or switched off during periods of eating or conversation alternatively the device may continue to operate but the tone will be generated only once during a period for example once each 10 minute period in an alternative embodiment not shown in the drawing the warning buzzer is replaced by a spoken message for example informing the patient that 34 you are grinding your teeth 34 that message is generated preferably by a solid state computer chip within the earpiece another embodiment uses a microcomputer within the earpiece which i detects background ongoing emg level i e the ambient electrical noise detected by the probe from the wall of the ear channel and ii establishes new threshold levels for example daily by processing the detected background emg over a predetermined period for example the mean level of the background level is determined over a 10 minute period and the threshold is set at 200 of the mean this will set off the warning audio signal if the detected electrical signal exceeds the mean threshold by 200 which would occur with teeth grinding a still further embodiment shown in fig8 has a tiny radio transmitter 30 which is within the earpiece i e within the body of probe body 1 the transmitter preferably a room range fm transmitter broadcasts to the receiver 31 which may be on the bedside table etc thee receiver 31 is part of a data processing system 32 which includes data storage 33 the patient 39 s emg data from the ear channel is received and stored over a period for example 1 to 2 hours.