An electrocardiographic signal measuring apparatus includes capacitive coupling type detection electrodes that detect an electrocardiographic signal of a subject without coming into contact with a skin of a body; a first amplifier that amplifies a detection signal detected by the detection electrodes; a feedback circuit that returns an inverted signal obtained by inverting an in-phase signal from the detection electrodes to the body of the subject via a feedback electrode; and guard electrodes placed via an insulator on a side, of the detection electrodes, opposite to a side facing the body of the subject. The detection electrode is connected to one of differential inputs of the second amplifier, the guard electrode is connected to the other of the differential inputs of the second amplifier, and outputs of the second amplifiers are connected respectively to differential inputs of the first amplifier.

Disclosed is an implantable device for measuring an evoked neural response. The implantable device comprises a stimulus source configured to deliver neural stimuli via one or more stimulus electrodes to neural tissue, the neural stimuli being configured to evoke a neural response from the neural tissue. The implantable device further comprises a measurement amplifier configured to amplify a signal sensed between a first input of the measurement amplifier by a first measurement electrode and a second input of the measurement amplifier by a second measurement electrode subsequent to a provided neural stimulus, the sensed signal comprising the evoked neural response. The implantable device further comprises a control unit configured to: control the stimulus source to deliver a neural stimulus; and measure the evoked neural response of the amplified sensed signal. The implantable device further comprises one or more impedance elements configured to provide a negative impedance to at least one of the first and second inputs of the measurement amplifier.

Disclosed is an implantable device for measuring an evoked neural response. The implantable device comprises a stimulus source configured to deliver neural stimuli via one or more stimulus electrodes to neural tissue, the neural stimuli being configured to evoke a neural response from the neural tissue. The implantable device further comprises a measurement amplifier configured to amplify a signal sensed between a first input of the measurement amplifier by a first measurement electrode and a second input of the measurement amplifier by a second measurement electrode subsequent to a provided neural stimulus, the sensed signal comprising the evoked neural response. The implantable device further comprises a control unit configured to: control the stimulus source to deliver a neural stimulus; and measure the evoked neural response of the amplified sensed signal. The implantable device further comprises one or more impedance elements configured to provide a negative impedance to at least one of the first and second inputs of the measurement amplifier.

A system-on-chip contactless physiological sensor (10) is provided which comprises a capacitive-sensor electrode (14) having a first capacitance (C1) and an amplifier device (18) connected to the capacitive-sensor electrode (14), the capacitive-sensor electrode (14) and amplifier device (18) at least in part forming an amplifier circuit for the physiological sensor (10). An artefact-reducing capacitor (20) is then connected in series between the capacitive-sensor electrode (14) and an input of the amplifier device (18), the artefact-reducing capacitor (20) having a second capacitance (C2) which is less than the first capacitance (C1). In this sensor (10), there is no impedance boosting input between the capacitive-sensor electrode (14) and the input of the amplifier device (18).

A system-on-chip contactless physiological sensor (10) is provided which comprises a capacitive-sensor electrode (14) having a first capacitance (C1) and an amplifier device (18) connected to the capacitive-sensor electrode (14), the capacitive-sensor electrode (14) and amplifier device (18) at least in part forming an amplifier circuit for the physiological sensor (10). An artefact-reducing capacitor (20) is then connected in series between the capacitive-sensor electrode (14) and an input of the amplifier device (18), the artefact-reducing capacitor (20) having a second capacitance (C2) which is less than the first capacitance (C1). In this sensor (10), there is no impedance boosting input between the capacitive-sensor electrode (14) and the input of the amplifier device (18).

Earphone apparatus includes dry electrophysiological electrodes and, optionally, other physiological and/or environmental sensors to measure signals such as ECG from the head of a subject. Methods of use of such apparatus to provide fitness, health, or other measured or derived, estimated, or predicted metrics are also disclosed.

Earphone apparatus includes dry electrophysiological electrodes and, optionally, other physiological and/or environmental sensors to measure signals such as ECG from the head of a subject. Methods of use of such apparatus to provide fitness, health, or other measured or derived, estimated, or predicted metrics are also disclosed.

A system and a method for recording neural signals. A neural interface system-on-chip for recoding the signals includes one or more electrodes integrated on a complimentary metal-oxide-semiconductor integrated circuit and coupled to one or more corresponding analog front end components. The analog front end components are configured to be programmable for recording one or more neural signals and to operate in at least one of the following selectable programmable modes: a voltage clamp mode and a current clamp mode. The neural interface system-on-chip also includes one or more analog to digital converter components that are coupled to the electrodes.

A system and a method for recording neural signals. A neural interface system-on-chip for recoding the signals includes one or more electrodes integrated on a complimentary metal-oxide-semiconductor integrated circuit and coupled to one or more corresponding analog front end components. The analog front end components are configured to be programmable for recording one or more neural signals and to operate in at least one of the following selectable programmable modes: a voltage clamp mode and a current clamp mode. The neural interface system-on-chip also includes one or more analog to digital converter components that are coupled to the electrodes.