Amyotrophic Lateral Sclerosis (ALS): Causes, Symptoms, Diagnosis and Treatment

Explore ALS causes, symptoms, diagnosis, progression and treatments, and learn what patients and families can expect as they face this complex neurodegenerative disease.

By Medha deb

Created on Oct 3, 2025

Explore ALS causes, symptoms, diagnosis, progression and treatments, and learn what patients and families can expect as they face this complex neurodegenerative disease.

Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrigs disease or motor neuron disease (MND), is a progressive neurodegenerative disorder that attacks the motor nerve cells responsible for controlling voluntary muscles. Over time, it leads to muscle weakness, disability, and eventually, loss of life. This disease affects people of all backgrounds, and while it remains incurable, ongoing research continues to improve the quality of life for those diagnosed with ALS.

What Is ALS?

ALS is characterized by the degeneration and death of both upper and lower motor neuronsnerve cells located in the brain and spinal cord that connect to muscles throughout the body. As these neurons deteriorate, the ability to control muscles involved in movement, speech, eating, and breathing is progressively lost. Although cognitive functions such as memory and the senses are largely preserved, muscle control declines steadily as the disease advances.

Upper Motor Neurons: Originate in the brain and carry impulses to lower motor neurons.
Lower Motor Neurons: Located in the spinal cord and brainstem; these directly communicate with muscles to initiate movement.

How Common Is ALS?

ALS is considered a rare disease, though it is the most common among the group of motor neuron diseases. Approximately 5,000 people in the United States are diagnosed with ALS each year, affecting about 2 per 100,000 individuals annually.

Types of ALS

There are two main types of ALS, defined by their causes:

Sporadic ALS: Around 9093% of ALS cases have no clear cause or family history. These occur seemingly at random and are believed to result from a combination of genetic and environmental factors.
Familial ALS: Comprising about 510% of cases, familial ALS is hereditary, caused by inherited genetic changes, and often runs in families. Sometimes, specific gene mutations (such as SOD1, C9orf72, TARDBP, FUS) are identified in these patients.

ALS can begin with different patterns of symptoms, leading to further classification:

Limb-Onset ALS: Symptoms start in the arms or legs, usually with muscle weakness or stiffness.
Bulbar-Onset ALS: Symptoms start with difficulties in speech or swallowing, due to involvement of the bulbar region of the brain.
Respiratory-Onset ALS: Rarely, breathing difficulties appear first.

Causes and Risk Factors

ALS most often develops without a clearly identifiable cause. Scientists believe that both genetic and environmental triggers contribute to nerve cell injury and death. Known risk factors include:

Age: Most individuals are diagnosed between the ages of 40 and 70.
Gender: Men have a slightly higher risk than women, particularly at younger ages. The risk equalizes with age.
Genetics: Having a first-degree relative with ALS increases risk, particularly for familial cases.
Environmental factors: Possible links include exposure to toxic substances, heavy metals, or repeated head injuries, though definitive causes are unproven.
Military service: Some research shows military veterans may have a higher-than-average risk.

Symptoms of ALS

The earliest ALS symptoms are often subtle and may go unnoticed. They vary greatly depending on which neurons are affected first. In general, symptoms include:

Muscle weakness, initially in one part of the body (such as a hand, arm, or leg)
Muscle atrophy (wasting)
Stiffness or spasticity of muscles
Muscle twitching (fasciculations)
Difficulty speaking (dysarthria), resulting in slurred speech
Difficulty swallowing (dysphagia)
Cramps or spasms
Tripping, dropping objects, or loss of manual dexterity
Difficulty lifting the front part of the foot (foot drop) resulting in a changed gait

**Upper Motor Neuron vs. Lower Motor Neuron Symptoms in ALS**
Symptom Type	Upper Motor Neuron	Lower Motor Neuron
Muscle Tone	Increased (spasticity)	Decreased (flaccid)
Muscle Weakness	Present	Present
Muscle Atrophy	Rare	Common
Reflexes	Hyperactive (exaggerated)	Reduced or absent
Fasciculations (Twitching)	Rare	Common

Progression of Symptoms

ALS symptoms gradually worsen over time, usually spreading to other regions of the body. Some additional developments include:

Difficulty standing, walking, or using the hands
Weakness spreading to other muscle groups
Loss of the ability to speak or swallow safely
Breathing difficulties due to weakening of respiratory muscles
Unintentional weight loss
Pseudobulbar affect: Involuntary episodes of laughing or crying

Eventually, most voluntary muscles become affected, resulting in near-total paralysis. However, senses such as touch, vision, and hearing, as well as bladder and bowel function, are largely preserved.

How Is ALS Diagnosed?

ALS diagnosis is often challenging, as early symptoms can resemble those of other neurological disorders. There is no single test for ALS. Instead, diagnosis typically includes:

Detailed medical and family history, including a discussion of symptom progression
Neurological examination to assess muscle strength, tone, coordination, and reflexes
Electromyography (EMG): Measures electrical activity in muscles to detect nerve or muscle dysfunction
Nerve conduction studies: Assess electrical conduction in nerves
Imaging (MRI) to rule out other conditions, such as tumors or cervical spine disease
Blood and urine tests to rule out alternative diagnoses
Genetic testing in suspected familial cases
Spinal tap (lumbar puncture) in selected cases

Stages of ALS

ALS can progress at different rates in different people, but typically follows these broad stages:

Early stage: Mild muscle weakness or stiffness; difficulty with tasks requiring manual dexterity; subtle speech or swallowing problems.
Middle stage: Muscle weakness spreads to other regions; increased difficulty with mobility, speech, and swallowing; muscle atrophy becomes more obvious.
Late stage: Most voluntary muscles are affected; difficulty moving, speaking, swallowing, and breathing independently. Complications such as respiratory failure develop.

How Is ALS Treated?

There is currently no cure for ALS. However, a range of therapies can help manage symptoms, slow progression, and maximize quality of life. These include:

Medications
- Riluzole and edaravone: FDA-approved drugs shown to modestly slow progression of ALS in some patients.
- Other medicines may help with symptoms such as muscle cramps, spasticity, excessive saliva, mood changes, and sleep problems.
Physical and Occupational Therapy
- Exercises to maintain mobility, manage spasticity, and delay muscle atrophy.
- Adaptive devices (walkers, wheelchairs, braces) to promote independence.
Speech and Swallowing Therapy
- Techniques to clarify speech for as long as possible; alternative communication devices (such as speech-generating tablets) as the disease progresses.
- Strategies to maintain safe eating and swallowing, including dietary modifications.
Respiratory Support
- Noninvasive ventilation (NIV) devices to assist breathing.
- Management of respiratory secretions and airway clearance.
- In some cases, invasive ventilation (tracheostomy).
Nutritional Support
- High-calorie and high-protein diets to counteract weight loss.
- Feeding tubes (PEG) may be placed in those who cannot safely swallow.
Psychosocial Support and Counseling
- Emotional, psychological, and practical support for patients and families.
- Planning for end-of-life issues, including advance directives and palliative care.

Clinical trials for new medications, gene therapies, and other interventions are ongoing, providing hope for future treatment breakthroughs.

Living with ALS

ALS deeply affects not only those who are diagnosed, but also their families and caregivers. Key aspects of coping with ALS include:

Multidisciplinary care teams: Specialists coordinate to address physical, emotional, and social needs.
Assistive technology: From wheelchairs to communication devices, technology can enable continued independence and interaction.
Home modifications: Installing ramps, grab bars, and adapted tools to support daily living as mobility changes.
Patient and caregiver support: Joining support groups and connecting to ALS associations can provide vital community and resources.

ALS Prognosis

The rate at which ALS progresses varies widely. The average life expectancy after diagnosis is between 2 to 5 years, though some individuals live 10 years or longer. The cause of death is most often related to respiratory failure.

Factors that may influence prognosis include the age at onset, pattern of symptom progression, and overall health.

Research and Future Directions

Scientists are continuing to advance understanding of ALS, with research targeting diverse areas:

Genetics: Identifying new gene mutations that contribute to ALS development.
Drug development: Exploring medicines to protect neurons or slow degeneration.
Stem cell and gene therapies: Investigational treatments aiming to replace or repair damaged neurons.
Biomarker discovery: Improving blood or spinal fluid tests to speed diagnosis and track progression.

Participation in clinical trials is essential for advancing research and discovering new therapies.

Frequently Asked Questions (FAQs)

Q: What are the first signs of ALS?

A: Early signs often include muscle weakness or stiffness, muscle twitching, difficulty with fine motor tasks (such as buttoning clothes), and slurred speech.

Q: Is ALS hereditary?

A: Most ALS cases are sporadic (not inherited), but about 510% of cases are familial, caused by inherited gene mutations.

Q: How is ALS diagnosed?

A: ALS is diagnosed using a combination of neurological examination, electromyography (EMG), nerve conduction studies, imaging scans, and tests to rule out other conditions. There is no single definitive diagnostic test.

Q: Is there a cure for ALS?

A: There is currently no cure, but available treatments can help manage symptoms, delay progression, and improve quality of life.

Q: What is the life expectancy with ALS?

A: The average life expectancy following diagnosis is 25 years, though some patients live longer, particularly those with slower progression and good supportive care.

Resources and Support

ALS Association: Information, community, and research updates for patients and families.
Muscular Dystrophy Association: Specialized clinics and resources for ALS management.
ClinicalTrials.gov: Search for ongoing clinical studies related to ALS.

Summary

ALS is a devastating disease that progresses relentlessly, but dedicated care, new treatment strategies, and ongoing research offer hope for improved outcomes. Early recognition and a multidisciplinary team approach are crucial for maximizing function and quality of life for those affected by ALS.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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