Life experience and the asymmetry of the human auditory system: clinical and auditory science laboratory implications

Abstract

It is now almost 60 years since Doreen Kimura first described the asymmetries of the human auditory system (HAS). It is 30 years since Kenneth Hugdahl, and almost 15 years since David Poeppel, did the same. Our knowledge of these asymmetries is now considerable and detailed. Here we review some of the literature concerning what is known about the asymmetry of the HAS, and use it to construct a simple model of how the central and peripheral components work together. The model details some of the asymmetry, the life-experience-dependant maturation of this asymmetry throughout the first two decades, possible reasons for the population variance in speech-in-noise perception, the central role of the corpus callosum, the involvement of the efferent auditory pathways, and the corticofugal control of the peripheral auditory system. Although our knowledge of HAS asymmetry remains incomplete, this should not prevent the introduction of required changes to the current practices of audiologists and auditory science researchers, practices which fail to recognize the existence of any asymmetry in the HAS. The model described here suggests a clear need for: “asymmetry sensitive” hearing test tools that provide normative data for the lifespan, closer childhood and aging-adult hearing monitoring, and the development of a range of auditory training modules. Notably, the model suggests that without such tools our HAS asymmetry knowledge will remain incomplete. The status quo is a preoccupation with understanding hearing through knowledge of the peripheral hearing system, no answers for those with a “normal audiogram” but with an obvious difficulty hearing speech-in-noise, limited success cochlear implant rehabilitation, and missed opportunities to successfully intervene with childhood hearing/speech/language development problems.

Association Between the Right Ear Advantage in Dichotic Listening and Interaural Differences in Sensory Processing at Lower Levels of the Auditory System in Older Adults

“…Studies investigating directed attention on DL suggest that older adults exhibit a reduced ability to switch attention (i.e., reduced cognitive flexibility) from the RE to the LE during the FL condition, while no difficulties are found in the FR condition (Andersson et al 2008; Takio et al 2009). Moreover, reduced cognitive flexibility in older adults has been significantly correlated with RE score during the FL condition in DL (Hommet et al 2010). Therefore, an increased REA in DL attributed to cognitive flexibility might reflect older adult’s difficulties to switch attention to the LE stimuli while simultaneously suppressing the RE stimuli during the FL condition.…”

“…As stated in the “introduction” section, two main hypotheses have been proposed to explain age-related changes in the magnitude of the REA in DL. Accordingly, the source of the increased REA’s magnitude in DL with advancing age may originate from either an age-related decline in cognitive abilities, such as working memory, attention, processing speed, and inhibitory control (Bellis & Wilber 2001; Hällgren et al 2001; Hommet et al 2010); and decreased central auditory processing due to an age-related decline of corpus callosum functioning resulting in reduced interhemispheric interaction (Gootjes et al 2006). Results from the present study strengthen the aforementioned age-related cognitive hypothesis by providing data indicating that both speed of processing and cognitive flexibility contribute to the enlarged REA among older adults.…”

“…These results demonstrate that older adults require an increased cognitive capacity to focus and report from the LE during DL. Moreover, a greater LE deficit has also been linked with reduced cognitive control (Hugdahl et al 2009) and reduced inhibitory control (Hommet et al 2010). Anderson et al (2008) suggested that older adults show reduced top-down modulation capacity to focus attention to the LE stimuli, while simultaneously suppressing the RE stimuli, during DL paradigms that require selective attention.…”

“…Anderson et al (2008) suggested that older adults show reduced top-down modulation capacity to focus attention to the LE stimuli, while simultaneously suppressing the RE stimuli, during DL paradigms that require selective attention. In summary, the source of an increased magnitude of the REA in DL among older adults would originate from an age-related decline of corpus callosum functioning resulting in reduced interhemispheric transfer (Goldstein & Braun 1974; Gootjes et al 2006), and an age-related decline in cognitive abilities, such as working memory, attention, processing speed, and inhibitory control (Bellis & Wilber 2001; Hällgren et al 2001; Hugdahl et al 2009; Hommet et al 2010).…”

Hafif bilişsel bozukluk ve Alzheimer hastalığında dikotik dinleme performansı

“…Farklı bir seçenek olarak da zorunlu koşulların sırası değiştirilebilir. 21 İki sözel uyarandan herhangi birinin bildirilmesi (NF koşulu) istenilen bir dikotik dinleme görevinde, genellikle sağ kulak avantajı gözlenmektedir. Sözel uyaran varlığındaki sağ kulak avantajını açıklayan "yapısal model-(bottom upaşağıdan yukarı)" ve "dikkat-(top down-yukarıdan aşağı) modeli" olmak üzere iki teorik model bulunmaktadır.…”