Minimally Invasive Monitoring Systems
The present invention provides systems and methods for ambulatory, long term monitoring of a physiological signal from a patient. At least a portion of the systems of the present invention may be implanted within the patient in a minimally invasive manner. In preferred embodiments, brain activity signals are sampled from the patient with an externally powered leadless implanted device and are transmitted to a handheld patient communication device for further processing.
1 . A minimally invasive system for ambulatory monitoring brain activity, the system comprising:
an implantable device adapted to be positioned between an outer surface of a patient's skull and at least one layer of the scalp and comprising components adapted to sample a brain activity signal and wirelessly transmit a data signal encoded with the sampled brain activity signal; and
an external device configured to transmit a signal to the implantable device to interrogate the implanted device and facilitate a substantially continuous sampling of the brain activity signal,
wherein the data signal encoded with the sampled brain activity signal from the implantable device is based on the interrogating signal transmitted from the external device and wherein the external device is configured to receive and store the wirelessly transmitted data signal encoded with the sampled physiological signal.
2 . The system of claim 1 wherein the implantable device is leadless, passive and externally powered and the external device comprises a signal generator that generates an output that powers the components of the implantable device.
3 . (canceled)
4 . The system of claim 2 wherein the components of the leadless implantable device comprises:
an antenna adapted to receive the output from the external device and to transmit the data signal; and
a microprocessor that is interrogated by the output from the signal generator and is adapted to sample the brain activity signal and encode the brain activity signal in the data signal that is transmitted by the antenna.
5 . The system of claim 1 wherein the signal from the external device comprises a radiofrequency signal and wherein the implantable device comprises a power source that powers the components of the implantable device and the data signal transmitted from the implantable device comprises a back-scattered radiofrequency signal.
6 . The system of claim 1 wherein the external device further comprises:
a digital signal processor that processes the sampled brain activity signal to estimate the patient's brain state; and
a user interface that is configured to provide an output to the patient regarding their brain state.
7 . The system of claim 6 wherein the brain state is indicative of the patient's propensity for a seizure.
8 . The system of claim 6 wherein the brain state is indicative of a propensity for a migraine headache, tremor, or episode of depression.
9 . A device for recording substantially continuously sampled EEG signals from a patient, the device comprising:
a signal generator for generating a radiofrequency signal that is configured to interrogate and illuminate one or more implantable devices, the implantable devices being configured to substantially continuously sample an EEG signal from the patient;
one or more antennas adapted to transmit the generated radiofrequency signal and receive a radiofrequency signal from the implanted device that is encoded with data that is indicative of the sampled EEG signal, wherein the radiofrequency signal from the implantable device is based on the radiofrequency signal transmitted from the signal generator; and
a memory for storing the data that is indicative of the substantially continuously sampled EEG signal.
10 . (canceled)
11 . The device of claim 9 further comprising a microprocessor for processing the data that is indicative of a sampled EEG signal to estimate the patient's brain state.
12 . The device of claim 11 wherein the brain state is indicative of the patient's propensity for a seizure.
13 . The device of claim 11 wherein the brain state is indicative of the patient's propensity for a migraine headache, tremor, or episode of depression.
14 . The device of claim 11 further comprising a user interface that is configured to indicate when the implantable devices are out of communication range.
15 . The device of claim 11 further comprising a user interface that is configured to provide a substantially continuous output communication to the patient regarding their brain state.
16 . The device of claim 15 wherein the output communication indicates if the patient is in a contra-ictal brain state, an unknown brain state, or a pro-ictal brain state.
17 . A leadless implantable device for monitoring a patient's EEG, the device comprising:
a leadless housing;
electronic components disposed within the leadless housing;
an antenna coupled to the electronic components, the antenna being configured to receive a radiofrequency signal that interrogates and temporarily illuminates the electronic components; and
a plurality of electrodes in communication with the electronic components, wherein the illuminated electronic components are configured to facilitate sampling of a EEG signal from a patient with the plurality of electrodes,
wherein the electronic components are configured to substantially continuously transmit a radiofrequency signal through the antenna that is encoded with data that is indicative of the sampled EEG signal to an external device.
18 . The device of claim 17 wherein the leadless housing is adapted to be implanted between a patient's skull and scalp.
19 . (canceled)
20 . The device of claim 17 wherein the leadless housing comprises a first portion that houses the electronic components and a second portion that houses the antenna, wherein a first electrode is disposed on one end of the second portion of the housing and a second electrode is disposed on one end of the first portion of the housing.
21 . The device of claim 20 wherein the first portion of the housing is shielded to substantially shield the electronic components.
22 .- 24 . (canceled)
25 . The device of claim 17 further comprising an anchoring assembly coupled to the leadless housing that couples the leadless housing to the skull or the scalp.
26 . (canceled)
27 . The device of claim 17 further comprising an internal power source that is in communication with the electronic components.
28 . The device of claim 17 wherein the electronic components comprise an energy scavenging assembly that derives and stores power from patient-based energy sources.
29 . The system of claim 11 wherein the implantable device comprises an energy scavenging assembly that derives and stores power from patient-based energy sources.
30 . An implantable device for monitoring a patient's brain activity signals, the device comprising:
a housing;
electronic components disposed within the housing;
an energy scavenging assembly that derives and stores power from patient-based energy sources;
an antenna coupled to the electronic components; and
a plurality of electrodes in communication with the electronic components, wherein the illuminated electronic components are configured to facilitate sampling of a brain activity signal from a patient with the plurality of electrodes,
wherein the electronic components are configured to substantially continuously transmit a radiofrequency signal through the antenna that is encoded with data that is indicative of the sampled brain activity signal to an external device.
31 . The device of claim 30 wherein the patient-based energy sources comprises movement of organs or bodily fluids.
32 . The device of claim 30 wherein the patient-based energy sources comprises kinetic movement or vibrations of the patient.