Amyotrophic lateral sclerosis (ALS) or often called Lou Gehrig's disease, after the baseball player who was diagnosed with it is a progressive nervous system disease that affects nerve cells in the brain and spinal cord, causing loss of muscle control.
The disorder typically progresses, the affected individual loses the ability to breathe due to diaphragm paralysis. Upon accepting artificial ventilation and with oro-facial muscle paralysis, the individual in most cases can no longer speak and becomes dependent on assistive and augmentative communication (AAC) devices, and may progress into the locked-in state (LIS) with intact eye-movement or gaze control.

Study in Nature communications successfully used technology to help communication in ALS patients, researchers used a neurofeedback strategy to modulate the firing rates of neurons in a paradigm allowing him to select letters to form words and sentences to express his desires and experiences.
Though others have evaluated communication in people with remaining muscle control, to the best of their knowledge, it is not known whether neural-based communication remains possible in a completely locked-in state said the researchers.
Researchers used implanted two 64 microelectrode arrays in the supplementary and primary motor cortex of a patient in a completely locked-in state with ALS. The patient modulated neural firing rates based on auditory feedback and he used this strategy to select letters one at a time to form words and phrases to communicate his needs and experiences.
To conclude, this case study has demonstrated that a patient without any stable and reliable means of eye-movement control or identifiable communication route employed a neurofeedback strategy to modulate the firing rates of neurons in a setting allowing him to select letters to form words and sentences to express his desires and experiences. It will be valuable to extend this study to other people with advanced ALS to address the aforementioned issues systematically.
Reference: https://www.nature.com/articles/s41467-022-28859-8