"Brain-computer interfaces (BCIs) are computer-based systems that acquire brain signals, analyze them, and translate them into commands that are relayed to an output device to carry out a desired action. BCIs represent a very active and promising field of research among devices for people with severe motor disabilities. As the currently available systems correspond to research prototypes, they are not adapted to daily live situations. On the other hand, some systems have recently been commercialized, principally for video games but they are not satisfactory for use as a substitute technology in disability.

A BCI's prototype for alternative communication using a virtual keyboard, the P300 Speller, has been developed by the National Institute for Research in Digital Science and Technology (Athena team - Nice University). This prototype includes an EEG-cap with gel based active electrodes. A recent study conducted on 20 patients with ALS (University Hospital, Nice) demonstrated the usability of the system and the patient satisfaction concerning the ease of use and utility. To achieve a system that can be used in daily live in severely disabled patients, technical developments are necessary.

The investigators have conceptualized and developed an ergonomic, comfortable, headset, including dry electrodes to allow a prolonged use of the system.

The purpose of the study conducted all along the development of the headset is to improve the developed system until a successful system is achieved. This study is a monocentric usability study conducted on ALS people.

Inclusion criteria

1. Age ≥ 18 years old
2. For women of childbearing potential, use of contraception for the duration of the study
3. Diagnosis of suspected ALS, possible, probable with ENMG, probable, defined according to the criteria of the World Federation of Neurology (revised El Escorial criteria, Airlie House Conference 1998)
4. Understanding of the objective of the study after describing the principle of the P300 Speller and the course of the study
5. Ability to follow the study procedure and to comply with the schedule of visits when entering the study
6. Expression of a P300 wave under the conditions of the study

Exclusion criteria

1. Psychiatric illness or dementia that may interfere with the patient's ability to follow study procedures
2. History of photosensitive epilepsy
3. Patient subject to protective measures
4. Non-correctable visual disturbances
5. Limited ability to concentrate.
6. Women who are pregnant or breastfeeding or who have planned a pregnancy during the course of the study.
7. Persons deprived of their liberty by a judicial or administrative decision