Hearing aid with ear EEG recording

A hearing aid comprising;

• a plurality of electrodes, where each of the plurality of electrodes is configured to provide an electrical stimulation to a user of the hearing aid and/or to measure a bio response signal of the user;
• a plurality of electrode channel circuits, where each of the plurality of electrode channel circuits includes:
• an operational amplifier comprising a first input terminal configured to receive the bio response signal and provide an amplified bio response signal, and the operational amplifier includes a first load input;
• a first DC offset unit configured to reduce the impact of DC offset in the electrode channel circuit of the plurality of electrode channel circuits by receiving a part of the amplified bio response signal and converting the received part of the amplified bio response signal to a feedback current signal which is transmitted to the first load input for providing balanced drain currents in the operational amplifier;
• an analog-to digital converter wherein the amplified electrical response signal is converted to a digital electrical signal via the analog-to-digital converter;
• wherein the first DC offset unit includes:
• a controller configured to provide a control signal based on the digital-electrical signal,
• an offset storage capacitor connected to the first input terminal of the operational amplifier or the first load input,
• a pulse current source configured to increase or decrease in discrete steps a voltage level of the offset storage capacitor based on the control signal, and
• wherein the offset storage capacitor is configured to maintain the voltage level at a level proportional to a DC offset voltage at the first input terminal or at the first load input for providing the balanced drain currents of the operational amplifier.