An increasing number of students are being diagnosed with auditory processing disorder (APD), a controversial condition that is difficult to distinguish from other learning disorders, says a recent article in Psychology of Schools.
School psychologists and other educators who work with children suspected of having APD should be aware of serious concerns about assessment tools and diagnostic practices for this condition, as well as concerns about insufficient research on the effectiveness of interventions, writes researcher Benjamin Lovett, Department of Psychology at Elmira College. Based on his review of 59 articles and studies on APD, the researcher says that another important concern is t
Based on his review of 59 articles and studies on APD, the researcher says that another important concern is the difficulty in differentiating APD from other disorders, particularly attention deficit/hyperactivity disorder (ADHD), reading disabilities and receptive language problems.
“In considering the lack of consensus concerning many APD issues, the technical limitations of assessment tools, and the thin evidence base for interventions, it seems that school psychologists should indeed be wary of the APD diagnosis and subsequent therapy recommendations,” the author writes.
“However, this wariness should not lead to dismissiveness. There are students who show poor performance on auditory processing tasks, and at least some of these students show functional impairments in listening and other skills.
APD is typically defined as the defective processing of auditory information in spite of testing for normal hearing. The individual with APD has normal sensitivity to the presence of sounds but has trouble interpreting the meaning of sounds. The individual may act as if she or he is hearing impaired.
The most common signs of APD include difficulties in following directions, understanding rapid speech, responding in noisy environments, singing or appreciating music and determining where a sound is coming from, according to the researcher. Red flags for teachers include difficulties participating in class, understanding stories that are read aloud, responding quickly to questions, trouble learning a foreign language and taking good notes from dictation.
Initial screening for APD typically begins with rating scales such as the Scale of Auditory Behaviors, which consists of questions about the child’s behaviors (e.g., how frequently does the child have difficulty following oral instructions or have difficulty hearing or understanding in background noise?). Like most screening instruments, APD rating scales are designed to be more sensitive than specific, the researcher writes, and many of the symptoms are associated with conditions other than APD, such as attention problems.
Very little research is available on the scales’ psychometric characteristics. One recent study that examined a questionnaire designed to be completed by teachers found little association between teachers’ ratings of children’s speech discrimination skills and their skills on formal testing.
Behavioral tests of auditory processing are used for both screening and diagnosis of APD. These measures examine how well students respond to auditory stimuli with a range of tasks such as repeating sounds or words, focusing on one kind of auditory stimuli while ignoring others or reporting on gaps in tones.
One widely used test, SCAN-3:A, designed for students 13 and older, has disappointing validity evidence in the research, Lovett says.
“Although the test has evidence of content validity (in that its tasks involve the skills described as being deficient in APD), other validity evidence is lacking,” he writes. There are few correlations in results among the measures’ various subtests, Lovett says.
Another study that examined 15 criterion-referenced tests and 5 norm-referenced tests found that few met evaluation standards for reliability, validity and clinical utility (sensitivity and specificity), according to the Psychology in Schools article.
Both the American Speech-Language-Hearing Association and the American Academy of Audiology recommend that a diagnosis of APD should be based on scores at least 2 standard deviations below the mean on at least 2 auditory processing tasks.
“Given the psychometric problems of the assessment tools reviewed earlier, even observed scores more than 2 standard deviations below the mean may yield confidence intervals that extend into the average range,” he writes.
Many students who come to school with APD diagnoses are accompanied by recommendations for management strategies. Some of these interventions are simple and consist of reducing background noise, increasing the intensity of important sounds or giving students preferential seating. Other modifications include closing windows, adding carpeting or padding the bottom of chair legs to decrease noise.
More intensive modifications include amplifying important sounds (the classroom teacher’s voice) by giving the teacher a microphone to wear and giving the child headphones or placing a speaker at the child’s desk or in a prominent place in the classroom. Although these modifications can be expensive, research shows they have benefits for all students, not just those with a diagnosis of APD, Lovett writes.
The processing deficiency can also be addressed by providing students with written notes so that they do not need to divide their attention between note-taking and careful listening. Some students are also given “listening breaks” scattered throughout the day or a separate room for testing so that there are fewer distractions.
“Although there is no published research evaluating these strategies in the APD population, their low cost and effort lead to their popularity,” the researcher writes.
Computer programs have been developed to provide exercises to help students’ increase auditory processing skills (Earobics and Fast ForWord). The exercises are similar to the behavioral tests used to assess APD. The hope is that by giving students practice with these kinds of tasks, students will, over time, increase their skills and that students’ improved skills will generalize to the classroom. The exercises are presented in a game-like format.
Lovett says the evidence of efficacy is skimpy. Only one methodologically rigorous study has shown the positive effects of certain exercises on auditory processing and more research is needed to replicate the results and determine whether the effects generalize to the classroom.
Some of the hypotheses about the causes of APD include traumatic brain injury, ranging from concussions to penetrating wounds, exposure to toxic substances and frequent ear infections early in life that cause intermittent auditory deprivation leading to dysfunctional development of the central pathways, the article says.
Lovett makes several recommendations for how educators and psychologists can help students with processing problems while being wary of the issues surrounding APD.
Before an APD Diagnostic Evaluation
- Consider alternative explanations before recommending an APD evaluation.
- Ensure that the student’s peripheral hearing sensitivity is normal. Rule out attention problems and consider the possibility that failing to listen may be a sign of noncompliant behavior.
- Because APD is one of the less established diagnoses, view it as a diagnosis of last resort.
- If a student has reading or language problems, point out that research does not show that these can be attributed to auditory processing deficiencies.
After an APD diagnosis
- If you have reason to question the diagnostic decision, be careful to be appropriately respectful of professionals in other fields.
- Examine the diagnostic evaluation report with special attention to the diagnostic tools that were used. If norm-referenced scores are not given, ask the diagnostician for more information.
- Review information about the diagnostic tests to educate school personnel about the appropriate interpretation of the student’s scores.
- Interpret the APD test results in the context of other information on the student. Look at ability/achievement assessments to determine whether deficiencies in these skills may have depressed the student’s performance on APD measures. If the student’s teacher reports hyperactive and impulsive behavior in addition to APD systems, a diagnosis of ADHD could account for all symptoms.
- If the diagnosis is accompanied by recommendations for interventions by the school, investigate the evidence for efficacy. Some strategies, such as preferential seating, may be implemented easily, but the school may want more evidence of effectiveness for other interventions, such as personalized amplification systems or computerized exercises.
“Auditory Processing Disorder: School Psychologist Beware?,” Benjamin Lovett, Psychology in the Schools, 2011, Volume 48, Number 8, pp. 855-867.