Systems, devices and methods for bilateral caloric vestibular stimulation

• US 9,532,900 B2
• Filed: 06/18/2012
• Issued: 01/03/2017
• Est. Priority Date: 12/17/2010
• Status: Active Grant

• Current Assignee: Scion Neurostim Incorporated
• Original Assignee: Scion Neurostim, LLC
• Inventors: Smith, Lanty L., Rogers, Lesco L., Black, Robert D.
• Primary Examiner(s): Stoklosa, Joseph
• Assistant Examiner(s): ZINK, AMANDA L
• Application Number:
  US13/525,765
• Publication Number:
  US 20120316624A1
• Time in Patent Office: 1,660 Days
• Field of Search: 606 27- 28, 607/96, 607112-113, 600/379
• US Class Current: 1/1
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61F 2007/0005 Ears
• CPC Class Codes: A61F 2007/0075 using a Peltier element, e.g. near the spot to be heated or cooled
• CPC Class Codes: A61F 2007/0093 programmed
• CPC Class Codes: A61F 2007/0095 with a temperature indicator
• CPC Class Codes: A61F 2007/0096 with a thermometer
• CPC Class Codes: A61F 2007/0296 Intervals of heating alternated with intervals of cooling
• CPC Class Codes: A61F 7/007 characterised by electric heating
• CPC Class Codes: A61F 7/12 Devices for heating or cooling internal body cavities
• CPC Class Codes: A61N 1/36036 of the outer, middle or inner ear
• CPC Class Codes: A61N 2/002 in combination with another treatment
• CPC Class Codes: A61N 2/006 for magnetic stimulation of nerve tissue

Abstract

An in-ear stimulation device for administering caloric stimulation to the ear canal of a subject includes (a) first and second earpieces configured to be insertable into the ear canals of the subject; (b) at least first and second thermoelectric devices thermally coupled to respective ones of the first and second earpieces; (c) a first heat sink thermally coupled to the first thermoelectric device opposite the first earpiece and a second heat sink thermally coupled to the second thermoelectric device opposite the second earpiece; and (d) a controller comprising a waveform generator in communication with the first and second thermoelectric devices, the waveform generator configured to generate a first control signal to control a first caloric output to the first thermoelectric device and a second control signal to control a second caloric output to the second caloric device.

Claims

1. An in-ear stimulation device for administering caloric stimulation to the ear canal of a subject, comprising:

(a) first and second earpieces configured to be insertable into the ear canals of the subject;

(b) at least first and second thermoelectric devices thermally coupled to respective ones of the first and second earpieces;

(c) a first heat sink thermally coupled to the first thermoelectric device opposite the first earpiece and a second heat sink thermally coupled to the second thermoelectric device opposite the second earpiece; and

(d) a controller comprising a waveform generator in communication with the first and second thermoelectric devices, the waveform generator configured to generate a first control signal to control a first caloric output to the first thermoelectric device and a second control signal to control a second caloric output to the second thermoelectric device, wherein the first caloric output is configured to induce a first degree of nystagmus of the subject when delivered to the subject in an absence of the second caloric output, and the second caloric output is configured to induce a second degree of nystagmus of the subject when delivered to the subject in an absence of the first caloric output, and the first and second caloric outputs are together configured such that when the first and second caloric outputs are delivered simultaneously to the subject, a reduced degree of nystagmus is induced that is less than that of either the first or second degree of nystagmus individually.

2. The in-ear stimulation device of claim 1, wherein the first control signal is different from the second control signal.

3. The in-ear stimulation device of claim 1, wherein the first control signal is out-of-phase with the second control signal.

4. The in-ear stimulation device of claim 1, wherein when a slope of the first control signal is increasing, a slope of the second control signal decreases, and when a slope of the first control signal is decreasing, a slope of the second control signal increases.

5. The in-ear stimulation device of claim 1, further comprising an electrical connection between the first and second earpieces, wherein the controller comprises an impedance monitor configured to measure an impedance value between the first and second earpieces.

6. The in-ear stimulation device of claim 5, wherein the impedance monitor generates an estimate of a thermal contact of the first and second earpieces responsive to the impedance value.

7. The in-ear stimulation device of claim 6, wherein the impedance monitor estimates a poor thermal contact of the first and second earpieces when the impedance value indicates an open circuit.

8. The in-ear stimulation device of claim 6, wherein the impedance monitor is configured to determine whether the first and second earpieces are in position in the subject'"'"'s ear canals during administration of the first and second control signals to thereby determine a patient compliance with treatment protocol.

9. The in-ear stimulation device of claim 6, wherein the waveform generator is configured to increase an amplitude of at least one of the first and second caloric outputs responsive to a decrease in the estimate of thermal contact.

10. The in-ear stimulation device of claim 1, wherein the first and second heat sinks each comprise an outer portion positioned outside of the respective first and second earpieces and an inner portion positioned inside respective earpiece internal cavities.

11. The in-ear stimulation device of claim 1, wherein the first and second heat sink outer portions comprise a plurality of fins.

12. The in-ear stimulation device of claim 1, wherein the first and second heat sinks comprise aluminum and have a weight between about 30 grams and about 70 grams.

13. The in-ear stimulation device of claim 1, wherein the first and second earpieces are formed from a rigid, thermally-conductive material.

14. The in-ear stimulation device of claim 1, wherein the first and second earpieces comprise aluminum.

15. The in-ear stimulation device of claim 1, wherein the first and second earpieces weigh about 9 grams or less.

16. The in-ear stimulation device of claim 1, wherein the first and second earpieces weigh about 4 grams or less.

17. The in-ear stimulation device of claim 1, wherein each of the first and second thermoelectric devices comprise a first plurality of thermoelectric devices and a second plurality of thermoelectric devices respectively.

18. The in-ear stimulation device of claim 17, wherein the first plurality of thermoelectric devices are thermally coupled to one another and the second plurality of thermoelectric devices are thermally coupled to one another.

19. The in-ear stimulation device of claim 1, wherein the first and second thermoelectric devices comprise a thin film thermoelectric device.

20. The in-ear stimulation device of claim 1, further comprising a headpiece configured to position the first earpiece in the right ear canal of the subject and to position the second earpiece in the left ear canal of the subject.

21. The in-ear stimulation device of claim 1, wherein the first and second control signals are configured such that the first and second caloric outputs are continuously temporally varying thermal waveforms and/or actively controlled waveforms.

22. The in-ear stimulation device of claim 1, wherein the first and second control signals are configured such that the first and second caloric outputs comprise at least one period of a temporally varying thermal waveform, and at least one period of stasis.

23. The in-ear stimulation device of claim 1, wherein the first caloric output cools one of the subject'"'"'s ear canals and the second caloric output heats the other of the subject'"'"'s ear canals.

24. The in-ear stimulation device of claim 1, wherein the first and second caloric outputs are configured to maintain a vestibular stimulation of the subject for at least five minutes.

25. The in-ear stimulation device of claim 23, wherein the vestibular stimulation for at least five minutes is sufficient to alter a vestibular phasic firing rate to thereby induce nystagmus over a period of at least five minutes.

26. The in-ear stimulation device of claim 24, wherein the nystagmus is sufficient to be detected using videonystagmography and/or electronystagmography.

27. The in-ear stimulation device of claim 1, wherein the first and second earpieces, the first and second heat sinks, and the first and second thermoelectric devices are configured so that the first and second earpieces are cooled by the respective first and second thermoelectric devices at a rate of about 15°

C. per minute or more and heated by the respective first and second thermoelectric devices at a rate of about 20°

C. per minute or more.

28. The in-ear stimulation device of claim 1, further comprising at least one fan coupled to each of the first and second heat sinks, respectively, and configured to increase thermal dissipation from the first and second heat sinks, respectively.

29. The in-ear stimulation device of claim 28, wherein the at least one fan comprises at least two fans.

30. The in-ear stimulation device of claim 28, wherein the at least one fan is configured to direct air in a direction toward the heat sink.

31. The in-ear stimulation device of claim 1, further comprising a securing member configured to secure the first and second earpieces in the ear canal such that an impedance value between the first and second earpieces is substantially constant.

32. The in-ear stimulation device of claim 31, wherein the securing member comprises a first ear enclosure having at least one adjustable bladder configured to increase in size to thereby decrease a pressure from the first earpiece in the ear canal, and to decrease in size to thereby increase a pressure from the first earpiece in the ear canal.

33. The in-ear stimulation device of claim 1, wherein the first and second earpieces further comprise a distal end configured to be inserted in the ear canal and a proximal end connected to the respective first and second thermal electric devices, wherein the first and second earpieces further comprise an insulating member on the proximal end thereof.

34. The in-ear stimulation device of claim 33, wherein the insulating member comprises silicone and is configured for positioning in the concha of the ear.

35. The in-ear stimulation device of claim 1, wherein the first and second earpieces include a pressure relief channel that is sized and configured such that fluid flows through the pressure relief channel during insertion of the earpiece into the ear canal to thereby relieve pressure in the ear canal of the subject during earpiece insertion.

36. The in-ear stimulation device of claim 1, further comprising a first temperature sensor coupled to the first earpiece and a second temperature sensor coupled to the second earpiece.

37. The in-ear stimulation device of claim 36, wherein the controller is in communication with the first and second temperature sensors and is configured to receive temperature information from the first and second temperature sensors, and the controller is configured to cease operation of the waveform generator if the temperature information indicates a temperature above or below a predefined temperature range.

38. The in-ear stimulation device of claim 1, further comprising a first temperature sensor coupled to the first heat sink and a second temperature sensor coupled to the second heat sink.

39. The in-ear stimulation device of claim 38, wherein the controller is in communication with the first and second temperature sensors and is configured to receive temperature information from the first and second temperature sensors, and the controller is configured to cease operation of the waveform generator if the temperature information indicates a temperature above or below a predefined temperature range.

40. The in-ear stimulation device of claim 39, wherein the controller is configured to store the temperature information and to analyze the temperature information to determine a likelihood that the first and second earpieces are in thermal contact with the ear canals of the subject during use.

41. The in-ear stimulation device of claim 1, wherein the controller comprises a voltage monitor that detects a voltage delivered by the waveform generator to the first and/or second thermoelectric devices, the controller being configured to cease operation of the waveform generator if the voltage is greater than a predefined voltage threshold.

42. The in-ear stimulation device of any of claims 41, further comprising a wired connection between the controller and the first and second thermoelectric devices, wherein the wired connection is configured to deliver the first and second control signals to the first and second thermoelectric device.

43. The in-ear stimulation device of claim 42, further comprising a first temperature sensor coupled to the first heat sink and a second temperature sensor coupled to the second heat sink.

44. The in-ear stimulation device of claim 42, wherein the first and second temperature sensors are configured to transmit temperature information wirelessly.

45. The in-ear stimulation device of claim 44, wherein the first and second temperature sensors are configured to transmit temperature information wirelessly to the controller.

46. The in-ear stimulation device of claim 44, wherein the first and second temperature sensors are configured to transmit temperature information wirelessly to an external device.

47. The in-ear stimulation device of claim 1, wherein the first and second caloric outputs are actively controlled waveforms.

48. The in-ear stimulation device of claim 47, where the waveforms of the first and second caloric outputs are independently controlled based on one or more of the following parameters:

temperature amplitude, frequency, time varying frequency, a phasic relationship between the waveforms of the first and second caloric outputs, stochastic and/or structured noise modulation of a temperature, frequency and/or phase of the waveforms of the first and second caloric outputs.

49. The in-ear stimulation device of claim 1, wherein the reduced degree of nystagmus comprises essentially no net horizontal nystagmus.

50. The in-ear stimulation device of claim 1, wherein the reduced degree of nystagmus comprises a reduced vertical nystagmus.

51. The in-ear stimulation device of claim 1, wherein when the first and second caloric outputs are delivered simultaneously to the subject, a reduced degree of dizziness and/or nausea results that is less than that a degree of dizziness and/or nausea when either one of the first or the second caloric outputs are delivered to the subject in an absence of the other one of the first or the second caloric outputs.

52. A method for delivering caloric stimulation to a subject, the method comprising:

positioning at least a portion of an in-ear stimulation device in the ear canals of the subject, the in-ear stimulation device comprising;

(a) first and second earpieces configured to be insertable into the ear canals of the subject;

(b) at least first and second thermoelectric devices thermally coupled to respective ones of the first and second earpieces; and

(c) a first heat sink thermally coupled to the first thermoelectric device opposite the first earpiece and a second heat sink thermally coupled to the second thermoelectric device opposite the second earpiece;

delivering a first control signal to control a first caloric output to the first thermoelectric device and a second control signal to control a second caloric output to the second thermoelectric device such that the first and second thermoelectric devices effect corresponding temperature changes to the first and second earpieces, respectively, to deliver caloric stimulation to the subject, wherein the first caloric output is configured to induce a first degree of nystagmus of the subject when delivered to the subject in an absence of the second caloric output, and the second caloric output is configured to induce a second degree of nystagmus of the subject when delivered to the subject in an absence of the first caloric output, and the first and second caloric outputs are together configured such that when the first and second caloric outputs are delivered simultaneously to the subject, a reduced degree of nystagmus is induced that is less than that of either the first or second degree of nystagmus individually.

53. The method of claim 52, further comprising adjusting the first and second caloric outputs in response to a heart rate variability measurement.

54. The method of claim 53, wherein the first and second caloric outputs are adjusted in response to heart rate variability measurements after an application of a treatment waveform.

55. The method of claim 52, wherein the first caloric output and the second caloric output are selected based on a region of a brain in which stimulation is desired.

56. The method of claim 52, wherein the first caloric output and the second caloric output vary over time so that the firing rates of the vestibular hair cells are modulated over time.

57. The method of claim 52, wherein the first and second caloric outputs are independently controlled based on one or more of temperature amplitude, frequency, time-varying frequency, phasic relationship between the first and second caloric outputs, and/or stochastic and/or structured noise modulation of waveform temperature, frequency or phase of the first and second caloric outputs.

58. The method of claim 52, further comprising treating a subject at least two to three times a week over a period of at least one week.

59. The method of claim 58, further comprising adjusting the first and second caloric outputs in response to an assessment of effect on symptoms.

60. The method of claim 52, wherein the first and second caloric outpus are actively controlled time-varying waveforms such that an intensity of the first and second caloric outputs is repeatedly adjusted in response to active feedback from first and second temperature sensors mounted on the first and second earpieces, respectively.