Techniques for data retention upon detection of an event in an implantable medical device

• US 9,259,177 B2
• Filed: 08/05/2014
• Issued: 02/16/2016
• Est. Priority Date: 11/02/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Drew, Touby A., Giftakis, Jonathon E., Carlson, David L., Panken, Eric J., Werder, Jonathan C., Graves, Nina M.
• Primary Examiner(s): Stice, Paula J
• Application Number:
  US14/452,312
• Publication Number:
  US 20150080674A1
• Time in Patent Office: 560 Days
• Field of Search: 600/513
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/165 Evaluating the state of mind, e.g. depression, anxiety
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4082 Diagnosing or monitoring movement diseases, e.g. Parkinson, Huntington or Tourette
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61N 1/36132 using patient feedback
• CPC Class Codes: A61N 1/3614 based on impedance measurement
• CPC Class Codes: A61N 1/36521 : the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36585 : controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3702 : Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/37252 : Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
• CPC Class Codes: A61N 1/37282 : characterised by communication with experts in remote locations using a network
• CPC Class Codes: G06F 16/2272 : Management thereof
• CPC Class Codes: G16H 10/60 : for patient-specific data, e.g. for electronic patient records
• CPC Class Codes: G16H 10/65 : stored on portable record carriers, e.g. on smartcards, RFID tags or CD
• CPC Class Codes: G16H 20/30 : relating to physical therapies or activities, e.g. physiotherapy, acupressure or exercising
• CPC Class Codes: G16H 40/63 : for local operation
• CPC Class Codes: G16H 40/67 : for remote operation

Abstract

Methods and apparatus for storing data records associated with a medical monitoring event in a data structure. These include initiating loop recording in an implantable medical device upon determination of a neurological event, wherein loop recording comprises storing a data record of a plurality of data records in a data structure, the plurality of data records representing information about determined neurological events. Methods and apparatus can further include determining a priority index for the plurality of data records based on severity levels of the determined neurological events and replacing older data records of the plurality of data records on the data structure with new data records according to the priority index, wherein the new data records selectively replace those data records in the data structure having the lowest associated priority index.

Claims

1. A method of selective data retention in an implantable medical device, the method comprising:

sensing a neurological event that includes ictal content;

creating a data record of the neurological event that includes the ictal content;

determining a severity level of the neurological event by analyzing the ictal content;

storing the data record in a data structure containing a plurality of data records, the plurality of data records representing information about a plurality of neurological events;

determining a priority index for the plurality of data records based on severity levels of the determined neurological events where the higher the severity level the higher the priority index; and

once the data structure is full, selectively replacing an existing data record in the data structure with a newer data record that has a higher priority index than the existing data record.

2. The method of claim 1, wherein the severity levels of the neurological events are based on a duration of the determined neurological events.

3. The method of claim 1, wherein the severity levels of the neurological events are based on a peak ratio of foreground to background ictal content of the determined neurological events.

4. The method of claim 1, wherein the severity levels of the neurological events are based on a spread of ictal content of the determined neurological events.

5. The method of claim 1, wherein storing the data record comprises initiating a loop recording upon detection of the neurological event.

6. The method of claim 5, wherein initiating loop recording occurs upon detection of a seizure.

7. The method of claim 1, wherein storing the data record comprises initiating loop recording upon manual user activation in response to a patient experiencing the neurological event.

8. The method of claim 1, wherein the data structure is present within a circular buffer.

9. An implantable medical device comprising:

a monitoring element configured to sense one or more signals associated with a plurality of neurological events that include ictal content;

a memory component configured to store a plurality of data records in a data structure and replace some of the data records of the plurality of data records stored on the data structure as new data records of the plurality of data records are received in the memory component, the plurality of data records associated with the neurological events and include the ictal content; and

a processing component, the processing component configured to detect the neurological events, create a data record of each neurological event and store a plurality of the data records in the memory component, determine a priority index for the plurality of data records based on severity levels of the detected neurological events, where the severity levels are based on analysis of the ictal content and where the priority index is higher for a higher severity level, and selectively replace an existing data record of the plurality of data records on the data structure with a newer data record having a higher priority index than the existing data record when the data structure is full.

10. The device of claim 9, wherein the processing component is configured to determine the severity levels of the neurological events based on a duration of the detected neurological events.

11. The device of claim 9, wherein the processing component is configured to determine the severity levels of the neurological events based on a peak ratio of foreground to background ictal content of the neurological events.

12. The device of claim 9, wherein the processing component is configured to determine the severity levels of the neurological events based on a spread of ictal content of the detected neurological events.

13. The device of claim 9, wherein the neurological events comprise seizures.

14. The device of claim 9, wherein the memory component comprises a circular buffer that contains the plurality of data records.

15. An implantable medical device comprising:

means for sensing a neurological event that includes ictal content;

means for creating a data record of the neurological event that includes the ictal content;

means for determining a severity level of the neurological event based on analysis of the ictal content;

means for storing the data record in a data structure containing a plurality of data records, the plurality of data records representing information about a plurality of neurological events;

means for determining a priority index for the plurality of data records based on severity levels of the determined neurological events where the priority index is higher for a higher severity level; and

means for selectively replacing an existing data record in the data structure with a newer data record that has a higher priority index when the data structure is full.