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Select a question below to see the response.
Purpose and Use
Are the SCAN—3 tests (both Children and Adolescents/Adults) screening or diagnostic tests?
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They are both. SCAN—3 contains three screening measures that can be used to determine if the entire battery should be administered. If an examinee fails the screening tests, or if there is a referral for diagnostic testing, then the audiologist can proceed with the diagnostic portion of the test. The criterion-referenced norms provide cut scores for determining pass/fail of the screening measures. The SCAN—3 diagnostic tests include standard scores with percentile ranks and confidence intervals that are important in the interpretation of test results. Overall, the nine tests of the SCAN—3 test batteries include all of the behavioral measures recommended in the recent Guidelines for the Diagnosis, Treatment, and Management of children and adults with central auditory processing disorder published in 2010 by the American Academy of Audiology. Further, most audiologists recognize that both SCAN-C and SCAN-A (the previous test versions) were diagnostic procedures that included four tests validated in previous studies of patients with confirmed central auditory lesions. The original SCAN test, published in the 1980s, was considered just a screening measure.
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Test Content
Why are there 3 S/N (signal-to-noise) ratios on the SCAN-3? How do I use them?
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We included three signal-to-noise (S/N) ratios in the SCAN-3 battery to determine the progression of children’s ability to hear in noise from “easy” to “very difficult.” In fact there were four S/N ratios earlier in the revision process but standardization studies found that the +4 dB S/N ratio did not add to the results, and it was removed in order to save examiner time. The different S/N ratios can help identify the optimal S/N ratio for a child to understand speech and can guide the examiner to make recommendations for classroom modification including assistive listening devices. See the table below for further discussion of S/N ratios.
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Administration
When should I choose to use the supplementary subtests of the SCAN-3?
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There are three supplementary tests in each level of the SCAN-3:
SCAN-3:C
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Auditory Figure-Ground (AFG) at +12 dB Signal-to-Noise Ratio
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Administer if the child does not pass the AFG at +8 dB screening test. The information can help identify a child with marked problems with auditory figure ground listening tasks, and to identify a target S/N ratio for a classroom assistive listening device.
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AFG at 0 dB Signal-to-Noise Ratio
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Administer if you want to know more about the child’s ability to listen in noise. If a child passes the 0 dB S/N test this level is more difficult. Young children are not expected to do well at this S/N ratio.
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Time Compressed Sentences (TCS)
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Administer if you want to know more about the child’s ability to process speech at a rapid rate.
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SCAN-3:A
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AFG at +8 dB Signal-to-Noise Ratio
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Administer if the examinee does not pass the AFG 0 dB screening test.
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AFG at +12 dB Signal-to-Noise Ratio
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Administer if you want to know more about optimal listening conditions that the examinee requires.
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TCS
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Administer if you want to know more about the examinee’s ability to process speech at a rapid rate.
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A student was given the SCAN-3 and the educational team was unaware that he had a concussion at the time. He has now been cleared by the medical staff and the team feels that the SCAN-3 administration is inaccurate and invalid. When can we re-administer the test without compromising our result?
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In view of the increasing literature on symptoms post-concussion the findings obtained soon after the concussion may be completely valid, reflecting the status of the auditory nervous system at the time the test was administered. For example, if the results were low or below normal, perhaps there was some post-concussion injury. If they were normal, perhaps there was no injury to the auditory pathways. Any change, especially improvement on retest, may reflect recovery from the concussion. For retest purposes, research indicates that a period of 3 to 4 weeks between tests is sufficient to allow accurate re-test findings.
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Scoring
On the SCAN-3 Competing Words – Directed Ear test, the manual states that:
1) A correct response is when the child repeats the words correctly in the directed order.
2) An incorrect response is one that is not in the directed order, no response or I don’t know.
If the child is meant to say 'waste, cage' and they say 'waste' only, mark 'waste' as correct and 'cage' as incorrect (no answer). What if the child responds with only 'cage' (i.e., only gives the left ear response)? Is this marked correct or incorrect?
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If the stimuli should be repeated as "waste – cage" then the answer "waste" only indicates a correct first word response and an error on the second word "cage."
If the child responds with only "cage" then "waste" (the first word the child was to reply) is an error and "cage" is correct.
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Interpretation
I want to make sure I’m interpreting my SCAN-3 results correctly. What type(s) of information do you have to help me?
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Chapter 4 of the manual includes the following interpretation supports:
- A description of each score type (e.g., ear advantage, composites, confidence intervals)
- Interpretive comments for each test (diagnostic and supplementary tests)
- Recommendations for intervention (management and/or remediation)
- Three (3) case studies (test results, interpretation, and intervention)
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Can the SCAN-3 be used to try to determine whether the finding on dichotic testing is from an auditory processing disorder (APD) or cognitive disorder?
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Yes. Compare the free recall dichotic test to the directed ear dichotic test results. If performance on the free recall dichotic test is substantially better than the directed ear dichotic test there is likely to be a problem of attention or cognition, added to the auditory processing performance. If performance on the free recall and directed ear dichotic tests are similar then one can assume that low performance is due to auditory processing deficiencies. One caution to that interpretation—if the child’s overall cognition and language are low, equal performance on the free recall and directed ear dichotic tests are expected. The child’s performance on dichotic testing is not expected to exceed the child’s cognitive/linguistic abilities.
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What criteria can be used to diagnose a child as having an auditory processing disorder (APD)?
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Performance at two standard deviations or poorer (i.e., standard scores of 4 or less) on a single test within the battery, or performance below one standard deviation (i.e., standard scores of 7 or lower) on two or more tests within the battery indicate the high probability of an APD being present. The AAA Guidelines for the Diagnosis, Treatment and Management of Children and Adults with Central Auditory Processing Disorder (2005) recommend similar criteria of a score two standard deviations or more below the mean for at least one ear on at least two different behavioral central auditory tests. In addition, remember that ear advantage scores are powerful indicators of hemispheric dominance for language and neurologically-based language/learning disorders. Therefore, exaggerated right-ear advantage or a left-ear advantage on any of the tests within the SCAN-3 battery has implications for the diagnosis of APD.
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I am the hiring manager at a law enforcement agency. I have been using the SCAN-3:A test batteries as a screening tool for dispatcher applicants for the past several years. I have noted with regularity that the applicants who do not meet the norms on the SCAN-3:A tests do poorly in the dispatch center. As the hiring manager, I want to incorporate passing the SCAN-3:A as an essential qualification in the hiring process for dispatchers. A few questions:
1) Can the SCAN-3:A be used as a tool in pre-employment?
2) Was there a multicultural bias in the standardization of the SCAN-3:A? Many of our applicants are Hispanic and English is a second language.
3) Was there a gender bias in the standardization of the SCAN-3:A test?
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First, although this use of the SCAN:3-A is interesting and apparently successful, the test has not been standardized for use in pre-employment placement decisions. Interestingly, the author of SCAN-3 tests, Dr. Robert Keith, proposed such use to the military some years ago. Second, there is a known factor that is well documented in the literature of the relationship between the person’s native language and performance on all tests of auditory processing. Typically persons for whom English is a second language will do less well than native speakers of English. Third and finally, the normative data base indicates that there is no gender bias in test results.
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Manuals, Record Forms, & Manipulatives
On the Audio CD, The Filtered Words (FW) subtest sounds quiet. Is there a problem with the CD?
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No. After verification of the standardization CD, the gold master CD that was sent to replication, and the current inventory, the CD recordings all match the sound levels upon which the SCAN-3 was standardized. After a thorough review of the conditions for standardization, the norms match the current CD output. The test appears to have less volume because the low pass filtering eliminates high frequency sounds of speech that we are used to hearing, and the overall acoustic energy is reduced.
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Why does the FW test appear to be so quiet?
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In the development of the SCAN-3, the FW subtest was made more difficult by design; the conditions of the task were changed from the previous edition to increase the precision and achieve better discrimination and a reduced false positive rate. Even though fewer children fail the FW test, it is included to identify those few who have a problem with degraded speech of this type. The test has been used throughout the history of auditory processing assessment, and contributes to the SCAN-3 composite score.
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The dB level of the stimuli in the Filtered Words subtest sounds noticeably "quieter" than the other subtests.
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Dr. Bill Carver, PhD, FASHA, FAAA from Auditec, Inc. completed the stimulus CD development in partnership with Pearson during the development process. He writes:
This is a situation that occurs when you filter out some of the spectrum. The question for the recordist/post-production professional is, “How do I level this?” I begin with the unaltered signal and level it to 0 dB VU, then filter it and forget about re-leveling. Why? Because when one sets level for each word, then filters, what-do-you-know, the words are no longer reaching 0 db VU but, in addition, are no longer similar to each other, i.e., they are no longer uniformly at the same level as observed on the VU meter. In addition, the loudness (our perception) does not seem to be reduced significantly. VU meters were designed to reflect how we perceive loudness, but they are not real ears. The ballistics (damping) of the meter is specified by the NAB. VU meters are completely different from peak meters and RMS meters - they are heavily damped. However when part of the spectrum is removed, VU meters do not tell the same story. Loudness does not necessarily diminish especially when it's the higher frequencies that are removed (by filtering). The low frequency power is still there!
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Technical Information
What settings should be used to be sure that the person being tested can hear the stimuli well?
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As indicated in the manual, if testing through an audiometer use the calibration tone to adjust the VU meter to zero. Then set the HL dial on the audiometer to 55-60 dB HL or so for comfortable listening at a level that is clearly heard. If you are not using an audiometer be sure to adjust the volume to an intensity that would sufficiently loud to be comfortable and clear to the listener. For example, adjust the volume to the same level that would give you comfortable loudness and clarity when listening to a radio broadcast. After starting the test do not change the volume again during the test.
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What is an acceptable background noise level in the room where I administer the SCAN-3 and still get valid test results?
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The SCAN-3 test results can be contaminated, and give false results when the background levels of the test environment are too high, essentially masking the test stimuli. A free smart phone app called the “decibel-o-meter” from the Amazon app store can be downloaded to measure background noise levels. The decibel-o-meter can be used to measure the background noise, and when they are excessively high (e.g. over 60dB) the examiner should search for a more quiet room. If you do not have a smart phone to measure the background noise levels use your clinical judgment. If the noise levels are high and distracting do not test. The test stimuli need to be comfortably loud, and if there is any question that the signal to noise ratio is poor (i.e., the SCAN-3 stimuli are not easily heard above the background noise in the test room), then the test should be discontinued and/or the results questioned.
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I put the audio CD into my CD drive and the track labels seem to be incorrect. Do I have the wrong disk?
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Not necessarily. If you use iTunes on the same computer you use to play the audio for SCAN administration, you may see track names/labels for the opposite SCAN disk (i.e. SCAN-3 for Children track names on the Adolescent & Adult CD and vice versa). The track names are not on the CD media at all, they are stored in a database with a company called Gracenote. Gracenote has track names, lyrics, etc. for billions of CDs. Certain media players like iTunes read a CD and automatically communicate with Gracenote over the internet to get the track names. We are working with Gracenote to correct their database and to make this less confusing for all customers, but the CD content itself is correct.
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In the protocol instructions, there is a figure/ground subtest that evaluates each ear individually and that there is a CD and earphones involved but where do you get these earphones and where do they plug in?
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Please refer to your SCAN-3: C Manual, page 5, Test Components and Equipment for this information: "The SCAN-3:C kit contains this Manual, Record Forms, and an audio compact disc (CD). You will need to provide a CD player with a track display or a two-channel audiometer; two sets of stereo headphones: one set for the child and one set for you to monitor the auditory stimuli; and a stereo Y-adapter if the CD player does not have two output jacks. SCAN-3:C can also be administered using a computer with a headphone jack into which a stereo Y adapter can be inserted."
It is very important that the headphones and y-adapter be in stereo: the test stimuli are sometimes delivered to one ear or the other. Stereo headphones and Y-adapters can be purchased rather inexpensively at any electronics store in your area.
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