APD evaluations at Auditory Processing Center typically involve testing the following areas:
- Peripheral auditory system- Assessment of outer, middle and inner ear structures and function to rule out a hearing loss
- Word recognition in quiet conditions and in noise – The listener’s ability to recognize single words using a recorded standardized word list presented at an average conversation level both in quiet, ideal listening conditions and in noise. The words in noise is a test of monaural low redundancy because each ear is tested separately. Comparing performance in quiet conditions and noise conditions helps control for problems with overall poor discrimination and decoding by determining if there is a significant decrease in performance in noise. This single word degraded speech task is helpful to determine how well the listener is able to recognize words when there are no context clues available to help figure out the word.
- Binaural Integration– Processing different information presented to both ears simultaneously. If listeners have difficulty dividing their attention to different auditory inputs when there is more than one thing to listen to, it will affect their ability to integrate the information. Listeners can exhibit problems with binaural integration and fit different profiles, requiring different types of treatment. For example, individuals with amblyaudia (lazy ear) will have an abnormal asymmetry consistently across tests (with much better performance in the dominant ear) but some listeners may have overall poor performance in both ears.
- Binaural Separation– Processing a message presented to one ear while ignoring a message presented to the opposite ear at the same time. If listeners have difficulty separating different sound inputs, they may be unable to direct their attention to focus on one ear while ignoring sound occurring from the opposite side. This is a skill we utilize all the time when we are on the phone or when the teacher is moving from one side of the room to the other side and we must ignore distracting noises from classmates.
- Spatial Processing– The functioning of the mechanisms in the low brainstem that use the spatial distribution of sound sources (location cues) to suppress unwanted sound and enable the listener to focus on sound coming from directly in front of them. Information can also be obtained about the listener’s ability to use differences in the vocal quality of different talkers. Individuals with a history of chronic otitis media (ear infections) when they were very young are at risk for a spatial processing disorder. This can make it very difficult to focus on the teacher’s voice when there are competing sounds in the classroom. This is one type of APD that can be completely remediated within a couple months.
- Temporal Processing (timing aspects of auditory processing)- assessed by measures of Temporal Resolution (the ability to detect the brief time interval between sequential speech sounds recognize individual speech sounds when they quickly follow one another) and Temporal Patterning /Auditory Pattern Recognition (determining similarities and differences in acoustic contours and being able to remember a sequence and verbally describe the patterns of sounds with words). The listener’s performance in different conditions is analyzed to determine if there are prosodic deficits and assess the efficiency of interhemispheric transfer of auditory and linguistic information.
- Auditory Closure– The ability to fill in and recognize an auditory signal when some of the information is distorted or missing in order to recognize the whole message. This includes Filtered Speech (high pitched sounds have been removed causing the words to sound muffled) and Time Compressed Speech (words and/or sentences presented at very rapid rate making it difficult to hear the rapid transitions between individual speech sounds).
- Auditory Figure-Ground– The ability to understand auditory messages in the presence of background noise or competing speech. This can be assessed monaurally (one ear at a time) or binaurally (both ears listening) and with either words or sentences. Some assessments can be used with children severe articulation errors or limited expressive language by having the child point to pictures representing the stimuli heard.
- Auditory Discrimination– The ability to distinguish between sounds to accurately identify sounds or words presented orally (such as /b/ and /d/ or the words “big” vs. “dig.”)
- Phonemic Synthesis – The ability to blend sounds into words by listening (without visual cues) Phonemic synthesis is a direct measure of phonemic decoding. It is a most important skill that underlies speech and language development and is closely associated with reading and spelling. Individuals with very poor phonemic synthesis have difficulty understanding what is said, making verbal associations, and with verbal recall.
- Auditory Vigilance /Auditory Attention– The ability to maintain concentrated attention to sound for an appropriate length of time. The listener must respond consistently to a target auditory stimulus over time and the clinical analyzes inattentive errors, impulsive responses, and any decrement in performance. This can be useful to help differentiate auditory attention problems from central auditory processing disorders.
- Auditory Memory involves the listener’s ability to take in the information heard, process that information, store it in his/her mind, and then recall what was heard. Auditory Short-Term Memory involves retaining what was just heard to immediately recall details.Auditory Sequential Memory is the ability to recall a sequence of auditory stimuli in the exact order it was presented. Rote-memory span is typically assessed with lists of digits and/or unrelated word recall. Auditory Working Memory refers to active processing. It involves the ability to hold information heard long enough to manipulate, and use the auditory information just presented. Working memory is required for problem solving such as math calculations. Tolerance-Fading Auditory Memory is a profile often seen in individuals with auditory processing disorder. Sometimes auditory memory is good in quiet conditions, but they have low tolerance for background noise because it makes the auditory memory traces fade too quickly. Auditory Organization is also related to auditory memory. Information must be stored in the correct order in a manner so that it can be retrieved easily from long-term memory. Poor auditory organization can affect the speed of processing/retrieval of information
- Auditory Comprehension in quiet and in noise– The ability to answers questions about what was heard. This can involve recalling details from directions and higher-order linguistic processing related to abstract concepts, making inferences, and coming to logical conclusions about what was heard.
Our test battery is modified as needed depending on the age of the individual, the primary concerns reported, and any cognitive, developmental, or severe/speech-language delays. We consider the needs of each person on a case by case basis based on individual circumstances, needs, and abilities. Early weaknesses in auditory processing skills can be identified in children as young as age 3 using tests normed on this age group and full APD evaluations can be performed on individuals ages 5 and up.
Some auditory processing tests can be administered to individuals with mild to moderate hearing loss. This can provide information on how well the individual can hear in noise with their hearing aids, yield useful information about individual’s need for remote microphone technology, and monitor the listener’s progress with auditory training.