Devices and methods for monitoring physiological information relating to sleep with an implantable device
View Patent ↗Described here are implantable devices and methods for monitoring physiological information relating to sleep. The implantable devices are generally designed to include at least one sensor for sensing physiological information, a processor for processing the physiological information using low computational power to detect a sleep stage, and a battery. The detected sleep stage information may then be used to indicate sleep quality, identify or monitor a medical condition, or guide treatment thereof.
1. An active implantable medical device for detecting a neurological state of a patient, the device comprising:
one or more electrodes configured to sense electrical brain activity; and
a control module connected to the one or more electrodes, and configured to:
detect a plurality of half waves within an electrographic signal corresponding to electrical brain activity sensed by the one or more electrodes; and
for each of the plurality of detected half waves:
determine an amplitude and a duration of the half wave; and
determine that the half wave is a qualified half wave when the amplitude of the half wave is within a range defined by a minimum half wave amplitude and a maximum half wave amplitude, and the duration of the same half wave is within a range defined by a minimum half wave duration and a maximum half wave duration; and
detect a particular neurological state based on a measure of the qualified half waves.
2. The device of claim 1 , wherein the measure is derived from a count of the number of qualified half waves that occur during a time window, and a particular neurological state is detected when the measure satisfies a criterion indicative of the particular neurological state.
3. The device of claim 2 , wherein:
the measure is an integer;
the criterion is a threshold; and
the particular neurological state is detected when the integer exceeds the threshold.
4. The device of claim 2 , wherein:
the measure is an integer;
the criterion is a range of integers; and
the particular neurological state is detected when the integer is within the range.
5. The device of claim 2 , wherein the control module is configured to detect a particular neurological state based on a measure of the qualified half waves by being further configured to:
classify each qualified half wave as one of a plurality of half-wave types; and
for each of the plurality of half-wave types, determine a half-wave-type number corresponding to the number of qualified half waves classified as the half-wave type.
6. The device of claim 5 , wherein the plurality of half-wave types comprises at least two of the following half-wave types: alpha half-wave, delta half-wave and theta half-wave.
7. The device of claim 1 , wherein the control module is further configured to control an output of an electrical stimulation therapy through at least one of the one or more electrodes, in response to a detection of the particular neurological state.
8. The device of claim 7 , wherein:
the particular neurological state includes at least one of: stage 1 sleep, stage 2 sleep, stage 3 sleep or stage 4 sleep; and
the control module is configured to output a first electrical stimulation therapy characterized as a high frequency stimulation therapy during either of a stage 3 sleep state or a stage 4 sleep state, and to output a second electrical stimulation therapy characterized as a low frequency stimulation therapy during a stage 2 sleep state.
9. The device of claim 7 , wherein:
the particular neurological state includes at least one of: stage 1 sleep, stage 2 sleep, stage 3 sleep or stage 4 sleep; and
the control module is configured to turn off electrical stimulation therapy during either of a stage 3 sleep state or a stage 4 sleep state.
10. A method of detecting a neurological state of a patient, comprising:
sensing electrical brain activity of the patient;
detecting a plurality of half waves within an electrographic signal corresponding to sensed electrical brain activity;
for each of the plurality of detected half waves:
determining an amplitude and a duration of the half wave; and
determining that the half wave is a qualified half wave when the amplitude of the half wave is within a range defined by a minimum half wave amplitude and a maximum half wave amplitude, and the duration of the same half wave is within a range defined by a minimum half wave duration and a maximum half wave duration; and
detecting a particular neurological state based on a measure of the qualified half waves.
11. The method of claim 10 , wherein the measure is derived from a count of the number of qualified half waves that occur during a time window, and a particular neurological state is detected when the measure satisfies a criterion indicative of the particular neurological state.
12. The method of claim 11 , wherein:
the measure is an integer;
the criterion is a threshold; and
the particular neurological state is detected when the integer exceeds the threshold.
13. The method of claim 11 , wherein:
the measure is an integer;
the criterion is a range of integers; and
the particular neurological state is detected when the integer is within the range.
14. The method of claim 11 , wherein detecting a particular neurological state based on a measure of the qualified half waves comprises:
classifying each qualified half wave as one of a plurality of half-wave types; and
for each of the plurality of half-wave types, determining a half-wave-type number corresponding to the number of qualified half waves classified as the half-wave type.
15. The method of claim 14 , wherein the plurality of half-wave types comprises at least two of the following half-wave types: alpha half-wave, delta half-wave and theta half-wave.
16. The method of claim 10 , further comprising controlling an output of an electrical stimulation to the patient, in response to a detection of the particular neurological state.
17. The method of claim 16 , wherein:
the particular neurological state includes at least one of: stage 1 sleep, stage 2 sleep, stage 3 sleep or stage 4 sleep; and
controlling an output of an electrical stimulation comprises: outputting a first electrical stimulation therapy characterized as a high frequency stimulation therapy during either of a stage 3 sleep state or a stage 4 sleep state, and outputting a second electrical stimulation therapy characterized as a low frequency stimulation therapy during a stage 2 sleep state.
18. The method of claim 16 , wherein:
the particular neurological state includes at least one of: stage 1 sleep, stage 2 sleep, stage 3 sleep or stage 4 sleep; and
controlling an output of an electrical stimulation comprises turning off electrical stimulation therapy during either of a stage 3 sleep state or a stage 4 sleep state.