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Otolaryngology-ENT Research

Review Article Volume 10 Issue 4

Speech in noise: hearing loss, neurocognitive disorders, aging, traumatic brain injury and more

Douglas L Beck,1 David R Larsen,2 Erin J Bush3

1Executive Director of Academic Sciences Oticon Inc, USA
2Director of Educational Services American Brain Council, USA
3Assistant Professor Division of Communication Disorders University of Wyoming, USA

Correspondence: Douglas L Beck Executive Director of Academic Sciences Oticon Inc Somerset NJ, USA

Received: May 31, 2018 | Published: July 13, 2018

Citation: Beck DL, Larsen DR, Bush EJ. Speech in noise: hearing loss, neurocognitive disorders, aging, traumatic brain injury and more. J Otolaryngol ENT Res. 2018;10(4):199-205. DOI: 10.15406/joentr.2018.10.00345

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Abstract

In this article, we explore and report the prevalence of speech in noise difficulties across multiple patient populations and reveal and speculate on management of the same. Speech in Noise problems is commonly associated with sensorineural hearing loss. However, some 15-20% of people with normal hearing have speech in noise difficulty, as do many people with neurocognitive disorders, advanced age, traumatic brain injury and more. As such, we conclude that testing and documenting speech in noise is of paramount importance for all people who have difficulty understanding speech in noise. Further, once speech in noise difficulty has been objectively identified and quantified, an appropriate goal would be to improve the patient’s speech in noise ability through aural rehabilitation, as well as modern technological advances.

Introduction

When people complain about not being able to listen or attend to a primary speaker, or when they report difficulty understanding speech in noise (SIN), audiologists should test and diagnose deeper than simply obtaining an audiogram. A comprehensive audiologic evaluation is warranted for people with hearing loss, as well as those with normal hearing who report difficulty listening in noise.

For “traditional” audiology patients, SIN complaints are common among people with sensorineural hearing loss such as presbycusis and/or noise induced hearing loss, as well as people with auditory processing disorders, auditory neuropathy spectrum disorder, synaptopathy and more. Therefore, it seems apparent a complete audiometric evaluation should include speech-in-noise testing. Likewise, a complete listening and/or communication assessment should include listening difficulties, a history of cognitive challenges or changes, as well as queries regarding traumatic brain injury (TBI), dementia or other neurocognitive disorders (NCDs). Many individuals with acquired cognitive challenges such as dementia, cognitive decline, traumatic brain injury (TBI), Alzheimer’s disease (AD) and other Neurocognitive Disorders (NCDs) report SIN difficulties. Tremblay and colleagues1 reported twelve percent of normal hearing adults experience difficulty attending to the primary speaker in the presence of multi-speaker babble. Hannula et al.2 reported up to 21% of normal hearing adults have difficulty following conversations which occur in noise. Thus, SIN difficulties represent a vast common thread across multiple disorders and etiologies.

Hearing and listening

Many people confuse hearing and listening. Hearing, is simply perceiving sound and is reflected by thresholds on an audiogram; a graph of intensity by frequency. Listening is the ability to make sense of sound by assigning meaning to it. Clearly, one must hear before one can listen. That is, sounds must be detected before the brain can assign meaning. The most common type and degree of hearing loss is bilateral sensorineural high frequency hearing loss (usually age-related hearing loss, often similar to, and often, indistinguishable from hearing loss due to noise exposure). However, patients with this hearing loss do not typically complain about sounds not being loud enough. Rather, they complain about the inability to understand speech in noise (SIN), which is (arguably) more of a listening problem than a hearing problem. The essence of the SIN problem is not that sound is absent; it is the inability of the brain to organize and apply meaning to the sounds perceived. Further, SIN problems can be present with or without hearing loss. That is, SIN problems might be thought of as a reflection of the brain’s inability to organize and decode sounds.3 “Listening is where hearing meets brain [4, pg. 1].”

Listening is where hearing meets brain

In the current audiology literature, the impact of hearing loss on NCDs is under intense investigation. Recent findings indicate untreated hearing loss often has a statistically significant, negative impact on quality of life and hearing loss has been identified as a modifiable risk factor for dementia.5,7 Indeed, among adults with reported normal audiometric hearing, some 12-21% report difficulty listening.2,7 The potential etiology of listening disorders in the presence of normal audiometric hearing is vast and includes; auditory processing disorders, spatial hearing disorders, central presbycusis, obscure auditory dysfunction (OAD), King-Kopetzky syndrome (KKS), auditory disability with normal hearing, idiopathic discriminatory dysfunction, hidden hearing loss (HHL), auditory neuropathy, deficits in auditory temporal processing, age-related factors affecting neural synchrony, synaptopathy, and more.7

When people complain about not being able to listen, or they are unable to attend to the primary speaker, or report difficulty understanding speech in noise (SIN), a deeper analysis is recommended and appears warranted. A complete audiometric evaluation should include and document speech-in-noise ability, and perhaps dementia screening tests in selected patients, to probe and understand the individual’s history with respect to hearing loss, listening difficulty and NCDs, thus facilitating appropriate referrals, improved recognition and documentation of the chief complaint, and an improved opportunity to effectively manage the reported difficulties.8

Improving the SNR in the presence of normal peripheral hearing

Roup, Post, and Lewis9s investigated the effectiveness of mild amplification for adults with normal hearing thresholds and subjective hearing difficulties. Their control group consisted of 20 adults with an average age of 22 years, the experimental group consisted of 17 adults with an average age of 31 years. Five of the 17 adults in the experimental group were diagnosed with Traumatic Brain Injury (TBI). Measurements were obtained using Hearing Handicap Inventory for Adults (HHIA), the Auditory Processing Questionnaire (APQ), the SCAN, Gaps in Noise Test, 500 Hz Masking Level Differences, Dichotic Digit Tests and the Speech Perception in Noise (SPIN) test at multiple signals to noise ratios (SNRs). Subjects were fitted with receiver-in-the-canal (RIC) hearing instruments with adaptive directional microphones and noise reduction circuits enabled. Hearing aids were worn about 4 hours daily for four weeks. The authors note significant differences between the two groups upon conclusion of the study. The experimental group (fitted with mild gain hearing aids) demonstrated improvement on the HHIA and APQ, as well as the SPIN test. Roup, Post, and Lewis9 note mild gain hearing aids (with noise reduction and directional microphones) are a viable option for people with normal hearing and subjective hearing difficulties.9

Post, Roup, and Lewis10 reported an increasing body of evidence demonstrating that adults with normal hearing sensitivity may report substantial difficulty understanding speech in complex listening situations. They report some hearing care professionals have fitted personal mild-gain amplification as an option to help these adults. Their results show that participants with normal hearing who received mild gain amplification demonstrated significant improvements with regard to their hearing handicap, as well as improvements in self-perceived auditory processing difficulties, and improved speech-in-noise performance, when compared to pre-fitting baseline measures. They report that for some adults with normal hearing sensitivity, hearing aid amplification may provide benefit with regard to reducing the difficulty of understanding speech in noise.10

Shojaei et al.,11 report the critical role of SNR for speech perception in the elderly and state the SNR is the most effective physical characteristic of speech sounds for understanding SIN. They note that older adults require a 3-4 dB improved SNR than younger adults to achieve the same understanding of SIN. In accordance with this, Smaldino & Crandell12 reported that children with normal hearing require a 10 dB better SNR than do adults, to achieve the same/similar performance.

Saunders et al.,13 reported TBI can impact the central auditory nervous system leading to speech understanding problems which are disproportionate to the often reported normal hearing thresholds. As such, FM systems allowed better speech perception in noise for some veterans with blast exposure.13

Beck, Doty-Tomasula and Sexton14 reported that for many people with Auditory Processing Disorders (APDs), improved access to the auditory signal is paramount. They noted the advantages of FM systems includes a realized reduction in distance (between the talker and listener), reduced reverb and reduced background noise, resulting in a more realistic/improved auditory signal and an improved SNR, allowing easier, less stressful and more enjoyable listening.14

Jensen reported 29 people with normal hearing (per their age group, average age approximately 66 years) and addressed listening effort (as measured by pupillometry) and speech understanding in noise. She notes there is a point at which people with normal hearing and people with hearing loss give up trying to listen (as the task becomes too difficult). In her study, she reports people with hearing loss give up more readily than those with normal hearing with regard to unaided SNRs. That is, people with normal hearing can participate in more challenging SNRs than people with hearing loss. However, specific modern hearing aid technologies have been shown to increase the SNR with a concomitant decrease in the amount of listening effort required. These technologies allow people with hearing loss to participate in more deleterious SNRs, than would have otherwise been expected. Therefore, people with hearing loss who use these technologies, may be able to actively communicate in more difficult listening situations.

Hearing loss and cognitive decline

Cognitive differences have been noted between older adults with hearing loss and matched groups without hearing loss.15,16 Like many other ailments, whether or not an individual experiences cognitive decline associated with aging is highly individualized. However, recent literature suggests it is likely that a history of brain injury and a history of hearing loss increase the likelihood of cognitive decline.17

Lin and colleagues18 stated, “Hearing loss is independently associated with accelerated cognitive decline and incident cognitive impairment in community-dwelling older adults” [18 p.1]. Pichora-Fuller & Kramer19 stated, “we hear with our ears, we listen with our brains, and we exert listening effort because we are motivated to communicate” [19 p.4S]. Edwards20 reported hearing loss and cognitive function interact via both top-down (i.e., cognitive) and bottom-up (i.e., sensory) processes. He stated the effects of hearing ability on cognitive function has been well-documented via studies of loudness and signal-to-noise ratio manipulation across various levels of hearing loss and across hearing aid signal processing. Further, Edwards20 reported directional microphone technologies and noise reduction algorithms improve reaction time, presumably based on a reduced cognitive load. As such, a reduced cognitive load potentially supports improved comprehension, improved memory access, and improved memory storage of information delivered via audition, and increased working memory capacity. Listening fatigue is also reduced via modern hearing aid technology presumably due to reduced listening effort. Edwards20 reported that the ability of modern hearing aids to capture and deliver spatial cues is also important regarding locating sound sources and using spatial separation to improve speech understanding.

Untreated hearing Loss: a medical issue and a modifiable risk factor for NCD

In a new report of more than 7000 people, hearing loss was statistically, significantly associated with all-type workplace and non-workplace injuries.6 Hearing loss has also been associated with increased use of emergency department visits for both males and females. Thus, is seems clear, hearing loss is a medical issue, untreated hearing loss has a multitude of medical and social consequences, and indeed, “hearing care is healthcare”.21

Livingston et al.,23 details nine potentially reversible (i.e., modifiable) population attributable fractions (PAFs, or risk factors) linked to dementia. That is, if one were to reduce or avoid these PAFs, their risk of dementia would decrease. The Lancet reported isolation, or lack of social contact has a PDF of 2.3%. Lack of exercise and lack of physical activity have a PAF of 2.6%, high blood pressure, type 2 diabetes & obesity combined have a PDF of 4%, depression has a PDF of 4%, smoking has a PDF of 5.5%, less education has a PAF of 7.5% and of note, hearing loss has a PAF of 9.1%.The evidence suggests approximately a third of dementia cases might be modifiable and they suggest anti-hypertensive medications (in appropriate patients), the consumption of a Mediterranean Diet (more fruits, veggies, nuts, beans, fish…) and regular exercise, as well as cognitive and brain training protocols and social activities are neuroprotective.22

Weinstein23 adds that by partially restoring communication ability, modern hearing aid amplification may serve as a buffer to maintain cognitive ability. Regarding social and emotional loneliness and depression, hearing aid amplification may improve the quality and quantity of social interactions, thus enabling participation in cognitively-stimulating activities.23 Amieva and colleagues16 reported, “hearing loss is associated with accelerated cognitive decline in older adults” and suggested “hearing aid use attenuates such decline” [16 p.2099].

Neuro cognitive disorders

Untreated hearing loss may eventually be recognized as a substantial pre-cursor to dementia and/or cognitive decline. Although people use “dementia” and “Alzheimer’s Disease” (AD) interchangeably in the literature, they are not synonymous. AD is a specific type, and is the most common form of, dementia.23 The term “dementia” does not indicate a specific disease. Rather, it indicates a range of symptoms such as a decline in memory or thinking skills significant enough to negatively impact a person's ability to perform everyday activities. Dementia has recently been re-named by the American Psychiatric Association (APA) in their DSM-5 as Neuro Cognitive Disorder (NCD).23 Thus, the term “NCD” will be primarily used throughout the remainder of this article.

Modifiable NCDs?

The Mayo Clinic24 reported certain causes of dementia [NCD] or dementia-like symptoms are reversible, such as those originating from infections and immune disorders, metabolic and endocrine abnormalities (e.g. thyroid problems), nutritional deficiencies (e.g. a vitamin B-12 or vitamin D deficiency), reactions to medications, depression, diabetes, smoking, cardiovascular factors, subdural hematomas or traumatic brain injuries (TBIs) and anoxia or sleep apnea.24 Irreversible and progressive contributors appear to originate in association with age, genetics, Alzheimer’s disease, mild cognitive impairment (MCI), Lewy body dementia, and frontotemporal dementia. Contemporary literature suggests AD is characterized by amyloid beta plaques and tau tangles facilitated by aging, genetics and multiple disease processes.25

The Livingston, Sommerlad & Orgeta22 report stated the most significant contributor to dementia is aging and related aging processes. However, in the last decade, researchers have identified multiple modifiable contributors to NCD and/or dementia and/or AD and exploration and documentation of these same factors continues.22

Dolgin22 reported that after more than 200 ineffective pharmaceutical trials, the hope of finding a medication to effectively stop or reverse Alzheimer’s has faded. However, the “one intervention at a time approach” has been enthusiastically replaced by a combined synergistic constellation of interventions, addressing a variety of modifiable risk factors and success has been reported.26

The Finnish geriatric intervention study to prevent cognitive impairment and disability involved more than 1200 seniors with Mild Cognitive Impairment (MCI, a common precursor to Alzheimer’s and other forms of NCD) evaluated the combined impact of diet, physical, mental, and social activity on cognitive ability, as compared to standard medical practice.27 After two years, this multi-domain lifestyle intervention proved to be significantly more effective in slowing or delaying cognitive decline than standard medical practice. Neuropsychological test scores improved for the majority of participants and performance on complex memory tasks was 40% higher in the intervention group. Executive functioning was 83% better in the intervention group, and processing speed was 150% higher in the intervention group. Of note, the control group (standard medical practice) had a 30% greater risk for cognitive decline. Indeed, the intervention group experienced an overall improvement in vitality, social function and general health, while the control group continued to decline overall.27,28

Furthermore, Fotuhi and colleagues29 reported a 12-week study of 127 seniors diagnosed with MCI using a multi-pronged “brain fitness” approach designed to address multiple risk factors. Their approach included a Mediterranean diet, physical and mental exercise, richer social interaction, meditation, sleep enhancement, and other stress management strategies. Of the 127 participants, 84% showed significant improvements in three or more areas of cognitive functioning. Of the 17 who had pre-and-post MRIs, more than half experienced growth in the volume of their hippocampus (i.e., the brain center for emotion and memory) thus supporting the idea that various multi-tiered, health-oriented interventions may be beneficial with respect to cognitive function.29

Traumatic brain injury

Traumatic brain injury (TBI) is an often-neglected, public health problem with more than one million injuries occurring in the United States annually.30,31 TBIs often result in lifelong consequences and outcomes which negatively impact a person’s physical abilities, cognitive skills, and emotional well-being.30,32 TBI survivors’ quality of life (QOL) frequently is diminished due to physical, cognitive, and emotional outcomes, as well as their frequent, resultant inability to return to work, school, or other pre-injury activities and hobbies.30

The traditional view of TBI recovery was that once the survivors’ outcomes plateaued, they were stable.33 Recently, researchers have found this is not the case through large longitudinal data sets. The CDC-initiated TBI Surveillance National Database and the National Institute on Disability and Rehabilitation’s Traumatic Brain Injury Model Systems (TBIMS) are both national databases.34 These databases provide extraordinary opportunities for research due to the vast number of individuals represented and the follow-up measures reported.35 The CDC currently has nearly 30 years of data34 and the TBIMS35 contains information on over 12,000 individuals with TBI.36 Many researchers have conducted long-term follow-up studies and have recently began to publish these results.37–42 Contrary to the traditional view, this contemporary data suggest that at 10 years post-injury, approximately 30% of survivors with moderate or severe injuries experience a decline in their outcomes. Furthermore, a subset of these survivors experienced degenerative and progressive motor and/or cognitive dysfunction.43,44

Researchers have shown associations between a history of TBI and dementia. Gardner and colleagues35 studied 164,661 patients admitted to hospitals with various types of traumatic injuries, 31.5% had a TBI. Between one and seven years after the traumatic incident, the researchers analyzed records for a diagnosis of dementia. They reported that 8.4% of those with a TBI later developed dementia, compared to 5.9% of the patients who admitted for a traumatic injury that did not include TBI. Hazard ratio calculations indicated ([HR], 1.46; 95% CI, 1.41-1.52; P < .001), that those with a history of TBI are at increased risk for dementia. Adjusted analyses, further suggested that for both moderate and severe TBIs, the increased risk of dementia was significant across all ages (55-74 yr.), whereas those with mild TBI had an increased risk after they turned 65 years of age35 suggesting that TBIs may increase the likelihood of young onset-dementia.44 Young onset-dementia is defined as dementia diagnosed prior to age 65.35,45 Corrigan & Hammond33 reported an incident of moderate or severe TBI is also associated with Parkinsonism.

Relatedly, individuals who have had multiple mild TBIs (or concussions) have been the focus of contemporary research studies. Chronic Traumatic Encephalopathy (CTE), specifically, has garnered increased attention. CTE, defined as a disease with an etiology of repeated head trauma, was the focus of a 2017 New York Times article. The article reported findings from a study in which researchers examined deceased football players’ brains. Eighty-seven percent of the players were diagnosed, posthumously, with CTE, including 110 of the 111 NFL players.46 In 2018, researchers reported that 42 of 100 New England Patriots members of the first three Super Bowl teams have alleged concussions and brought legal action against the National Football League and a helmet manufacturer. These professional football players have reported symptoms of brain injury caused by repetitive head impacts from practices and professional sporting competitions.46

While some researchers hesitate to call CTE a type of dementia and there is not full consensus on all of its diagnostic features,44 there is some consensus on its description with notable commonalities to other types of dementia. That is, CTE is a chronic, progressive, neurodegenerative condition that can affect individuals’ cognitive performance, behavior, affect/mood, and sensory/motor skills.[47–49]

Studies have demonstrated those with mild TBI are at a more than 3-fold greater risk of dementia than un-injured counterparts51 and males who sustained brain injuries at an early age were more likely to have young onset-dementia.45 Nordstrom and colleagues45 found that Swedish men (N=811,622) who served in the Army at an average age of 18, were at an increased risk for young onset-dementia three decades later, if they had incurred a TBI. This risk was not associated with AD, but was strongly associated with other types of NCD after only one mild TBI (HR=1.7; p<0.05) and more so after a severe injury (HR=2.6; p<0.05), after adjusting for premorbid cognitive functioning and alcohol abuse.45

Traumatic brain injury and hearing loss

Clinicians, medical professionals, case managers and others should ensure that audiologic concerns (i.e, thorough audiometric diagnostic evaluations and management) are addressed and obtained early in the diagnostic and rehabilitation process so therapies addressing concomitant challenges (e.g., psychological, speech, language, educational/vocational, and emotional) are more impactful, effective and allow the individual to experience greater life participation in these therapeutic processes.52,53 The United States has experienced a dramatic upsurge in TBI. Some of this may be due to a heightened awareness of brain injury54 such as the recent media attention to CTE cited previously. Additionally, U.S. military personnel returning home from combat are more likely to have brain injuries (or Blast injuries) as well as hearing loss, tinnitus, or dizziness.55

Blast injuries are often associated with other concomitant health problems. Injuries sustained from improvised explosive devices (IEDs) account for 78% of battlefield head and neck injuries56 and frequently result in a brain injury as well.51 Blast waves are often destructive to the auditory system as they impact gas and/or fluid-filled structures57,58 and may cause middle and/or inner ear damage.59 Xydakis and colleagues60 estimated 35% of blast injury survivors had a tympanic membrane rupture. Further, research with Marines who sustained combat injuries during operation Iraqi Freedom II, demonstrated ear injuries are the most common singular combat injury.61 Despite the frequency with which the ear is injured and a conductive hearing loss occurs, the most frequently experienced hearing loss is sensorineural.62

Civilian survivors of brain injuries frequently contend with hearing loss. In fact, hearing loss after pediatric brain injury occurred in 50% of survivors. Sixty-four percent of children with brain injuries had conductive hearing losses, half of which resulted from temporal bone fractures. Sensorineural hearing losses for this population were variable in terms of severity, whether they were unilateral or bilateral, and whether they were symmetric.63

In a contemporary review of 99 veterans exposed to munitions blasts in combat-related conflicts and had hearing thresholds better than 40 dB and with appropriate scores on the Mini Mental State Exam (MMSE), and all of whom reported difficulty understanding speech in noise, were treated with multiple interventions.67 Veterans issued a wireless FM system found it useful in work related meetings, in restaurants, during lectures, while using public transportation, while watching television and more. The authors reported that in some locations, veterans were issued low gain hearing aids with remote (wireless) microphones and the authors stated these were more or less equivalent to FM systems. The authors reported that in the lab, these systems are “highly effective at improving speech understanding in noise…”.67 Finally, the authors concluded that FM systems, or remote microphone systems via Blue Tooth offers effective intervention for blast exposed veterans with normal or near-normal hearing and “functional hearing difficulties, and should be routinely considered as an intervention approach for this population when possible.”

Hoover and colleagues76 reported auditory complaints after mild traumatic brain injury (MTBI). They reported 33 listeners, of whom 13 (mean age 47 years) had experienced MTBI. SIN tests revealed 84% of the MTBI group had SIN deficits, as compared to 9% of the 11 people in the matched group (mean age 49 years). The authors note that in addition to a thorough auditory and communications need assessment, the role of the audiologist may include counseling and the provision of technology to facilitate greater participation regarding skills of daily living and participation in rehabilitation.76 Furthermore, Gallun, Papesh, and Lewis77 noted that an advantage for younger and middle-aged people, who have experienced TBI, is their willingness and enthusiasm to embrace technological advantages. They note audiologists who have worked with blast exposure patients with normal and near normal hearing have successfully prescribed minimal gain hearing aids for these people, with and without FM systems.77

Treatment options and considerations

Individuals who experience speech in noise difficulty and have hearing loss, listening disorders, TBI or NCDs may benefit substantially from an improved signal-to-noise ratio (SNR). Understanding speech in noise is arguably a common auditory problem among the elderly, and among those who have experienced TBI, APD and NCDs. As the signal to noise ratio decreases (i.e., as background noise approaches and exceeds the loudness of the signal of primary interest) a considerable reduction of speech perception occurs.66 Improved SNRs can be accomplished with modern hearing aids, remote microphones, assistive listening devices (ALDs) and more.64,65

Of course, deleterious SNRs are not exclusively a problem of the elderly or those with NCDs, the same problem has had a consistent negative influence on modern school systems. Indeed, children, too, must exert considerable listening effort as the SNR deteriorates, thus leaving fewer cognitive resources available for the learning tasks at hand.66

Indeed, vast technological offerings in modern hearing aids are available through which patients can wear cosmetically pleasing and very sophisticated hearing aids with and without wireless remote microphones, to enhance the SNR, while offering excellent sound quality, user satisfaction and improved speech in noise results. Beck & Le Goff5 suggested that improving the SNR might ultimately be considered among the most pragmatic goals of modern hearing aid fittings. Their reported results are statistically significant-even when compared to newer technologies introduced in the last few years.5

Indeed, traditional HA users struggle with understanding speech in noise and in other challenging listening conditions68 although of note, those with better cognitive skills appear to experience better success with Has.69,70 Cognitive abilities such as visual digit monitoring, visual letter monitoring tasks,70 working memory capacity,71 cognitive storage and capacity69 attention and more, all contribute to the individual’s ability to understand speech in noise.

Contemporary, sophisticated HAs offer sound processing strategies which increase the quality of sound,72 user satisfaction73 and reduce noise levels5 through an improved signal-to-noise ratio (SNR) which may reduce brain processing load (i.e., listening effort) while listening or attending to speech in noise.74 These strategies can provide easier and more effective listening in difficult listening situations (where social interaction takes place) such as restaurants, cafes or at a family dinner at home, and are often characterized by annoying, distracting and elevated noise levels.75–78

Summary & discussion

Hearing and listening are often confused as synonymous, yet they are unique processes. Hearing perceives sound and largely involves the peripheral auditory nervous system, whereas listening involves, and is arguably a derivative of cognitive ability, occurring in the central nervous system. Listening might be described as applying meaning to sound. The ability to apply meaning to sound is a major consideration with regard to hearing loss, APD, TBI, NCD and other individuals.

Finally, with regard to hearing aid amplification and cognitive health, it appears imperative to provide the brain with maximal auditory information. Technologies are available which substantially reduce background noise, increase the signal-to-noise ratio, avail vastly improved sound quality, and some maintain spatial cues.5,72,73 Improving these factors is essential to improving the brain’s ability to listen (i.e., derive meaning from sound), particularly in challenging background noise. Amplification interventions (such as those noted above) may improve the SNR, which can enhance an individuals’ quality of life, and may in the near future, prove to serve a neuroprotective role with regard to cognitive decline associated with hearing loss and some neurocognitive disorders.

Acknowledgements

None.

Conflict of interest

The author declares there is no conflict of interest.

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