Cortical deafness is a rare hearing disorder caused by damage in the brain’s hearing centers. People with cortical deafness do not perceive sounds even though the ears and eardrums may be healthy. Symptoms include sudden or gradual loss of sound awareness, trouble understanding speech, and confusion in noisy places. It can follow strokes, head injury, infection, or lack of oxygen, and it affects adults more often than children. Treatment focuses on rehabilitation, speech and hearing therapy, and managing the cause, and outcomes vary based on brain recovery rather than hearing aids alone.
Overview
Cortical deafnessSymptoms
Cortical deafness causes sudden, profound hearing loss even though the ears and ear tests may be normal. People may not perceive any sounds or speech, struggle to localize noises, and often notice this after a stroke or head injury.
Outlook and prognosis
Many living with cortical deafness have stable hearing loss, but progress depends on the brain injury’s cause, size, and location. Some regain limited sound awareness with neurorehabilitation and assistive tech, though understanding speech often remains difficult. Early, intensive therapy supports communication and safety.
Causes and risk factors
Cortical deafness usually follows injury to both brain auditory centers from stroke, trauma, encephalitis, tumors, or oxygen deprivation. Risk factors for cortical deafness include age, high blood pressure, smoking, diabetes, atrial fibrillation, head injury, and severe brain infections.
Genetic influences
Genetics plays a limited role in cortical deafness. Most cases result from acquired brain injury (e.g., stroke, trauma), though rare inherited conditions affecting brain development or metabolism can contribute. Genetic testing is considered when onset is early or syndromic.
Diagnosis
Cortical deafness is diagnosed through combined hearing tests and neurologic evaluation. Normal ear exam with absent sound understanding prompts brain imaging (MRI/CT) and auditory evoked potentials. The diagnosis of cortical deafness relies on matching test results with lesion location.
Treatment and drugs
Treatment for cortical deafness centers on communication support and safety. Care often includes intensive speech and auditory therapy, visual communication options (like captioning or sign support), assistive devices, and environmental adaptations. Regular neurology and audiology follow-up helps track changes and tailor strategies.
Symptoms
Cortical deafness affects how the brain processes sound, so people may not hear voices or everyday noises even when their ears are healthy. Day to day, this can mean missing alarms, the phone, or a loved one speaking right beside you. Early symptoms of cortical deafness may appear suddenly, especially after a stroke or head injury, and hearing devices usually don’t help. A healthcare professional can help sort out what’s typical aging and what warrants a closer look.
Sounds and speech can seem to vanish all at once, often after a stroke or head injury. In cortical deafness, people may not perceive any noises, including environmental sounds like traffic or alarms.
Turning up the volume doesn’t help because the brain isn’t detecting the sound itself. In cortical deafness, headphones, hearing aids, or shouting do not restore understanding.
There’s no ear pain, pressure, or blockage, and ear exams may look fine. Hearing aids or wax removal don’t help because cortical deafness is a brain-based condition.
Important sounds like doorbells, smoke alarms, or a baby crying are easily missed. This can create safety concerns at home and in traffic.
How people usually first notice Cortical deafness?
People with cortical deafness are often first noticed when hearing tests look normal for the ears themselves, but they still can’t make sense of sounds or speech, as if everything goes silent despite no ear blockage. This can appear suddenly after a stroke, head injury, or brain infection, or be recognized when someone doesn’t respond to alarms, voices, or environmental sounds even though the eardrums and hearing nerves test fine. Doctors usually suspect it when brain imaging shows damage in the auditory areas of both temporal lobes and specialized tests reveal that sounds reach the brainstem but aren’t processed into meaningful hearing; these are the first signs of cortical deafness.
Types of Cortical deafness
Cortical deafness is rare and can look different depending on which parts of the brain’s hearing pathways are affected and how widespread the injury is. People with cortical deafness often have normal ear exams, but the brain can’t make sense of sound, so daily conversations, alarms, or even music may not register. Symptoms don’t always look the same for everyone. When people ask about types of cortical deafness, clinicians often describe patterns based on severity and whether meaning is lost, which helps explain the different day-to-day challenges people face.
Complete cortical deafness
People cannot consciously hear sounds even when the ears and hearing nerve are working. This is usually linked to damage in both sides of the brain’s primary hearing areas. Early symptoms of cortical deafness can include a sudden inability to detect speech or environmental sounds after a stroke or injury.
Partial cortical deafness
Some sound awareness remains, like noticing a loud clap, but speech and softer everyday sounds are missed. Conversations may feel like muffled noise, and recognizing words is very limited. Background noise often makes this worse.
Auditory verbal agnosia
People hear sounds but cannot understand spoken words, even though they can often read and write. Voices may sound clear, yet speech is like an unknown language. Non-speech sounds, like a doorbell or a dog bark, may still be recognized.
Auditory agnosia (nonverbal)
Everyday noises are heard but not identified, such as failing to recognize a ringing phone or a car engine. Speech understanding can be better preserved than recognition of environmental sounds. This can make safety cues harder to rely on.
Auditory neglect
Sounds coming from one side of space are ignored or not noticed, often after right-hemisphere brain injury. People may respond only to voices or noises on their “good” side. This can affect conversations in groups or crossing streets.
Transient or improving form
Hearing awareness and speech understanding may partially return over weeks to months as swelling settles or the brain adapts. Recovery can be uneven, with good days and harder days. Rehabilitation focuses on communication strategies and safety skills.
What genetics can tell you about symptoms
Some people with cortical deafness have damage in both auditory cortices from genetic conditions like mitochondrial disorders, causing sudden or progressive “hearing” loss despite normal ears. Variants in genes affecting brain wiring or myelin (for example, POLG or PMP22) can add speech comprehension difficulties, sound localization problems, and slowed processing.
Causes and risk factors
Major causes include strokes that harm both hearing areas, severe head injury, brain infection, or a lack of oxygen. Cortical deafness can also follow brain tumors, immune system inflammation in the brain, or carbon monoxide poisoning. Doctors distinguish between risk factors you can change and those you can’t. Risk factors for cortical deafness include high blood pressure, diabetes, and high cholesterol. Smoking, heavy alcohol use, an irregular heartbeat, older age, and a family history of stroke or clotting problems can raise risk.
Environmental and biological risk factors
Cortical deafness happens when the hearing centers in the brain are damaged, most often by events that affect both sides of the auditory cortex. Understanding risk factors can help explain why early symptoms of cortical deafness sometimes appear after a stroke, head injury, or severe lack of oxygen. Doctors often group risks into internal (biological) and external (environmental). The points below focus on those influences so you can see what tends to raise the chances.
Blood vessels become more fragile over time and strokes are more common. When both temporal lobes are affected, cortical deafness is more likely.
Long-standing high blood pressure damages brain vessels and raises the chances of blocked or bleeding strokes. If both hearing cortices are involved, cortical deafness can result.
Irregular beats such as atrial fibrillation can send clots to the brain. Clots that reach both sides of the auditory cortex increase the risk of serious central hearing loss.
Conditions that make the blood clot too easily increase brain artery blockages. Multiple strokes affecting both temporal lobes can trigger cortical deafness.
Genetic risk factors
Genetic causes of cortical deafness are uncommon, but certain inherited conditions can make the brain’s hearing centers more vulnerable to injury. Some risk factors are inherited through our genes. These include disorders that trigger stroke-like events, small-vessel changes, or developmental differences in the auditory cortex. The impact and timing can vary widely, even within the same family.
Mitochondrial disorders: In some inherited mitochondrial conditions, stroke-like episodes can injure both sides of the temporal lobes where sound is processed. Early symptoms of cortical deafness may include sudden difficulty detecting sounds despite normal ear checks. Family members can be affected differently depending on how much of the mitochondrial change they carry.
Hereditary small-vessel disease: Gene changes that stiffen or damage tiny brain arteries can cause repeated strokes in the auditory cortex. When both sides are affected, cortical deafness can occur even if the ears are healthy. A family pattern of early strokes or migraines can be a clue.
Cortical malformations: Some gene changes alter how the auditory cortex forms before birth, leading to under-developed or misplaced circuitry. This can disrupt sound awareness from infancy or early childhood. In severe, bilateral cases, this may lead to cortical deafness.
Inherited metabolic diseases: Certain genetic conditions that affect how cells break down and recycle substances can damage the cortex and nearby pathways over time. As these disorders progress, central hearing can fade and, rarely, result in cortical deafness. Early diagnosis through genetic testing can guide surveillance and support.
Familial clotting risks: Inherited clotting tendencies can raise the chance of strokes that affect both auditory cortices. The risk is usually low, but paired injuries can lead to cortical deafness. Testing is considered when strokes occur at a young age without a clear cause.
Chromosome changes: Missing or extra pieces of DNA that include brain-development genes can increase the chance of bilateral temporal-lobe differences. Depending on which genes are involved, central hearing may be mildly affected or, rarely, severely impaired. Genetic counseling can clarify what a specific change means for relatives.
Family history signals: Multiple relatives with central hearing problems, unexplained language loss, or early strokes can suggest a shared inherited cause for cortical deafness. This pattern helps doctors choose the right genetic tests. Awareness of risks can be empowering for families planning ahead.
Lifestyle risk factors
Cortical deafness is often a downstream result of bilateral strokes or severe head injury, so habits that influence vascular health and safety are key. Addressing modifiable behaviors can lower the chances of those triggers and improve overall brain resilience. Below are the main lifestyle risk factors for Cortical deafness through their impact on stroke and traumatic brain injury risk.
Tobacco accelerates atherosclerosis and increases blood clotting, raising the chance of strokes that can injure auditory cortex. Quitting reduces stroke risk within months and continues to compound benefits over years.
Binge or chronic heavy drinking elevates blood pressure and atrial fibrillation risk, driving both ischemic and hemorrhagic strokes. Limiting intake to low-risk levels reduces these hazards.
Cocaine, amphetamines, and similar stimulants cause vasospasm and hypertensive surges that sharply increase stroke risk. Avoidance substantially lowers the chance of sudden brain injury.
High sodium, added sugars, and trans or saturated fats worsen hypertension, diabetes, and dyslipidemia that predispose to stroke. A Mediterranean-style pattern with vegetables, legumes, whole grains, and unsalted nuts supports vascular health.
Risk prevention
Cortical deafness usually happens when both sides of the brain’s hearing areas are damaged, most often by stroke, severe head injury, or infections that affect the brain. Prevention focuses on lowering your risk of those brain injuries and acting fast if warning signs appear. Prevention can mean both medical steps, like vaccines, and lifestyle steps, like exercise. Small, steady habits—plus timely medical care—offer the best protection.
Keep blood pressure in a healthy range to reduce stroke risk that can injure the brain’s hearing centers. Check it regularly and treat high readings with lifestyle changes and medicines if needed.
If you have atrial fibrillation or other irregular rhythms, stroke risk rises. Ask about blood thinners and rhythm control to protect brain blood flow.
Keeping blood sugar and LDL cholesterol in target ranges helps prevent vessel damage that leads to stroke. Use food choices, activity, and medications as advised to stay on track.
Smoking damages blood vessels and greatly raises stroke risk. Quitting lowers that risk fairly quickly and improves overall brain health.
Transmission
People often ask if cortical deafness is contagious; it isn’t. Cortical deafness cannot be transferred from one person to another by touch, droplets, sex, or blood because it results from damage to the brain’s hearing centers, most often after a stroke, severe head injury, or lack of oxygen. If a brain infection caused the injury, that infection may have been contagious, but cortical deafness itself does not spread. Because cortical deafness is usually acquired rather than inherited, family members and close contacts are not at increased risk; in the uncommon situations tied to developmental brain differences, a genetic counselor can discuss the family’s specific situation.
When to test your genes
Test your genes if hearing loss appears suddenly without clear ear damage, runs in your family, or started early in life—especially with balance, vision, or neurological changes. Genetic results can confirm a diagnosis, guide imaging and specialist care, and flag risks for relatives. If you’re planning a family, testing can inform reproductive options.
Diagnosis
You might notice sudden trouble hearing everyday sounds even though your ears and hearing aids seem fine. Cortical deafness affects how the brain processes sound, so the first clues often come from daily moments—missing a doorbell or not reacting to loud noises. Tests may feel repetitive, but each one helps rule out different causes. Here’s how cortical deafness is diagnosed and what your care team may check next.
Your provider asks when hearing changes began and what they look like day to day. They also review past strokes, head injuries, infections, or migraines that could affect the hearing centers in the brain.
A careful look at the ear canal and eardrum helps rule out blockages or infection. Normal findings here point attention toward the brain rather than the outer or middle ear.
Pure-tone audiometry and tympanometry check how well sound travels through the ears. Many people with cortical deafness show results that don’t match what they’re experiencing, suggesting a central (brain) cause.
These quick measures assess the inner ear’s hair cell function. Normal emissions support that the ears themselves work, guiding the diagnosis of cortical deafness toward the brain level.
Stages of Cortical deafness
Cortical deafness does not have defined progression stages. It usually follows a sudden brain event—such as a stroke or head injury affecting both sides of the brain’s hearing centers—so any changes over time reflect the injury and recovery pattern, not a predictable step-by-step course. Early symptoms of cortical deafness can include not reacting to everyday sounds even when the ears and standard hearing checks seem normal. Different tests may be suggested to help confirm what’s going on, such as a detailed hearing assessment, brain imaging (MRI or CT), and brainwave-based hearing checks, with follow-up visits to monitor any improvement.
Outlook and prognosis
Many people ask, “What does this mean for my future?”, especially after being told they have cortical deafness. Day to day, people with cortical deafness often rely on visual cues, written communication, and assistive tech; with practice, conversations, work meetings, and travel can become more manageable. The outlook is not the same for everyone, but the cause of the brain injury and how much of the auditory cortex is affected usually shape recovery.
Prognosis refers to how a condition tends to change or stabilize over time. Some people regain limited awareness of sound or make gains through rehabilitation, while others remain unable to consciously perceive sounds despite normal ear function. If cortical deafness stems from a single, small stroke and therapy starts quickly, partial improvement is more likely than when both sides of the auditory cortex are damaged or when injuries are ongoing, such as repeated strokes. Early symptoms of cortical deafness can be subtle after a mild injury—like hearing a noise without recognizing it—and careful follow-up helps track change.
With ongoing care, many people maintain safety and independence by adapting their environment—vibrating or flashing alarms, captioned media, and clear communication plans with family and coworkers. Mortality depends on the underlying cause rather than cortical deafness itself: risks come from the brain event that led to it (for example, stroke, severe head trauma, or a lack of oxygen), along with any related conditions like heart disease. Looking at the long-term picture can be helpful. Talk with your doctor about what your personal outlook might look like, including whether further brain imaging, hearing tests, or speech-language therapy could support recovery and day-to-day life.
Long-term effects
Cortical deafness happens when the hearing parts of the brain are injured, so sounds are not consciously heard even if the ears are working. Long-term effects vary widely, depending on the cause, the size of the injury, and time since it happened. Many people notice early symptoms of cortical deafness right after a stroke or head injury, and the long-term picture often includes lasting difficulty detecting speech and everyday sounds. Some regain partial awareness of sounds over months, while others have persistent gaps that change how they communicate and navigate daily life.
People may not consciously hear voices, music, or alarms even with normal ear tests. The brain does not register sound input reliably. In cortical deafness, this can be constant or fluctuate.
Understanding spoken words can remain very limited. Some later shift from complete unawareness to word deafness, recognizing tones or rhythms but not meaning.
Everyday noises like phones, sirens, or footsteps may be missed or misidentified. This affects orientation and situational awareness.
Many rely more on lip-reading, captions, and written notes to connect. Conversations in groups or noisy places remain especially challenging in cortical deafness.
How is it to live with Cortical deafness?
Living with cortical deafness can feel confusing because hearing tests may show that the ears pick up sound, yet the brain does not recognize it as meaningful. Day to day, many rely on visual cues, written communication, and structured routines to navigate conversations, alarms, and safety signals, and some find that sudden noises still startle without conveying information. For family, friends, and coworkers, clear visual attention, face-to-face communication, captioning, and patience make interactions smoother and less tiring for everyone. With planning, assistive technology, and supportive communication habits, many build dependable systems that reduce frustration and help keep life social, safe, and active.
Treatment and drugs
Cortical deafness is treated by focusing on what helps you communicate and stay safe day to day, because there’s no proven medicine or surgery that reliably restores hearing when the brain’s sound-processing areas are affected. Care usually centers on intensive speech and language therapy, auditory rehabilitation, and alternative communication methods like lip-reading, sign language, or text-to-speech tools; hearing aids or cochlear implants generally don’t help unless there is a separate inner-ear problem. You might picture this as a team effort between you and your doctor, with neurologists, audiologists, and speech-language therapists working together to tailor training and devices to your needs. Addressing related issues—such as stroke risk factors, seizures, migraines, or mood changes—can also improve daily function; a doctor may adjust your dose to balance benefits and side effects if medicines are used for those conditions. Supportive care can make a real difference in how you feel day to day, so ask your doctor about the best starting point for you.
Non-drug treatment
Day-to-day life with cortical deafness can change how you communicate, work, and stay safe at home and in public. Beyond prescriptions, supportive therapies can build new communication pathways and strengthen other senses that help you understand speech and sound cues. Early symptoms of cortical deafness can be subtle—like struggling to follow conversation in quiet rooms—so tailored support is key. Plans are individualized and may evolve over time as skills improve or needs shift.
A speech-language pathologist helps build practical communication routines and compensatory skills. Training often focuses on clear articulation, paced conversation, and using context to fill gaps. Family coaching is usually part of care.
Structured listening exercises aim to strengthen any remaining sound awareness and pattern recognition. Sessions may pair sounds with visual or touch cues to reinforce learning. Progress is tracked and adjusted over time.
Systematic lip-reading practice teaches you to read mouth movements, facial expressions, and gestures. This can make face-to-face conversations smoother and less tiring. Good lighting and steady pacing boost success.
Learning sign language or using augmentative and alternative communication (AAC) offers a reliable backup or primary method. Options range from basic signs and picture boards to text-based devices. Not every approach works the same way, so personal fit matters.
Your genes may have an impact on how drugs work for you
Medicines used around cortical deafness—like seizure control, stroke prevention, or mood and sleep support—can work differently because gene variants affect how fast your body activates, breaks down, or transports them. Genetic testing sometimes guides safer dosing, reduces side effects, and avoids drug interactions.
Pharmacological treatments
There’s no single medicine that restores hearing in cortical deafness. Treatment focuses on the cause—such as stroke, seizures, inflammation, infection, or migraine—and on complications like brain swelling or mood changes. Drugs that target symptoms directly are called symptomatic treatments. When cortical deafness follows a stroke, time-sensitive therapies may help protect brain tissue.
Alteplase (tPA) or tenecteplase can dissolve a clot in an ischemic stroke when given very early. If early symptoms of cortical deafness appear with sudden stroke signs, emergency treatment may limit damage.
Aspirin or clopidogrel helps prevent new clots after an ischemic stroke. These are often started once brain bleeding has been ruled out.
Apixaban, rivaroxaban, dabigatran, or warfarin reduce stroke risk when cortical deafness stems from a cardioembolic source like atrial fibrillation. Dosing and choice depend on kidney function, bleeding risk, and other medications.
Levetiracetam, lamotrigine, or valproate treat seizures that can accompany temporal lobe injury. Preventing seizures protects the healing brain and can stabilize attention and memory.
Genetic influences
Most cases of cortical deafness are not inherited; they usually follow damage to the brain’s hearing centers from events like stroke, infection, or head injury. Genetics is only one piece of the puzzle, but it can shape a person’s underlying risk for these brain changes. Rare inherited conditions that affect small blood vessels, the brain’s wiring (myelin), or the way cells make energy can make strokes or inflammation more likely in the areas that process sound. Very rarely, differences in brain development present from birth—sometimes tied to gene changes—can lead to cortical deafness or severe auditory processing problems. Genetic testing is usually considered when cortical deafness appears at a young age, when other unexplained neurological symptoms are present, or when several relatives have similar issues. While genetics doesn’t change the early symptoms of cortical deafness, understanding family history can guide which evaluations to consider and how to manage risk factors.
Is Cortical deafness genetic?
Genetics plays a limited role in cortical deafness. Most cases result from acquired brain injury (e.g., stroke, trauma), though rare inherited conditions affecting brain development or metabolism can contribute. Genetic testing is considered when onset is early or syndromic.
Pharmacogenetics—how genetics influence drug effects
Cortical deafness is most often the result of brain injury, so genes usually don’t cause it, but they can shape how you respond to medicines used in care and recovery. If the hearing loss followed a stroke, certain inherited differences can make the blood thinner clopidogrel work poorly, so your team may choose a different antiplatelet or strategy. With warfarin, gene differences that affect vitamin K pathways can change the dose you need and your bleeding risk. If seizures occur, specific HLA types can raise the chance of severe skin reactions with carbamazepine or phenytoin, and testing may guide safer options, particularly in people of Asian ancestry. Genes can influence how quickly you process some antidepressants, opioid pain relievers like codeine and tramadol, and other medicines used during rehabilitation, which can affect side effects and benefit. Pharmacogenetic results do not replace clinical judgment; they’re usually used alongside your diagnosis, other medicines, and regular follow-up to make the drugs around cortical deafness care safer and more effective.
Interactions with other conditions
Cortical deafness often appears after a stroke or serious head injury, so it commonly coexists with other brain-related issues like trouble finding words, slowed thinking, or seizures. Doctors call it a “comorbidity” when two conditions occur together. When epilepsy or migraine is present, brief spells may further disrupt how sounds are noticed or understood, and mood conditions like anxiety or depression can add fatigue and make communication feel more draining. If there’s also peripheral hearing loss or long-standing ear disease, hearing devices may help those parts, but cortical deafness limits how well the brain can make sense of the sound; some medicines used for seizures, sleep, or anxiety can also blunt attention and listening effort. Watching for early symptoms of cortical deafness alongside any warning signs of stroke or new neurologic changes can guide faster evaluation and more coordinated care across neurology, audiology, and rehabilitation.
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 sudden silences after illness or injury—voices moving, lips shaping words, yet no sound reaching awareness. Families and communities once noticed patterns: after a severe fever, a head trauma, or a stroke, someone who previously heard well could no longer make sense of any sound, even though the ears themselves looked healthy.
First described in the medical literature as a puzzling mismatch between normal ear exams and profound hearing loss, cortical deafness gradually became understood as a problem in the brain’s hearing centers rather than in the ear. Early neurologists documented cases following strokes that affected both sides of the brain’s auditory regions. Initially understood only through symptoms, later physicians added autopsy findings and, eventually, brain scans to show where sound processing had broken down.
From early theories to modern research, the story of cortical deafness reflects advances in brain science. In the late 19th and early 20th centuries, doctors debated whether people were truly “deaf” or unable to recognize sounds; careful bedside testing showed that even simple noises—claps, bells, or spoken words—were not perceived at all. As medical science evolved, reports distinguished cortical deafness from related conditions like auditory agnosia (hearing a sound but not recognizing its meaning) and pure word deafness (hearing sounds but not understanding speech).
With the arrival of electroencephalography and, later, CT and MRI, clinicians could link new hearing problems to specific injuries in the temporal lobes. These tools confirmed what earlier observers suspected: damage to both sides of the brain’s auditory pathways is usually required for true cortical deafness. In recent decades, awareness has grown as stroke care improved and more people survived, allowing doctors to recognize this rare outcome sooner.
Over time, descriptions became more nuanced. Some people with cortical deafness showed partial recovery, moving from complete unawareness of sound to limited detection or recognition; others remained profoundly affected. Rehabilitation stories—learning to rely on lip-reading, written communication, or tactile cues—added a human dimension to the clinical notes. Historical differences highlight why careful testing matters: what looks like typical hearing loss on first glance can, in rare cases, be a brain-based disorder.
Today, the history of cortical deafness guides practical care. Knowing the condition’s history helps clinicians separate it from peripheral hearing problems, choose the right brain imaging, and set realistic expectations for recovery. Each stage in history has added to the picture we have today, shaping how teams support people living with cortical deafness and their families after a life-changing silence.