A system (1000, 1100) for bi-hemispheric brain wave measurements, including a first device (1002, 1102) and a second device (1003, 1103), wherein said first device is adapted to be worn in or at a first ear of a person subject to the measurements, wherein said second device is adapted to be worn in or at a second ear of said person and wherein: said first device comprises a first and a second electrode (1005, 1105) adapted for measuring a first brain wave signal, first data acquisition means (1007a, 1107a) adapted for providing first digital data representing said first brain wave signal, first brain wave signal processing means (1008a, 1108a) configured for analyzing at least said first digital data, a first device controller (1009a, 1109a) configured to control the operation of the first device (1002, 1102) and first wireless link (1011a, 1111a) means; said second device (1003, 1103) comprises a third and a fourth electrode (1006, 1106) adapted for measuring a second brain wave signal, second data acquisition means (1007b, 1107b) adapted for providing second digital data representing said second brain wave signal, second brain wave signal processing means (1008b, 1108b) configured for analyzing at least said second digital data, a second device controller (1009b, 1109b) configured to control the operation of the second device (1003, 1103) and second wireless link means (1011b, 1111b); wherein said first and said second brain wave signal processing means are adapted to derive a characteristic feature of a brain wave signal based on an analysis method selected from a group including time-frequency analysis, time-domain analysis and data-driven signal decomposition; wherein said first brain wave signal processing means is adapted to combine a first characteristic feature and a second characteristic feature, wherein the first characteristic feature is derived unilaterally from the first device of the system and the second characteristic feature is derived unilaterally from the second device of the system, whereby a combination of unilateral signal features is provided; wherein said first and second wireless link means are adapted to establish a wireless connection (1004, 1104) between said first and said second device and wherein said wireless connection is an inductive short range radio. said first device comprises a first and a second electrode (1005, 1105) adapted for measuring a first brain wave signal, first data acquisition means (1007a, 1107a) adapted for providing first digital data representing said first brain wave signal, first brain wave signal processing means (1008a, 1108a) configured for analyzing at least said first digital data, a first device controller (1009a, 1109a) configured to control the operation of the first device (1002, 1102) and first wireless link (1011a, 1111a) means; said second device (1003, 1103) comprises a third and a fourth electrode (1006, 1106) adapted for measuring a second brain wave signal, second data acquisition means (1007b, 1107b) adapted for providing second digital data representing said second brain wave signal, second brain wave signal processing means (1008b, 1108b) configured for analyzing at least said second digital data, a second device controller (1009b, 1109b) configured to control the operation of the second device (1003, 1103) and second wireless link means (1011b, 1111b); wherein said first and said second brain wave signal processing means are adapted to derive a characteristic feature of a brain wave signal based on an analysis method selected from a group including time-frequency analysis, time-domain analysis and data-driven signal decomposition; wherein said first brain wave signal processing means is adapted to combine a first characteristic feature and a second characteristic feature, wherein the first characteristic feature is derived unilaterally from the first device of the system and the second characteristic feature is derived unilaterally from the second device of the system, whereby a combination of unilateral signal features is provided; wherein said first and second wireless link means are adapted to establish a wireless connection (1004, 1104) between said first and said second device and wherein said wireless connection is an inductive short range radio.