CD443- Final Exam
CD443- Final Exam CD 443
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This 24 page Study Guide was uploaded by Leah Larabee on Tuesday January 20, 2015. The Study Guide belongs to CD 443 at University of Alabama - Tuscaloosa taught by Dr. Hay-McCutcheon in Fall2014. Since its upload, it has received 309 views.
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Date Created: 01/20/15
EVOlLllIlOl l 3 Change OVBT39 time Natural selection mechanism for the change CHAPTER 13 Charles Darwin 0n the Origin of Species by Means of Natural Selection Published November 24 1859 o The two main points 1 That contemporary species arose from ancestors Through a process of descent with modification with natural selection as the mechanism 2 Challenged the notion that the Earth was relatively young and populated by unrelated species 0 The basic idea of natural selection Organisms can change over generations Individuals with certain heritable traits leave more offspring than others The result of natural selection is evolutionary adaption He based his theory of natural selection on two key observations 1 Observation 1 Overproduction All species tend to produce excessive numbers This leads to a struggle for existence 2 Observation 2 Individual variation Variation exists among individuals in a population Much of this variation is heritable Conclusion Unequal reproductive success natural selection Those individuals with traits best suited for the local environment leave more fertile offspring Biological Evolution Fossils Are preserved remnants or impressions left by organisms that lived in the past Are often found in sedimentary rocks The fossil record Supports evolution Is the ordered sequence of fossils as they appear in rock layers Reveals the appearance of organisms in a historical sequence 0 Paleontologists Are scientists that study fossils Have discovered many transitional forms that link past and present Biogeography Is the study of the geographic distribution of species Comparative anatomy Is the comparison of body structure between different species Confirms that evolution is a remodeling process Homologous structures Is the similarity in structures due to common ancestry Comparative embryology Is the comparison of structures that appear during the development of different organisms Comparative embryology of vertebrates supports evolutionary Whale theory Examples of natural selection include 1 Pesticide resistance in insects 2 The development of antibioticresistant bacteria T 3 Drugresistant strains of HIV gt73 Mutations and Sexual Recombination O39 C Produce genetic variation E5 0 Muta tions Are changes in the DNA of an Original phenotypes furcolor organism population 0 Sexual recombination Shuf es alleles during 1 meiosis Of all causes of microevolution only natural selection promotes adaptation I I The modern synthesis is the fusion of genetics 51 With eVOIUtionary biOIOgY a Directional selection b Disluptive selection c Stabilizing selectio Directional selection o Shifts the phenotypic quotcurvequot of a population 0 Selects in favor of some extreme phenotype Disruptive selection 0 Can lead to a balance between two or more contrasting morphs in a population Stabilizing selection 0 Maintains variation for a particular trait within a narrow range Sicklecell disease 0 Affects about one out of every 400 African Americans 0 Is more common among African Americans but why Confers resistance to the disease malaria Is adaptive in the African tropics where malaria is common CHAPTER 14 Microevolution Changes in allele frequencies within populations Often associated with adaptation Can be measured from one generation to the next Macroevolution Major changes in the history of life Origin of new species Generates biological diversity Species Are groups of organisms whose members have the potential to interbreed with one another in nature to produce fertile offspring reproductively isolated from other such groups The gene pools of two or more populations must be separated from each other 0 Allopatric Speciation Species evolve in geographic isolation Usually associated with a geographic barrier preventing members of two populations from mating with one another Involves independent evolution of the populations after the barrier arises Geographic barriers like deep canyons and oceans can isolate populations As the surface of the earth changes so do the chances that different organisms might interbreed Chances for allopatric speciation increase if the population is small Small populations are more likely to have restricted gene pool founder effect Small populations can change more rapidly by both genetic drift and natural selection 0 Sympatric Speciation Species evolve without geographic isolation species remain together with potential to interbreed Probably associated with a genetic barrier due to a single mutational event Important in plants but not widespread among animals More difficult than allopatric speciation because it requires a subdivision of the gene pool of a single population Keeping those subdivisions isolated requires special circumstances 0 Segregation of habitat 0 Major alterations in mate recognition or behavior 0 Genetic incompatibility Accidents during cell division that lead to extra chromosome sets are one mechanism of sympatric speciation Polyploidy is the condition of having extra sets of chromosomes Evolution is how organisms change over time 0 Some polyploid plants have more than one parent species Pace of Speciation Gradualism o Mechanism envisioned by Darwin Slow and steady accumulation of small changes leads to Curvier Lines production of species over vast stretches of time Leads to the prediction that the fossil record should show numerous forms in a continuous series of change from ancestral to descendant species Punctuated Equilibrium o Mechanism proposed by Eldredge and Gould Species diverge in spurts of rapid change followed by long periods of stasis Leads to the prediction that the fossil record should show the most drastic changes in appearance at the time that new species branch from parent species Unfortunately the fossil record does not support the hypothesis that speciation occurs as a gradual process Fossil species show remarkable consistency of form over long periods of time New species appear suddenly Old species disappear suddenly Evolution incorporates both gradual and punctuated episodes 0 Gradual changes include microevolution the changes in allele frequencies within populations These changes may not be preserved in fossil record eg sickle cell anemia or moth coloration 0 Rapid changes include macroevolutionary events such as the production of new species through polyploidy or through other genetic mutations Because rapid changes can take thousands of years many have resulted from microevolutionary processes Straight Line Reproductive Barriers Prezygotic barriers prevent mating or fertilization between species 0 Can result from natural selection Temporal isolation o Mate at different times of year Habitat isolation o Occupy different habitats land water Behavioral isolation 0 Blue footed boobies and many other animals use complex courtship displays in selecting mates Because other species cannot mimic these displays offspring are not produced Mechanical isolation 0 Differences in the shapes of their shells prevent them from succeeding Snails Gametic isolation 0 Although the sperm and eggs of these two sea urchin species are released into the water they are unable to fuse because the proteins on the surface of the eggs and sperm cannot bind to one another Postzygotic barriers prevent survival or reproduction of hybrid offspring 0 Not the result of natural selection May be instrumental in selection for prezygotic barriers Hybrid inviability 0 Different salamander species sometimes mate but the offspring fail to complete development Hybrid sterility 0 Different species may mate and produce viable offspring that are sterile preventing further mixing of gene pools Mules Hybrid breakdown o The first generation of hybrids may be both viable and fertile but due to genetic factors the offspring of these hybrids are weak feeble or sterile Changes that can lead to speciation can involve development and expatiation Evodevo is the scientific interface between evolutionary biology and the study of embryonic development 0 Naming Species Species Panthera pardus El E1 quot39 Family Felidae 13 IE IZIIZIEI Order Carnivora Domain Eukarya Archaea 1 st En Inna Humanuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu uh0p87 1 Domain Eukaryota Kingdom Animilia Phylum Chordata M Mammalia Order Primates Family Hominidae Genus Homo 93991953quot 51 Sapiens CHAPTER 18 Ecology o Is the scientific study of the interactions between organisms and their environments Environment 0 The abiotic componen The nonliving chemical and physical factors in an environment Energy source Temperature Water Wind Rocks and Soil 0 The biotic componen The living factors in an environment Four levels of Ecology 1 Organismal ecology Is concerned with evolutionary adaptations that enable individual organisms to meet the challenges posed by their abiotic environments 2 Population ecology Is concerned with populations groups of individuals of the same species living in the same area Concentrates mainly on factors that affect population density and growth 3 Community ecology Is concerned with communities assemblages of populations of different species Focuses on how interactions between species affect community structure and organization 4 Ecosystem ecology Is concerned with ecosystems which include all the abiotic factors in addition to the community of species in a certain area Focuses on energy ow and the cycling of chemicals among the various abiotic and biotic factors 0 The biosphere I Is the global ecosystem 0 Global distribution patterns Re ect regional differences in climate and other abiotic factors 0 Habitats Are specific environments in which organisms live 0 Three types of adaptations Enable organisms to adjust to changes in their environments 1 Physiological o The ability to acclimate 2 Anatomical 0 Some type of change in body shape or anatomy 3 m o Respond to change in the environment by moving to a new location 0 Population ecology o Is the study of how members of a population interact with their environment 0 Focuses on factors that in uence a population s size growth rate density and structure Biomes o A major terrestrial or aquatic life zone characterized by vegetation type in terrestrial biomes or the physical environment in aquatic biomes Aguatic Biomes o Freshwater biomes Lakes streams rivers and wetlands Salinity Usually a salt concentration less than 1 Use for drinking water crop irrigation sanitation and industry Two categories 0 Standing water Includes lakes and pond o Flowing water Includes rivers and streams 0 Marine biomes Oceans intertidal zones coral reefs and estuaries Salinity Usually a salt concentration 3 o Wetlands Transitional biome between an aquatic ecosystem and a terrestrial one Among the richest of biomes in species diversity 0 Estuaries Are areas where a freshwater stream or river merges with the ocean Are one of the most biologically productive environments on Earth Terrestrial biomes are determined primarily by climate especially temperature and rainfall o If the climate in two geographically separate areas is similar the same type of biome may occur in them 0 Are named for major physical or climatic features and for their predominant vegetation The Water Cycle All parts of the biosphere are linked by the global water cycle and by nutrient cycles Tree Line Altitude effects vegetation and animal distribution Geographic Range 0 The area over which a species is found 0 Limitations Competition for resources Intolerable conditions Physical obstacles 0 Sustainable development Balances human needs with the health of the biosphere CHAPTER 19 Population 0 Group of individuals of a single species that occupy a defined area Population Ecology 0 Study of factors that affect population density and growth Population Density 0 Is the number of individuals of a species per unit of area or volume 0 Measuring Markrecapture method Animals are trapped marked and then recaptured after a period of time Population Age Structure The age structure of a population is the proportion of individuals in different age groups Breeding male fur seals thousands h The age structure of a population can help us understand the history of a population s survival or reproductive success and how it relates to environmental factors Also a useful tool for predicting future changes in a population Population Growth Model The growth rate is the change in population size per time interval Exponential Growth Model Describes the rate of expansion of a population under ideal unregulated conditions Key feature is the rate at which a population grows depends on the number of individuals already in the population Logistic Growth Model The reality of a Limited Enviroment 500 A O 450 0 400 350 39 300 250 200 Population size N 150 100 In nature a population may grow exponentially for a while but eventually one or more environmental factors will limit its growth Populationlimiting factors restrict population growth Describes growth of an idealized population that is slowed by limiting factors L O on O5 1915 1925 1935 19 Biotic potential Maximum rate of growth of a population under ideal conditions Determined Number of offspring produced by each member Length of time individuals reach reproductive maturity Raito males to females Number of reproductive age individuals Usually follows Exponential Growth Curve I shape Exponential Growth Rate 0 Population doubles repeatedly over similar time periods 0 How to calculate M Divide 72 by the growth rate per year Human Population Growth 0 Increased biotic potential factors Agricultural development Improved medical care Vaccines Antibiotics Improved transportation Improved housing 0 O O Advances in communication 0 Rate is 12 year Carrying Capacity 0 Is the number of individuals in a population that the environment can just maintain with no net increase or decrease The US Endangered Species Act Defines an endangered species as one that is quotin danger of extinction throughout all or a significant portion of its range Defines a threatened species as one likely to become endangered in the foreseeable future CHAPTER 20 Community Is an assemblage of species living close enough for potential interactions Interspecific Competition May occur when two or more species in a community rely on similar limiting resources May limit population growth of the competing species 0 Ecological Niche Is the sum total of a species use of the biotic and abiotic resources in its environment Is the species ecological role Russian ecologist G F Gause studied the effects of interspecific competition in two closely related species of protists o This concept is the Competitive Exclusion Principle Simply stated two species cannot coexist in a community if their niches are identical There are two possible outcomes of competition between species with identical niches 1 Extinction of one species 2 Evolution of one species to use a different set of resources Predator Interaction in which one species the predator kills and eats another the prey 0 Many predators Have adaptations such as claws teeth fangs stingers or poison to help catch and subdue prey Are fast and agile Most predators have acute senses Defenses for prey 0 Passive defenses such as hiding Camou age or cryptic coloration Makes a potential prey difficult to spot against its background 0 Active defenses such as escaping Distraction displays 0 Direct the attention of the predator away from a vulnerable prey to another prey that is more likely to escape 0 Mechanical defenses such as hard shells or quills Animals with chemical defenses are often brightly colored This is a caution to predators called warning coloration Mimicry Is a copycat adaptation in which one species mimics the appearance of another 0 Coral VS King snake o Behavioral defenses include Alarm calls Mobbing Mutualism symbiotic relationship Both species benefit from an interaction 10 loss at o Anemone and Clown fish each level Trophic structure x r f Divides species in a community based on their v l k consumers main sources of nutrition A food chain is the sequence of food transfer between trophic levels 0 Detritivores Consume detritus often known as scavengers o Decomposers fungi Secrete enzymes that digest molecules in organic material fungi and bacteria Derive their energy from the dead material left by all trophic levels 0 Eutrophication Rapid growth of plant life leading to death of animal life resulting I i J1 Carnivore Tertiary consumers M C Carnivore 39 7 ex Secondary consumers r V Carnivore from excessive organic or Pr39marli consumers 1norgan1c nutr1ents Food Webs L gt y Producers 39 J Phytoplankton A terrestrial food chain A marine food chain The feeding relationships in an ecosystem Are typically not as simple as in an unbranched food chain Are usually woven into elaborate food webs o Humans rely on biodiversity for I Food clothing shelter I Oxygen soil fertility medicinal substances Biological magnification Is a process in which toxins become more concentrated in successive trophic levels of a food web Ex accumulation of mercury in fish 0 We I Is the use and reuse of chemical elements within the ecosystem Quaternary tertiary and secondary consumers Tertiary and secondary consumers Secondary and primary consumers Primary consumers quotquot i r I u Producers plants 39 1 i Producers get 2 Energy from Energy Pyramids Sunlight Energy ows through an ecosystem when consumers feed on producers 0 Cannot be recycled within an ecosystem but must ow through continuously 0 Limits the length of food chains I The diversity of a community has two components 1 Species richness the total number of different species in the community 2 Relative abundance of the different species Four main nutrients that cycle And problems 1 Carbon Cycle Since the Industrial Revolution the concentration of C02 in the atmosphere has been increasing due to the burning of fossil fuels and wood and to deforestation 2 Phosphorous Cycle Sewage treatment facilities and fertilizers Also add large amounts of phosphates to aquatic systems causing eutrophication of lakes 3 Nitrogen Cycle Sewage treatment facilities and fertilizers Add large amounts of nitrogen to aquatic systems causing heavy growth of algae 4 Water Cycle Destruction of tropical rain forest Will change the amount of water vapor in the air May alter local and global weather patterns Causes of Declining Biodiversity Habitat Destruction Invasive Species Overexploitation of wildlife quotWe do not inherit the earth from our ancestors we borrow it from our children CD 443 Final Exam Hearing Aid Considerations Sensorineural 0 Inner ear cochlea outer hair cells effected 0 Degree depends on how damaged the hair cells are Most sensory neural and conductive benefit from hearing aids Hearing aids do not provide normal hearing 0 They amplify the sounds making them more audible Hearing aids miniature amplifiers o Capturing incoming sounds increase intensity then deliver it to the ear How Hearing Aids work 1 Sound is picked up by the microphone Converts acoustic signal to electrical signal 2 This electrical signal is amplified or processed in some way 3 The receiver converts the electrical signal back to an acoustic signal In a BTE sound is delivered to ear canal by the earmold Types of processors or circuits 0 Analog I Sound is processed as a continuous electrical signal generated by the microphone I Signal is modified by electronic components I Hearing aid characteristics are adjusted by screw settings 0 Digital I Electrical signal from mic is converted into 1 s and 0 s I Computer chips carry out the various signal modifications Characteristics are programmed using specialized software I Can store multiple sets of characteristics First true digital hearing aids debuted in 1998 0 Hybrid or digitally programmable I Sound remains in analog form electrical signal I Electronic circuits modify the signal I Hearing aids settings are controlled using computer software and stored in the hearing aid digitally I Can have multiple settings stored I Debuted around 1990 0 Hearing aid features Characteristics 0 Gain I Increase in level the HA provides The difference in dB between the output and the input This is how much amplification the hearing is providing Specified in dB 0 Gain output level input level I Ex Input 40 dB SPL Output 70dB SPL Gain 3920 HR I The more sever the hearing loss is the more gain you need Prescriptive formulas are used to determine how much gain the patient needs at each frequency Try to make sounds audible but comfortable 0 Frequency Response I How much gain is provided by different frequencies Key I Issue with HA general Cannot provide a lot of high frequency Gain Axis amplification amplifiers are not capable of it Frequency xAxis I Can be adjusted several ways For Analog HA have screw pots on the faceplate of HA For digital and hybrid the response is programmable I Ideal goal Maximize audibility of speech Some formulas use the articulation index to prescribe gain 0 Inputoutput function 110 I Shows how HA output changes as a function of input level Linear HAs have constant gain for all input levels to some max output Key In nonlinear HAs gain varies depending on input level Input X Axis o Lowlevel sounds are amplified more they Output Y Axis get more gain than highlevel sounds 0 Most HA are nonlinear I Special prescriptive formulas have been developed for nonlinear HAs They set the I 0 characteristics based on the patient s loudness growth function 0 Measured using rating scales 0 Goal make speech audible not uncomfortable Components 0 Microphone I Omnidirectional Single microphone picks up sound equally form all directions I Directional 2 or more mic Designed to give strongest response to sounds in front of the wearer The best way to improve speech understanding in noise w HA May have switch or be automatic 0 Am lifier rocessor I Can be analog or digital I Linear or nonlinear o m I Converts electrical signal back to an acoustic signal for delivery to ear 0 Volume control wheel I Used for older hearing aids I Hand held device now used to increase volume I User can adjust gain as desired Nonlinear aids do this automatically often called automatic gain control AGC 0 y I Usually the largest part of the HA 0 Telecoil inside the HA I Helps person connect to other devices they want to use Telephone I Picks up magnetic signals From an analog telephone From an induction loop 0 Around a room 0 Around the neck I User switcher aid from M to T 0 Automatic volume control 0 Multiple memories I Digital hearing aids are capable of storing different volume settings for different situations I Can have different internal settings for different listening environments 0 Remote control I For controlling volume or switching between programs 0 Earmold material for BTE I Not open ear I Need to get the ear impression to select the type of mold to use Hard or soft hypoallergenic o Directional microphone I Will be pointed in front of the individual so the sound will be presented to them Can have in back to pick up background noise I May improve speech understanding in noise I Can turn on and off Hard with analog Problem with Telecoil and directional microphone o The switch 0 May be too complexhard to manipulate for some people 0 Some companies offer automatic switching for directional mic Hearing Aid selection May occur immediately after evaluation or as a separate appointment Tasks to complete 0 Medical clearance referral or waiver o Loudness growth measures I It helps set the gain by finding the uncomfortable level comfortable level and threshold to find the dynamic range 0 Earmold impressions I Need for In the canal In the ear Behind the ear Do not need for openfit HA 0 Pretesting for later validation I Sound field testing I Speech in noise I Questionnaires Selection involves matching HL with 0 Communication needs 0 Style 0 Technology Considerations 0 Required gain and desired features I The larger HA the greater gain and more features 0 Physical condition of outer ear I Including size cerumen production skin sensitivity 0 Cosmetic concerns 0 Financial concerns I Average prices by Analog 935 What to consider quot o m a 39 I Whether they are quot397 teChnOIOgy Mnlmum b I N906 r quotiii quot391 V D BMWM 61 Lit g 1 Madurai handicapped by HL Avoid situations Am because of HL Wm 025 2640 4155 5685 35100 10115 Cause problems at Average Hearing Loss In dB HL work I Will they benefit from HA If Mild HL in one ear and its bothersome to them a HA wont benefit them If Profound HL won t benefit Need cochlear implant I Do they want HA If a patient is brought in by family member who is frustrated but patient does not want They wont use it 0 Type style of HA I Type degree and configuration of HL are most important determinants of The style and features of HA Type and signal processing 0 HA features 0 Monaural vs binaural fitting I Advantages of binaural Better sound localization Binaural summation 0 Its easier to hear with two ears than one because brain puts it together Improved speech recognition in noise More natural sound quality Avoid auditory deprivation effects o If someone has cochlear IMP in one ear and HA in other AUD encourage this because if they want to get cochlear IMP later on some stimulation is better than none 0 Use it or you ll lose it Auditory stimulation pathways my not be open I When not to have binaural Asymmetrical HL When one ear is not canditate 0 Poor word recognition ability 0 Physical status Mild hearing loss 0 Binaural benefits increase as HL is more severe o Expectations I Patient needs a realistic picture of what to expect I Reasonable goals Significant benefit in both quiet and noise 0 Noisy conditions will always be harder than quiet conditions Soft sounds quotsoft but audiblequot average sounds comfortable loud sounds loud but not uncomfortable Conformable fit Ones own voice sounds acceptable no occlusion effect No feedback when HA is in ear Types of hearing aids Openfit 0 New in 2005 o Fitted to the ear with a narrow tube 0 Digital feedback cancellation 0 Excellent for highfrequency hearing losses 0 Lead to large increase BTE behind the ear sales Body Aid wornl Earhook Mode J 0 Not seen as often selec g l i 39 omo quot tit anrmold 0 Used by Severe Profound Volume t 7 39 0 One of the more powerful HA control Case Behind the Ear BTE Battery compartment 0 Hook is behind the ear and attaches to earmold o Mild to Moderate In the Ear Aid ITEl o Bigger than ITC and has more power 0 Good for someone with a Moderate HL In the Canal Aid ITCI o Smaller than BTE 0 Has less amplification it is smaller 0 Good for someone with a Mild HL Completely in the Canal Aid CIC 0 Little fishwire that allows to take out the aid Inthecanal C ompletelyinthecanal 0 Good for Mild HL because it is small device Eyeglass Aid 0 HA is part of the eye glasses 0 Not common today Bone conduction Aid 0 Not used much anymore 0 Replaced by the bone anchor HA BAHA o Stimulates the cochlea directly bypasses outer and middle ear where problems are 0 A pain for individuals to wear 45 days to try HA and return Behind the Ear In the Ear In the Canal Completely in the Canal Implantable HAs Conventional HAs have limitations 0 Insufficient amplificationgain I 80 dB gain at 1 KHz vs 80 dB gain at 4 KHz 0 Acoustic feedback I in high gain HA or ITE aids o Distortion of spectral shape and phase shifts I best gain in 500 Hz to 2000 Hz region miss lows and highs 0 Nonlinear sound distortion I With high level output can get distortions o Occlusion effect feeling of something in ear is uncomfortable I Tight seal uncomfortable pressure aural fullness 0 Cosmetic I Malformation of pina may prevent from correct fitting 0 Abnormalities in the ear canal prevent use of conventional HA Types of Implantable HAs 1quot Implantable middle i ear hearing aids Chart Labeled A Conventional airconducting HA B Implantable aids with piezoelectric actuator Moves incus and stapes to Conventional BD all type of cochlea hearing aid Middle Ear HA C Implantable aids with piezoelectric sensory and actuator Directly impacts TM D Implantable aids with magnetic actuator Directly affects malleus incus with magnet E Boneanchored hearing aid BAHA device Use for conductive losses I Chronically draining ears I Discomfort from levels with traditional HAs I Large mastoid bowl or meatoplasty I Otosclerosis I Canal atresia I Drilled into the mastoid bone All trying to stimulate the ossicles Implantable Middle Ear HAs Employ a microphone and a signal processor that amplify and alter the signal 0 The HAs convert the electrical signal into a mechanical energy that is transferred directly to the ossicular chain Piezoelectric transducer 0 Ossicles are connected to an amplifier using a piezoelectric crystal vibrator Electromagnetic transducer 0 Generates a magnetic field via coil that carries current I In turn this encodes the output of the mic 0 Does not directly contact ossicular chain 0 Rely on electromagnetic transmission to a unit that is attached to ossicles The Otologics MET middle ear transducer Uses piezoelectric transducer Original MET was semiimplantable Now fully implantable marketed as the Carina Uses a subcutaneous microphone rather than external mic OOOO plantable LC Boulder Hearing Aid Fitting and Verification HAF 1 Before HAF Verify using electroacoustic analysis in the HA test box Process o Ln I r Y PPM 39 ltci39e39i39 39 A Cochlear lmplant i C 391 i f a r 2 i n n Iquot kz 9 p IJ 39 Iquot I l 1 Put HA in box 2 Present signals in confined space 3 Get a print out of what HA can do in terms of gain frequency response I 0 function What this does is compares the HA function to the manufactory specifications 2 During HAF fit the HA using realear measurements Realear measurements identify what all the individual needs 0 Measuring how HA is operating from the persons ear Process 1 First put mic to persons ear wo HA to get characteristics of ear canal 2 Then measure with HA in 3 Then adjust HA to get appropriate gain frequency response I 0 function according to what individual needs 3 Another method Functional gain Measure aided pure tone thresholds in the soundfield and compare to unaided Functional gain difference between these two measurements NOT RECCOMENDED as replacement of real ear 4 Can also use speech measures to verify performance Quality judgments Recognition abilities in Q and N 5 Other things to check Aid fits securely in ear No feedback at desired volume setting Comfort shouldn t have to break in Patient can manipulate Cosmetic appeal Cochlear Implants CI If all most of inner hair cells are gone Cochlear implants are needed Cochlear implants bypass the usual pathway OE amp ME and stimulate the auditory nerve directly 0 Electrode array is fed through scala tympani Two components 1 External Components bodywom processor Microphone Microphone lt g x 0 Picks up acoustic signal and converts it 7 z to an electrical signal 39 0 Then sends it along the electrode array to the speech processor gtM net Speech processor I Transmmmgm o Extracts key acoust1c features of speech Transmitting coil 0 Sends processed signal to internal device Speech processor 2 Internal Components Receiverstimulator o Receives processed signal from the transmitter o Sends it to the electrode array Electrode array 0 Electrodes attempt to replace the hair cells 0 They do a good job but cannot fully replace them How the Cochlear implant works Microphone picks up sound Info is sent from mic to speech processor Speech processor analyzes info then converts to electrical code Coded signal travels to transmitter which sends it through skin to receiver Receiver decodes signal sends code to electrodes Electrodes stimulate nerve P S rPSNNtquot Speech Processing Strategies CI speech processing is digital processing Speak Spectral Peak 0 Focus spectral characteristics of speech 0 Delivers lowfrequency info to electrodes near apex highfrequency info to electrodes near base I These frequencies aspects are being ltered then sent to electrode arrays CIS Continuous Interleaved Sampling 0 Focus temporal timing ques of speech M0515 guns SCHfile o Stopping and starting soundword flound 15 TeChamcal 039quot ACE Advanced Combination Encoder dUCk Ike 0 Combines these two strategies 0 Optimizes frequency and timing information How well do CI users do Used to be to get an implant you needed a Profound HL and Corner Audiogram Before Implant WRC suprathreshold scores are about 3040dB SL above SRT threshold Now it is a Moderately Severe Profound o Openset sentences in quiet 85 correct after implant 0 Speech in noise remains very difficult History of Cochlear Implants 1972 first CI implanted in an adult 0 Only had one signal channel 0 Approved for children above 2 years in 1980 1985 multichannel CI approved by FDA for adults n Annrnvnd fnr children nhnvn 7 vnnrc in 1000 Criteria used to have a loss above 100 dB HL and no benefit from HA 0 Adults I Now loss must be greater than 7080 dB HL 0 Children Greater than 12 months I Must be greater than 90 dB HL I So they can develop speech 0 2010 over 70000 American s had CI s Other Candidacy Considerations Medical condition of Cochlea Presence of support system Integrity of Auditory Nerve Realistic expectations of benefit Benefit gained from HA Commitment to longterm rehab The Cochlear Implant Team Consists of a multidisciplinary team 0 Otolaryngologist I Medical decisions and surgery 0 Audiologist I Determines the audiological candidacy I Programs the speech processor 0 Other team members may include I SLP Psychologist I Teachers of the hearing impaired Social workers I Parents 0 Treatment Plans 0 May include pretraining I For adults Speech reading Managing communication breakdowns I For Children Conditioning for play audiometry 0 After surgery I Usually 34 weeks of healing before the processor is turnedonquot 0 Initial fitting and programming I Takes 12 hours I Audioligist use special software to program or quotmapquot speech processor 0 Neural Response Telemetry NRT I Just the Auditory Nerve Responses after the electrodes have been innervated Mapping the Speech Processor 0 Audiologists determine the dynamic range for each electrode 0 Establishing quotTquot threshold and C loud but comfortable levels 0 This is setting the quotmapquot I Map is set to keep all stimulation within this range Usually very narrow 0 Most systems allow multiple maps 0 2nd programming session 2 weeks later 0 Reevaluate dynamic range I Adjust maps 0 Begin screening auditory abilities Auditory training 0 Amount and duration vary widely I Depends on age length of deafness which clinic
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