A device for measuring the turbidity of cerebrospinal fluid includes, a source of a light signal comprising having one or more wavelength(s), such that at least part of the emitted light signal passes through the cerebrospinal fluid; a flow element including an inlet and an outlet, the flow element being suitable for allowing cerebrospinal fluid to flow between the inlet and the outlet; an opaque element, arranged to absorb at least part of the emitted light signal after it has passed through the cerebrospinal fluid, and to allow another part of the emitted light signal to be reflected after it has passed through the cerebrospinal fluid; and an optical detector configured to detect the light signal after it has passed through the cerebrospinal fluid.

A medical device may include a lower housing, a printed circuit board (PCB) received within the lower housing, a top housing, two plungers received in gaps within the top housing, and strain gauges mounted to the PCB. The strain gauges may define two polygons aligned with the two plungers. The two plungers may be in contact with the strain gauges such that a force on a plunger is transferred to the strain gauges in contact with the respective plunger. The load magnitude and load location may be determined based on the measured strain of the strain gauges.

A soft conductive composition can include: a crosslinked silicone composition; and single-walled or multi-walled carbon nanotubes in the silicone composition. A neural probe or other implant can include the soft conducive composition on a least a portion of the implant body. A method of making an implant can include: selecting PDMS precursors; cross-linking the PDMS precursor to obtain an elastic modulus of about 3-9 kPa or +/−1%, 5%, 10%, 20%, or 50%; selecting the carbon nanotubes; introducing the carbon nanotubes into the crosslinked PDMS to form a soft conductive composite composition; and coating the soft conductive composite composition onto at least a portion of an implant. A method of measuring properties at a neural interface can include: providing a neural probe having a soft conductive composition; implanting the neural probe having the soft conductive composition at a neural interface; and measuring a property with the neural probe.

An electrode measuring the presence of an analyte is described as one embodiment. The electrode includes a working conductor with an electrode reactive surface and a first reactive chemistry that is responsive to the analyte. The electrode further includes a first transport material that enables flux of the first analyte to the first reactive chemistry and a second transport material that supplies a reactant to the first reactive chemistry. Wherein the first reactive chemistry does not contact the electrode reactive surface while at least partially shadowing a portion of the electrode reactive surface.

Described herein is an implantable device having a sensor configured to detect an amount of an analyte, a pH, a temperature, strain, or a pressure; and an ultrasonic transducer with a length of about 5 mm or less in the longest dimension, configured to receive current modulated based on the analyte amount, the pH, the temperature, or the pressure detected by the sensor, and emit an ultrasonic backscatter based on the received current. The implantable device can be implanted in a subject, such as an animal or a plant. Also described herein are systems including one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transmit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Also described are methods of detecting an amount of an analyte, a pH, a temperature, a strain, or a pressure.

An implantable nerve stimulator is implanted in a patient near a nerve target. The implantable nerve stimulator has a plurality of electrodes through which stimulation is provided to the nerve target. The relative location of the nerve target and the electrodes may be determined by applying stimulation to the nerves via each of the electrodes, determining an effect of the stimulation for each of the electrodes, and mapping a location of the nerve relative to the electrodes based on the effect of the stimulation for each of the electrodes.

An implantable neurostimulator-implemented method for managing tachyarrhythmias through vagus nerve stimulation is provided. An implantable neurostimulator, including a pulse generator, is configured to deliver electrical therapeutic stimulation in a manner that results in creation and propagation (in both afferent and efferent directions) of action potentials within neuronal fibers of a patient's cervical vagus nerve. Operating modes of the pulse generator are stored. A maintenance dose of the electrical therapeutic stimulation is delivered to the vagus nerve via the pulse generator to restore cardiac autonomic balance through continuously-cycling, intermittent and periodic electrical pulses. A restorative dose of the electrical therapeutic stimulation is delivered to prevent initiation of or disrupt tachyarrhythmia through periodic electrical pulses delivered at higher intensity than the maintenance dose. The patient's normative physiology is monitored via a physiological sensor, and upon sensing a condition indicative of tachyarrhythmia, is switched to delivering the restorative dose to the vagus nerve.

A system is disclosed herein for providing a kinetic assessment and preparation of a prosthetic joint comprising one or more prosthetic components. The system comprises a prosthetic component including sensors and circuitry configured to measure load, position of load, and joint alignment. The system further includes a remote system for receiving, processing, and displaying quantitative measurements from the sensors. The kinetic assessment measures joint alignment under loading that will be similar to that of a final joint installation. The kinetic assessment can use trial or permanent prosthetic components. Furthermore, adjustments can be made to the applied load magnitude, position of load, and joint alignment by various means to fine-tune an installation. The kinetic assessment increases both performance and reliability of the installed joint by reducing error that is introduced by elements that load or modify the joint dynamics not taken into account by prior assessment methods.

A multi-sensor system may include a catheter that has lumen, is flexible, is made of a polymer, and has a circular cross section that has an outer diameter of no more than 0.5 cm; and one or more sensors that sense multiple characteristics of material flowing within the lumen, including at least two of the following: flow rate, pressure, and composition of the material. A multi-sensor system may include a catheter that has lumen, is flexible, is made of a polymer, and has a circular cross section that has an outer diameter of no more than 0.5 cm; and one or more sensors that sense multiple characteristics of material flowing within the lumen, including at least two of the following: flow rate, pressure, and composition of the material.

A load sensing assembly for a spinal implant includes a set screw having a central opening that extends from a first end of the set screw toward a second end of the set screw. The second end of the set screw is configured to engage with an anchoring member. The load sensing assembly includes an antenna, an integrated circuit in communication with the antenna, where the integrated circuit is positioned within the central opening of the set screw, and a strain gauge in connection with the integrated circuit. The strain gauge is located within the central opening of the set screw in proximity to the second end of the set screw.