Prevalence of clinical referrals having hearing thresholds within normal limits

Abstract

The prevalence of normal cases was 5.1% among the children and 0.9% among all adults. For younger adults (17-60 years, n = 1025), the prevalence was 4.0%. Based on comparison with those referred with hearing loss, we estimate the prevalence of APD among children and adults, defined as listening problems despite normal audiometry, to be about 0.5-1.0% of the general population.

Cortical and Sensory Causes of Individual Differences in Selective Attention Ability Among Listeners With Normal Hearing Thresholds

“…As many as 5%-10% of listeners who seek audiological treatment have NHTs (Hind et al, 2011). This review focuses on two specific mechanisms that can lead to poor outcomes for listeners with NHTs when trying to understand speech in noisy settings, which may send them to the audiologist: (a) deficits in the control of cortical attention networks that filter out neural responses to unwanted sounds and (b) sensory deficits arising due to a loss of ANFs in the absence of elevated hearing thresholds (cochlear synaptopathy).…”

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I n a sizeable minority of cases, patients seeking audiological treatment have normal hearing thresholds (NHTs) but report difficulties understanding speech when there are competing sound sources (Hind et al, 2011). Such listeners are said to have "central auditory processing disorder" or "auditory processing disorder" (Furman, Kujawa, & Liberman, 2013;Kujawa & Liberman, 2009;Lin, Furman, Kujawa, & Liberman, 2011;Rosen, Cohen, & Vanniasegaram, 2010), a catchall diagnosis that says nothing about the underlying causes of the communication difficulties, making it difficult to develop effective treatments.

The challenge of understanding speech in settings where there are multiple sound sources is known as the cocktail party problem, a term originally coined by Cherry (1953).

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Age-Related Changes in Processing Simultaneous Amplitude Modulated Sounds Assessed Using Envelope Following Responses

“…Emerging evidence has shown that the loss of hearing thresholds due to changes in the periphery does not account for all the changes in hearing seen with age (Dubno et al 1984;Ruggles et al 2012;Fullgrabe et al 2015). Neural deficits due to loss of spiral ganglion and ribbon synapses (Sergeyenko et al 2013) or imbalances in the composition of neurotransmitters (Caspary et al 2008) in the central auditory pathway could account for the deficits seen in temporal processing and sound segregation at suprathreshold sound levels, which persist in subjects with clinically Bnormalĥ earing thresholds (Hind et al 2011). These neural deficits can be detected objectively in both human populations and animal models using auditory evoked potentials such as auditory brainstem responses (ABRs) a n d e n v e l o p e f o l l o w i n g r e s p o n s e s ( E F R s ) (Parthasarathy and Bartlett 2011;Ruggles et al 2012;Sergeyenko et al 2013;Shaheen et al 2015).…”

Diagnostik auditiver Verarbeitungs- und Wahrnehmungsstörungen bei Kindern

“…Heute wird geschätzt, dass 0,5-1 % aller Kinder Schwierigkeiten beim Zuhören und Verstehen haben, obwohl die Ergebnisse im Tonschwellenaudiogramm ein regelrechtes peripheres Hörvermögen belegen [6]. Auch ältere Patienten klagen häufig über Probleme mit dem Verstehen, die disproportional zu den Ergebnissen im Reintonaudiogramm sind.…”