Types of Hearing Loss - Tagged PDF

Unit 3, Lecture 3 Types of Hearing Loss/Audiograms Air Conduction (AC) Testing  Pure tones presented through the headphones  Tests the integrity of the entire peripheral system ◦ If hearing loss is identified, we cannot localize the problem  Could be outer, middle, inner, or...

Unit 3, Lecture 3 Types of Hearing Loss/Audiograms Air Conduction (AC) Testing  Pure tones presented through the headphones  Tests the integrity of the entire peripheral system ◦ If hearing loss is identified, we cannot localize the problem  Could be outer, middle, inner, or pathways to the brain  Or a combination of any of these Bone Conduction (BC) Testing  Pure tones are presented through a bone oscillator ◦ Oscillator is placed on mastoid process  Bony prominence behind the pinna ◦ Oscillator will vibrate the skull and stimulate the cochlea directly ◦ B/C testing will bypass outer and middle ear and stimulate the inner ear directly ◦ < or [=Right BC threshold ◦ > or ]= Left BC threshold Threshold  Term used to define the least intensity required for a patient to perceive an auditory stimulus 50% of the time ◦ How soft of a sound can the patient hear Audiograms  Graph used by audiologists to plot hearing loss  Plots intensity (dB) as a function of frequency ◦ X axis = frequency in Hz  Ranges from 125 to 8000 Hz ◦ Y axis = intensity in dB  Ranges from –10 to 120 dB Audiograms  Symbols- these are placed at the intersection of Hz/dB to identify a person’s thresholds. ◦ Uniform across facilities ◦ Right Air Conduction = red=O ◦ Left Air Conduction= blue=X ◦ Right Bone Conduction = < or [ ◦ Left Bone Conduction = > or ] Create an Audiogram… Right ear (O) and Left ears (X)  250Hz – 30 dB  500 Hz – 30 dB  1000 Hz – 30 dB  2000 Hz – 35 dB  4000 Hz – 35 dB  8000 Hz - 40 dB On your Audiogram…  Add BC for Right () Ears  250Hz – 30 dB  500 Hz – 30 dB  1000 Hz – 30 dB  2000 Hz – 35 dB  4000 Hz – 35 dB  8000 Hz - 40 dB Using Air & Bone Information to diagnose TYPE of hearing loss  If bone conduction responses are better than air conduction responses then the loss is due to a problem with outer / middle ear  If bone conduction responses are equal to air conduction responses then the loss is due to a problem in the inner ear or deeper Degree of hearing loss  Terms used to describe the amount of hearing loss a patient has.  Refer to page 294, Figure 11.4 in text. Threshold dB HL Term < 26 Normal hearing 26 – 40 Mild loss 41 – 55 Moderate loss 56 – 70 Moderately severe loss 71 – 90 Severe loss >90 Profound loss What is the degree of hearing loss for your audiogram? Degree of hearing loss  Examples of dB HL ◦ Water dripping = 15 dB HL ◦ Normal conversation = 50 dB HL ◦ Dog barking = 70 dB HL ◦ Airplane = 120 dB HL There are 3 types of hearing loss:  Conductive  Sensorineural  Mixed Types of hearing loss  Conductive hearing loss ◦ Pathology is localized to the outer and/or the middle ear ◦ Problem with “conducting” sound to the cochlea ◦ Confirmed by the presence of air-bone gaps on the audiogram.  Air conduction is > 10 dB worse than bone conduction  Bone conduction must be in the normal range in conductive hearing loss ◦ Usually correctable by medical intervention Types of hearing loss  Sensorineural hearing loss ◦ Pathology is localized to the inner ear or central system ◦ Absence of air-bone gaps on the audiogram  Air = bone  Not usually correctable by medical intervention Types of hearing loss  Mixed hearing loss ◦ Any conductive hearing loss with an underlying sensorineural component  Combination of conductive and sensorineural ◦ Presence of air-bone gaps on the audiogram but bone is no longer in normal hearing range ◦ More difficult to diagnose What is the Type of hearing loss for your audiogram? Reading Audiograms  Must report ◦ Unilateral vs. bilateral  Is the loss in one ear or both ◦ Symmetric vs. asymmetric  Is the loss the same in each ear or is there > than a 10 dB HL difference between ears ◦ Degree of loss  Mild, moderate, etc… ◦ Type of loss  Sensorineural, conductive, or mixed Is the hearing loss on your audiogram symmetrical? Is the hearing loss unilateral or bilateral? Reading Audiograms  Frequencies involved or “shape” of hearing loss ◦ Flat ◦ Sloping ◦ “cookie bite” ◦ High, mid, or low frequencies  Example ◦ Patient presents with a (unilateral, bilateral), (symmetric, asymmetric), (mild, moderate,…), degree of (sensorineural, conductive, mixed) hearing loss.  Describe your audiogram. Try to include degree, type, symmetry, shape all in one concise sentence. Create an Audiogram and Describe  Right ear:  Left Ear: ◦ AC: 250 Hz – 8000 ◦ AC: 250-8000 Hz @ Hz @ 30dB 50dB ◦ BC: 250-8000Hz @ ◦ BC: 250-8000Hz @ 10dB 10dB Create an Audiogram and Describe  Right and Left Ears ◦ AC and BC:  250Hz – 75dB  500Hz – 80dB  1000Hz- 85dB  2000Hz – 90 dB  4000Hz – 100dB  8000Hz – 110dB