Lessons I learned from an important neuroaudiology conference

As part of my work for the Alliance, I enjoy learning about different conditions to help families in our community understand them. Because of his hemispherectomy, my son has a central auditory processing disorder, so I’m especially interested in this topic. 

Sometimes children prefer to wear headphones after hemispheric surgeries, usually because they are overwhelmed by the sounds around them. Brain surgeries that affect parts of the brain involved in hearing and listening can result in central auditory processing disorder (CAPD) (also called auditory processing disorder (APD)). This is when the brain has trouble making sense of the sounds it hears. It’s not about how well the ears hear sounds but how the brain understands them, especially speech. People with CAPD might have difficulty understanding what people say in noisy places, following directions, and telling similar sounds apart.

Not every child will have an auditory processing disorder after epilepsy surgery. But surgeries that involve parts of the brain that process sounds, like the temporal lobe or corpus callosum, can increase the chances of APD. How much the disorder shows up can differ for each person depending on the type of surgery, which brain areas are involved, and the person’s unique brain structure.

In one case study, before surgery, a patient could understand speech normally both in quiet and noisy environments. After the first resection surgery on the right side of the brain, their ability to recognize speech in noisy conditions, especially with the left ear, got worse but was still mostly normal. One year later, another surgery on the same side of the brain kept his speech recognition in quiet environments and understanding of non-speech sounds (like pitches and environmental noises) intact. However, their ability to recognize speech in noisy conditions became severely impaired.

Nagle S, Musiek FE, Kossoff EH, Jallo G, Boatman-Reich D. Auditory processing following consecutive right temporal lobe resections: a prospective case study. J Am Acad Audiol. 2013 Jul-Aug;24(7):535-43.

Lessons from the Pathways conference

Recently, I attended the symposium “Pathways: Quest for the Best in CAPD/NeuroAudiology.” This event was organized by Dr. Frank Musiek and Dr. Jennifer Shinn, well-known neuroaudiology experts (they’re both involved in our symptom surveillance initiative after hemispherectomy.) They gathered a group of specialists to share their knowledge about important topics such as:

• Diagnosis Techniques: Advanced methods for diagnosing CAPD.
• Therapeutic Approaches: Effective therapies and training to assist people with CAPD.
• Latest Research: New insights into improving daily life for those with hearing issues.

Highlights from the Symposium

Historical Perspective on Neuroaudiology

Dr. Frank Musiek (he’s on our scientific advisory board) talked about the history of neuroaudiology and explained why dichotic listening tests (listening to different sounds in each ear) are important for finding sound processing problems. He said that temporal processing and auditory brainstem response (ABR) are important tools for diagnosis and should be used more in audiology. He also stressed the need for more research on auditory processing disorders in children, like developmental dyslexia, to help with early diagnosis and treatment.

Neurological Conditions and APD

Professor Doris-Eva Bamiou talked about how neurological conditions like stroke and dementia affect how people process sounds. She explained that even if someone passes regular hearing tests, they might still have trouble understanding speech or recognizing sounds. Early detection and regular screening can greatly help manage these auditory processing problems. Using assistive devices and learning about APD can significantly improve the quality of life for loved ones with neurological conditions.

Complexity of APD Evaluation and Treatment

Dr. Jeanene Ferre explained that APD is a complex disorder. She stressed the need for thorough tests to understand it better. Different types of APD need special treatment plans. Auditory processing disorder often occurs with conditions like ADHD and learning disabilities. For parents, knowing about APD is important for helping their child. Strategies like listening programs and environmental changes can greatly improve a child’s daily life.

Taking a team approach is important, including the parent and child, audiologists, speech therapists, teachers, and doctors. Dr. Ferre emphasized the importance of a collaborative and comprehensive approach to managing APD effectively.

Sound Processing, Brain Function, and Well-Being

Sound processing is important for our brain function and overall well-being. An amateur musician and well-known auditory researcher, Dr. Nina Krauss , explores this intricate relationship in her book, “Of Sound Mind: How Our Brain Constructs a Meaningful Sonic World.” She spoke about how our brains make sense of sound and why it’s important to understand this process. Krauss does research on how a head injury, like a concussion, can change how our brains process sound. She suggests using rhythm-based therapies, like music, to help the brain recover. Krauss also says that activities like sports or exercise are good for our brains.

Understanding how our brains react to sound and movement can help us stay healthy and recover from injuries better. Krauss talked about her “BEAMS hypothesis,” a theory about how the brain processes sound. Our brain’s ability to understand and process sounds, like speech or music, is shaped by our genetics, learning environments, and musical training.

Treatment Options: Counseling, Auditory Training, and Hearing Aids

Dr. Alyssa Davidson focused on different ways to help with central auditory processing problems. Her research shows that it is important for patients with CAPD to reflect on their own listening abilities and challenges. Through a case study on a retired service member, she shared that auditory training can make a big difference in understanding speech and improving quality of life.

She highlighted the potential benefits of low-gain hearing aids for those with normal hearing but significant self-reported hearing difficulties. She shared data showing that these patients reported comparable benefits to those with hearing impairments.

While her focus is on adults, she also shared research that shows similar benefits of low-gain hearing aids in children with auditory processing disorder.

Therapy and Technology for Auditory Processing Deficits

Dr. Jennifer Shinn shared the story of a 39-year-old recreational pilot who had trouble processing sounds quickly, especially in noisy places, despite having normal peripheral hearing. He also had problems with reading, foreign languages, and paying attention. Tests showed that his ears didn’t work well together, and he processed sounds slowly. To address these issues, he was offered therapy and started using special hearing aids (mild gain amplification with remote microphone technology). The therapy (dichotic interaural intensity difference training or DIID) aimed to improve his auditory processing deficits by training his weaker ear to hear better. After six weeks of therapy and using the new hearing aids, he said he could hear better in conversations and wasn’t as tired from listening. He even succeeded in his pilot training. This case highlights how combining therapy and assistive technology can help people manage auditory processing deficits.

Understanding Corpus Callosum Damage

Dr. Musiek shared a case of a 22-year-old musician who had a car accident and damaged the corpus callosum in his brain, which helps transfer information between the two sides of the brain. This injury caused sensory problems, like trouble with touch and hearing. Tests showed issues similar to those seen in split-brain patients and children with learning disabilities linked to corpus callosum issues. For example, the man had trouble recognizing objects with his left hand, even though his eyes worked fine. Musiek said that cases like this help us understand how the brain works and why people might have sensory problems. It’s important to connect what we see in tests with what’s happening inside the brain to figure out how to help people with these problems.

Early Detection with the Pitch Discrimination Test (PDT)

Dr. Maria Abramson introduced her screening tool: the Pitch Discrimination Test (PDT). This simple yet effective test can help check if preschool kids can tell the difference between sounds. Children are asked to listen to two tones and say if they sound the same or different, similar to the “beep beep” sound of the cartoon character Road Runner. By testing 90 typically developing preschoolers, Abramson found that the PDT works well for identifying hearing differences important for understanding speech.

She shared her case study of a child who struggled with kindergarten readiness tests but improved after doing exercises to improve hearing (auditory discrimination training) and using special hearing technology (remote microphone technology). Abramson encourages doctors and others who work with kids to use tests like the PDT early on to help catch and fix hearing problems.

Closing Remarks

Dr. Frank Musiek concluded the symposium by emphasizing the importance of combining scientific research with how doctors treat patients daily. He said audiologists must have a solid understanding of science to keep neuroaudiology moving forward. Audiologists can provide better care by linking what they learn in research to how they help care for patients.

Overall, this was a fascinating symposium. It provided compelling information about the newest research and treatments for CAPD, which can help us understand and manage this complex condition. I’m looking forward to seeing where neuroaudiology research takes us. 

Resources for Further Learning on CAPD after Epilepsy Surgery

• Hearing and Auditory Processing– Frank Musiek, PhD, CCC-A, discusses hearing and auditory processing after large resective/disconnective pediatric epilepsy surgery. 
• Hearing and Listening After Hemispherectomy – our comprehensive guide
• Assessment Areas After Epilepsy Surgery –Audrey Vernick explores educational assessments for children who have had epilepsy surgery.
• School-Based Audiology Assessments After Epilepsy Surgery – In this session, Amanda Levy, Au.D., clinical and educational audiologist, and Daphne Magdaleno, a parent of a child who had hemispherectomy, discuss the importance of audiology assessments and the impact of CAPD in school.

Related research

Abramson MK, Lloyd PJ. Development of a Pitch Discrimination Screening Test for Preschool Children. J Am Acad Audiol. 2016 Apr;27(4):281-92. doi: 10.3766/jaaa.14052. PMID: 27115239. 

Bamiou DE, Musiek FE, Luxon LM. Aetiology and clinical presentations of auditory processing disorders–a review. Arch Dis Child. 2001 Nov;85(5):361-5. doi: 10.1136/adc.85.5.361. 

Bamiou DE, Sisodiya S, Musiek FE, Luxon LM. The role of the interhemispheric pathway in hearing. Brain Res Rev. 2007 Nov;56(1):170-82. doi: 10.1016/j.brainresrev.2007.07.003. 

Cline T, Colgrove N, Bush M, Lee J, Powell D, Andersen A, Weihing J, Musiek F, Shinn J. Behavioral and Hemodynamic Changes Following Dichotic Training in Patients with Neurological Deficits of the Auditory Nervous System: A Case Series. J Am Acad Audiol. 2021 Jan;32(1):45-53. doi: 10.1055/s-0040-1719095. Epub 2021 Mar 4. PMID: 33662998.

Davidson AJ, Ellis GM, Jenkins K, Kokx-Ryan M, Brungart DS. Examining the Use and Benefits of Low-/Mild-Gain Hearing Aids in Service Members with Normal Hearing Thresholds and Self-Reported Hearing Difficulties. Healthcare (Basel). 2024 Mar 1;12(5):578. doi: 10.3390/healthcare12050578. 

Dillon H, Cameron S. Separating the Causes of Listening Difficulties in Children. Ear Hear. 2021 Sep/Oct;42(5):1097-1108. doi: 10.1097/AUD.0000000000001069. 

Ferre, Jeanane. Treating Central Auditory Processing Disorders (CAPDs) among Children and Adults | Canadian Audiologist

Han SH, Lee EM, Choi EJ, Ryu HU, Kang JK, Chung JW. Changes in Central Auditory Processing in Patients with Mesial Temporal Lobe Epilepsy after Anterior Temporal Lobectomy with Amygdalohippocampectomy. J Clin Neurol. 2016 Apr;12(2):151-159.

Kraus N. Memory for sound: The BEAMS Hypothesis [Perspective]. Hear Res. 2021 Aug;407:108291. doi: 10.1016/j.heares.2021.108291. Epub 2021 Jun 6. PMID: 34146833.

Kraus N, Colegrove D, Otto-Meyer R, Bonacina S, Nicol T, Cunningham J, Krizman J. Subconcussion revealed by sound processing in the brain. Exerc Sport Mov. 2023 Summer;1(3):1-4. doi: 10.1249/esm.0000000000000011. 

Kuk F, Jackson A, Keenan D, Lau CC. Personal amplification for school-age children with auditory processing disorders. J Am Acad Audiol. 2008 Jun;19(6):465-80. doi: 10.3766/jaaa.19.6.3. 

Samara M, Thai-Van H, Ptok M, Glarou E, Veuillet E, Miller S, Reynard P, Grech H, Utoomprurkporn N, Sereti A, Bamiou DE, Iliadou VM. A systematic review and metanalysis of questionnaires used for auditory processing screening and evaluation. Front Neurol. 2023 Aug 8;14:1243170. doi: 10.3389/fneur.2023.1243170. 

Strait DL, Kraus N. Can you hear me now? Musical training shapes functional brain networks for selective auditory attention and hearing speech in noise. Front Psychol. 2011 Jun 13;2:113. doi: 10.3389/fpsyg.2011.00113. 

Weihing J, Chermak GD, Musiek FE. Auditory Training for Central Auditory Processing Disorder. Semin Hear. 2015 Nov;36(4):199-215. doi: 10.1055/s-0035-1564458. PMID: 27587909; PMCID: PMC4910543.