SECTION 6: DIAGNOSTIC CLASSIFICATION TERMS AND NORMATIVE DATA

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Derek McGee
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1 SECTION 6: DIAGNOSTIC CLASSIFICATION TERMS AND NORMATIVE DATA Revision:

2 Diagnostic Classification Terms and Normative Data Classification of magnitude of hearing loss Normal 0 15 db HL Borderline normal (adults) Minimal hearing loss (children) Mild Moderate Moderately Severe Severe Profound 91 + Classification of audiometric configuration Flat: High Frequency: No more than 5-10 db change per octave. Progressively greater loss for higher frequencies. Slope 15 db per octave or steeper. Low Frequency: Trough: Irregular: Progressively less loss for higher frequencies. 20 db or more loss in mid frequencies than in extremes. Loss that does not fit above categories. Classification of word recognition scores Score in % Classification Magnitude of Problem Normal or None Excellent Good Mild. No difficulty in good listening conditions, some trouble in poor conditions Fair Moderate. Some trouble in good conditions, real trouble in poor conditions Poor Severe. Can just get along in good listening conditions Very Poor Extreme. Cannot rely on listening alone 0-20 Extremely Poor Complete. Hearing serves as a supplement to visual communication. Classification of QuickSIN Scores Score in SNR Loss Classification Location of Directional Benefit 0-2 db Normal Very noisy environments Noisy environments 3-6 db Mild SNR Loss 7-15 Moderate SNR Loss 15+ Severe SNR Loss Quiet and minimally noisy environments Quiet Revision:

3 S e c o n d P T P A e r d c B e H n L t S c o r e First Percent Correct Score 95% Confidence Limit for PBmax on NU6 25-word list.plot score according to PTA on left ordinate and percent correct score on the abscissa. If it falls in the shaded area, it is considered disproportionately low. (Adapted from Dubno et al.,1995) 95% Critical differences for 25-word list. Plot first and second score according to the abscissa and right ordinate. If it falls within the arrow, the two scores are not significantly different (Adapted from Thornton & Raffin, 1978) Revision:

4 Use of Pure Tone Averages The tradition in clinical audiology has been to use the pure tone average of thresholds at 500, 1000, and 2000 Hz for two different purposes. First, the pure tone average is compared to the speech thresholds as an indirect assessment of the intertest reliability. Second, the pure tone average can be utilized when classifying the degree or magnitude of the hearing loss (e.g. mild, moderate, severe, or profound). In cases with either normal hearing or those with a hearing loss having a relatively flat configuration, the three-frequency average is used for both of the purposes stated above. However, if the configuration of the hearing loss is either sloping or rising, the best two-frequency or Fletcher average is typically used to assess the reliability of the results. However, the impact of the hearing loss upon receptive communication is such cases may be underestimated if the degree or magnitude of the hearing loss is classified on the basis of the best two-frequency average ( Hz). Therefore, the following recommendations are made: 1. For comparison with the SRT, use the three-frequency average for flat losses or the twofrequency average for sloping, falling, or rising configurations as appropriate. 2. Always use the traditional three-frequency average when classifying the degree or magnitude of the hearing loss regardless of the configuration. If the resulting classification (mild, moderate, etc.) seems inappropriate, use descriptive terms for the degree and configuration, rather than the traditional classification. Revision:

5 Classification of immittance findings (tympanometry and reflexes) 1. It is recommended that clinicians and students not describe the tympanogram by using the Jerger classification of Type A, B, C, etc.; instead the results should be reported in narrative form. 2. With respect to middle ear pressure, the following guidelines and terminology are recommended: -50 to +50 dapa: Normal middle ear pressure -55 to -150 dapa: Slight negative pressure -155 to -250 dapa: Substantial negative pressure > -250 dapa: Excessive negative pressure The last two categories of substantial and excessive should be followed by a statement such as often associated with Eustachian tube dysfunction. 3. Static compliance: recommended guidelines and terminology: Static Compliance Description Type Child: cm 3 (ml) Eardrum mobility was normal Type A Adult: cm 3 (ml) Normal compliance with Eardrum mobility was normal with substantial Type C >-150 dapa pressure negative pressure suggesting Eustachian tube dysfunction Child: <.20 cm 3 (ml) Eardrum mobility was somewhat reduced Type As Adult: <.30 cm 3 (ml) Child: >.90 cm 3 (ml) Eardrum mobility was substantially increased Type Ad Adult: > 1.30 cm 3 (ml) suggesting a hypermobile TM No measurable compliance Eardrum mobility was substantially reduced, a Type B No measurable compliance with large physical volume condition often associated with middle ear fluid Physical volume of ear canal was large, consistent with perforated TM or patent pressure equalization tube. 4. Acoustic reflex findings: recommended guidelines and terminology: Present at 100 dbhl or < present at expected levels Present at 100 dbhl or < present at reduced sensation levels With mild or moderate SNHL consistent with a cochlear disorder,(<65 db SL) Positive Reflex Decay Testing revealed acoustic reflex decay suggesting the possibility of a retrocochlear pathology. Revision:

Classification of magnitude of hearing loss (adapted from Clark, 1981; Anderson & Matkin, 1991)

Classification of magnitude of hearing loss (adapted from Clark, 1981; Anderson & Matkin, 1991) Diagnostic Classification Terms and Normative Data The following are agreed upon definitions to be used in clinical reports. However, full interpretation of audiological results should be made within the