The Speech Comprehension and Auditory Processing Laboratory (SCAUP Lab) conducts research in the areas of speech comprehension and discrimination, intelligibility, and auditory processing, including the development of innovative methods of assessment and the creation of test materials in New Zealand English.
Title: The use of monaural, low-redundancy, low-pass filtered speech material in the assessment of Auditory Processing Disorder in the elderly
Investigator: Ali Abu-Hijleh
Primary Supervisor: Dr Greg O'Beirne
Associate Supervisors: Dr Natalie Rickard, Dr Megan McAuliffe
Summary of Research: We have developed an adaptive low-pass filtered speech test for the assessment of auditory processing skills in children and adults (with Andrew McGaffin in 2006 and Uta Heidtke in 2009). We have evidence to suggest that the performance of adults on the test deteriorates with age, indicating that the UCAST filtered words test may actually show more promise as a test of auditory processing in older adult participants. While this test cannot by itself distinguish between age-related disorders of auditory processing and amodal cognitive function, the use of test items with spectral content almost entirely below 1 kHz does eliminate the well-documented influence of high-frequency audiometric threshold on test performance.
Title: Diagnosis of Auditory Processing Disorder (APD) in Children Using an Adaptive Filtered Speech Test
Investigator: Uta Johanna Heidtke
Primary Supervisor: Dr Natalie Rickard
Associate Supervisors: Dr Greg O'Beirne, Dr Megan McAuliffe
Summary of Research: This study involves the development of a new, clinically useful computer-based adaptive low-pass filter speech test. Low-pass filtered speech tests are commonly utilised in APD testing, but are usually carried out using a constant level of low-pass filtering (e.g. a fixed 1 kHz corner frequency) which makes them prone to ceiling and floor effects. As a consequence, the efficacy and accuracy of these tests is significantly compromised. The purpose of this study was to counter these effects by utilising the University of Canterbury Adaptive Filtered Speech Test (UCAST) - a computer-based adaptive procedure intended to improve the efficiency and sensitivity of the test over its constant-level counterparts. A comprehensive APD test battery was carried out on a number of children who were identified as having auditory processing deficits and on a control group of normally-hearing children not suspected of any auditory processing or learning difficulties. In addition, the UCAST was administered to examine whether the low-pass filter limit at which the children score a certain percentage of words correct was correlated with i) their score on the APD battery, and ii) their score on the Filtered Word subtest of SCAN-C. The results will contribute to collecting normative data on typically developing children and children with listening difficulties, and to improve our understanding of the underlying nature of auditory processing disorders in children.
Title: New Zealand version of the Digit Triplets Test
Investigator: Sharon King
Primary Supervisor: Dr Greg O'Beirne
Associate Supervisors: Dr Natalie Rickard, Dr Megan McAuliffe
Summary of Research: The Digit Triplets Test is a well-established and widely-used method of hearing screening in adults. The fact that it is an adaptive speech-in-noise test (rather than an absolute threshold test) means that it can be delivered by non-calibrated means (e.g. over the telephone, or via the internet). It has successfully been used to screen the hearing of hundreds of thousands of people in Europe, but is not yet used in New Zealand. We are currently recording New Zealand and Australian English versions of the Digit Triplets Test. The recording of this speech material and piloting of the test could lead the way to the widespread implementation of the test throughout Australasia, via telephone, internet, and as a smart-phone app.
Title: Computer-based assessment of auditory processing disorders in school-aged children: A pilot study
Investigator: Caroline Smales
Primary Supervisor: Dr Natalie Rickard
Associate Supervisors: Dr Megan McAuliffe, Dr Greg O'Beirne
Summary of Research: An important step towards effective identification and treatment of children with listening difficulties is to develop improved methods of assessing listening skills and differentially diagnosing auditory processing disorders.
A test that is commonly used internationally as part of a standard APD assessment is the Frequency Patterns Test. New Zealand norms for this test have been established, but interpretation of this test is complicated by the multiple listening and cognitive skills involved. Good performance on the test depends on auditory discrimination skills, auditory short-term memory, auditory sequencing, and linguistic labelling and verbal reporting of a sequence of tone stimuli. In addition, the task, like all APD tests, is dependent upon good concentration and focused attention, yet this test, like others, does little to engage a child’s attention or provide motivation.
A computer-based version of this test, using engaging computer animations and an interactive interface, will be developed and trialed on typically developing school-aged children with no history of listening difficulties. The software will then be used to manipulate (i) contrast and (ii) complexity of auditory stimuli, in an attempt to determine whether these parameters have an impact on the performance of a child with APD on a sequential auditory frequency patterns task.
The outcome of this work will be improved differential diagnosis of APD in children, which will ultimately lead to improved social and educational outcomes for children with listening difficulties.
Title: Speech Understanding Abilities in Older Adults with Sensorineural Hearing Loss
Investigator: Phillipa Wilding
Primary Supervisor: Dr Megan McAuliffe
Associate Supervisors: Dr Greg O'Beirne, Dr Natalie Rickard
Summary of Research: Older adults with hearing loss have greater difficulty understanding speech than younger adults with equivalent hearing, particularly when the acoustic signal is experimentally degraded. The extent to which this is due to peripheral hearing, central auditory processing or cognitive factors is unknown. Furthermore, age-related changes to the speech mechanism result in natural degradations to signal quality. However, previous studies involving hearing impaired listeners have not utilised naturally degraded speech signals. This study will determine: (1) whether older hearing impaired listeners have significantly greater difficulty understanding speech from older versus young adult speakers and (2) whether any individual differences are related to peripheral, cognitive, or central auditory processing factors.
Title: Personal FM Systems in children with auditory processing disorders
Investigator: Fiona Yip
Primary Supervisor: Dr Natalie Rickard
Associate Supervisors: Dr Megan McAuliffe, Dr Greg O'Beirne
Summary of Research: Approximately 3-5% of school aged children exhibit listening difficulties resulting from impaired neural function, despite having normal hearing sensitivity. Many of these children have difficulty understanding speech in the presence of background noise, and yet spend much of their day in classrooms, trying to hear and understand their teacher’s voice over a high level of competing noise. This difficulty is reflected in poor spatial stream segregation abilities in these children – that is, their ability to separate out a target signal from competing background signals.
One strategy for helping to overcome the signal-to-noise ratio problems that are inherent in classroom environments is the use of personal FM systems. These devices enable a speaker’s voice to be delivered directly to a listener’s ears without the degrading effects of distance, reverberation and background noise.
This study will identify school-aged children with spatial stream segregation difficulties using a new test (the LiSN-S test), and then fit these children with an FM system specifically designed for children with normal peripheral hearing. These children will wear their FM for a period of 3 months in the classroom, and at the end of that period, outcome measures including qualitative assessments, academic assessments and phonological awareness measures will be used to define the benefit that FM systems provide.
