Auditory agnosia is a rare neurological condition that affects how the brain makes sense of sounds. People with auditory agnosia can hear, but they have trouble recognizing everyday sounds, spoken words, or music. It can follow a stroke, brain injury, or certain neurodegenerative diseases, and symptoms may be stable or change over time. Treatment focuses on speech and language therapy, hearing strategies, and addressing the underlying cause. Not everyone will have the same experience, and many people live safely with support and tailored rehabilitation.
Overview
Auditory agnosiaSymptoms
Auditory agnosia causes trouble recognizing sounds despite normal hearing tests. People may struggle to understand speech (especially in noise), identify familiar voices or everyday noises, or follow music. Many rely on lip-reading or context, while hearing sensitivity remains intact.
Outlook and prognosis
Many living with auditory agnosia can learn practical workarounds—like lip-reading support, written cues, and structured listening therapy—that improve day-to-day communication. Prognosis varies by cause and extent of brain involvement. Early, consistent rehabilitation often leads to meaningful gains.
Causes and risk factors
Auditory agnosia usually follows damage to both temporal lobes, most often from stroke, traumatic brain injury, or encephalitis. Risk rises with vascular factors (high blood pressure, atrial fibrillation), brain infections, tumors, or neurosurgery. Rarely, developmental brain differences cause similar symptoms.
Genetic influences
Genetics plays a limited role in auditory agnosia for most people; it’s usually acquired after brain injury, stroke, or infection. Rarely, inherited neurodevelopmental or neurodegenerative conditions increase risk. Specific genetic variations are not routinely tested or clearly predictive.
Diagnosis
Clinicians review symptoms, confirm normal hearing with audiology, and assess sound recognition and language with neuropsychological and speech tests. Brain MRI helps identify temporal lobe injury. The diagnosis of auditory agnosia rests on impaired sound recognition despite intact hearing.
Treatment and drugs
Treatment for auditory agnosia focuses on improving understanding of sounds through speech-language therapy, auditory training, and tailored communication strategies. Therapists may use written cues, visual supports, and environmental adjustments. Management often includes treating underlying causes, like stroke-related changes, and ongoing rehab.
Symptoms
Conversations can suddenly feel confusing, like the words are clear but the meaning won’t land. Early symptoms of auditory agnosia often show up when listening to speech, music, or everyday sounds that no longer make sense even though hearing seems normal. This condition, auditory agnosia, affects how the brain processes and recognizes sounds rather than the ears themselves. Symptoms vary from person to person and can change over time.
Words can sound crisp but stripped of meaning. You might catch syllables yet miss the message. People with auditory agnosia often rely more on lip-reading.
Common noises like doorbells, alarms, or a kettle may not register as what they are. This can cause safety concerns or delays in responding. Some only identify the sound after seeing the source.
Tunes that were once familiar may feel flat or unrecognizable. Keeping rhythm is often easier than following melody. This music-recognition problem can be part of auditory agnosia.
Familiar voices can be hard to identify without seeing the person. Phone calls may be especially challenging. Loved ones often notice the changes first.
How people usually first notice Auditory agnosia?
People often first notice auditory agnosia when familiar sounds suddenly stop making sense—voices may be heard clearly but not understood, or everyday noises like a ringing phone or a dog bark are recognized as “a sound” without meaning. This can follow a stroke, head injury, seizures, or certain neurodegenerative conditions, so the first signs of auditory agnosia usually appear abruptly or subacutely, with normal hearing tests but trouble recognizing spoken words (pure word deafness), environmental sounds, or music. Families and doctors typically pick up on the mismatch between intact hearing and difficulty identifying sounds, prompting a neurological evaluation and brain imaging.
Types of Auditory agnosia
Auditory agnosia affects how the brain makes sense of sounds, which can change everyday moments like following a conversation, recognizing a tune, or telling a voice from background noise. People may notice different sets of symptoms depending on their situation. Clinicians often describe them in these categories: verbal (speech), nonverbal (environmental sounds and music), and associative versus apperceptive forms. When people look up types of auditory agnosia, they often mean these recognized clinical variants, which can overlap or vary in severity over time.
Verbal agnosia (pure word deafness)
Hearing is intact, but speech sounds do not resolve into meaningful words. People may understand written language and lip-read better than spoken words. Background noise can make this gap even more noticeable.
Environmental sound agnosia
Everyday sounds like a doorbell, siren, or dog bark are hard to identify even though the sound is heard. Safety cues may be missed because the brain does not link the sound to its source. Vision-based cues often become the main workaround.
Music agnosia (amusia)
Melodies feel unfamiliar or off-key recognition is lost despite normal hearing. Some have trouble telling pitch changes or following a tune, while speech understanding stays relatively intact. Musicians may notice subtle deficits first.
Associative auditory agnosia
The sound is perceived clearly but not linked to meaning. People may describe a sound’s qualities yet cannot name or recognize its source. Recognition can improve when paired with a visual cue.
Apperceptive auditory agnosia
The brain struggles to form a stable sound pattern from what is heard. Sounds feel distorted or fragmented, making recognition and naming difficult. Even with visual prompts, identification may remain limited.
Phonagnosia (voice agnosia)
Familiar voices are hard to recognize despite normal hearing and speech understanding. People may rely on context or visual cues to tell who is speaking. This can strain social interactions and phone conversations.
Bilateral versus unilateral lesions
Bilateral temporal damage often produces broader or more severe forms across types of auditory agnosia. Left-sided injury more often affects speech sounds, while right-sided injury more often affects music and voice recognition. Not everyone will experience every type.
What genetics can tell you about symptoms
Some people with genetic changes affecting the brain’s sound-processing hubs (like in FOXP2 or GRIN2A pathways) struggle to recognize everyday sounds or spoken words despite normal hearing tests. Variants that disrupt how neurons connect or time signals can cause word deafness, environmental sound confusion, or both.
Causes and risk factors
Auditory agnosia most often follows damage to the brain’s hearing areas in the temporal lobes from stroke, head injury, or encephalitis. It can also develop with brain tumors, multiple sclerosis, or neurodegenerative diseases that involve these regions. Risk factors for auditory agnosia include things that raise stroke risk, like high blood pressure, diabetes, smoking, high cholesterol, and atrial fibrillation. Rarely, genetic differences in brain development or childhood epilepsy syndromes can lead to auditory agnosia in children. Some risks are modifiable (things you can change), others are non-modifiable (things you can’t).
Environmental and biological risk factors
Auditory agnosia means the brain has trouble making sense of sounds, even when the ears work well. Doctors often group risks into internal (biological) and external (environmental). The elements below outline factors that can raise the chance of auditory agnosia, especially when the temporal lobes are affected.
Blocked or bleeding vessels in the brain can injure sound-processing areas. Strokes near the auditory cortex raise the likelihood of auditory agnosia.
A blow to the side of the head can bruise or shear the temporal lobes. Damage around primary hearing areas may trigger auditory agnosia.
Infections such as herpes simplex can inflame the temporal lobes. Swelling or cell loss there can leave lasting problems recognizing speech or everyday sounds.
Severe infection of the brain’s coverings can spread inflammation into nearby tissue. When auditory pathways are affected, features of auditory agnosia may appear.
Genetic risk factors
Auditory agnosia is most often acquired after brain injury or inflammation, but a small number of cases trace back to inherited factors. These involve genes that shape development of the hearing areas or that change how nerve cells communicate, especially in childhood epilepsy‑aphasia syndromes. Carrying a genetic change doesn’t guarantee the condition will appear. When early symptoms of auditory agnosia overlap with seizures or language regression, a genetic cause is more likely and may guide testing.
GRIN2A variants: Changes in the GRIN2A gene can lead to epilepsy‑aphasia syndromes where understanding spoken words suddenly worsens. Some children develop auditory agnosia together with seizures and language regression. These variants may be inherited or arise as new changes.
Perisylvian malformations: Rare gene changes that alter the folding and wiring of the language‑hearing regions can cause perisylvian brain differences. This can disrupt sound recognition and comprehension, contributing to auditory agnosia. Inheritance varies, and some cases occur without any family history.
Family history: Clustering of epilepsy, speech disorders, or language loss in close relatives points to shared genetic susceptibility. In these families, trouble recognizing sounds or words may appear in childhood and fluctuate over time.
De novo changes: A genetic variant that appears for the first time in a child can affect brain circuits for sound processing. This can set the stage for central hearing problems even when parents and siblings have no similar history. Such variants are usually found through specialist‑ordered genetic testing.
Chromosomal microchanges: Small missing or extra pieces of chromosomes can disrupt genes crucial for temporal‑lobe development. When these regions are involved, people may have central hearing problems such as auditory agnosia. These changes are typically detected with a chromosomal microarray.
Variable expression: The same genetic change can lead to very different symptoms, from mild language delay to clear difficulty recognizing spoken words. This variability makes individual risk hard to predict. Genetic counseling can help interpret results for a family.
Lifestyle risk factors
While uncommon, auditory agnosia most often follows brain events such as stroke or traumatic injury, and certain daily habits can raise or lower those risks. The lifestyle risk factors for auditory agnosia largely mirror habits that increase vascular events or head trauma that damage the auditory cortex. Choices that support brain and heart health may reduce risk and can also aid recovery if an injury occurs.
Tobacco use accelerates atherosclerosis and raises clotting risk, increasing the chance of strokes that can damage auditory processing areas. Quitting reduces stroke risk within months to years.
Frequent binge or high-volume drinking raises blood pressure, atrial fibrillation, and stroke risk that can injure auditory cortex. Moderating intake or abstaining lowers these risks.
Low activity worsens blood pressure, cholesterol, and insulin resistance, raising stroke risk linked to auditory agnosia. Regular aerobic movement improves vascular health and lowers cerebrovascular events.
Diets high in sodium, trans fats, and ultra-processed foods promote hypertension and atherosclerosis that can lead to stroke-related auditory agnosia. Emphasizing plants, fiber, and unsaturated fats supports brain blood flow.
Risk prevention
Auditory agnosia often follows damage to the parts of the brain that make sense of sounds, so prevention focuses on protecting brain health and lowering stroke and injury risks. Prevention can mean both medical steps, like vaccines, and lifestyle steps, like exercise. If you notice early symptoms of auditory agnosia—such as trouble recognizing a ringing phone or a dog bark despite hearing them—seek prompt medical care. Quick action can limit lasting problems if a stroke or brain infection is the cause.
High blood pressure is the top driver of strokes that can injure sound‑processing areas. Keep it in a healthy range with diet, movement, stress control, and medicines if prescribed.
High blood sugar and unhealthy cholesterol damage blood vessels and raise stroke risk. Regular checks, nutrition changes, and medication when needed protect your brain.
Smoking and vaping harm blood vessels and make clots more likely. Quitting lowers stroke risk and helps prevent brain injuries linked to auditory agnosia.
Regular physical activity supports healthy blood vessels and reduces stroke risk. Start with one small habit—like daily movement or better sleep.
Transmission
Auditory agnosia is not contagious and can’t be “caught” from someone else. It doesn’t spread through air, touch, or bodily fluids, and there’s no known genetic transmission of auditory agnosia in most cases.
Most people develop auditory agnosia after changes in the brain’s hearing centers, such as a stroke, a head injury, or an infection that affects the brain; these are one‑person events, not things that pass between people. It can occasionally be seen in childhood within broader developmental or neurological conditions, but even then it isn’t something that spreads from person to person.
When to test your genes
Consider genetic testing if you have persistent difficulty recognizing sounds despite normal hearing tests, especially with a family history of similar issues or related neurodevelopmental conditions. Testing is also reasonable when symptoms start early in life or cluster with language, learning, or epilepsy features. Results can guide tailored therapies, surveillance, and family planning.
Diagnosis
Auditory agnosia is typically identified when everyday sounds or spoken words seem clear to the ears but don’t make sense to the brain. You might notice small changes in daily routines, like recognizing a doorbell by sight rather than sound, or needing captions even though hearing tests look normal. Doctors usually begin by asking about what you’re noticing in different listening situations and then use targeted exams to separate hearing from sound recognition. The goal in the diagnosis of auditory agnosia is to confirm the pattern and rule out other causes that can look similar.
Your clinician asks when and where sound recognition is hardest. They’ll check whether trouble is mainly with speech, non-speech sounds, or both.
Standard audiometry checks whether hearing thresholds are in a typical range. This helps ensure the problem isn’t due to hearing loss.
Words and sentences are presented in quiet and in background noise. Results help separate hearing ability from recognizing what speech means.
You’re asked to identify everyday sounds like a phone ring or dog bark. This can show if the issue is limited to speech or includes non-speech sounds.
Stages of Auditory agnosia
Auditory agnosia does not have defined progression stages. It’s usually tied to where and how the brain is affected (often after a stroke, head injury, or certain infections), so symptoms may stay steady, improve with therapy, or change if the underlying condition changes. Different tests may be suggested to help confirm the diagnosis and rule out hearing problems, since early symptoms of auditory agnosia can look like simple hearing difficulty. Evaluation often includes a hearing exam, sound-recognition tasks with a speech-language pathologist, neuropsychological testing, and brain imaging such as MRI; sometimes EEG is used if seizures are a concern.
Outlook and prognosis
Many people ask, “What does this mean for my future?”, especially after being told they have auditory agnosia. Day to day, people with auditory agnosia often learn to rely more on written cues, lip-reading, or context—glancing at the kettle to confirm a boil instead of trusting the whistle, or setting phone alerts with vibration instead of ringtones. The outlook is not the same for everyone, but the trajectory usually depends on the cause—stroke, brain injury, seizures, neurodegenerative disease, or a developmental difference—and how quickly therapy and underlying issues are addressed.
Prognosis refers to how a condition tends to change or stabilize over time. When auditory agnosia follows a stroke or head injury, some functions can improve in the first 6 to 12 months as the brain heals and with speech-language therapy; early symptoms of auditory agnosia like trouble recognizing familiar sounds may soften as the brain forms workarounds. If the cause is a progressive condition, difficulties may slowly increase over years, and planning for assistive tech and communication strategies becomes key. Isolated auditory agnosia without an ongoing disease process usually does not affect life span; mortality is shaped by the underlying cause rather than the agnosia itself.
Looking at the long-term picture can be helpful. With ongoing care, many people maintain independence by pairing hearing with other senses—captions, text-to-speech, visual alarms, and structured listening practice. The road may not be straight, but gains often come from small, steady adjustments rather than one big change. Talk with your doctor about what your personal outlook might look like, including whether your cause is likely to improve, stay stable, or progress, and which therapies can support the best function for you.
Long-term effects
Auditory agnosia can leave everyday sounds feeling unfamiliar, which can make conversations, alarms, and media hard to interpret even when hearing tests are normal. Long-term effects vary widely, depending on the cause (such as stroke or infection), the brain areas involved, and age. Many people see partial recovery over months to years, while others have lasting gaps in recognizing words, environmental sounds, or music. Early symptoms of auditory agnosia are often mistaken for hearing loss, which can delay the right support and planning.
Understanding spoken words can stay patchy, especially in fast or complex speech. People with auditory agnosia may rely more on context to follow conversations. Misheard words can lead to frequent clarifications.
Visual cues like lip movements and facial expressions often become essential. In auditory agnosia, people may struggle when they cannot see the speaker. Phone calls and masked conversations can remain difficult.
Background noise can blur speech and everyday sounds. This listening effort can lead to mental fatigue over a day. Crowded settings may remain particularly challenging.
Sirens, alarms, or timers may be hard to recognize quickly. People with auditory agnosia might notice delays responding to urgent sounds. This can increase reliance on visual alerts.
How is it to live with Auditory agnosia?
Living with auditory agnosia can feel like the world’s sounds arrive without their labels—you hear the tone and volume, but everyday noises and spoken words may not click into meaning. Many handle this by relying more on context, lip-reading, written cues, and visual alerts, which can make conversations slower and noisy places exhausting. For family, friends, and coworkers, clear communication—facing the person, speaking steadily, reducing background noise, and using text or captions—makes a big difference. With patience, routines, and supportive technology, many build confident ways to navigate work, relationships, and public spaces.
Treatment and drugs
Treatment for auditory agnosia focuses on improving day-to-day communication and safety, since medicines don’t reverse the condition. Rehabilitation usually includes speech-language therapy to strengthen listening strategies, sound discrimination, and lip-reading, often paired with auditory training exercises and assistive technology like captioning tools or visual alerts for doorbells, phones, and alarms. Alongside medical treatment, lifestyle choices play a role, such as practicing slow, clear conversation in quiet settings, reducing background noise, and using written cues at work or home. If auditory agnosia follows a stroke, head injury, or seizure disorder, treating the underlying cause—stroke rehabilitation, seizure control, or migraine management—may help stabilize or improve symptoms. Ask your doctor about the best starting point for you, and whether referral to a speech-language pathologist or neuropsychologist could tailor therapy to your needs.
Non-drug treatment
Auditory agnosia affects how the brain makes sense of sounds, so day-to-day tasks like following conversations or recognizing alerts can feel confusing. Non-drug treatments often lay the foundation for making listening easier and safer. Early symptoms of auditory agnosia can include trouble understanding speech despite normal hearing tests. The aim is to build practical skills, reduce strain, and use tools that make sound information clearer.
A speech-language pathologist teaches ways to follow speech using visual cues, pacing, and summaries. Practice includes lip and facial cue use, structured conversations, and step-by-step listening drills.
Guided exercises help the brain better tell apart speech sounds and patterns. Sessions may use computer programs or therapist-led drills that gradually add background noise.
Reducing background noise and echo can make speech easier to follow. Soft furnishings, closing doors, and choosing quiet seating away from speakers or kitchens can help.
Remote microphones or FM systems send a speaker’s voice directly to headphones or earbuds, improving the signal over noise. Even when hearing tests are normal, these tools can reduce listening effort.
Your genes may have an impact on how drugs work for you
Think of treatment like adjusting a sound system: the same volume knob doesn’t work for everyone because wiring differs from person to person. Genetic differences in drug-metabolizing enzymes and brain receptors can change medication dose needs, benefits, and side-effect risks.
Pharmacological treatments
Medicines for auditory agnosia focus on the underlying cause, since no drug directly “restores” sound recognition. For everyday life, that often means treating a stroke, seizures, inflammation, infection, or migraine that triggered the change, while pairing medicine with rehab like speech and auditory therapy. Not everyone responds to the same medication in the same way. Early symptoms of auditory agnosia—like recognizing voices one day and struggling the next—should prompt urgent evaluation, because some causes are time-sensitive.
In sudden ischemic stroke, alteplase or tenecteplase can dissolve the clot if given within the emergency time window. This may limit brain injury in the auditory areas and improve recovery.
Aspirin or clopidogrel help prevent new ischemic strokes after an initial event. They reduce the risk of further damage that could worsen sound recognition.
If a stroke came from atrial fibrillation or a heart clot, apixaban, rivaroxaban, dabigatran, or warfarin lower the chance of another event. This targets the root cause rather than auditory symptoms themselves.
Atorvastatin or rosuvastatin lower LDL cholesterol and stabilize plaques after stroke. Over time, this helps reduce future brain injury that could aggravate auditory agnosia.
Genetic influences
Most cases of auditory agnosia are acquired after injury to the brain, such as a stroke, infection, or head trauma, rather than being inherited. In children, rare epilepsy-related disorders or developmental brain conditions—some linked to specific gene changes—can produce similar sound-recognition difficulties. In adults, progressive diseases that sometimes have genetic forms, like certain types of dementia, can also affect how the brain interprets sounds. Genetics is only one piece of the puzzle, but it may contribute when early symptoms of auditory agnosia appear in childhood alongside seizures, developmental delays, or other neurological features in the family. If your clinician suspects a broader syndrome, they may discuss genetic counseling or testing to look for an underlying cause. For most people with isolated auditory agnosia, however, genetic testing is not routinely needed, and care focuses on treating the trigger (for example, stroke care or seizure control) and on rehabilitation.
Is Auditory agnosia genetic?
Genetics plays a limited role in auditory agnosia for most people; it’s usually acquired after brain injury, stroke, or infection. Rarely, inherited neurodevelopmental or neurodegenerative conditions increase risk. Specific genetic variations are not routinely tested or clearly predictive.
Pharmacogenetics—how genetics influence drug effects
Medicines don’t directly fix auditory agnosia, but genetics can still shape parts of care when drugs are used for related issues like seizures, stroke prevention, or supporting attention and mood during therapy. Not every difference in response is genetic, but some inherited patterns can change how your body handles certain drugs. If seizures are part of the picture, a specific immune‑system gene pattern seen more often in people of Asian ancestry can raise the risk of rare, severe skin reactions with some seizure medicines; knowing this may steer doctors toward safer options. Genes that influence how quickly your liver processes medicine can also guide safer dosing of drugs such as phenytoin or some benzodiazepines that might be prescribed for seizures, anxiety, or muscle tension while you recover. When auditory agnosia follows a stroke, gene differences can affect how well blood thinners like clopidogrel work, or how much warfarin you may need to avoid bleeding while still preventing another event. In practice, any genetic insights are used alongside your medical history and goals to tailor medicines, while speech‑language and auditory rehabilitation remain the core treatment of auditory agnosia.
Interactions with other conditions
Auditory agnosia often appears alongside other brain-related conditions, especially after a stroke or head injury, and it can overlap with language problems like aphasia or difficulties understanding speech in noisy places. When both are present, it may be hard to tell whether missed words come from trouble processing sound meaning or from a language issue; early symptoms of auditory agnosia can be mistaken for simple distraction or hearing loss during recovery. Doctors call it a “comorbidity” when two conditions occur together. Auditory agnosia can also be seen in temporal lobe epilepsy and in some neurodegenerative diseases, such as Alzheimer’s disease or frontotemporal dementia, where changes in thinking and memory may further strain day-to-day communication. Coexisting hearing loss or tinnitus can complicate things, since hearing devices may improve volume but not the brain’s ability to recognize sounds, so care plans often need both hearing support and cognitive or speech therapy. It’s worth telling your care team about all diagnoses and medications so they can coordinate strategies that fit your specific mix of symptoms.
How genes can cause diseases
Humans have more than 20,000 genes, each carrying out one or a few specific functions in the body. One gene instructs the body to digest lactose from milk, another tells the body how to build strong bones and another prevents the body's cells from beginning to multiply uncontrollably and developing into cancer. As all of these genes combined are the building instructions for our body, a defect in one of these genes can have severe health consequences.
Through decades of genetic research, we know the genetic code of any healthy/functional human gene. We have also identified that in certain positions on a gene, some individuals may have a different genetic letter from the one you have. We call these hotspots "Genetic Variations" or "Variants" in short. In many cases, studies have been able to show that having the genetic letter "G" in the position makes you healthy, but having the letter "A" in the same position disrupts the gene function and causes a disease. Genopedia allows you to view these variants in genes and summarizes all that we know from scientific research, which genetic letters (Genotype) have good or bad consequences on your health or on your traits.
History
Throughout history, people have described puzzling moments when hearing seemed intact but meaning slipped away. A neighbor’s voice might sound clear, yet the words feel like an unfamiliar tune. A ringing phone is heard, but its purpose doesn’t register. These everyday slips likely appeared in diaries and bedside notes long before modern testing could separate hearing ability from understanding. Families sometimes recalled that after a stroke or head injury, a relative could hear noises but struggled to recognize spoken words or everyday sounds like doorbells or sirens.
First described in the medical literature as a problem of “sound recognition,” auditory agnosia gradually took shape as doctors compared careful bedside observations with brain findings from strokes, infections, and injuries. Early clinicians noticed that some people could repeat sounds or identify pitches, yet could not link what they heard to meaning. Over time, descriptions became more precise: some people mainly lost understanding of speech (often called word deafness), others could not recognize environmental sounds, and a few had difficulty with music. These patterns often followed injuries in the brain’s temporal lobes, especially on both sides, which help the brain sort out complex sound patterns.
In recent decades, awareness has grown as hearing tests, brain imaging, and speech-language assessments became more refined. This helped confirm that auditory agnosia is not a problem of the ears but of how the brain processes and labels sounds. Researchers mapped which regions support different “streams” of sound processing, showing why one person might struggle mostly with spoken words while another has trouble identifying everyday noises. Advances in testing also separated auditory agnosia from conditions with similar symptoms, such as hearing loss, attention problems, or language disorders that affect both speaking and understanding.
Current studies build on a long tradition of observation by linking clinical histories with imaging and, in rare genetic conditions or neurodegenerative diseases, with broader brain changes over time. These findings explain why early symptoms of auditory agnosia can vary from subtle trouble following fast speech to a sudden inability to recognize common sounds after a stroke. Historical differences highlight why modern care starts by ruling out hearing loss and then looks closely at how the brain handles sound.
Looking back helps explain the present approach: tailored rehabilitation that leans on other senses, slower speech, captioning, or visual cues, while speech-language therapy works on rebuilding recognition pathways. The history of auditory agnosia shows a steady shift—from confusing, scattered reports to a clearer understanding of how the brain assigns meaning to what we hear.