Amyotrophic lateral sclerosis (ALS): an animated, cited guide

This page needs JavaScript for its animations. The outline and key answers are below, and every claim in the full version carries a numbered citation.

Not medical advice. ALS Companion is an educational synthesis of published literature. It does not replace a clinician.

What is in it

What ALS is Who gets it, the numbers, and the ways it starts.
Upper and lower motor neurons Two neurons, two sets of signs, animated.
TDP-43 and what goes wrong A protein leaves the nucleus and clumps.
Genes: C9orf72, SOD1 and more Familial ALS, repeat expansions and genetic testing.
Diagnosis and criteria The Gold Coast, revised El Escorial and Awaji criteria, as a calculator.
The differential Conditions that can look like ALS, and how they differ.
ALSFRS-R and the course The 12-item scale, the progression rate and the stages.
Riluzole, edaravone and others What each drug targets and what the trials found.
Tofersen An antisense drug that lowers SOD1, for SOD1-ALS.
Breathing and NIV Weak breathing muscles, the tests, and when ventilation is offered.
Swallowing and feeding tubes Why weight matters and when a gastrostomy is discussed.
Living with ALS Communication, cognition, symptoms, planning and end of life.
Nursing care Assessment, giving the medicines, teaching and documentation.
Toward a cure Every route under study, with the evidence for each.
History and people From Charcot to tofersen.
Flashcards, quiz and glossary Revision for students.
Sources Every reference behind the guide.

Part 1 · The disease

What ALS is

Amyotrophic lateral sclerosis (ALS), also called motor neuron disease, damages both the upper motor neurons in the brain and the lower motor neurons in the brainstem and spinal cord, so muscles weaken, waste and stiffen. ¹⁸⁰ It starts in one region of the body and spreads. Choose where it starts and press Play.

Where it starts

Timeline

Schematic, not to scale, and not anyone's forecast. Darker shading means more of that region is affected. The order of spread is a common pattern, not a rule. The month marks are mean times from onset in people who had died at one London clinic, with all onset types together ⁴⁵¹. Other cohorts differ, and many people live much longer.

Exam hookALS = upper plus lower motor neuron signs, spreading from one region. UMN: brisk or spreading reflexes, spasticity. LMN: weakness, wasting, fasciculations. ¹⁸⁰ Sensory loss, eye-movement palsy and sphincter disturbance argue against it ¹⁹⁴; eye-movement and sphincter motor neurons are relatively spared until late ^255,319.

In plain wordsThe nerves that move muscles slowly stop working, so muscles get weak. Feeling and the muscles that move the eyes are usually spared. It usually begins in one place, such as a hand or the voice, and spreads over months to years.

Key numbers

These are ranges from population registers and reviews. A number for a population does not describe any one person.

How common, by source

Different methods give different numbers. Pick a measure, then tap a bar to see where it comes from.

Measure

Where sources disagree

The ways ALS can look

The same disease process can start in different places and involve mostly upper or mostly lower motor neurons. These patterns, called phenotypes, differ in how fast they usually progress. Choose one.

Shading is a typical pattern, not a rule. Survival bars are medians from onset in one London cohort of 1188 people ⁵³⁶.

How the decline is measured over time, with the ALSFRS-R and King's stages, is in ALSFRS-R and the course. Why both kinds of motor neuron fail is in Upper and lower motor neurons.