A device for measuring and/or stimulating a brain activity, preferably an EEG device, comprising means for transmitting and/or detecting physiological signals produced by the brain of an individual, and a support for the transmission and/or detection means, wherein the support is configured to extend over the top of the individual's head, the support comprising means for removably attaching to an accessory intended to be worn by the individual, on his or her head, such as an audio headset, the support being configured such that, when the device is worn by the individual, the means for transmitting and/or detecting physiological signals are held in substantially close contact with the individual's head by the accessory.
