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6 Causes of Slurred Speech

Slurred speech can be caused by something as simple as lack of sleep—or as serious as a stroke. Here’s how to tell the difference.
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Last updated September 9, 2021

Slurred speech questionnaire

Use our free symptom checker to find out what's causing your slurred speech.

Slurred speech questionnaire

Use our free symptom checker to find out what's causing your slurred speech.

Slurred speech symptom checker

What is slurred speech?

Slurred speech is when you have trouble speaking, your words are slow or garbled, or your words run together. When you talk, many components of your nervous system work together to form words. When these parts don’t work correctly, your speech can become distorted, or “slurred.” The medical term for slurred speech is dysarthria.

Slurred speech includes problems pronouncing words and regulating the speed or pace of your speech. It can range from a barely noticeable problem to one that’s so severe that others can’t understand what you’re saying.

People often describe slurred speech as feeling like you’re trying to talk with your mouth full of marbles.

Common causes of slurred or slow speech include drinking too much alcohol and not getting enough sleep. In these cases, the slurring will stop once you’re sober again and have gotten rest, respectively.

There are also other causes of slurred speech such as a stroke (a medical emergency), brain tumor, Bell’s palsy, or a serious migraine.

Does slurred speech always need to be treated?

"People often think slurred speech is a minor symptom that does not need a medical evaluation. As our speech and ability to speak is our main form of communication, it is important to look for correctable causes." —Dr. Karen Hoerst

Should I go to the ER for slurred speech?

You should call 911 if:

  • Your slurred speech starts suddenly.
  • You have other symptoms, such as a sudden or severe headache and weakness or numbness of one side of your body.
  • Your tongue, face, or lips are swelling, which could mean you’re having an allergic reaction.

Causes

1. Stroke or TIA (transient ischemic attack)

Symptoms

  • Slurred speech
  • Drooping of one side of the face
  • Weakness or trouble controlling one side of the body
  • Numbness in the face, arm, or leg
  • Difficulty walking
  • Sudden loss of vision or double vision
  • Sudden, severe headache

A stroke occurs in the brain because the blow flow in a blood vessel is blocked. It can also happen when a blood vessel ruptures or leaks. This affects the blood supply to parts of the brain, which leads long-term damage. If it affects the area of the brain responsible for speech, it can cause slurred speech.

A transient ischemic attack, or TIA, is sometimes called a "mini stroke." A TIA is a temporary interruption of blood flow that causes the same symptoms as a stroke, but improves without any permanent damage to the brain or symptoms.

For example, if you have slurred speech because of a TIA, once the blood flow is restored to that area of the brain, the slurred speech goes away. But people who have a TIA are at a high risk of having a stroke in the future, especially if their risk factors are not treated. Risk factors are the same for stroke and TIA and include smoking, obesity, and cardiovascular disease.

It’s extremely important to call 911 right away if you suddenly have slurred speech. Getting immediate treatment is critical to minimizing permanent damage. Paramedics can begin treating you in the ambulance on the way to the hospital, so it’s better to call 911 than go to the ER yourself.

Treatments for strokes and TIAs include medications to break up blood clots and surgery to remove blood clots from the vessels. If your stroke is from bleeding in the brain, you may need surgery to repair a blood vessel.

Following treatment, your doctor will recommend medications to prevent another TIA or stroke. These typically include drugs that prevent clots from forming in the blood (like aspirin or other blood thinners) and cholesterol medication to prevent plaque from building up on the walls of the blood vessels. You may also need to take medication to control your blood pressure.

Speech therapy is recommended to help treat problems with speech.

Slurred speech questionnaire

Use our free symptom checker to find out what's causing your slurred speech.

Slurred speech symptom checker

2. Bell’s palsy

Symptoms

Bell’s palsy is a relatively common condition that affects the facial nerve, which is responsible for movement of your face.

In Bell’s palsy, the nerve gets inflamed typically because of a recent viral infection. This inflammation can cause the facial nerve to not work as well, leading to drooping and slurred speech.

Bell’s palsy usually improves in a few months, but medications such as steroids and antiviral drugs are typically given to help speed the process. If nerve problems continue, physical therapy is recommended. In rare instances, surgery may be needed to help improve facial muscle function.

3. Brain tumor

Symptoms

  • Slurred speech or speech difficulties
  • New or changing headaches
  • Weakness or coordination and balance problems
  • Abnormal vision
  • Confusion
  • Seizures

A brain tumor is an abnormal growth of cells in the brain. A brain tumor may be cancerous (malignant) or noncancerous (benign). Both types can cause symptoms including slurred speech.

The diagnosis of a tumor in the brain or spinal cord is based on an exam and imaging of the brain, such as an MRI or CT scan. A biopsy (tissue sample) may be needed to determine what type of tumor it is.

Some tumors, such as a small noncancerous tumor, do not need treatment, though your doctor will recommend periodic MRI scans to make sure it hasn’t changed.

Most larger or cancerous tumors do require treatment, which may consist of chemotherapy, radiation, or surgery. If you develop physical or cognitive (mental) problems from the tumor, rehabilitation such as physical therapy, occupational therapy, or speech therapy may be needed.

4. Multiple sclerosis

Symptoms 

  • Slurred speech
  • Blurred vision or decreased vision, typically in one eye
  • Weakness or trouble walking
  • Numbness or pins-and-needles sensation on your face, arm, or leg (typically on one side)
  • A band-like squeezing sensation around the chest or abdomen
  • Difficulty focusing
  • Fatigue

Multiple sclerosis, or MS, is a central-nervous system disease that affects the cells of the brain and spinal cord. In MS, a fatty tissue that surrounds nerve fibers (myelin) is attacked. Myelin helps to insulate the electrical signals sent through the nerves. When there is a problem with this fatty tissue, information sent to and from the brain can be disrupted.

MS is most common in young adults between the ages of 20 and 50, according to the National MS Society.

MS is not curable, but treatments have dramatically improved the ability to control MS, so people usually have fewer symptoms and less disability.

Treatment includes medications that may be taken orally or injected or infused through an IV line. Physical therapy and speech therapy are commonly used to help in physical recovery, and medications can be used to treat other symptoms, such as depression, pain, and fatigue.

5. Amyotrophic lateral sclerosis (ALS)

Symptoms

  • Difficulty with speech, including slurred speech
  • Progressive weakness and difficulty balancing
  • Muscle cramps, twitching, and stiffness
  • Difficulty swallowing

Amyotrophic lateral sclerosis (ALS) is also known as Lou Gehrig’s disease. It affects nerve cells called motor neurons that control your movement.

The disease primarily causes a loss of strength, impaired swallowing and speech, and in most cases, difficulty breathing because of impaired respiratory muscles. It is a progressive disease, meaning that symptoms are mild at first and worsen over time.

Previously, it was thought that ALS doesn’t affect a person’s mental ability. But it’s now known that people with ALS can get a specific type of dementia called frontotemporal dementia (FTD). That condition can affect behavior, mood, and speech.

Symptoms of ALS can develop in adults of any age, but it’s most commonly diagnosed in people who are between the ages of 40 and 70, according to the ALS Association.

While there are some medications that can be used to delay the progression of the disease, there is currently no cure for ALS. Treatment includes rehabilitation with physical therapy, occupational therapy, speech therapy, and respiratory therapy.

6. Migraine

Symptoms

A migraine causes a severe headache that is often accompanied by nausea and sensitivity to light or sound. But some migraines don’t cause head pain.

Other symptoms that involve the nervous system can occur. Some of these sensory symptoms are called “auras.” These distortions can cause visual changes, including flashing lights or distorted vision. People may feel tingling or numbness of their face, arm, or leg.

In some types of migraine, people may even develop slurred speech and weakness of the face, arm, or leg. These are also symptoms of a stroke, so it may be hard to figure out which condition you have. If you develop sudden slurred speech or weakness, go to the ER immediately.

In an acute migraine attack, medications can be used to stop a migraine that has already started, such as triptans or newer medications called CGRP inhibitors. These medications can be in pill form, inhaled form, or injectable medications.

Migraine prevention can include taking medications for blood pressure, anticonvulsants, or even antidepressants. In some instances, Botox treatments are used to prevent migraine.

Behavior and lifestyle changes such as exercise, improved sleep, and healthy diet or weight loss are also often recommended to help decrease the number of migraine headaches you experience.

Slurred speech questionnaire

Use our free symptom checker to find out what's causing your slurred speech.

Slurred speech symptom checker

Other possible causes

It may not be a stroke

"There are so many possible causes of slurred speech. Most of the time we need a detailed history and physical exam to guide the diagnosis and treatment." —Dr. Hoerst

Slurred speech may occur from alcohol intoxication or tiredness. It can also be a side effect of medications like high dose pain medications, antipsychotic medications or even some allergy medications like antihistamines. Other causes include:

  • Infections such as urinary tract infections or electrolyte imbalances (particularly in elderly people).
  • Brain infections such as meningitis or encephalitis.
  • Problems that affect your mouth or throat, such as poorly fitting dentures, dental infections, dental numbing medications, swelling in your throat, or muscle or nerve problems.
  • An allergic reaction, especially if you notice slurred speech along with tongue swelling, lip swelling, or shortness of breath.

Specialty treatment options

Does slurred speech always need to be treated?

"Early speech therapy can not only help with early improvement but also with diagnosis. Speech-language pathologists have special training in detecting the various types of slurred speech, which helps to determine the possible causes."—Dr. Hoerst

  • Speech therapy is the most common treatment for slurred speech.
  • Injected medications such as Botox are sometimes used, depending on the cause of slurred speech.
  • Medications to improve nerve and muscle function.
  • Surgery.
Hear what 1 other is saying
Can't speakPosted May 17, 2021 by J.
Since I was about 30 years old, I started having weird moments where I could not speak. It felt like my brain had to take a second to recalibrate before I could speak again. The first time it happened I was driving as well. It didn't affect my ability to drive but I could not talk to my friend at all. I am 43 now and the other morning it happened a bunch of times in a row but seemed to disappear the next day. Most of the time I feel totally fine and I am also a very active person. I drink about 3 days a week when playing disc golf but am definitely not an alcoholic. I smoke as well but am quitting as I write this. I should also mention that this last time it was bad, I had random body parts going numb. Didn't seem to be one side over the other but definitely seconds of numbness here and there. Anyone experience this type of random speech loss over 13 years or so?
Dr. Hoerst is a board-certified Neurologist. She received her undergraduate degree in Neuroscience from the University of Scranton in 2005 and Jefferson Medical College (now Sidney Kimmel Medical College) in 2009. She completed an internal medicine internship, neurology residency and vascular neurology fellowship at Thomas Jefferson University Hospital in Philadelphia (2014). After completing her...
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