Common Questions About Acoustic Neuroma

### What Exactly Is an Acoustic Neuroma?

You’ve probably first encountered the term “acoustic neuroma” while Googling mysterious ear symptoms, or perhaps you’ve heard it mentioned in a medical context and are now piecing together the puzzle. It’s understandable to feel a bit lost when faced with a medical diagnosis or a new medical term. Let’s break down exactly what an acoustic neuroma is, so you can feel more informed and less adrift.

It’s a Tumor, But Not Usually Cancerous

The most crucial thing to understand right off the bat is that an acoustic neuroma is a tumor. However, the word “tumor” often conjures images of aggressive, life-threatening cancers. This is where the nuance comes in. Acoustic neuromas are almost always benign, meaning they are non-cancerous. They grow slowly and do not spread to other parts of the body. The primary concern with acoustic neuromas isn’t their metastatic potential, but rather the problems they can cause due to their location and their gradual growth.

Where Does It Grow? Understanding the Vestibular Schwannoma Connection

The term “acoustic neuroma” is actually a bit of a misnomer, which can add to the confusion. Technically, these tumors arise from the Schwann cells that produce the myelin sheath, a protective covering, around nerves. The nerve most commonly affected is the vestibular nerve, which is responsible for your sense of hearing and balance.

Vestibular Schwannoma: This is the more medically accurate term for the tumor. It highlights that the tumor originates from the Schwann cells of the vestibular nerve.
Acoustic Nerve: While the vestibular nerve is the primary site, the tumor can often extend to involve the adjacent cochlear nerve (responsible for hearing) and sometimes even the facial nerve. Because it affects the “acoustic” (hearing) function, the term “acoustic neuroma” became popular and sticks.

So, while you might hear both terms, know that they generally refer to the same condition. The growth typically begins in the internal auditory canal, a small, bony tunnel within the skull that houses the vestibular and cochlear nerves, along with the facial nerve. As it grows, it can then extend into the cerebellopontine angle (CPA), a space at the base of the brain.

What’s the Difference Between a Neuroma and a Schwannoma? (Spoiler: Not Much Here)

You might wonder about the subtle distinction between “neuroma” and “schwannoma.” In the context of acoustic neuromas, these terms are often used interchangeably, and for good reason. A neuroma is a general term for a tumor of nerve tissue. A schwannoma is specifically a tumor of the Schwann cells. Since acoustic neuromas are tumors of Schwann cells that affect the nerve, “vestibular schwannoma” is more precise, but “acoustic neuroma” accurately describes the common symptoms and affected nerve. Don’t let the terminology itself be a source of anxiety; focus on the nature of the growth.

The Slow and Steady Approach to Growth

One of the defining characteristics of acoustic neuromas is their slow rate of growth. For many people, these tumors can exist for years, even decades, without causing significant symptoms or being detected. However, the slow growth means that as the tumor gets larger, it exerts increasing pressure on the surrounding nerves and structures. This pressure is what ultimately leads to the symptoms you might be experiencing or concerned about. The size of the tumor at diagnosis can vary widely, from a few millimeters to several centimeters.

### What Are the Most Common Symptoms of an Acoustic Neuroma?

Recognizing the symptoms is often the first step you’ll take on the path to diagnosis. Because acoustic neuromas grow slowly and press on delicate nerves, the symptoms tend to develop gradually and can be subtle at first. For many, they might be dismissed as signs of aging, stress, or other common ailments. However, if you notice a persistent or progressively worsening combination of these symptoms, it’s worth investigating.

The Big Three: Hearing Loss, Tinnitus, and Dizziness

These three symptoms are the most frequently reported by individuals with acoustic neuromas and are often closely linked due to the tumor’s location affecting the auditory and vestibular systems.

Hearing Loss: This is the most common symptom and typically affects one ear (unilateral). You might notice a gradual decline in your ability to hear, particularly high-frequency sounds. It might be described as:
Difficulty understanding speech, especially in noisy environments.
A feeling that the affected ear is “muffled” or not picking up sounds as well as it used to.
Needing to turn up the volume on the TV or phone more than usual when using one ear.
Being unable to localize the source of sounds as effectively.
It’s important to note that this hearing loss is often sensorineural, meaning it originates from damage to the inner ear or the auditory nerve itself, rather than a blockage in the ear canal or middle ear.

Tinnitus: This refers to the perception of ringing, buzzing, hissing, or other sounds in one ear that aren’t externally produced. For many, this is the first symptom they notice. The quality and loudness of the tinnitus can vary greatly from person to person. It can be constant or intermittent, and it can sometimes be quite distressing, impacting sleep and concentration.

Dizziness or Vertigo: This symptom relates to problems with balance. You might experience:
A feeling of spinning (vertigo) or unsteadiness.
Lightheadedness or a sense of imbalance.
Difficulty with coordination or walking, especially in the dark or on uneven surfaces.
This is because the vestibular nerve, which sits very close to the tumor, is responsible for sending information to your brain about your head’s position and movement. As the tumor grows, it can disrupt these signals.

Less Common, But Still Significant Symptoms

While the triad of hearing loss, tinnitus, and dizziness are the most prevalent, other symptoms can emerge as the tumor increases in size, particularly as it begins to press on other cranial nerves in the cerebellopontine angle.

Facial Weakness or Numbness: The facial nerve (cranial nerve VII) also travels through the internal auditory canal. As an acoustic neuroma grows, it can compress this nerve, leading to:
Tingling or numbness on one side of the face.
A feeling of heaviness or drooping on one side of the face.
In more advanced cases, visible weakness, such as difficulty closing the eyelid, smiling, or raising the eyebrow on the affected side.

Headaches: While not as common as the auditory and vestibular symptoms, headaches can occur, especially with larger tumors. These might be:
Dull, persistent headaches, often located on the side of the tumor.
Headaches that worsen with changes in position.
This is likely due to pressure on surrounding structures or increased intracranial pressure in more significant cases.

Changes in Taste: Rarely, the tumor can affect branches of the facial nerve that control taste sensation, leading to a metallic taste or a change in how you perceive flavors on one side of the tongue.

Ear Fullness or Pressure: Some individuals report a feeling of fullness or pressure in the affected ear, similar to what you might experience during an ear infection or high altitude changes.

Swallowing Difficulties: In very large tumors that significantly compress the brainstem or other cranial nerves involved in swallowing, difficulties with swallowing (dysphagia) can arise. This is a less common symptom, typically associated with advanced stages of the condition.

The key takeaway here is to pay attention to unilateral (one-sided) symptoms, especially those that are persistent or progressively worsening. If you’re experiencing a combination of these, don’t hesitate to schedule a consultation with your doctor or an audiologist.

### How is an Acoustic Neuroma Diagnosed?

Receiving an acoustic neuroma diagnosis can be a journey involving several steps, from recognizing your symptoms to undergoing imaging tests. It’s important to remember that your doctor will be looking for a pattern of symptoms and using specialized tools to confirm the presence, size, and location of any potential tumor. This diagnostic process aims to rule out other conditions and provide a clear picture for treatment planning.

The Initial Consultation: Your Doctor’s Role

The diagnostic process often begins with you discussing your symptoms with your primary care physician or an Ear, Nose, and Throat (ENT) specialist.

Detailed Medical History: You’ll be asked to describe your symptoms in detail: when they started, how they’ve progressed, and if they are constant or intermittent. Be prepared to talk about any changes in your hearing, any ringing in your ears, and any dizziness or balance issues you’ve experienced.
Physical Examination: The doctor will perform a general physical exam and a focused examination of your ears, nose, and throat. They will also conduct basic hearing and balance screening tests. This helps them assess your current state and rule out more common ear conditions like infections or wax buildup.

Audiological Testing: Pinpointing Hearing and Balance Issues

If your primary doctor suspects an auditory or vestibular issue, they will likely refer you to an audiologist for more specialized testing. This is often a crucial step in identifying potential acoustic neuromas.

Pure-Tone Audiometry: This test measures your ability to hear pure tones at different frequencies and volumes. It helps determine the amount and type of hearing loss in each ear. For acoustic neuromas, this often reveals a progressive, unilateral sensorineural hearing loss, particularly in the higher frequencies.
Speech Audiometry: This tests how well you can understand spoken words. You might be asked to repeat words or phrases heard at various volumes, often in the presence of background noise. Difficulty understanding speech, especially in noisy environments, is a common finding with acoustic neuromas.
Tympanometry: This test assesses the function of your middle ear and eardrum. While it doesn’t directly diagnose an acoustic neuroma, it helps rule out other middle ear issues that could cause similar symptoms.
Otoacoustic Emissions (OAEs): This non-invasive test measures the response of the inner ear (cochlea) to sound. It can detect early damage to the sensory hair cells within the cochlea, which can be an indicator of an acoustic neuroma.
Auditory Brainstem Response (ABR) or Brainstem Evoked Response Audiometry (BAER): This sophisticated test measures electrical activity in the auditory nerve and brainstem in response to sound. It’s highly sensitive to abnormalities along the auditory pathway. For acoustic neuromas, it can detect a delay in signal transmission along the auditory nerve, even when hearing loss is mild or not yet noticeable on standard audiograms. Large gaps between waves, especially in the interval between wave I (from the auditory nerve) and wave V (from the brainstem), can be highly suggestive of an acoustic neuroma.

Imaging Studies: The Definitive Step

While audiological testing can strongly suggest the presence of an acoustic neuroma, imaging studies are essential for definitive diagnosis and for determining the tumor’s size and location.

Magnetic Resonance Imaging (MRI): This is the gold standard for diagnosing acoustic neuromas.
How it Works: MRI uses powerful magnets and radio waves to create detailed cross-sectional images of the brain and its structures. It’s excellent at differentiating soft tissues.
With Gadolinium Contrast: For acoustic neuromas, the MRI is almost always performed with an injection of a contrast dye called gadolinium. This dye accumulates in the tumor, making it light up brightly on the images, allowing for precise visualization of its boundaries and its relationship to surrounding nerves and the brainstem.
Advantages: MRI provides highly detailed images, allowing for the detection of even small tumors, and it doesn’t involve radiation.

Computed Tomography (CT) Scan: While MRI is preferred, a CT scan might be used in certain situations.
How it Works: CT scans use X-rays to create cross-sectional images.
Limitations for Acoustic Neuromas: CT scans are generally less sensitive than MRI for detecting small acoustic neuromas, especially those within the internal auditory canal. They are better at visualizing bone structures. However, they can be useful if MRI is not an option due to contraindications (e.g., pacemakers) or if there’s a suspicion of bony abnormalities in the internal auditory canal.

It’s important to remember that the entire diagnostic process, from your first symptom to a definitive MRI, can take time. Be patient with the process and communicate openly with your healthcare providers.

### What Are the Treatment Options for Acoustic Neuroma?

Once an acoustic neuroma has been diagnosed, the next crucial step is to discuss treatment options. The “best” treatment isn’t a one-size-fits-all answer; it depends on a variety of factors, including the size of the tumor, the severity of your symptoms, your age, your overall health, and your personal preferences. Your medical team will carefully weigh these elements to recommend a course of action tailored to your specific situation. Generally, there are three main avenues: observation (“watchful waiting”), surgery, and radiation therapy.

1. Observation (Watchful Waiting)

For many individuals, especially those with very small tumors that are not causing significant symptoms, observation is a perfectly valid and often preferred approach. This strategy acknowledges the slow growth rate of most acoustic neuromas.

Who is this for? This option is typically considered for:
Small tumors (often less than 1-2 cm).
Asymptomatic or mildly symptomatic tumors.
Older patients with co-existing health conditions.
Patients who wish to avoid the potential risks of surgery or radiation.
What does it involve? You will be closely monitored with regular imaging studies (usually MRI scans) at prescribed intervals (e.g., every 6-12 months initially, then potentially less frequently if the tumor remains stable). Regular audiological testing will also be conducted to track hearing function.
Pros:
Avoids the risks associated with surgery or radiation.
Preserves hearing and facial nerve function in the short term.
Allows you to avoid medical interventions unless necessary.
Cons:
The tumor may continue to grow, eventually requiring intervention.
Requires ongoing vigilance and regular medical appointments.
There’s always the psychological aspect of knowing a tumor is present and growing.

2. Surgery

Surgery is often the primary treatment option for larger acoustic neuromas or those causing significant symptoms. The goal is to remove the tumor while preserving the function of nearby nerves, particularly the facial nerve, and to prevent further growth. The surgical approach depends on the tumor’s size and location.

Types of Surgical Approaches:
Retrosigmoid/Suboccipital Craniotomy: This is the most common surgical approach. An incision is made behind the ear. A small section of the skull is removed to access the tumor in the cerebellopontine angle. Neurosurgeons can often achieve good tumor removal with this method while having a good chance of preserving facial nerve function. Hearing preservation is less likely with this approach, especially for larger tumors.
Translabyrinthine Approach: This approach also involves an incision behind the ear, but it goes through the mastoid bone and the inner ear structures to reach the tumor. This approach offers excellent access to the internal auditory canal and cerebellopontine angle, but it always results in the loss of hearing in the operated ear. It is often preferred for smaller tumors when hearing preservation is not a concern.
Middle Fossa Craniotomy: This approach involves a smaller incision above the ear and access to the tumor from above. It is typically used for very small tumors located within the internal auditory canal, offering the best chance for hearing preservation. However, it can be technically challenging for larger tumors.

Goals of Surgery:
Complete Resection: Removing the entire tumor.
Subtotal Resection: Removing as much of the tumor as possible, especially if complete removal risks significant nerve damage. Residual tumor may require further treatment.
Facial Nerve Preservation: This is a top priority. Surgeons meticulously identify and protect the facial nerve during the operation.
Hearing Preservation: This is a goal for many, particularly with smaller tumors and specific surgical approaches, but it is not always achievable.

Risks of Surgery: As with any major surgery, there are potential risks, including infection, bleeding, cerebrospinal fluid (CSF) leak, damage to nearby nerves (facial nerve weakness, balance problems, swallowing difficulties), anesthesia complications, and in rare cases, stroke or death.

3. Radiation Therapy

Radiation therapy is another effective treatment option, particularly for individuals who are not good candidates for surgery or for managing residual tumor after surgery. It uses focused beams of radiation to damage or destroy tumor cells and prevent further growth.

Types of Radiation Therapy:
Stereotactic Radiosurgery (SRS) – e.g., Gamma Knife, CyberKnife: This is a highly precise form of radiation therapy. Multiple beams of radiation are delivered to the tumor from different angles, converging at the tumor site with very high doses, while sparing surrounding healthy tissues. It is typically delivered in a single session or a few sessions. SRS is usually reserved for smaller tumors (typically less than 3 cm).
Fractionated Stereotactic Radiotherapy (FSRT): Similar to SRS, but the radiation is delivered in multiple smaller doses over several weeks. This can be used for larger tumors or when SRS is deemed too intense.

Goals of Radiation Therapy:
Tumor Control: The primary aim is to stop tumor growth or shrink it. It rarely eradicates the tumor completely.
Preservation of Nerve Function: Radiation therapy, when delivered precisely, aims to preserve the function of the auditory and facial nerves. However, some hearing loss or facial weakness can still occur over time as a delayed effect of radiation.

Pros of Radiation Therapy:
Non-invasive (no surgical incision).
Lower risk of immediate complications compared to surgery.
Often associated with a higher chance of hearing preservation than surgery for similar-sized tumors.
Cons of Radiation Therapy:
Hearing loss and tinnitus can still worsen over months or years.
Facial nerve weakness can develop as a delayed side effect.
Long-term effects are still being studied, though it’s generally considered very safe and effective for tumor control.
Tumor may not shrink significantly, and growth can still be a concern, albeit at a slower rate.

The decision about which treatment path to take is a collaborative one between you and your medical team. Open communication about your concerns, expectations, and potential risks and benefits is paramount.

### What Factors Influence the Treatment Decision?

You might be wondering how your doctors arrive at a specific treatment recommendation. It’s not an arbitrary choice; rather, it’s a carefully considered decision based on a multifaceted evaluation. Understanding these factors can empower you to ask more informed questions and participate more actively in your care plan.

Tumor Size and Growth Rate

This is perhaps the most significant factor influencing treatment.

Small Tumors (e.g., < 1-2 cm): For very small, asymptomatic, or mildly symptomatic tumors, observation is often the initial approach. If symptoms develop or the tumor shows signs of growth, then surgery or radiation may be considered.
Medium Tumors (e.g., 2-4 cm): These tumors often present with more noticeable symptoms and are typically candidates for either surgery or radiation therapy, depending on other factors.
Large Tumors (e.g., > 4 cm): Larger tumors are more likely to cause significant symptoms and pose a greater risk of compressing the brainstem and other vital structures. Surgery is frequently recommended for complete or subtotal removal. Radiation may be used for residual tumor after surgery or as an alternative if surgery is not feasible.
Growth Rate: If imaging shows the tumor is growing rapidly, intervention is more likely to be recommended sooner than if it has been stable for years.

Patient Age and Overall Health

Your physical condition plays a vital role in determining the safety and suitability of different treatments.

Younger Patients: For younger, otherwise healthy individuals, more aggressive treatment options like surgery or radiation might be considered to provide long-term tumor control and prevent future complications. The goal is often to address the tumor definitively.
Older Patients or Those with Significant Comorbidities: For older individuals or those with other serious health issues (e.g., heart disease, lung disease), the risks associated with surgery might outweigh the potential benefits. In such cases, observation or less invasive radiation therapy might be preferred. The focus shifts to managing symptoms and maintaining a good quality of life.

Symptom Severity and Impact on Quality of Life

The symptoms caused by the acoustic neuroma are a major driver of treatment decisions.

Mild or No Symptoms: If you have a small tumor but are experiencing minimal or no symptoms that significantly impact your daily life, watchful waiting is a very reasonable option.
Significant Symptoms: If symptoms like profound hearing loss, debilitating vertigo, or facial paralysis are significantly affecting your ability to work, socialize, or perform daily activities, intervention becomes more pressing. The goal of treatment shifts to alleviating these symptoms and improving your quality of life.
Progression of Symptoms: Even if symptoms are not severe, their rapid progression can be an indicator that intervention is needed to prevent further damage or complications.

Hearing Status in the Affected Ear

The potential for hearing preservation is a key consideration, especially for younger patients or those who rely heavily on bilateral hearing.

Good Hearing: If the hearing in the affected ear is still relatively good, especially for smaller tumors, surgical techniques aimed at hearing preservation (like the middle fossa approach) or stereotactic radiosurgery might be strongly considered.
Poor or Absent Hearing: If hearing is already significantly compromised or absent in the affected ear, the priority might shift away from hearing preservation. This can make the translabyrinthine surgical approach, which offers excellent tumor access, a viable option, or it might lessen the urgency of intervention if other symptoms are manageable.

Preservation of Facial Nerve Function

This is almost always a paramount concern for any treatment involving the ear and skull base.

Risk Assessment: All treatment options are evaluated for their potential risk to the facial nerve. Surgeons and radiation oncologists use advanced techniques to identify and protect this nerve.
Surgical Decisions: The surgeon’s experience and the chosen surgical approach play a significant role in the likelihood of preserving facial nerve function.
Radiation Decisions: Precision in radiation delivery is crucial to minimize damage to the facial nerve.

Patient Preferences and Values

Ultimately, the decision-making process is a partnership between you and your medical team. Your personal values, beliefs, and comfort level with different risks and outcomes are essential.

Risk Tolerance: Are you more comfortable with the risks of surgery or the potential for delayed effects from radiation? Do you prioritize avoiding intervention for as long as possible?
Lifestyle Considerations: How might potential side effects impact your profession, hobbies, or family life?
Goals of Care: What are your primary objectives? Is it symptom relief, maximizing lifespan, preserving specific functions, or avoiding interventions altogether?

Your healthcare providers will present you with all the pros and cons of each viable option, discuss their experience and success rates, and answer your questions thoroughly. Understanding these influencing factors helps you engage in a meaningful dialogue to make the best choice for your specific situation.

### What is the Long-Term Outlook and Follow-Up Care for Acoustic Neuroma?

Many people grapple with the question of what comes next after diagnosis and treatment. The “long-term outlook” for an acoustic neuroma is generally positive, especially with modern diagnostic and treatment capabilities, but it’s important to understand what that entails. It involves ongoing monitoring and sometimes managing residual effects.

Positive Prognosis with Modern Care

For the vast majority of individuals diagnosed with acoustic neuroma, the outlook is very good.

Non-Cancerous Nature: As we established, these tumors are benign. They don’t spread. This fundamentally limits their potential for being fatal in the way cancerous tumors can be.
Effective Treatment: Whether through observation, surgery, or radiation, the primary goals—stopping tumor growth, removing the tumor, and preserving vital functions—are often successfully achieved.
Slow or Stopped Growth: Once treated (surgically removed or irradiated), the growth of the tumor is effectively halted. Even with observation, many small tumors never significantly grow.

Ongoing Monitoring and Follow-Up

Regardless of the treatment chosen, long-term follow-up care is almost always necessary.

Regular Imaging (MRI): This is crucial, especially for those who opted for observation or underwent subtotal resection. MRIs are used to:
Detect Recurrence: For those who had a complete resection, there’s a small chance of recurrence from microscopic residual tumor cells. Regular MRIs help detect this early.
Monitor Residual Tumor: If only part of the tumor was removed, MRIs are essential to monitor the remaining portion and ensure it’s not growing.
Track Stability: For observed tumors, MRIs confirm that they remain stable in size.
The frequency of these scans will decrease over time if the tumor is stable, but often a lifetime of monitoring is recommended.

Audiological Monitoring: Regular hearing tests are important for:
Tracking Hearing Changes: Even after successful treatment, hearing loss in the affected ear may continue to progress slowly over years, especially after radiation.
Detecting Occult Growth: Changes in hearing can sometimes be an early indicator of tumor regrowth.
Monitoring the Good Ear: It’s also important to monitor the hearing in the opposite ear to ensure overall auditory health.

Neurological and Facial Nerve Assessments: Your medical team will periodically assess:
Facial Nerve Function: Checking for any signs of weakness or changes in sensation.
Balance and Gait: Evaluating your stability and any persistent dizziness.
Other Cranial Nerve Functions: Depending on the tumor’s location and symptoms, other nerve functions may be assessed.

Managing Residual Symptoms

While treatment can be very effective, some symptoms may persist or develop as a result of the tumor or its treatment.

Hearing Loss: If hearing was not preserved, you may need to adapt with strategies like hearing aids (in the non-affected ear), assistive listening devices, or learning lip-reading.
Tinnitus: Tinnitus can sometimes persist or even worsen after treatment. Management strategies include sound therapy, counseling, and tinnitus masker devices.
Facial Weakness/Numbness: If facial nerve function was affected, rehabilitation and physical therapy might be recommended. In some cases, surgical options can be explored for cosmetic or functional improvement.
Balance Problems: Physical therapy and vestibular rehabilitation can often help improve balance and reduce dizziness.
Fatigue or Headaches: These can sometimes be post-treatment symptoms and may be managed with lifestyle adjustments or medical intervention.

Living with an Acoustic Neuroma

For many, after the initial period of diagnosis and treatment, life returns to a new normal.

Information and Support: Understanding your condition and attending regular follow-ups can reduce anxiety. Support groups and patient advocacy organizations can provide valuable emotional and informational resources.
Awareness: Being aware of potential signs of recurrence or new symptoms is important, but try not to be overly vigilant to the point of constant worry. Regular medical check-ups are designed to catch any issues early.
Healthy Lifestyle: Maintaining a healthy lifestyle can support overall well-being and potentially aid in recovery and managing any lingering symptoms.

The long-term outlook for acoustic neuroma is overwhelmingly positive. With a proactive approach to monitoring and management, most individuals live full and productive lives after diagnosis and treatment. Your ongoing relationship with your healthcare team is key to ensuring your continued health and well-being.

FAQs

What is an acoustic neuroma?

An acoustic neuroma, also known as a vestibular schwannoma, is a non-cancerous tumor that develops on the main nerve leading from the inner ear to the brain. It usually grows slowly and can cause hearing loss, tinnitus, and balance problems.

What are the symptoms of acoustic neuroma?

Symptoms of an acoustic neuroma can include hearing loss, ringing in the ear (tinnitus), dizziness, and problems with balance. In some cases, the tumor can also cause facial numbness or weakness.

How is acoustic neuroma diagnosed?

Acoustic neuroma is typically diagnosed through a combination of a patient’s medical history, a physical examination, and imaging tests such as MRI or CT scans. These tests can help to determine the size and location of the tumor.

What are the treatment options for acoustic neuroma?

Treatment options for acoustic neuroma include observation, radiation therapy, and surgical removal of the tumor. The choice of treatment depends on the size and location of the tumor, as well as the patient’s overall health and preferences.

What are the potential complications of acoustic neuroma?

Complications of acoustic neuroma can include permanent hearing loss, facial weakness or paralysis, and balance problems. In some cases, the tumor can also put pressure on the brainstem, leading to more serious neurological issues.