NeuroSky Inc. and Emotiv Systems Inc. are among the companies vying to emerge in the brain-wave market using electroencephalograph, or EEG, technology.

Uses include concentrating and relaxing, improving mental health, and games:

London-based MyndPlay Ltd. is using NeuroSky chips inside its own headset to enable viewers to control the outcome of movie scenes by concentrating and relaxing. Two prisons in England show inmates a gangster-themed film from MyndPlay that teaches them to stay calm during threatening situations.

Some doctors believe mind-controlled games can provide more than fun and relaxation, by improving mental health. SuperBetterLabs Inc. is attempting to introduce cognitive therapy into games optimized for NeuroSky and Emotive headsets.

NecoMiMi headset, a fashion accessory that has taken fans of Japanese animé by storm, is a set of catlike ears that perk up when the wearer’s concentration intensifies, and flatten out when relaxed.