Overview

Amyotrophic lateral sclerosis (ALS) is a progressive neurological disorder classified under motor neuron diseases. It damages nerve cells in the brain and spinal cord that control voluntary muscle movement, leading to increasing muscle weakness and loss of coordination. Over time, individuals experience difficulty walking, speaking, swallowing, and eventually breathing.

There is currently no cure for ALS, and its exact cause remains unknown, although some cases are inherited. The disease does not impair intelligence or sensory functions such as vision or hearing, and it is not contagious. While ALS is life-limiting, available treatments can help manage symptoms and improve quality of life.

ALS is also known as Lou Gehrig’s disease, named after the famous baseball player who died from the condition.

What Is Amyotrophic Lateral Sclerosis?

ALS affects the motor neurons responsible for voluntary actions like walking, chewing, speaking, and swallowing. Early signs often include muscle twitching, limb weakness, or slurred speech. As the disease advances, patients gradually lose the ability to move, communicate, and eat independently. Most deaths occur due to respiratory failure.

ALS can affect anyone, but it is more commonly diagnosed in individuals aged 40–70 across all racial and ethnic groups.

Types of Amyotrophic Lateral Sclerosis

ALS is categorized into two main types based on its cause:

• Sporadic ALS:
  This is the most common form, accounting for approximately 90–95% of cases. It occurs without a known cause or family history.
• Familial ALS:
  This inherited form represents about 5–10% of cases and is passed down through one or both parents.

Symptoms of Amyotrophic Lateral Sclerosis

Symptoms vary depending on which motor neurons are affected and often worsen over time. Early symptoms may resemble those of other neurological conditions.

Early symptoms include:

• Difficulty walking or performing routine tasks
• Tripping or frequent falls
• Weakness in legs, feet, ankles, hands, or arms
• Slurred speech or trouble swallowing
• Emotional outbursts such as inappropriate laughing or crying
• Muscle stiffness, spasms, or twitching
• Overactive reflexes and clonus
• Cognitive or behavioral changes

Progressive symptoms include:

• Muscle cramps and constant twitching
• Increasing difficulty using arms and legs
• Thick or unclear speech
• Fatigue and muscle wasting
• Rapid weight loss

Advanced-stage symptoms include:

• Shortness of breath and breathing difficulties
• Inability to stand or walk independently
• Problems chewing and eating
• Severe weight loss due to increased calorie burning
• Anxiety and depression
• Paralysis

Causes of Amyotrophic Lateral Sclerosis

The exact cause of ALS is unknown, but research suggests a combination of genetic and environmental factors may contribute.

• Genetic factors: Mutations in certain genes can lead to the breakdown of motor neurons.
• Environmental factors: Exposure to toxins, viral infections, or physical injuries may increase risk.

When to Seek Medical Attention

Anyone experiencing symptoms such as persistent muscle weakness, difficulty speaking, swallowing, or breathing should consult a healthcare professional immediately. Prompt evaluation can help manage symptoms more effectively.

Diagnosis of Amyotrophic Lateral Sclerosis

Diagnosing ALS in its early stages is difficult because its symptoms overlap with other neurological disorders. To rule out other conditions, doctors may use:

• Electromyography (EMG): Measures electrical activity in muscles
• Nerve conduction studies: Evaluates nerve signal transmission
• MRI scans: Identifies abnormalities in the brain or spinal cord
• Blood and urine tests: Excludes other causes
• Lumbar puncture: Examines spinal fluid
• Muscle biopsy: Helps rule out muscle diseases

Risk Factors for ALS

Although anyone can develop ALS, certain factors increase risk:

• Age over 40
• Male gender (risk equalizes with age)
• White or non-Hispanic ethnicity

Each year, approximately 1–2 people per 100,000 are diagnosed with ALS.

Treatment Options for Amyotrophic Lateral Sclerosis

While treatments cannot cure ALS or reverse nerve damage, they can slow disease progression, relieve symptoms, and improve quality of life.

Medications

The FDA has approved the following treatments:

• Riluzole: May extend survival by several months; requires liver monitoring
• Edaravone: Helps slow functional decline; administered intravenously or orally
• Sodium phenylbutyrate and taurursodiol: May delay disease progression; ongoing studies continue

Doctors may also prescribe medications to manage symptoms such as muscle spasms, fatigue, pain, depression, excessive saliva, sleep problems, and emotional instability.

Supportive Therapies

• Respiratory care: Includes breathing exercises, ventilatory support, or tracheostomy in advanced stages
• Physical therapy: Maintains strength, flexibility, and mobility
• Occupational therapy: Helps patients adapt to daily activities using assistive devices
• Speech therapy: Improves communication and introduces alternative methods such as communication boards or electronic devices
• Nutritional support: Ensures adequate calorie intake; feeding tubes may be required
• Psychological and social support: Addresses emotional, financial, and social challenges

Complications of ALS

ALS can lead to several complications, including:

• Breathing difficulties and increased pneumonia risk
• Loss of speech and communication ability
• Choking due to swallowing problems
• Malnutrition and rapid weight loss
• Mobility issues and pressure sores
• Cognitive changes, emotional lability, or dementia (in rare cases)
• Mood disorders such as anxiety and depression

Frequently Asked Questions (FAQs)

Is ALS common?
In the U.S., approximately 12,000–15,000 people are living with ALS, with around 5,000 new diagnoses each year.

Can ALS be prevented?
No, ALS cannot currently be prevented.

What communication devices help ALS patients?

• Voice amplifiers
• Writing pads and alphabet boards
• Electronic speech-generating devices
• Palate lifts
• TTY telephone relay systems