Neurological Tinnitus

Tinnitus is the perception of sound in the ear when there is no external source. Tinnitus isn’t considered a medical issue. Instead, it’s considered a symptom. It’s usually a sign that something is wrong with your auditory system.

Tinnitus noises can manifest as ringing, clicking, whooshing, thumping, humming, buzzing, or roaring. The frequency or degree of the noise is dependent on its underlying cause. The pitch of the noise also varies.

In some cases, the tinnitus noise can be low and negligible. In others, the noise can be so high that it interferes with daily activities. Tinnitus can affect one or both ears. Depending on the cause, tinnitus can be temporary or permanent.

Common causes of tinnitus are sudden or constant exposure to loud sounds, earwax blockage, trauma or injury to the head, growth of tumors in the ear, autoimmune inner ear diseases, ototoxic medications, and ear infections.

Besides ringing in the ear, tinnitus can be accompanied by other symptoms like an inability to concentrate, difficulty sleeping, and an inability to hear conversations, especially in crowded places.

The Structure of the Ear

Our ears are responsible for hearing and balance. Each ear is divided into three major parts: the outer, middle, and inner ear.

The Outer Ear

The outer ear, also known as the external ear, consists of two major parts: the earlobe and the pinna. The pinna is skin and cartilage, and it’s the shell-like part of the external ear that directs sound waves outside the ear into the auditory canal.

The ear canal transmits the sound wave to the eardrum, which vibrates when the sound hits it. The eardrum or tympanic membrane is a thin membrane that separates the outer and middle ear.

The Middle Ear

The middle ear is an air-filled space between the outer and inner ear that contains three tiny bones, also known as ossicles. The three ossicles are called incus, stapes, and malleus. These three bones form a link between the eardrum and the inner ear through the cochlea.

When the eardrum begins to vibrate, it transmits the vibration to the ossicles. The ossicles amplify the sound and transmit the vibration to a thin membrane between the middle and inner ear known as the oval window.

The Inner Ear

The inner ear contains two major structures; the cochlea and three semicircular canals. 

The cochlea, which is responsible for hearing, is filled with fluids and also contains the Corti. The Corti holds thousands of specialized sensory hair cells.

When vibrations get to the inner ear, the inner ear fluid forms tiny waves. These tiny waves make projections in the hair cells known as cilia vibrate. The hair cells convert this vibration into nerve signals or impulses and send them to the brain, interpreting them as sound.

The semicircular canals also contain hair cells. Unlike cochlea’s hair cells, these hair cells detect movement. 

When your head moves, the fluid in the semicircular canals moves. The hair cells detect this movement, and then they send nerve impulses about the body’s position and head relative to gravity to your brain.

This lets your body make the changes in posture necessary to help you stay balanced. When this function is interrupted, you can experience vertigo or loss of balance.

Types of Tinnitus

Tinnitus is classified based on the type of sound patients experience and the tinnitus’s cause. Below are common types of tinnitus:

1. Subjective Tinnitus

Subjective tinnitus is the most common type of tinnitus. It is also known as non-vibratory or non-auditory tinnitus. Only tinnitus patients can hear the subjective tinnitus noise.

Exposure to loud sounds often causes subjective tinnitus, which can lead to hearing loss. Subjective tinnitus can appear and disappear suddenly, and it can last for 3 to 12 months. 

In cases where the inner ear’s hair cells are damaged, the tinnitus can become permanent or degenerate to hearing loss.

2. Objective Tinnitus

Objective tinnitus, also known as vibratory tinnitus or pseudo-tinnitus, is a rare kind of tinnitus caused by involuntary movements, twitching, or muscle contractions.

Eustachian tube dysfunction, neurologic disease, or muscle spasms around the middle ear can cause objective tinnitus. Unlike subjective tinnitus, accurate tinnitus sounds can be heard by an external observer.

In most cases, the tinnitus noise in the ear will disappear when the cause of the tinnitus is identified and treated.

3. Pulsatile Tinnitus

Tinnitus can present itself as a rhythmic noise that aligns with q tinnitus patient’s heartbeat. A change in the blood flow in the blood vessels close to the ear is usually the culprit. Pulsatile tinnitus is also known as synchronous pulse tinnitus, vascular tinnitus, or rhythmic tinnitus.

Pulsatile tinnitus is often a loud and distracting whooshing or thumping sound. A change in blood flow or difficulty in the blood vessels closest to the ear can also cause this type of tinnitus.

4. Neurological Tinnitus

Neurological tinnitus refers to two different aspects of tinnitus. Disorders like Meniere's disease that primarily affect the brain's auditory functions cause neurological tinnitus. 

The term neurological tinnitus can also describe how auditory nerves react to hearing loss. 

While during objective tinnitus, the patient hears actual sounds produced by disturbances in the cardiovascular system, in most tinnitus cases, patients think they hear sounds because of neurological dysfunction.

Understanding Neurological Tinnitus

It’s important to know what a neurological disorder or disease is to understand neurological tinnitus.

A neurological disorder is a disorder that affects the brain and the nerves found throughout the body and the spinal cord. Neurological disorders are often accompanied by muscle weakness, loss of sensation, poor coordination, and paralysis.

Causes of neurological problems include genetic disorders, congenital abnormalities or disorders, brain injury, spinal cord injury, nerve injury, degeneration, trauma, brain tumor, and malnutrition.

Neurological diseases can affect vision, cognition, movement, communication, or hearing, depending on where the damage happened or the nerve affected. In neurological tinnitus, the part of the brain responsible for receiving sound signals is affected.

Neurological Causes of Tinnitus

Neurological causes of tinnitus include head injury, multiple sclerosis, acoustic neuroma, syphilis, meningitis, whiplash, cerebellopontine-angle tumors, infections such as Lyme disease, and otitis media.

Damaged Hearing

When someone has normal hearing, neurological activity goes unnoticed. When your hearing is damaged or diminished, this neurological activity is "uncovered."  

The brain automatically turns up sensitivity in the hearing system to compensate during hearing loss, so a patient perceives neural activity as sound.  

Additionally, the brain engages a filtering mechanism that readily detects tinnitus among other signals along the auditory pathways. The increase in the tinnitus patient’s intensity makes the tinnitus patient more uncomfortable, which results in anxiety and stress. 

Anxiety and stress can further worsen tinnitus, so doctors occasionally prescribe anti-anxiety drugs to tinnitus patients.

Meniere’s Disease

Disorders like Meniere's disease can cause neurological tinnitus because they affect the brain's auditory functions. As you move your head, the inner ear fluid (endolymph) moves. Movement causes nerve receptors to signal the brain. 

With Meniere's disease, a buildup of endolymph interferes with balance and hearing signals between the ear and the brain. One result is tinnitus. Fluid volume changes because of things like:

  • Genetic predisposition

  • Blockage or anatomic abnormality leading to drainage problems

  • Abnormal immune response

  • Infection

The disease usually only affects one ear, and typically patients are in their 40s or 50s. Depending on the cause of the endolymph changes, medication or lifestyle changes can improve symptoms. It’s a chronic condition, but the disease often goes into periods of remission. 

While doctors usually use the phrase neurological tinnitus to talk about tinnitus caused by something like Meniere's Disease, they also use the term to differentiate between objective tinnitus caused by cardiovascular problems and subjective tinnitus. 

Tinnitus Treatments

Depending on the causes, tinnitus can be temporary or permanent. The duration of tinnitus is dependent on its underlying cause.

Tinnitus caused by earwax blockage often disappears after removing the earwax because the earwax merely blocked the ear canal and prevented sound from passing through; little or no damage was done to the ear.

If a more serious medical condition like an autoimmune inner ear disease or Meniere's disease caused the tinnitus, the likelihood of the tinnitus being permanent is higher. If prompt medical attention is not given to the ear, underlying conditions can permanently damage the ear’s structures.

Although there is no cure for tinnitus, certain treatments and therapies can help alleviate the clinical symptoms and make it possible for tinnitus patients to go about their daily activities without much interference.

An ENT doctor often prescribes treatment or therapy after conducting an audiological test. Below are commonly recommended tinnitus therapies:

1. Treating the Underlying Cause

If a blood vessel condition causes tinnitus, treating the blood vessel condition with the appropriate medication or surgery can expel the tinnitus.

Similarly, if tinnitus is caused by an ototoxic medication, discontinuing the medication will make the tinnitus disappear. The same applies to tinnitus caused by earwax blockage; once you remove the ear wax, tinnitus symptoms will disappear.

2. Noise Suppression

Since permanent tinnitus cannot be cured, your doctor may recommend devices to suppress the tinnitus noise. Devices used for noise suppression in tinnitus patients are called masking devices or white noise machines.

Masking devices are machines that produce environmental or static sounds. This effectively helps manage neurological tinnitus, where the noise from background neurological activities causes the sound.

White noise devices help create enough background sound to make the noise from neurological activities less obvious.

In the absence of real noise-masking devices, you can use fans, air conditioners, and humidifiers to produce white noise.

Masking devices are similar to hearing aids; they produce a continuous low-level white noise, suppressing the tinnitus noise and making it less noticeable.

3. Counseling

Considering the effect of tinnitus on patients’ emotional and psychological health, counseling is often a part of the recommended therapies.

Counseling aims to help tinnitus patients change how they perceive, think, or feel about their symptoms. This makes the tinnitus more bearable.

The major counseling options for tinnitus are cognitive behavioral therapy and tinnitus retraining therapy.

Cognitive Behavioral Therapy is carried out by a licensed psychologist who teaches tinnitus patients coping techniques that will enable them to complete their daily activities without difficulty.

Tinnitus Retraining Therapy (TRT) combines sound masking devices and counseling by a trained professional or an audiologist. The tinnitus patient receives a masking device to reduce the tinnitus symptoms while receiving counseling.

Besides helping with tinnitus, counseling can help patients cope with other problems linked to tinnitus, such as depression and anxiety.

4. Medications

Even though there is no specific medication for tinnitus, certain medications such as antidepressants and anti-anxiety drugs are often prescribed to tinnitus patients. Most tinnitus patients suffer anxiety and depression.

The relationship between tinnitus and anxiety is circular; tinnitus noise causes anxiety, and anxiety increases tinnitus.

Medications that combat anxiety and depression help alleviate the tinnitus symptoms by breaking this cycle.

Conclusion

As you already know, neurological tinnitus is caused by the brain problem, not the ears. That’s why it’s not possible for you to self-medicate.

“Nothing replaces a full and complete medical evaluation by a trained ENT doctor for symptoms of tinnitus.” - Drew Sutton, MD, Board-Certified Otolaryngologist.

Identifying the exact cause of tinnitus and prescribing the appropriate treatment is the work of an audiologist or a healthcare professional. It’s important always to visit your doctor when you experience ringing or other noises in your ear.



Sources:

Tinnitus | NHS

Tinnitus: Characteristics, Causes, Mechanisms, and Treatments | NCBI

Tinnitus Treatment Options | ATA

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Drew Sutton M.D.

Drew Sutton, MD is a board-certified otolaryngologist. He has extensive experience and training in sinus and respiratory diseases, ear and skull base surgery, and pulmonary disorders. He has served as a Clinical Instructor at Grady Hospital Emory University for more than 12 years.

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