Abstract: An insomnia or vigilance monitor comprising one or more electrodes (1a,1b) for obtaining an electrical signal from a subject over a period of epochs, the electrical signal being related to the sleep or wakefulness stage type being experienced by the subject; and a processor (5) adapted to analyze the electrical signal and assign a sleep or wakefulness stage type to each epoch to generate a hypnogram. Methods of monitoring sleep or vigilance using the mastoid site are also disclosed. Further disclosures relate to a method of training and testing a first neural network for use in a physiological monitor, and a method of assigning a class to an epoch of a physiological signal obtained from a subject as a set of samples.

Abstract: A self contained hand held fetal detector comprises an ultrasonic receiver and transmitter (23). Selectively actuable ultrasonic receiving and transmitting circuits (25,21) are connected to the ultrasonic receiver and transmitter (23) with a controller (24) for actuating either the ultrasonic receiving circuit (25) or the ultrasonic transmitting circuit and a loudspeaker (29) connected to the ultrasonic receiving circuit (25) for generating an audio output signal. The detector comprises a single unit (13) and the controller (24) modifies at least one of the transmitted and received signals, to prevent interference in the received ultrasound.

Abstract: Apparatus for analyzing ECG signals from a patient in the form of a data stream comprises a data stream monitor to locate for each heart beat a trigger point (26,37,25) having a constant temporal displacement with respect to the location of a portion of the ECG signal (31-34) which may include micropotentials. A processor (15) determines which are acceptable beats and, where a heart beat is acceptable, generates and stores an average from successive portions. The resolution at which the average is stored is such that micropotentials present are detectable. The processor is adapted to store a set of averages generated during a corresponding number of time intervals.

Abstract: A magnetic field generating assembly used in NMR apparatus includes a primary magnetic field generator for generating a primary magnetic field which is substantially homogeneous in the working region. The primary magnetic field generator is constructed such that an object to be examined can be introduced from outside the assembly into the working region in a direction transverse to the direction of magnetic flux through the working region. Gradient magnetic field coils are provided for imposing one or more magnetic field gradients through the working region. The gradient magnetic field coils are movable relative to the primary magnetic field generator for positioning locally to the position of an object to be examined in the working region.

Abstract: An ambulatory monitor for monitoring the action of a pacemaker and the cardiac response of a patient fitted with a pacemaker. The monitor comprises a detection electrode coupled in use to the patient for detecting pacemaker pulses and cardiac responses; an analyser connected to the detection electrode fora) analysing the relationship between the detected pacemaker impulses and cardiac responses,b) analysing the shape and timing of the cardiac responses, andc) generating corresponding data signals; and a recorder for recording the data signals.

Abstract: A magnetic field generating assembly comprises at least two counter-running, nested coils (31-33) positioned between and spaced from opposed pole pieces (42, 43). The pole pieces (42, 43) are mounted to a wall of iron (38-41) surrounding the coils, the walls providing a substantially closed magnetic flux path. The arrangement is such that forces on the coils (31-33) due to magnetic flux in the wall are substantially balanced. The gap between the coils (31-33) and at least one of the pole pieces (42, 43) is sufficient to accommodate a human body. The opposed pole pieces (42, 43) are non-planar so that when working currents flow in the coils (31-33) a magnetic field is generated in working regions (48, 49) situated in the gap between the coils and the pole pieces having homogeneities suitable for performing a nuclear magnetic resonance experiment.

Abstract: A magnetic field generating assembly including self-contained modules formed from relatively high temperature superconducting material. A magnetic flux guide, such as a yoke, is positioned relative to the modules so that magnetic flux generated by the modules is coupled into the flux guide.

Abstract: Magnetic field generating apparatus for example for use in a nuclear magnetic resonance system comprises a first set of coils for generating a first magnetic field in a working volume outside the volume defined by the coils. A separate, second coil is provided spaced from the first set of coils for generating a second magnetic field in the working volume. The arrangement is such that the resultant magnetic field in the working volume is substantially homogeneous. An active shield coil may optionally be provided around the first set of coil.

Abstract: A magnet assembly (1) particularly for use in NMR apparatus comprises a first superconducting coil assembly (A,A'-C,C') for generating a first magnetic field; and a second superconducting coil assembly (D-F) for generating a second magnetic field. The second superconducting coil assembly (D-F) is electrically connected in series with the first superconducting coil assembly (A,A'-C,C'). Each coil assembly (A,A'-C,C'; D-F) generates magnetic fields where corresponding components are of substantially the same order of magnitude whereby a resultant, uniform magnetic field is generated in a working volume (3). The second magnetic field opposes the first magnetic field externally of the magnet assembly (1).