Low Frequency Hearing Loss: What It Is and What You Can Do

Globally, approximately 466 million people experience some form of hearing loss, with projections suggesting this number could double by 2050. Low frequency hearing loss is no exception to this. There are various triggers and causes of this condition, but it’s understood that hearing loss prevalence increases with age.

In this guide, we’ll define low frequency hearing loss and understand its impact on patients. We’ll also discover the types of low frequency hearing loss, who is more likely to experience them, and the available treatment options.

Defining Low Frequency Hearing Loss

Low-frequency hearing loss (LFHL) is a condition where individuals struggle to hear sounds in the low-frequency range, typically between 20 to 200 Hz. It is one of the signs of hearing loss and various underlying conditions.

Also called reverse slope hearing loss, LFHL is less common than high frequency hearing loss, which impairs the ability to hear high-frequency sounds. It appears as a downward slope on an audiogram, with more hearing loss in lower frequencies. Many don’t notice it early since speech clarity is mostly intact. However, background noise can make conversations harder to follow.

Below are more specific examples of what you cannot hear if you have LFHL.

What You Cannot Hear

People with LFHL may struggle to hear deep or rumbling sounds. Examples include:

• Male voices, especially over the phone.

• Bass sounds or tones in music.

• Thunder, heavy machinery, or distant traffic.

• Vowel sounds like “o” and “u,” which carry lower frequencies.

• Background hums from air conditioners or refrigerators.

Impact on Daily Life

Phone calls can be frustrating since lower-pitched voices sound muffled. In group settings, background noise can overpower speech, making conversations harder to follow. Alarm tones, like deep sirens or car engine sounds, may go unnoticed, posing safety risks. Some find relief with a hearing aid in Toronto, but processing low tones can still be difficult. Speech recognition depends on the severity of hearing loss and how well the brain adapts to amplified sound.

Parts of the Ear

Understanding the auditory system helps explain low frequency hearing loss. Sound waves travel through the outer ear, down the ear canal, and into the middle ear, where three tiny bones amplify sound vibrations. These vibrations reach the inner ear, where hair cells are crucial in detecting different sound frequencies. The auditory nerve then transmits these signals to the brain for processing. If any part of this system is damaged, it can lead to conductive hearing loss or sensorineural hearing loss.

Low Frequency Hearing Loss Types

Toronto hearing tests help identify low-frequency hearing loss, specifically through the use of an audiogram, by showing a pattern where the line on the graph starts at the lower left and slopes upward. There are two general types of low frequency hearing loss: conductive and sensorineural. Both affect low-pitched sounds but differ in causes and treatment.

Conductive Hearing Loss

Conductive low-frequency hearing loss occurs when sound waves cannot travel efficiently through the ear canal, middle ear, or outer ear. Common causes include ear infections, fluid buildup, or structural issues like a perforated eardrum. In many cases, medical treatment or surgery can restore hearing.

Sensorineural Hearing Loss

Sensorineural low-frequency hearing loss is caused by damage to the inner ear or auditory nerve, leading to a decreased ability to hear low-pitched sounds. It is often linked to genetic conditions or aging-related hearing loss. Unlike conductive hearing loss, this type is usually permanent, but hearing aids or cochlear implants may help.

Causes of Conductive Low Frequency Hearing Loss

Conductive low-frequency hearing loss can result from blockages, structural abnormalities, or infections that disrupt the movement of sound vibrations.

Otosclerosis

Otosclerosis is a condition where abnormal bone growth in the middle ear stiffens the tiny bones responsible for sound transmission. This reduces their ability to vibrate properly, leading to gradual hearing loss, often affecting low frequencies first.

Serous Otitis Media

Also known as secretory otitis media, this condition happens when fluid accumulates in the middle ear due to infections, allergies, or Eustachian tube dysfunction. The trapped fluid dampens sound waves, making low-pitched sounds harder to hear until the fluid drains or is treated.

Causes of Sensorineural Low Frequency Hearing Loss

Various factors can contribute to sensorineural low frequency hearing loss, ranging from natural aging to genetic disorders and sudden medical conditions.

Aging

Over time, the tiny hair cells in the inner ear deteriorate, reducing their ability to detect and transmit low-frequency sounds. This gradual decline is a common part of age-related hearing loss, though its severity varies from person to person.

Sudden Hearing Loss

A sudden drop in hearing can result from viral infections, exposure to loud noises, or a rapid decrease in cerebrospinal fluid pressure. This abrupt change often requires immediate medical attention to prevent permanent damage.

Cerebrospinal Fluid Pressure

Low cerebrospinal fluid (CSF) pressure can interfere with inner ear function, affecting sound processing and balance. This condition may develop due to head trauma, spinal leaks, or certain neurological conditions.

Genetic Disease

Inherited conditions can contribute to LFHL from birth or emerge later in life. Some disorders specifically affect cochlear development or the auditory nerve, making low-pitched sounds harder to perceive.

Mondini Dysplasia

This congenital condition occurs when the cochlea is not fully developed, leading to incomplete sound transmission. Individuals with Mondini Dysplasia often experience fluctuating or progressive hearing loss.

Ramsay Hunt Syndrome

Caused by the varicella-zoster virus, this syndrome can lead to facial paralysis and inner ear damage. Hearing loss from Ramsay Hunt Syndrome is often accompanied by vertigo and tinnitus.

Wolfram Syndrome

A rare genetic disorder, Wolfram Syndrome is linked to diabetes mellitus and progressive hearing loss. Individuals with this condition may experience worsening low-frequency hearing impairment over time.

Ménière’s Disease

Ménière’s disease affects the inner ear, causing episodes of vertigo, tinnitus, and fluctuating hearing loss. It often impacts low frequencies first, making deep sounds and voices harder to detect.

Low Frequency Hearing Loss Diagnosis

Audiologists use specific tests to assess low-frequency hearing loss and determine its cause. Key diagnostic steps include:

1. Pure-Tone Audiometry – Measures hearing thresholds at various frequencies. LFHL appears as a downward slope in the low-frequency range.

2. Speech Audiometry – Evaluates speech perception, especially in background noise, to detect how LFHL affects communication.

3. Tympanometry – Tests middle ear function by measuring eardrum movement, helping diagnose conductive LFHL caused by fluid buildup or otosclerosis.

4. Otoacoustic Emissions (OAE) Test – Assesses inner ear hair cell function, detecting sensorineural causes like Ménière’s disease or genetic disorders.

5. Auditory Brainstem Response (ABR) Test – Examines nerve pathways between the inner ear and brain to rule out neurological conditions.

6. Imaging Tests (MRI/CT Scan) – Identifies structural issues, tumors, or inner ear abnormalities contributing to LFHL.

7. Cerebrospinal Fluid (CSF) Pressure Test – Determines if fluid imbalances are affecting inner ear function.

Get Tested for Low Frequency Hearing Loss

If you experience subtle symptoms like difficulty hearing deeper sounds or group conversations, a hearing test from an audiologist is essential. A free hearing test may be available through national health programs or hearing health organizations.

Low Frequency Hearing Loss Treatment

Early diagnosis by an audiologist helps prevent worsening hearing loss and guides treatment options. If you struggle to hear deep sounds, seek professional evaluation promptly.

Hearing Aids

Hearing aids provide considerable support for those with low frequency hearing impairment, helping to amplify deeper sounds. Some cases may also benefit from cochlear implants if hearing aids do not provide enough improvement.

What Else You Can Do

Lifestyle changes such as avoiding loud noise, managing risk factors like diabetes mellitus, and seeking professional advice from an audiologist can help maintain hearing health. Speech therapy may also improve speech clarity and help individuals understand speech better in challenging listening environments.

Conclusion

Low frequency hearing loss can make it difficult to hear sounds that are important for communication and daily life. While it may not always be as recognized as high frequency hearing loss, treatment options like hearing aids, speech therapy, and medical intervention can provide considerable support. If you notice a decreased ability to hear phone conversations and low pitch sounds, seek professional advice and get a hearing test. Early intervention can help improve speech quality and preserve your ability to hear properly.