Amyotrophic lateral sclerosis, often called ALS or motor neuron disease in some settings, progressively damages nerve cells involved in voluntary muscle movement. As these motor neurons lose their ability to signal muscles, people can develop weakness, stiffness, difficulty speaking or swallowing and, eventually, trouble breathing.
ALS varies considerably from person to person. Some people lose speech or hand movement while they can still think clearly and understand language. That gap between an intact desire to communicate and declining muscle control is one reason researchers are developing brain-computer interfaces.
In a speech BCI study, sensors may record neural activity associated with a person's attempt to speak, while software converts the signals into text or a synthetic voice. Such systems aim to provide an alternative means of communication; they do not stop the underlying nerve disease or replace comprehensive clinical care.
When reading an ALS-related BCI result, check the participant's remaining movement and speech, the degree of assistance required and how performance changed over months or years. Results from one person's illness stage may not transfer directly to another's.