Central Auditory Processing Disorder Flashcards
Intro for CAPD:
Define CAPD
Two Models
Overview of profiles
ASHA (2005): CAPD = difficulties in the processing of auditory information in the central nervous system
Based on auditory test results, language impairment, and academic difficulties, two theoretical models were proposed to better guide clinicians in their interventions with CAPD patients: the Buffalo Model (Katz, 1992; Stecker, 1998) and the Bellis/Ferre Model (Bellis & Ferre, 1999). The Bellis/Ferre Model is composed of three primary CAPD subtypes —Auditory Decoding Deficit, Prosodic Deficit, and Integration Deficit. Listening difficulties in noisy environments or when speech is degraded belong to the Auditory Decoding Deficit subtype (Bellis & Ferre, 1999). Prosodic Deficit is defined as difficulty understanding the intent of verbal messages, whereas Integration Deficit involves problems with tasks requiring both cerebral hemispheres to cooperate (Bellis & Ferre, 1999). The Bellis/Ferre Model uses a combination of abnormal and normal test results to determine specific deficits (Jutras et al., 2007).
Ashley’s Diagnostic Profile: clinical presentation and description
Clinical guidelines for diagnosis of CAPD recommend the application of a test battery approach and the test battery should consist of two or more behavioral CAPD tests that are sensitive to the integrity of the central auditory nervous system (ASHA, 2005; AAA, 2010). Based on Ashley’s performance on the numerous CAPD assessments a diagnosis of CAPD is warranted. Using the Bellis-Ferre model, this child fits the profile of an auditory decoding deficit, which is defined as having difficulties in the discrimination of speech sounds. Hallmark CAPD test findings in those with an auditory decoding deficit include poor scores on monaural low-redundancy speech tests, in which the patient is presented a compromised speech signal that for which acoustic information is lost due to filtering, masking, or time compression. Ashley performed abnormally on monaural low-redundancy tests of auditory figure ground and low-pass filtered words, in addition to demonstrating borderline-normal performance on a test of time-compressed speech. Additionally, auditory decoding deficits are sometimes conceptualized as an inaccurate encoding of the auditory cortex because of early childhood chronic otitis media, consistent with Ashley’s case history (Bellis & Ferre, 1999).
Other tests and the implications:
Dichotic Digits–Within Normal Limits bilaterally
Competing Sentences–Within Normal Limits right ear, Abnormal left ear
Staggered Spondaic Words–Abnormal bilaterally for competing conditions
Pitch Pattern Sequence (verbal)–Within Normal Limits binaurally
Gaps in Noise–Within Normal Limits binaurally
The SSW test and the dichotic digits test are assessments of dichotic listening that target the process of binaural integration. Her poor performance on the staggered spondaic words test only in competing conditions could potentially reflect reduced ability for dichotic listening; however, with lessened linguistic demand, the child performed within normal limits on the dichotic digits test contradicting previous indications of any severe difficulty with dichotic tasks and could reflect a coinciding language processing disorder. The competing sentences test reflects the child’s ability for binaural separation and is highly related to language processing ability. The child performed within normal limits for her right ear and abnormally for her left ear, which may reflect an immaturity of the auditory cortex that will self-correct over with time. Normal performance on the gaps in noise test reflects good ability of the child for temporal resolution and effective interhemispheric transfer of information. Normal performance on the pitch pattern sequence test with verbal responses indicates the child is successfully able to complete targeted processes of temporal ordering and linguistic labeling (reflecting good interhemispheric transfer of information).
factors that may impact academic performance
Ashley’s academic performance may be influenced by her auditory decoding deficit, particularly in areas of spelling or reading which are related to speech-sound discrimination abilities (Bellis & Ferre, 1999). Children with this CAPD profile experience difficulty with the targeted process of auditory closure, which may be attributed to lesions of the auditory cortex. With an auditory decoding deficit, understanding speech in a quick and accurate manner is a notably difficult task; this may be reflected in difficulty understanding verbal academic material, particularly when there is new vocabulary being used. In addition, Ashley may require assistance with learning to read fluently and meet other academic milestones under the burden of greater auditory fatigue (Bellis & Ferre, 1999).
Recommendations (General)
Because of the non-modularity of the central nervous system, pediatric patients with CAPD will also frequently experience a range of comorbid issues, including speech–language, cognitive (including attention), and psychoeducational delays (Musiek et al., 2005). There is consensus that interventions for children with APD should be customized and deficit focused, as well as multi-disciplinary (ASHA, 2005; Bellis & Anzalone, 2008).
Recommendations: Auditory Training
To improve on the inaccuracies and inefficiencies that are noted in understanding speech and other functions, therapy is recommended that is directed at narrowing the phonemic boundaries (i.e. sharpening the perception) of the affected sounds. Direct remediation via auditory training aims to improve an individual’s auditory performance by altering the way the brain processes sound (Bellis & Anzalone, 2008). The Phonemic Training Program is a basic program to improve auditory decoding. The purpose of this program is to improve the speed and accuracy of processing speech, which improves a child’s ability to understand speech by improving the accuracy and speed of processing phonemes (Russo et al., 2005).
Recommendations: Environmental
Since the classroom is a critical auditory environment for children, Ashley’s classroom should undergo environmental modifications to maximize her success. Environmental recommendations involve making the learning environment highly redundant through frequent checks for comprehension, employing visual or multimodality cues and hands-on demonstrations to augment verbally presented information (Bellis & Anzalone, 2008). The child should be required to expend as little extra energy as possible to obtain critical information. It is also critical that efforts are made to reduce reverberation and noise and ultimately enhance the signal to noise ratio (SNR) for the student. An initial effort to enhance the student’s SNR is through preferential seating. In choosing the ideal seating arrangement, depending on the proximity of the teacher to the students and the arrangement of desks in the room, room lighting, use of overhead projectors or other potentially noisy equipment, the front row may be the least beneficial placement for a child with APD. If it is impossible to provide an adequate SNR for a child with a decoding deficit, then an FM system should be considered (Bellis & Ferre, 1999).
Recommendations: Johnston FM study
Johnston et al. (2009) studied a group of children with CAPD compared to normal control peers on measures of speech perception, academic performance, and psychosocial status; the children with CAPD wore binaural EduLink remote microphone hearing aids at home and at school for at least 5 months and demonstrated that all children in the experimental group improved on measures of speech perception in quiet and in noise irrespective of whether the child has a hearing in noise deficit at the beginning of the study and that the children improved on measures of academic performance and psychosocial status.. The results of the study are indicative of improvement in hearing ability because of treatment-induced neuroplastic development.
