Assessment and Diagnosis

​

Since decades ago, auditory processing (AP) assessment and APD diagnosis have relied on a battery of tests applied to investigate specific listening skills. They are behavioural tests, which means that they rely on individuals' responses and encompass speech and non-speech sounds. Some were designed to simulate everyday listening situations such as speech in noise tests or tests in which the individual has to focus on a message and ignore others; others involve the ability to differentiate similar sounds. Because they are much more complex than a basic hearing test, they are not usually applied in children younger than seven years. Most listening and cognitive skills are still developing before this age; thus, the results could be misinterpreted.

​

Although those tests have been used for decades to diagnose APD, currently, there are at least three central issues still extensively debated regarding AP assessment and APD diagnosis. The first is the fact that there are still no universally accepted criteria for APD diagnosis (Wilson and Arnott, 2013; Vermiglio, 2016; Moore, 2018, BSA, 2018; Dillon & Cameron, 2021). The selection of protocols, including choice and number of tests and questionnaires, as well as the way of interpreting test results, still vary between services. Thus, it is not surprising to find an AP assessment significantly different from one performed in another clinic. In fact, this is one of the main reasons why the topic APD is still so controversial. Research has shown, for instance, that depending on the criteria adopted, the rate of potential APD diagnosis can vary between 7% to 96% (Wilson and Arnott, 2013), a finding that would question the validity of any APD diagnosis. The second issue is the strong influence of non-auditory factors on AP tests (Moore, 2012; Murphy et al., 2013; Tomlin et al., 2015; Dillon & Cameron, 2021). Unlike basic hearing tests, AP tests are more complex; they can rely on speech processing, executive function, attention and memory. Thus, an abnormal result on an AP test could simply result from an underlying condition involving general memory, for instance, or any other condition involving the other aspects. The third issue is the lack of correlation between everyday listening difficulty and AP tests' results, which indicates that those tests have not been successful in outlining the daily listening struggles presented by the individual (Dillon et al., 2012; Moore, 2012; Barry et al., 2015).

​

In the last decade, there have been a considerable number of studies trying to address those issues by suggesting alternative ways of assessing listening skills (Dillon et al., 2012; Barry et al., 2015; Chermak et al., 2017; Dillon & Cameron, 2021). There is still no consensus regarding a particular and best way of assessing it; however, some important topics have been highlighted:

1. There is no doubt that before the AP assessment, an initial audiological evaluation is essential to investigate the function of the peripheral part of the auditory system (outer, middle and inner ear). Pure-tone audiometry should also include extended high-frequency (EHF), given the recent studies associating EHF hearing loss and speech in noise perception difficulties (Motlagh Zadeh et al., 2019; Hunter et al., 2010). This first step is important to differentiate the developmental and secondary APD, for instance. The secondary APD would need appropriate medical care so the precise aetiology (cause of APD) could be first established and the management options discussed before the AP assessment.

1. The first step of the AP assessment is to outline the individual’s listening difficulty taking into account a broader perspective that includes all the key listening aspects such as language, memory, social interaction, attention and executive function. The investigation of those potential underlying factors is imperative as they might significantly contribute to those listening concerns. Reliable and well-validated questionnaires can provide that information. They can also capture everyday listening difficulties and indicate how the individual is coping with specific real-world listening situations. This approach would minimize the problem regarding the lack of correlation between tests' results and real-world difficulties and it would also provide essential information about how non-auditory sensory factors are impacting tests' results. A multidisciplinary approach will be important to interpret the AP tests results if the individual has other relevant concomitant conditions.

2. It has become a consensus that a long evaluation with numerous AP tests should be avoided (Dillon et al., 2012; Cameron et al., 2015; BSA, 2018; Moore, 2018). Instead, a shorter battery of tests using only well-standardized tests would be ideal. The BSA recommends the inclusion of tests involving speech perception in both quiet and noise to determine the influence of language and spatial processing tests such as LiSN-S to investigate Spatial Processing Disorder. On the other hand, Dillon et al. (2012) suggest a hierarchical test battery (instead of a fixed test battery), in which a specific order of testing is considered in a results-dependent manner. In addition to AP tests, digit span tests are also included to investigate short-term and working memory performance (Cameron et al., 2015). This approach might allow a better investigation of the nature of the listening difficulties as it considers a more integrative approach between tests. In addition, it includes the investigation of memory skills, which is one of the key aspects of listening in general.

​

Management

 

The management programme must be individualized and designed according to the assessment's result. It must not be only test-driven, which means only based on the test's results. It must also include functionally driven strategies to promote an immediate and effective change in the individual's life. The BSA suggests the inclusion of three main aspects:

• Modification of the listening environment

This item refers to all types of changes to improve the signal (message) and reduce the background noise. It includes, for instance, the use of remote microphone in meetings or the classroom. This remote microphone consists of a personal listening device (a wireless microphone that transmits voice to a individual's receiver in the ear) that bypasses high-level classroom noise and transmits clearer speech to the individual's ears (Bamiou & Murphy, 2018). Another new type of technology is the Personal Sound Amplification Products (PSAPS). They are simple digital hearing amplifiers developed for individuals (adults) with normal hearing who need some boost in volume. There is still no evidence that they are effective for children with APD. Preferential seating in the classroom as well as teacher/speaker adaptations, such as face the listener and use clear speech, are also helpful strategies.

• Auditory training

Auditory training (AT) is a set of strategies applied to develop or improve auditory abilities (Chermak & Musiek, 2002). The improvement is explained by neuroplasticity, which is the capacity of the brain to modify its connection in response to stimulation and environmental experiences. In order to be effective, the training has to be intensive (e.g., 30 min, 3 to 4 days a week during at least six weeks) and progressively challenging. The training can be delivered by combining formal sessions with the audiologist using the audiometer and computer-based AT programmes and apps at home. Research has demonstrated that AT is very effective in improving the auditory skills trained. However, the learning generalization to untrained skills, such as language or cognition, is controversial (Murphy et al., 2015). This is important when setting clear expectations regarding the AT effectiveness, especially if the individual also presents with concomitant conditions such as dyslexia or language impairment.

• Use of compensatory strategies

It includes individual listening strategies related to self-regulation and problem solving, according to the individual's strengths and weaknesses. This programme of strategies can be appropriately designed when the individual's everyday listening difficulties are specifically outlined through those questionnaires already mentioned.

​

References:

• Bamiou DE, Murphy CFB. (2018). Auditory Processing Disorders across the age span. In book: Scott-Brown´s Otorhinolaryngology and Head and Neck surgery. June. Publisher: Taylor and Francis

• Barry JG, Tomlin D, Moore DR, Dillon H. (2015). Use of Questionnaire-Based Measures in the Assessment of Listening Difficulties in School-Aged Children. Ear Hear. 36(6):e300-13

• British Society of Audiology APD SIG. (2018). APD Position Statement and Practice Guidance.

• Cameron S, Glyde H, Dillon H, King A & Gillies K. 2015. Results from a national central auditory processing disorder service: A “real world” assessment of diagnostic practices and remediation for CAPD. Semin Hear; 36: 216-236.

• Chermak GD, Musiek FE. Auditory training: principles and approaches for remediating and managing auditory processing disorders. Semin Hear. 2002;23:297–308.

• Chermak, G.D., Bamiou, D-E., Iliadou, V., & Musiek, F.E. (2017). Practical guidelines to minimize language and cognitive confounds in the diagnosis of CAPD: A brief tutorial. Int  J Audiol, 56, 493-500

• Dillon H., Cameron S., Glyde H., et al. (2012). An opinion on the assessment of people who may have an auditory processing disorder. J Am Acad Audiol. 23, 97–105

• Dillon H, Cameron S. Separating the Causes of Listening Difficulties in Children. Ear Hear. 2021 Jun 16.

• Hunter LL, Monson BB, Moore DR, Dhar S, Wright BA, Munro KJ, Zadeh LM, Blankenship CM, Stiepan SM, Siegel JH. (2020) Extended high frequency hearing and speech perception implications in adults and children. Hear Res. 397:107922.

• Moore DR. Listening difficulties in children: bottom-up and top-down contributions. (2012) J Commun Disord. 45(6):411-8.

• Moore D.R. (2018). Editorial: Auditory Processing Disorder. Ear Hear. 39(4): 617-620.

• Murphy CF, La Torre R, Schochat E. (2013) Association between top-down skills and auditory processing tests. Braz J Otorhinolaryngol. 2013 Nov-Dec;79(6):753-9.

• Vermiglio A.J. (2016) On Diagnostic Accuracy in Audiology: Central Site of Lesion and Central Auditory Processing Disorder Studies. J Am Acad Audiol. 27(2):141-56.

• Motlagh Zadeh L, Silbert NH, Sternasty K, Swanepoel W, Hunter LL, Moore DR. (2019). Extended high-frequency hearing enhances speech perception in noise. Proc Natl Acad Sci U S A. 19;116(47):23753-23759

• Wilson, W. J., & Arnott, W. (2013). Using different criteria to diagnose (central)

auditory processing disorder: How big a difference does it make? J Speech Lang Hear Res, 56, 63–70.

• Wilson, W. J. (2018) Evolving the concept of APD. Int J Audiol, 57, 240–248.