Individualization of hearing aid signal processing based on cognitive measures.
2013 (English)Conference paper, Abstract (Refereed)
Hearing instruments use complex processing anticipatedto improve speech understanding. While many listenersbenefit from such processing, others do not and thesedifferences are potentiated by adverse listening conditions.Unwanted artefacts of hearing aid signal processing maycontribute to adverse listening conditions (Mattys et al.,2012). Under such conditions cognitive processingresources are allocated to the recovery of degradedinformation at the auditory periphery, leaving fewerresources for understanding the message.Working memory refers to the capacity to hold andmanipulate a set of items in mind, such as speechfragments. A number of recent studies indicate thatindividual working memory capacity influences theindividual benefit of hearing aid signal processing. Ng etal., (under revision) examined the effects of binarymasking noise reduction (Wang et al., 2009) in hearingaids on memory processing of speech perceived in acompeting speech background, using a sentence-finalword identification and recall test. The reading span testwas also administered. The reading span test assessesthe simultaneous processing and memory aspects ofworking memory. Noise reduction lowered the negativeeffect of noise on memory performance. Participants withgood working memory capacity obtained a further benefit.Lunner and Sundewall-Thorén (2007), among others,showed that the individual benefit of fast wide dynamicrange compression was associated with individual workingmemory capacity. Persons with high working memorycapacity benefited most from fast acting compression whilethe persons with low working memory capacity benefitedmost from slow acting compression. Arehart, Souza, Bacaand Kates (in press) showed that elderly individuals withlow working memory capacity were more disadvantagedby frequency compression processing during speechrecognition in noise than elderly individuals with highworking memory capacity. It is possible that the negativeeffects of fast acting wide dynamic compression andfrequency compression for persons with low workingmemory are due to unwanted artefacts of signalprocessing.In conclusion, the benefits of certain givenimplementations of complex processing in hearing aidshave to be weighed against the extra cognitive load thatsuch processing seems to engender, possibly as a resultof unwanted artefacts. Although complex processing mayaid speech understanding in noise for individuals withhearing impairment and especially those with goodworking memory capacity, it seems that for someindividuals with lower working memory capacity, thedrawbacks may outweigh the benefits. This should betaken into account when hearing aids are fitted.
Place, publisher, year, edition, pages
IdentifiersURN: urn:nbn:se:liu:diva-105113OAI: oai:DiVA.org:liu-105113DiVA: diva2:703681
The Association for Research in Otolaryngology, February 16-20, 2013, Baltimore, Maryland