What is Amyotrophic Lateral Sclerosis (ALS)?

A progressive neurodegenerative disease affecting motor neurons in the brain and spinal cord, leading to loss of voluntary muscle control and eventually respiratory failure. The primary target condition for communication BCIs.

What category does Amyotrophic Lateral Sclerosis (ALS) belong to in BCI?

Amyotrophic Lateral Sclerosis (ALS) is a Clinical Conditions concept in brain-computer interface science.

Amyotrophic Lateral Sclerosis (ALS) — BCI Glossary

Amyotrophic Lateral Sclerosis (ALS) — also known as Lou Gehrig's disease in the United States or motor neuron disease (MND) in the UK and Australia — is a fatal neurodegenerative disease that selectively destroys upper and lower motor neurons. As motor neurons die, the muscles they control weaken and eventually fail. ALS is the most common indication for communication BCI clinical trials.

Disease Progression and BCI Relevance

ALS spares sensory neurons, cognitive function, and autonomic systems in most patients — individuals with ALS typically retain full awareness and intellect even as they lose all voluntary muscle control. This creates the ideal scenario for a BCI:

The person's neural intent (what they want to do or say) is fully preserved in motor cortex
The neuromuscular pathway (spinal motor neurons and muscles) that normally executes that intent is destroyed
A BCI can "bypass" the destroyed pathway by reading motor cortex directly

As ALS progresses, patients sequentially lose:

Fine motor control (limb weakness)
Gross motor control (arm and leg paralysis)
Speech and swallowing (bulbar onset affects ~30% first; limb onset is more common)
Respiratory function (ultimate cause of death without ventilatory support)

BCIs are most relevant at stages 2-4, when patients cannot use conventional assistive technology (eye gaze, switch scanning) due to loss of voluntary movement.

Epidemiology

Prevalence: ~30,000 in the US; ~450,000 worldwide
Incidence: ~5,000 new US diagnoses per year
Median survival: 2-5 years from symptom onset; ~10% survive >10 years
Age of onset: Typically 55-75; younger-onset ALS (~5%) often associated with familial mutations (SOD1, C9orf72, FUS, TARDBP)

ALS in BCI Trials

ALS has been the primary indication in nearly every invasive BCI trial:

Neuralink PRIME: First participant Noland Arbaugh had cervical spinal cord injury (not ALS); second and subsequent participants target ALS/quadriplegia
Synchron SWITCH/COMMAND: Exclusively ALS/MND patients
BrainGate2: Mixed ALS and SCI/stroke
Blackrock Utah Array: Both ALS and SCI

FDA regulatory pathway: ALS BCIs typically pursue Humanitarian Device Exemption (HDE) — which requires less clinical evidence than PMA — given the small ALS population size (<8,000 US patients eligible for a given BCI indication), OR full PMA if seeking broader paralysis indication.