A wearable device (1) able to be worn on a users head for controlling the cerebral activity of a user during sleep comprises a band assembly (2). The band assembly (2) comprises- a front band (3), generally curve shaped, able to be placed against a forehead of the user, comprising two front band ends (3a)- an upper band (4) generally curve shaped, able to be placed against a top head of the user, comprising two front band ends (4a)- a first and a second side bands (5).Each of the side bands (5) compriseso a first side band end (5a) connected to an upper band end (4a) and a second side band end (5b),o a channel (14) extending between the first and second side band ends (5a, 5b) able to guide an adjustment element (13). The adjustment element (13) is able to extend from the first side band end (5a) of the first side band (5) to the first side band end (5a) of the second side band (5), ando at least one electrode (8) able to be in contact with the users head.Each side band (5) are connected to a front band end (3a).
