Memory tests using item-specific weighted memory measurements and uses thereof

• US 20020016531A1
• Filed: 08/08/2001
• Published: 02/07/2002
• Est. Priority Date: 08/06/1999
• Status: Active Grant

• Current Assignee: Herman Buschke
• Original Assignee: Herman Buschke
• Inventors: Buschke, Herman
• Granted Patent: US 6,689,058 B2
• Time in Patent Office: Days
• US Class Current: 600/300
• CPC Class Codes: A61B 5/16 Devices for psychotechnics using teaching or educational appliances G09B1/00 - G09B7/00; Testing reaction times ; Devices for evaluating the psychological state
• CPC Class Codes: A61B 5/165 Evaluating the state of mind, e.g. depression, anxiety
• CPC Class Codes: A61B 5/4088 Diagnosing of monitoring cognitive diseases, e.g. Alzheimer, prion diseases or dementia
• CPC Class Codes: G09B 19/00 Teaching not covered by other main groups of this subclass teaching or practice apparatus for gun-aiming or gun-laying F41G3/26
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment
• CPC Class Codes: G16H 50/70 for mining of medical data, e.g. analysing previous cases of other patients

Abstract

This invention relates to a method for increasing the usefulness, sensitivity and specificity of tests that measure memory and facets of memory, including learning, retention, recall and/or recognition. Specifically, the sensitivity and specificity of such tests are enhanced by selectively weighting the value of specific items recalled by the test subject, either by weighting such items within any specific testing trial or across numerous testing trials. Also disclosed are various methods of reducing ceiling effects in memory tests. The invention also provides improved tests which employ item-specific weighting for the diagnosis of Alzheimer'"'"'s Disease and other dementia characterized by memory impairment, as well as a method of screening for and evaluating the efficacy of potential therapeutics directed to the treatment of such dementia.

Claims

1. A method for measuring memory in a subject, comprising the steps of:

(a) assigning a separate weighted value to each item in a list of items to be recalled from memory;

(b) presenting the list of items to a subject;

(c) recording items recalled by the subject; and

(d) analyzing the assigned values of items recalled by the subject.

2. The method of claim 1, further comprising introducing an interference delay between presentation and recordation.

3. The method of claim 1, wherein the values are weighted according to the probability of recall of that item by members of a reference group.

4. The method of claim 1, wherein the values are weighted according to the order in which the items are presented to the subject.

5. The method of claim 1, wherein the values are weighted according to the relative difficulty of recalling the item.

6. The method of claim 1, wherein the step of analyzing the assigned values comprises calculating a score for the subject based on the weighted values and comparing the score to a reference score.

7. The method of claim 6, wherein the reference score establishes memory impairment.

8. The method of claim 7, wherein the memory impairment is indicative of dementia.

9. The method of claim 8, wherein the dementia is Alzheimer'"'"'s Disease.

10. A method for measuring memory in a subject, comprising the steps of:

(a) presenting to a subject a list of items to be recalled from memory by the subject;

(b) recording items recalled by the subject;

(c) assigning a separate weighted value to each item recalled by the subject; and

(d) analyzing the assigned values of items recalled by the subject.

11. The method of claim 10, further comprising introducing an interference delay between presentation and recordation.

12. The method of claim 10, wherein the values are weighted according to the probability of recall of that item by members of a reference group.

13. The method of claim 10, wherein the values are weighted according to the order in which the items are recalled by the subject.

14. The method of claim 10, wherein the values are weighted according to the relative difficulty of recalling the item.

15. The method of claim 10, wherein the step of analyzing the assigned values comprises calculating a score for the subject based on the weighted values and comparing the score to a reference score.

16. The method of claim 16, wherein the reference score establishes memory impairment.

17. The method of claim 16, wherein the memory impairment is indicative of dementia.

18. The method of claim 17, wherein the dementia is Alzheimer'"'"'s Disease.

20. The method of claim 19, further comprising introducing an interference delay between presentation and recordation.

21. The method of claim 19, wherein the values are further weighted according to the probability of recall of that item by members of a reference group.

22. The method of claim 19, wherein the values are further weighted according to the relative difficulty of recalling the item.

23. The method of claim 19, wherein the step of analyzing the assigned values comprises calculating a score for the subject based on the weighted values and comparing the score to a reference score.

24. The method of claim 24, wherein the reference score establishes memory impairment.

25. The method of claim 24, wherein the memory impairment is indicative of dementia.

26. The method of claim 25, wherein the dementia is Alzheimer'"'"'s Disease.

28. The method of claim 27, wherein the value of each item recalled in each trial is weighted according to whether the item has been recalled in the preceding trial or the following trial.

29. The method of claim 28, wherein the values are further weighted according to the probability of recall of that item by members of a reference group.

30. The method of claim 27, wherein the values are further weighted according to the order in which the items are presented to the subject.

31. The method of claim 27, wherein the values are further weighted according to the relative difficulty of recalling the item.

32. The method of claim 28, wherein the step of analyzing the assigned values comprises calculating a score for the subject based on the weighted values and comparing the score to a reference score.

33. The method of claim 32, wherein the reference score establishes memory impairment.

34. The method of claim 33, wherein the memory impairment indicates dementia.

35. The method of claim 34, wherein the dementia is Alzheimer'"'"'s Disease.

37. The method of claim 36, further comprising a third trial, in which items not recalled by the subject from memory in the first or second trials are presented to the subject in the third trial.

38. The method of claim 36, wherein the value of each item recalled in each trial is weighted according to whether the item has been recalled in the preceding trial or the following trial.

39. The method of claim 38, wherein the value of each item recalled in each trial is further weighted according to whether the item was recalled by the subject with or without presentation.

40. The method of claim 36, wherein the step of analyzing the assigned values comprises calculating a score for the subject based on the weighted values and comparing the score to a reference score.

41. The method of claim 40, wherein the reference score establishes memory impairment.

42. The method of claim 41, wherein the memory impairment is indicative of dementia.

43. The method of claim 42, wherein the dementia is Alzheimer'"'"'s Disease.

44. The method of claim 36, wherein the step of analyzing the assigned values comprises calculating the number of trials before the subject recalls an item for the first time.

45. The method of claim 36, wherein the step of analyzing the assigned values comprises calculating the number of trials before the subject recalls an item without presentation after said item has been recalled with presentation in a previous trial.

46. The method of claim 36, comprising calculating the number of trials before the subject recalls an item across two successive trials without presentation.

47. A method of screening agents directed to the treatment or prevention of dementia characterized by memory impairment, comprising the steps of:

(a) performing the method of claims 6, 15, 23, 32 or 40 to obtain a first score;

(b) providing a selected agent to a subject;

(c) performing the selected method of step (a) to obtain a second score; and

(d) analyzing the effect of the selected agent on the second score.

19. A method for measuring memory in a subject, comprising the steps of:

(a) presenting a list of items to a subject to be recalled from memory by the subject;

(b) recording items recalled by the subject;

(c) assigning a separate weighted value to each item recalled by the subject, wherein the value for each item is weighted according to the period of retention of the item by the subject before recall; and

(d) analyzing the assigned values of items recalled by the subject.

27. A method for measuring memory in a subject, comprising the steps of:

(a) in a first trial, presenting a list of items to a subject to be recalled from memory by the subject;

(b) recording items that are recalled by the subject from memory;

(c) repeating the steps of (a) and (b) at least two more times;

(d) assigning a separate weighted value to each item recalled by the subject from memory in each trial; and

(e) analyzing the assigned values of the items recalled by the subject.

36. A method for measuring memory in a subject, comprising the steps of:

(a) in a first trial, presenting a list of items to a subject to be recalled from memory by the subject;

(b) recording items that are recalled by the subject from memory;

(c) in a second trial, presenting to the subject items not recalled by the subject from memory in the first trial;

(d) recording all items recalled by the subject from memory;

(e) assigning a separate weighted value to each item recalled by the subject from memory in each trial; and

(f) analyzing the assigned values of the items recalled by the subject.

48. A method of screening agents directed to the treatment or prevention of dementia characterized by memory impairment, comprising the steps of:

(a) administering a conventional serial processing memory test to members of a control group;

(b) providing a selected agent to members of a test group and administering a serial processing memory test to members of the test group;

(c) generating serial position curves for each group using the results of the serial processing memory tests;

(d) selectively weighting items of the serial position curves to generate weighted serial position curves; and

(e) determining the effect of the selected agent on the test group by analyzing the serial position curves of the control group and the test group.

49. A method of screening agents directed to the treatment or prevention of dementia characterized by memory impairment, comprising the steps of:

(a) administering a conventional serial processing memory test to members of a group;

(b) providing a selected agent to members of the group and again administering the conventional serial processing memory test to members of the group;

(c) generating serial position curves for the group using results of the serial processing memory tests before and after providing the selected agent;

(d) selectively weighting items of the serial position curves to generate weighted serial position curves; and

(e) determining the effect of the selected agent by analyzing the serial position curves before and after administration of the selected agent.

50. A method of reducing ceiling effects in serial processing memory tests, comprising introducing an interference delay between (a) presentation of a list of items to a subject wherein said items are to be recalled from memory by the subject and (b) first recall of the items by the subject from memory.

51. A method of reducing ceiling effects in serial processing memory tests using free and cued recall, comprising scoring the test by selectively weighting the value of each item recalled by the subject without presentation of a cue.

52. A method for measuring memory in a subject, comprising the steps of:

(a) serially presenting to a subject a list of items to be recalled from memory together with an associated cue for each item, where each cue is a common adjective describing the associated item;

(b) serially presenting to the subject the associated cue for each item to be recalled from memory by the subject, where the cues are serially presented in reverse order than the initial presentation order in step (a);

(c) recording each item recalled by the subject after presentation of the associated cue;

(d) assigning a separate weighted value to each item recalled by the subject, wherein the value for each item is weighted according to the period of retention of the item by the subject before recall; and

(e) analyzing the assigned values of items recalled by the subject.

53. The method of claim 52, wherein the step of analyzing the assigned values comprises calculating a score for the subject based on the weighted values and comparing the score to a reference score.

54. The method of claim 53, wherein the reference score establishes memory impairment.

55. The method of claim 54, wherein the memory impairment is indicative of dementia.

56. The method of claim 55, wherein the dementia is Alzheimer'"'"'s Disease.