Charles I. Berlin Ph.D.

1. Differentiating Auditory Processing Disorders from Auditory Neuropathy Spectrum Disorders in the Deaf-Blind Population Charles I. Berlin Ph.D. Clinical Professor of Otolaryngology Head and Neck Surgery and CSD at University of South Florida, and Clinical Coordinator All Children's Hospital Center for Auditory Neuropathy

2. What does it sound like to have: • Peripheral Hearing loss vs. Auditory Neuropathy vs. CAPD • Digression into underlying auditory physiology beginning with some of the relationships of speech to hearing. • Demonstrations and videos.

3. Auditory Neuropathy Spectrum Disorders vs. CAPD • Very easy to differentiate with the use of tympanometry, middle ear muscle reflexes, otoacoustic emissions and, if needed, an Auditory Brainstem Response.

4. How do we test for them • Peripheral hearing loss, stemming from damage to the outer hair cells and cochlea. • (Central) Auditory Processing Disorders • Auditory neuropathy spectrum disorders: • Tympanometry • Middle Ear Muscle Reflexes • Otoacoustic Emissions • Auditory Brainstem response

5. Tympanometry Alone http://vimeo.com/ncdb/tympanometry-alone Copy the above URL into your browser view video.You must be connected to the Internet to view the video.

6. Tympanometry (3x) and Middle Ear Muscle Reflexes http://vimeo.com/ncdb/tympanometry-reflexes Copy the above URL into your browser view video.You must be connected to the Internet to view the video.

7. Otoacoustic Emissions by Distortion Products http://vimeo.com/ncdb/otoacoustic-emissions Copy the above URL into your browser view video.You must be connected to the Internet to view the video.

8. Auditory Brainstem Response with clicks being presented rapidly to the ear. http://vimeo.com/ncdb/abr-to-clicks Copy the above URL into your browser view video.You must be connected to the Internet to view the video.

9. Behavioral Observation by localization http://vimeo.com/ncdb/behavorial-audiometry Copy the above URL into your browser view video.You must be connected to the Internet to view the video.

10. Auditory Processing Disorders Thierry Morlet, Ph.D.

11. Auditory Processing • How our brain processes the sounds we hear • Central auditory processing includes auditory mechanisms that underlie the following abilities: • Sound localization/lateralization • Auditory discrimination • Auditory pattern recognition • Temporal aspects of audition • Auditory performance with competing signals • Auditory performance with degraded acoustic signal

12. The development of language is dependent on the identification of sounds (including assessment of factors such as intensity, frequency and timing). This capacity enables the detection of phonemes and is the basis of auditory language reception and utilization. Production of a sound mirrors the perception individuals have of the sound. Central auditory processing manifests differently in every individual child. Auditory Processing and Language

13. Auditory Processing Disorders • In children, auditory processing disorder (APD) presents as difficulty processing speech despite audiometrically normal hearing. • Commonly, this difficulty is most pronounced in the presence of competing background noise, which, unfortunately, represents most typical real-world listening situations. • The causes of APD are not known, and in all likelihood, APD as broadly defined represents a family of auditory processing deficits stemming from multiple causes.

14. Auditory Processing Disorders • Approximately 5% of school-aged children have some type of APD. • APD can impair a child’s speech and language development, leading to listening and learning deficits. • Its diagnosis is complex and often is not made until learning deficits are well established impairing the child’s development for several years. • The lack of knowledge regarding the etiology of APD makes its management unpredictable.

15. Awareness/ detection Discrimination Recognition Figure Ground Synthesis Memory and sequential memory Temporal resolution Closure Binaural separation/ integration Attention Auditory Processes that are affected • Auditory processing disorders are difficult to differentially diagnose apart from other learning disorders

16. Indicators of APD Disorders • Poor reading & spelling • Low class participation • Withdrawn • Responds inappropriately • Poor receptive/expressive language • Difficulty understanding in poor acoustical settings • Attention problems

17. Risk Factors for APD • Neurologic dysfunction and disorders, e.g., • neonatal risk factors (e.g., asphyxia, CMV) • head injury • seizure disorders • Chronic otitis media in preschool years • Academic underachievement or failure • Family history of academic underachievement • Co-existing disorder (s)

18. Co-existing Disorders: The Same Brain • APDs • Specific language impairment (SLI) • Learning disabilities (LDs) • Reading disorders (dyslexia) • AD/HD • Emotional & psychological disorders • Developmental delay • Other neurologic deficits • and Autism spectrum disorders

19. Neurologic Bases

20. APD • Understanding the source of a communication problem • Peripheral or central or both? • Physiologic “versus” behavioral methods • Application of cortical auditory evoked potentials • Documenting effect of training • Neural plasticity • Importance of tests battery and cross-check

21. Diagnosis of APD • Ideal minimal test battery • Electrophysiological measures • Immittance measures: Tympanometry AND acoustic reflexes • Otoacoustic Emissions • Auditory evoked potentials • Behavioral measures • Pure tone & speech audiometry in quiet and in noise • Assessing all of the individual processes of CAP

22. Auditory Physiologic Responses • Middle ear muscle reflexes • Otoacoustic Emissions (OAE) • Suppression of OAEs • Auditory Brainstem Response (ABR) • Eight nerve and brainstem • Middle Latency Response • Thalamo-cortical pathways • Cortical Responses • N1-P2 or vertex response • P300 response • Mistmatch negativity (MMN)

23. Auditory Neuropathy Spectrum Disorder or APD? • Auditory Neuropathy/Dys-Synchrony • Synchrony disorder, possible pre-neural site • Cochlear implants a management option • ABR, MEMR absent • Central APD • More diffuse in nature, peripheral synchrony usually within normal limit • Cochlear implant not useful • ABR, MEMR usually normal

24. APD and the Peripheral Auditory System • One possible cause of APD that has received attention recently is a disruption of processes in the peripheral auditory system; this led to the reclassification of central auditory processing disorder as APD. • Studies of peripheral auditory afferent pathways using click auditory brainstem responses in children with APD have been inconclusive. • ABRs are present in children with APD. • However, recent measures of speech auditory brainstem response show that the response in children with APD is delayed and less precisely timed, suggesting that their difficulties in higher-level language processes may have roots in the basic representation of sound as low as the brainstem.

25. Middle Latency Responses • The middle latency responses arises from the upper brainstem and primary auditory projection areas. • MLR latencies decrease with age in normal children. • Changes can be seen well into childhood, and adult characteristics are not reached until 10-12 years of age. • Longer MLR latencies in children with APD.

26. Auditory Evoked Related Potentials • AERPs provide an objective means of evaluating how the auditory cortex codes acoustico-phonetic cues crucial to speech and language processing with high temporal precision, including in presence of background noise. • AEPRs also inform about hemispheric lateralization. • Can be obtained regardless of whether the subject is attending to the stimuli or not which excludes the factor attention as a possible confounding factor (MMN). • The obligatory AERP consist of a series of vertex positive and negative peaks (P1, N1, P2 and N2). • Mature by mid teens • Can be recorded at younger ages • Neural Plasticity From Wunderlich and Cone-Wesson, 2006

27. Asymmetries of the Auditory System • In normally hearing individuals, anatomical and functional observations from the cochlea up to the cortex are in favor of a right ear advantage (REA), a feature hypothetically linked to the fact that in almost all right handed and most left handed people, speech is processed predominantly in the left cerebral hemisphere. • Both afferent and efferent auditory pathways show asymmetrical features which suggests that competing signals from both ears are processed with a REA which enables the left hemisphere to process speech appropriately in difficult listening situations. • Stimuli with complex speech-like acoustic properties, including rapid spectrotemporal changes, yield greater activation in auditory cortex over the left hemisphere, regardless of whether right ear, left ear, or binaural stimulation is used. • The left hemisphere is specialized from birth for processing specific properties of speech and children exhibit the right ear advantage as early as the first year of life.

28. Asymmetries in children with APD • Evidence of abnormalities in the cortical development of auditory areas in children with APD • Abnormal asymmetries in the perisylvian region of the temporal lobe with an absence of left hemispheric advantage for this region. • Abnormalities in auditory hemispheric specialization, in right ear advantage and in AERP have been reported in children with APD. • Abnormal functioning of the left temporal cortex in some children with APD suggest that the functional specialization of both hemispheres is impaired in these children and that damage to the left hemisphere disrupts mechanisms critical for processing brief, rapidly changing acoustic cues. • Enlarged AERP response in the right hemisphere could indicate differences in hemispheric lateralization in that children with APD may rely more on right hemisphere function when processing language, which has been suggested to serve as a compensation for improper functioning of the left hemisphere language areas.

29. P300 • Dependent on focusing of attention and subtle cognitive processes • Can use speech stimuli of various types (discrimination, semantic distinctions, etc…) • Can probe psychophysical function (discrimination of two tones, etc…) • P300 is present in children with APDs but with longer latencies and reduced amplitudes as compared to controls.

30. Mismatch Negativity • Neuronal response to minimal changes in acoustic stimuli • Objective • Passively elicited • Pitch, phonemes, temporal and spectral cues, etc… • Diminished mismatch negativity (MMN) responses to rapidly changing stimuli in APD compared to normal children.

31. Efferent Auditory Pathways

32. Efferent Auditory Pathways • The medial olivocochlear system (MOCS) innervates the outer hair cells. This implies that the acoustic signal stimulating the cochlea can be modified before it reaches the brain. • The MOCS constitutes one of the physiological mechanisms underlying perceptual intensity discrimination in noise. • In normally hearing adults and children, activation of the MOCS improves speech-in-noise intelligibility. • The MOCS is active after term birth in humans. Its development is asymmetrical (in favor of the RE).

33. MOCS in Children with APD • Recent studies showed some evidence of an impairment of MOCS function in children with APD or language impairment with a decrease in TEOAE suppression despite normal hearing thresholds. • MOCS dysfunction has been shown in subjects with other deficits such as in autistic children and children with selective mutism. • Several studies showed an inverted pattern of MOCS asymmetry in children with specific language impairment and in children with selective mutism versus controls. • Auditory training can change MOCS asymmetry in children with specific language impairment leading to bigger suppression in the right ear than the left ear after training. This finding was observed as well in children with reading disabilities following audiovisual training.

34. Efferent Suppression in Normal Children

35. Suppression in Children with APD

36. Management of APD • Requires interdisciplinary approach • Should • Be extensive • Maximize opportunities for generalization • Reduce functional deficits • Include salient reinforcement to induce learning • Comprehensive intervention management should include • Direct skill remediation by SLP • Compensatory strategies by Aud • Environmental changes by teachers and/or parents

37. Intensive & Computer-Based Programs for Development of Auditory Processing Skills • Cognitive Concepts • Earobics • cogcon.com • Scientific Learning • FastForword (FFW) • scilearning.com • Lindamood Bell Learning Processes • LIPPS and Seeing Stars • Lindamoodbell.com

38. Intervention

39. Language Skills Pre andPost Fast Forword

40. Efferent Suppression Pre-FFW

41. Efferent Suppression Post-FFW

42. MLRs Pre and Post FFW

43. MLRs Pre and Post FFW

44. Conclusions • Like children with ANSD, children with APD have the basic difficulty of understanding any speech signal presented under less than optimal conditions. • We are still not sure what causes APD. Diagnosis is complicated and usually not realized in a timely fashion. Management of APD is difficult and success is not guaranteed. • Despite sharing many common outcomes with ANSD, APD can easily be distinguished from ANSD.