7. The Ossicles

2.7.1. Malleus aka hammer Consists of head, neck and 3 processes (handle/manubrium; anterior process; lateral proces) Manubrium embedded in middle fibrous layer of tm Point of greatest retraction Umbo, Manubrium is embedded here Head connected to body of the incus

2.7.2. Incus a.k.a anvil Consists of a body and two arms or processes; long and short Anterior portion of body integrates with Malleus End of the long process is the lenticular process Lenticular process connects with the stapes Malleus and Incus are connected rigidly and rock and weave together

2.7.3. Stapes a.k.a stirrup Smallest bone of the human body Consists of head, neck and two crura (posterior and anterior) and a footplate Footplate occupies space in oval window Annular ligament

2.7.4. Oval Window Above the promontory Filled by a membrane that supports the base of the stapes Move in and out with movement of the Stapes

2.7.5. Round Window Below the promontory Covered by very thin tough elastic membrane Circular shaped Opens into the basal turn of the scala tympani of the cochlea Closed by a thin membrane called the secondary tympanic membrane? Give is from the round window

2.7.6. What surrounds the middle ear? Lateral/membranous wall Medial/cochlear wall Superior/cranial wall On the otherside of this wall is the brain Epitympanic recess Inferior/Jugular wall Floor of the middle ear space Jugular Fauca Anterior/carotid wall Toward the front of the head Carotid artery running there Posterior/mastoid wall Temporal bone Palpate the mastoid bone behind your ear It is not scilliated Connection of the malleus and incus are such that movement of the umbo for the Tympanic Membrane causes them to rotate Rocks back and forth on an axis This force is transferred to the stapes Movement of stapes results in inwards and outward motion of the oval window Unaltered by gravity Position maintained by ligamental connection Sound pressure from larger TM area is concentrated to small surface area of oval window (increases the sound pressure) Tensor tympani increases eardrum tension Stapedius stiffens the stapes Sound is transferring from air to a fluid system

2.7.7. Middle Ear disorder Otitis media More common in males If infection goes on, individual can get mastoiditis Fluid is usually not infected Facial Palsy Barotrauma bar Cholesteotoma Otosclerosis Originates in Inner ear Causes conductive hearing loss Targets the stapes Ossicle Deformities Treatments for Middle Ear Disorders Antibiotics Myringotomy

3. Inner Ear

3.1. Vestibular System

3.1.1. Osseus Labyrinth

3.1.2. For balance, information is gathered from the visual, proprioceptive/ somatosensory adn vestibular body systems

3.1.3. This information is respectively controlled by the cerebellum

3.1.4. Forces of gravity

3.1.5. Ability to keep yourself in space Despite inertia from outside

3.1.6. Visual system is taking info from environment Proprioceptive deals with somatosensory stiff

3.1.7. When does Cerebellum become unhappy in relation to these three systems Motion sickness With a car, eyes are fixed on a book, steady motion

3.1.8. Utricle

3.1.9. Saccule

3.1.10. Three Semicircular Canals Horizontal (lateral) Inferior (posterior) Superior (anterior) Arranged at 90 degree angles to one another Membranous Housed in a large bony casing Arranged to cover all dimensions in space Tiny hairs in semicircular canals Hairs with tiny peripheral connections that form the vestibular portion of the 8th cranial nerve Cell bodies that come together form Scarpa's ganglion

3.1.11. Endolymph and Perilymph

3.1.12. Temporal bone is a bony labyrinth Inside bony labyrinth is a bony labyrinth

3.1.13. Between membranous labyrinth is you perilymph

3.1.14. Vestibular system is a carving of the temporal bone

3.1.15. Helps determine forces of gravity Help figure out what direction head is in Fluid in motion

3.1.16. Perilymph is the fluid that is continous throughout the semicircular canals

3.1.17. Fluid in the vestibule in the fluid filled cavity is filled with perilymph

3.1.18. Cochlear duct has endolymph

3.2. Cochlear System

3.2.1. Membranous Labyrinth

3.2.2. Cochlear needs neural impulse or electrical information in order to process soundwaves into an energy that can be interpreted by the auditory nerve

3.2.3. Scala vestibuli

3.2.4. Scala media

3.2.5. Scala Tympani

3.2.6. Reissner's membrane

3.2.7. Basilar Membrane

3.2.8. Organ of Corti

3.2.9. Process of Cochlea Round window gives while oval window pushes Scala tympani has perilymph like Scale vestibule Vibration also move ot Scala media and vibrate endolymph Vibation in Oval window transfers to Perilymph Perilymph then moves to Scala vestibule

3.2.10. Endolymph Contained within the scala media, Semicircular canals utricle and saccule High in potassium and very low in sodium and calcium

3.2.11. Perilymph Contained within the scala vestibuli, scala tympani and between the membranous canals and bony housing Low in potassium and high in sodium and calcium Mechanical and chemical movement in ears When haircells shear they trigger neural stimulation Opening of Ion channels Positively charged potassium, triggers a polar reaction to the hair cells

3.2.12. Basilar Membrane Frequency placemap along the basilar membrane Thin High frequency sounds along the base Flaccid and thick low frequencies at the apex

3.2.13. Scala Media/Cochlear Duct Blood supply that sits on the modiolis Has both hair cells and support cells Provide structural support for hair cells When Hair cells bend, shearing action occurs with cericilia

3.2.14. Organ of Corti Sits on top of basilar membrane Sit on basilar membrane Auditory nerve endings are within Basilar Membrane Outer hair cells will cause difficulty with speech recognition Hearing loss of 40 to 60 db Increase in hearing loss when damage to both Outer and Inner hair cells occurs Outer and inner hair cells Otoacoustic emissions Hair cells produce a sound that is measurable Not being able to measure sound is indicative of hair cell damage Not 100% proof that you have something wrong with hair cells, because soudn has to travel through the middle ear - if middle ear has a problem you won't be able to tell where the problem is coming from

3.2.15. Bipolar sensory Nueron 30000 afferent neuron and 1800 efferent neurons within the cochlear Stimulus is received in the dendrites (electrical impulses) and sent to cell body This impulse is transmitted along the axon Afferent neurons carry impulses from cochlea to central auditory nervous system Efferent neurons carry info from superior olivary complex Back down into the ear There are different degrees of neural impulses This is dependant on the shearing When the hair cell is sheared, there is a chemical release that comes from within the hair cell Larger movement of stapes elicits more fluid movement which displaces basilar membrane and consequently the hair cells are stimulated Greater intensity of sound more manipulation of hair cells Continuous pressure breaks down hair stems Greater force will lead to damaged hair cells More electrical stimulation that will occur Mechanical theory looks at the shearing action Chemical theory says that when hair cells deform, opens up ion channel Potassium is mixing Release stimulates nerve ending Electrical theory Electrical impulse is coming down hair cell Back down into basilar membrane Cochlear potential that works Spiral Ganglion

3.2.16. Vestibularcochlear Connects systems of balance and hearing to the brain Travel together through the internal auditory canal by means of VIII CN to the brain stem

3.2.17. Hearing loss and Disorders Cochlear portion of 8th cranial nerve What is the auditory pathway like for pieces for the 8th cranial nerve Any hearing disorders resulting in hearing loss is Sensory neural Anything damaging cochlea or nerve results in sensory neural hearing loss

3.2.18. Vertigo True feeling of turning, people tend to be nauseous Any occupation of driving\ Nystagmus accompanies Crystals

3.2.19. SNHLI May be severe or profound Typically affects high frequencies Speech discrimination problems are common Do not hear well in noisy environments Dysacusis; Hypacusis Tinnitus They speak louder You should enunciate and speak slower to them but not louder Many speech sounds are in higher frequencies Very difficult for individuals with sensory type neural loss Want to articulate clearly Different from conductive hearing loss Diplacusis binuralis: double hearing Diplicusis monoralis

3.2.20. Prenatal Herediatry factors for sensory neural hearing loss Rh Factor Baby has but mom does not Mom's body will attack that baby

3.2.21. Childhood Birth trauma Drugs Head Trauma High fevers Kidney Infection Noise Otitis Media Prematurity Surgery (middle ear) Systemic Illness Venereal disease Viral Infection

3.2.22. Adulthood Childhood diseases Autoimmune inner-ear disease Meniere’s disease Otosclerosis Presbycusis Vasospasm

3.3. Helps brain interpret sound

3.4. 100 moving parts

3.5. Encased in the Temporal Bone

3.6. Vestibular and Cochlear makeup labyrinth

3.6.1. Vestibular portion responsible for balance

3.6.2. Cochlear portion responsible for hearing

4. Audiological Assessment

4.1. Test Battery

4.1.1. Case History and Consent

4.1.2. Physical Examination

4.1.3. Pure Tone Testing Measure of frequency against intensity Define a decibel dB SPL dB HL Objective is to determine the sensitivity of human auditory system across the frequency range ANswer certain questions Does patient have hearing impairment How severe is the hearing impairment What type of hearing impairment SHould occur in sound proof booth/room Make sure very little background noise Do not put booth in a busy area with traffic Make sure the client is only responding to tones that are being presented Pure tone Air Measures sensitivity of outer, middle and inner ear Pure tone Bone Measures sensitivity of inner ear and VIII CN Isolating inner ear Determining what type of hearing loss individual has Pure tone When you interpret an audiogram you are comparing the two Anything below 25dB at all Frequencies is normal hearing range for Human Adults Kids is under 15dB Sensorineural Hearing loss is when air-bone gap is within 10dB of each other Conductive Hearing loss Mixed Hearing loss Must determine faintest sound client can hear at each frequency for both Air conduction and Bone conduction Bone Conduction Bones are set into vibration Bone conduction by Air conduction Manipulation of air Encourages Tympanic to vibrate Inertial response of middle ear stimulates Ossicles Compressional/Distortional What is a pure tone audiometer What does it have? Components Earphones/Transducers Circum-aural Insert Function Pure tones are directed from the audiometer to the diaphragm of the earphone cuase it to vibrate in sync with the frequency and intensity selected Components of Bone conduction: Bone conduction vibrator Plastric Strap (forehead) Spring-steal (headband) (Mastoid) Normal adults hear 25dB or less at all frequencies (children 15dB or less 30dB = whisper 55dB = normal speech 70dB = shouting 90dB = machinery (over 90dB can cause damage) Speech Audiometer Can be part of clinical audiometer Input received from mic, CD, or tape recorder How loud stimuli is AIr conduction from -10dB to 110dB HL Sound field Equipment 911 Factory check; Self check Maintenance Troubleshooting Calibration Sweeps of barely audible sound to make sure you hear them Always calibrating by sending to dealer to repair or tune Other How do you test a patient Subject should be visible Communication should be possible Provide instruction Subject/Client should not hear the tester When the Client is in a separate room Providing bulk of instruction, getting client comfortable in booth MUST BE ABLE TO HEAR CLIENT AND COMMUNICATE WITH THEM Audiologist must place patient in proper position for testing Client/Patient has a responsibility Subject must be asked about recent Noise exposure Subject must be asked if they have Tinnitus Subject must be asked if they have better hearing in the left or right ear Informal assessment of how severe hearing loss is before test starts Clear instructions on testing Before removal of hearing aids I am going to test your hearing by measuring the quietest sounds that you can hear. As soon as you hear a sound (tone), press the button (or raise finger/hand). Keep it pressed (or raised) for as long as you hear the sound (tone), no matter which ear you hear it in. Release the button (or lower your finger/hand) as soon as you think you no longer hear the sound (tone). Do you understand Begin with better ear Sound Field Bone Conduction Testing Masking

4.1.4. ABR/OAE Testing

4.1.5. Management and Treatment

5. Auditory nerve and Central auditory pathway

5.1. From cochlea to the auditory cortex

5.1.1. Internal auditory canal

5.1.2. 10mm long

5.1.3. Carries the VIII CN, internal auditory artery, fibres of the VIII CN

5.2. This is a complex system

5.2.1. THere are afferent (ascending and efferent (descending) nerve fibres

5.3. Brain stem

5.3.1. Midbrain

5.3.2. Pons Responsible for connecting medulla to cerebellum

5.3.3. Medulla Oblongata Digestion Autonomic involuntary function Breathing Swallowing Centre for circulation

5.3.4. Cerebellum Responsible for coordination of voluntary movement Located posteriorly to brain stem Ataxia Common injury to cerebellum

5.3.5. Thalmus Located on top of brain stem Mass of brain matter Receives auditory and visual information that makes its way to the cortex Motor control At the level of the cerebellum, the medulla oblongata Cerebello ponteen angle

5.4. Auditory portion of 8th cranial nerve

5.4.1. Part of it will descend into dorsal of the cochlear nucleus

5.4.2. Part of it will ascend into the front of the cochlear nucleus

5.4.3. AUditory portion of 8th cranial nerve

5.4.4. Part of it iwll descent into dorsal of the cochlear nucleus

5.4.5. Part of it will ascend into the front of the cochlear nucleus

5.5. Process

5.5.1. I Internal auditory canal

5.5.2. C Cochlear Nucleus The cochlear nuclei, represents the highest centre at which the processing of neural stimuli represents auditory information obtained from just one ear Auditory nerve fibers end here All information received by cochlear nucleus is unilaterally received Fibers travel unilaterally or cross over, contralateral interaction

5.5.3. S Superior olivar complex Takes information from both ears Timing of sound Intensity of sound Helps brain figure out where sound is coming from Also the area where efferent activity kicks in If ear heard extremely loud sound Helps attenuate really loud sound

5.5.4. L Lateral liniscus Major pathway for transmission of impulses from ipsilateral lower brain stem (there are contralateral fibres received as well) Three choices Some fibres terminate here Some go to contralateral lemniscus Some go to inferior colliculus Lateral meniscus Analyzes the quality of sound

5.5.5. I Inferior colliculus Receives afferent information from both superior olivary complexes. Neurons from here to the medial geniculate body are the third or fourth link in the ascending pathway. If there is damage to Cochlear nucleus There will be damage to colliculus

5.5.6. M Medial geniculate Body Ventral portion primarily responsible for auditory information Last subcortical relay station for auditory impulses No decussations Referred to as the auditory nucleus of the thalamus At this point it only sends information ipsilaterally to cortex

5.5.7. B Brain Frontal lobe Parietal lobe Occipital lobe Temporal lobe

5.5.8. Auditory Cortex Portion of the auditory cortex responsible for frequency characteristics Portion of auditory cortex focused on temporal aspects Frontal area has to do with memory Temporal area

5.5.9. Room for error in Auditory pathway INtrinsic redundancy Distinguishing sounds coming in doesn’t affect them Some people might have an auditory bombardment from amount of stimulation they are receiving Some children may have Central auditory processing disorder Extrinsic Redundancy Disorders that occur Speech messages

6. What is an Audiologist?

6.1. “By virtue of academic degree clinical training, and license to practice/ or professional credentials, is uniquely qualified to provide a comprehensive array of professional services”

6.2. Are able to diagnosis if there is hearing loss or not

6.2.1. o But cannot give diagnosis of another medical condition that could lead to loss.

6.3. They can provide treatment independent or with a CDA

6.3.1. o Treatment to auditory, vestibular disorders

6.3.2. o And work with hearing loss prevention

6.4. Audiology began after ww2 to help veterans return to civilian life.

6.4.1. o Came from otology and speech pathology

6.5. Work for rehabilitation and habilitation

6.5.1. o Rehabilitation: returning to previous skills that been affected

6.5.2. o Habilitation: working on skills that are needed

6.6. Qualification

6.6.1. o Masters in Canada

6.6.2. o Doctor in USA

6.6.3. What they do

6.6.4. o Test hearing

6.6.5. o Fit hearing aids

6.6.6. o Hearing aid computer programming

6.6.7. o Industrial monitoring

6.6.8. o Educational and research

6.6.9. o Management of tinnitus and cerumen

6.6.10. o Balance assessment

6.6.11. o CAP testing

6.7. CASLPO assessment of adults with hearing loss

6.7.1. An adult with a hearing loss o Someone 19 and older with loss or at risk o An impairment that limits activity or compromises auditory function

6.7.2. - The essentials o Audiometric test environment (ANSI standards) o Audiometer with insert, headphones, and bone oscillator o Otoscope – light magnifying thing o Acoustic immittance measurement system – to see middle ear, such as fluid o Infection control standards – properly cleaned, proper personal equipment (PPE)

6.7.3. Practice standards E.1

6.7.4. o Audiologist must have the required resources in order to perform hearing assessment in adults Practice standard E.3

6.7.5. o Audiologists must make appropriate and expedient referrals when they do not have the required resources to meet the needs of the patient/client

6.7.6.  If your machine Hasn’t been calibrated, if it’s on the brink etc.

6.7.7.  If theres no gloves or no clean tools etc Practice Standard F.1

6.7.8. o Audiologist must refer when their competencies or services delivery are not sufficient to meet the patient/client needs or safely manage the risks

6.7.9.  Practice Guideline G.1

6.7.10. o Audiologists should consider modification or discontinuation of an assessment if the presenting condition of the external ear or ear canal requires treatment

6.7.11.  Examine external ear Blood Fluid Inflammation Other infectious substance Impacted cerumen

6.7.12.  May get pressure to treat but use clinical judgement, stay on cautious side and document everything Standard I.1

6.7.13. o Audiologists must obtain informed consent to the hearing assessment Practice standard I.2

6.7.14. o Audiologists must obtain knowledgeable consent to collect and manage information obtained during hearing assessment

6.7.15.  Parents’ consent (written and documented) to send to another health care provider

6.7.16.  Unless in a hospital setting Consent, you must relay information

6.7.17. o What procedures are being done

6.7.18. o Expected responses

6.7.19. o Any associated risks

6.7.20. o Explanation of outcome and interpretation

6.7.21. o Treatment and follow-up Consent is an act, physician must outline the procedure, steps, and risks Must be more than signature must also be full consent. Combative patient: fights back, turns away, looks distressed; no consent and must be documented Practice guideline I.1

6.7.22. o Audiologists should conduct the procedures covered in this PSG in a manner which is patient/client centered and linguistically and culturally sensitive.

6.7.23.  Research

6.7.24.  Thorough case history

6.7.25.  Talk to parents

6.7.26.  ESL: interpreter, if patient consents a family member, Test must not be translated must be a test in that language must be a registered translator for a medical procedure

6.7.27. employement settings o hospital o doctor’s office o private practice o university o school for hearing impaired o industry – going into business giving advice on minimizing loud noises etc o research

6.7.28. why do we need this sense?

6.7.29. Learning to talk

6.7.30. Safety

6.7.31. Keep us “in touch”

6.7.32. Monitoring function

6.7.33. Spatial awareness

6.7.34. Psychosocial effects o Withdrawn o Suspicious/paranoid o Antisocial o Embarrassment Trouble learning Make errors

7. Sound and it's Measurement

7.1. A force

7.2. A vibrating system

7.3. A medium

7.4. A hearing mechanism

7.5. Pure tone Audiometry

7.5.1. Otoscope and Audioscope

7.5.2. What is pure tone audiometry

7.5.3. What is a pure tone audiometer

7.5.4. How do you test as a patient

7.6. The essentials needed…

7.6.1. A force What is required to influence or affect the velocity of a particular body

7.6.2. A vibrating system Until the vocal folds start vibrating, air particles are motionless To and fro movement of a mass Vocal folds vibrate in response to air pressure from the lungs

7.6.3. A medium Air to Liquid Length of vocal folds also affects sound being created

7.6.4. A hearing mechanism Mechanism to receive sound waves after it passes through medium

7.7. SOUND

7.7.1. Physical” a series of distubrances of molecules within, and propagated through, an elastic medium such as air” Science = Hearing Measure of frequency

7.7.2. Psychological: “an auditory experience- the act of hearing something” Art = listening Loudness and Pitch

7.8. WAVES

7.8.1. “The succession of molecules being shoved together and then pulled apart

7.8.2. Molecules being pushed around

7.8.3. With regard to the wave we must garner info about its frequency and intensity

7.8.4. DIfferent frequencies and intensities in terms of sound waves

7.8.5. Velocity Speed at which sound wave is travelling Dependent on medium Air, Liquid, solids Sound waves travels through air at 340m/s

7.8.6. Something may provide impedance for the sound waves Friction Mass Stiffness Ossicular chain Tympanic Membrane Attenuation reduction in energy that occurs

7.8.7. 3 Different forms of vibration Vibration of strings VIbration of Air And Vibration

7.8.8. Free Vibration

7.8.9. Forced Vibration When there is a force applied, and its controlling the vibrations

7.8.10. The lowest rate of a sounds vibration is its fundamental frequency Complex sounds such as speech do not have the fundamental frequency Single frequency tones do not occur in a natural environment Will be introduced to patients

7.8.11. Speech has Different and variable frequencies

7.8.12. Puretones are sinusoidal Speech do not have Sinusoidal wave

7.8.13. Periodic Repeat

7.8.14. Aperiodic waveforms Do not repeat over time

7.8.15. Amplitude and Phase Frequency is dependent on things like length

7.9. Frequency

7.9.1. Characteristic of sound proportional related to frequency that tells us about the wave length

7.9.2. When you think about the sound wave it has Short waves and Long waves

7.9.3. Wave length is proportional to the degree of frequency Shorter wave gives higher frequency Longer wave gives lower frequency

7.9.4. Waves are measured in 1 second measurements More sound waves smushed in the 1 second measurement HZ is measure of Frequency 250 sound waves in one cycle 250 HZ

7.9.5. Period is the time it is to complete cycle Short waves have shorter period Produce higher frequencies as a result Longer waves have longer periods

7.9.6. Shorter strings will produce higher frequencies

7.9.7. Greater Mass will produce lower frequencies

7.9.8. Air is the least elastic medium, compared to liquids and solids

7.10. Rationale…

7.10.1. If i seocnd, 1000 compressions and rarefactions, frequency of 1000 cps/HZ

7.10.2. 1kHZ = 1000 HZ

7.10.3. Ear is most sensitive to 500 to 8000 Hz

7.10.4. Subsonic and Ultrasonic

7.10.5. Subsonic is below human hearing level

7.10.6. Ultrasonic is faster than the speed of sound

7.10.7. 250 Hz 500 Hz 1000 Hz are the integers used

7.11. Intensity

7.11.1. Measured in Decibels dB Not an absolute value Patients can hear negative dB Measure of relative power, of one sound compared to another

7.11.2. Amount of sound energy per unit of area

7.11.3. Distance that sound has to travel from point of equilibrium to top of sound wave Strength of the sound

7.11.4. Increased force applied to that medium It will generate icnreased intensity But frequency will be static 250 Hz tone Increased the amplitude if more force is applied

7.11.5. Physical component Loudness is psychological component

7.12. Phase

7.12.1. The relationship in time between two or more waves

7.12.2. In phase: Two tones that might occur at the same time Same frequency and same Amplitude Compression and refraction of air molecules is happening at the same time Will heighten the wave and amplitude will double

7.12.3. Opposite phase

7.12.4. Destructive interference Two tones going somewhere Presented 180 degrees of each other Cancel each other out Sound booth testing with little ones Sound can bounce in the booth If they bounce together out of phase they will cancel each other out

7.13. Sound Waves

7.13.1. Amplitude is the distance the wave travels from point of equilibrium Greater the amplitude greater intensity of sound Greater force leads to greater amplitude which results in higher intensity Intensity measured in dB

7.13.2. Period

7.14. Pure tone Testing

7.14.1. Bone conduction

7.14.2. Air conduction

7.14.3. Both of which will present a sound to the client

7.14.4. Behavioural test Requires Patient confirmation

7.15. So…

7.15.1. Sound is everywhere

7.15.2. SOund gives us awareness, ives communication link

7.15.3. Sound allows langauge development and learning

7.15.4. Sound provides comfort (music) and