Techniques for user-activated data retention in an implantable medical device

• US 8,024,029 B2
• Filed: 11/02/2005
• Issued: 09/20/2011
• Est. Priority Date: 11/02/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Werder, Jonathan C., Drew, Touby A., Giftakis, Jonathon E., Graves, Nina M., Carlson, David L.
• Primary Examiner(s): Patel; Niketa
• Assistant Examiner(s): Lavert; Nicole F
• Application Number:
  US11/264,915
• Publication Number:
  US 20060094972A1
• Time in Patent Office: 2,148 Days
• Field of Search: 607/27, 600/510, 600/522
• US Class Current: 600/510
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/335 using integrated circuit memory devices
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/37 Intracranial electroencephalography [IC-EEG], e.g. electrocorticography [ECoG]
• CPC Class Codes: A61B 5/384 Recording apparatus or displays specially adapted therefor
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• 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: G16H 40/63 for local operation

Abstract

Apparatus for storing data records associated with a medical monitoring event in a data structure. Upon indication by a patient of a possible manifestation of a neurological event, the implanted device obtains and stores data in the data record in a first data structure that is age-based. Before an oldest data record is lost, the oldest data record may be stored in a second data structure that is priority index-based. The priority index may be determined by a severity level and may be further determined by associated factors. The implanted device may organize, off-load, report, and/or display a plurality of data records based on an associated priority index. Additionally, the implanted device may select a subset or composite of physiologic channels from the available physiologic channels based on a selection criterion.

Claims

1. A medical device for monitoring physiologic activity, comprising:

(A) a monitoring element configured to obtain at least one physiological signal;

(B) an event detection component configured to determine an occurrence of a neurological event based on the at least one physiological signal;

(C) a memory component configured to store the at least one physiological signal as a plurality of data records, each data record representing information about an associated event, the memory component comprising a first data structure and a second data structure; and

(D) a processing component operably interfacing with the monitoring element and the memory component and configured to;

(i) replace at least a portion of an existing data record in the first data structure with a new data record;

(ii) determine an associated priority index of the existing data record; and

(iii) store in the second data structure at least the portion of the existing data record that was replaced from the first data structure if the associated priority index of the existing data record exceeds a threshold criterion.

2. The medical device of claim 1, wherein the processing component is configured to assigns a high priority index to the new data record if the event detection component determines possible occurrence of the neurological event based on the at least one physiological signal.

3. The medical device of claim 1, further comprising:

(E) an external device, wherein the processing component is configured to assign a high priority index to the new data record if the external device initiates recording of the new data record.

4. The medical device of claim 3, wherein the external device is an external activator device.

5. The medical device of claim 3, wherein the external device is an external wearable device.

6. The medical device of claim 5, wherein the external wearable device is selected from the group consisting of a wearable patch, a wristwatch, and a wearable computing device.

7. The medical device of claim 1, further comprising:

(E) an external device, wherein the processing component is configured to assign a higher priority index to the new data record if the external device initiates recording of the new data record but the event detection component has not determined the possible occurrence of the neurological event.

8. The medical device of claim 1, wherein the processing component is configured so that (D)(iii) is performed only if the old priority index is greater than another priority index of another data record in the second data structure, and wherein the other data record is marked for deletion.

9. The medical device of claim 1, wherein the processing component is configured so that (D)(iii) comprises compressing at least a portion of the old data record that is stored in the second data structure.

10. The medical device of claim 1, wherein the determination in (D)(ii) further comprises:

(1) determine an old severity level that is associated with the existing data record, wherein the old severity level is a metric of an associated neurological event'"'"'s severity.

11. The medical device of claim 1, wherein the store in (D)(iii) further comprises:

(1) wherein store is performed only if the old priority index is greater than an other priority index of another data record in the second data structure, and wherein the other data record is deleted.

12. The medical device of claim 1, wherein the first monitoring element is a plurality of monitoring elements associated with a set of physiological channels and the associated priority index is based on slew-rate limited output associated with the set of physiologic channels.

13. A medical device, comprising:

(A) a first monitoring element configured to obtain a plurality of neurological signals;

(B) a second monitoring element configured to obtain a plurality of physiological signals;

(B) an event detection component configured to determine an occurrence of a neurological event based on the neurological signal and the physiological signal;

(C) a memory component configured to store the plurality of neurological signals and the plurality of physiological signals as a plurality of data records, each data record associating a respective neurological signal and physiological signal and representing information about an associated neurological event, the memory component comprising a first data structure and a second data structure; and

(D) a processing component operably interfacing with the first and second monitoring element and the memory component and configured to;

(i) replace at least a portion of an existing data record in the first data structure with a new data record;

(ii) determine an associated priority index of the existing data record; and

(iii) store in the second data structure at least the portion of the existing data record that was replaced from the first data structure if the associated priority index of the existing data record exceeds a threshold criterion.

14. The medical device of claim 13, wherein the determination in (D)(ii) is based on a severity of a neurological event associated with the neurological signal.

15. The medical device of claim 13, wherein the priority is based on slew-rate limited output associated with the set of physiologic channels.

16. The medical device of claim 13, wherein the priority is based on a relative chronological occurrence of the associated neurological events.