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Med 4- Dementia

Med 4- Dementia. Cognitive assessment, evaluation, tests and interpretation. Dr. Frank Molnar Associate Professor of Medicine University of Ottawa Division of Geriatric Medicine. Medical Director, The Ottawa Hospital Geriatric Day Hospital. Objectives.

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Med 4- Dementia

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  1. Med 4- Dementia Cognitive assessment, evaluation, tests and interpretation. • Dr. Frank Molnar • Associate Professor of Medicine University of Ottawa Division of Geriatric Medicine. Medical Director, The Ottawa Hospital Geriatric Day Hospital

  2. Objectives • Describe the principles related to screening for cognitive impairment in high risk elderly and simple tests or tools that can be used. • Compare and contrast common assessment tools in dementia in terms of their utility, advantages and limitations. • Describe an approach to the evaluation of an elderly person with dementia in terms of differential diagnosis of potential cause(s).

  3. Objective 1 Describe the principles related to screening for cognitive impairment in high risk elderly and simple tests or tools that can be used.

  4. In order to truly understand the results of the studies to be reviewed we need to understand: The definitions of sensitivity and specificity How sensitivity and specificity are affected by: Cut-off values employed Overlap of cognitive scores Choice of test The Preliminary Event

  5. Definitions • Sensitivity • % of diseased persons identified as diseased (score below cut-off) • Specificity • % of normal persons identified as normal (score above cut-off)

  6. 1. Sensitivity and specificity are affected by the cut-off score employed

  7. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx x x x x x x x xx x x x x x x x x Specificity = 25% xx x x xx x xxx x x xx xx xx xxx x x x xx xxx xx x xx x x Sensitivity = 100% 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  8. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx x x x x x x x xx x x x x x x x x xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x Specificity = 50% Sensitivity = 87.5% 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  9. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx x x x x x x x xx x x x x x x x x xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x Specificity = 75% Sensitivity = 75% 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  10. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx xx x x x x x x xx x x x x x x x x xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x Specificity = 100% Sensitivity = 62.5% 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  11. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx xx x x x x x x xx x x x x x x x x xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x Specificity = 100% Sensitivity = 35% 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  12. Take Home Message #1 • Sensitivity and Specificity for any given test are dependent on cut-off score studied • For scales where high scores are good and low scores are bad (MMSE, MOCA) • When cut-off is lowered • Sensitivity decreases • Specificity increases • When cut-off is raise • Sensitivity increase • Specificity decreases

  13. Sensitivity vs. Specificity

  14. 2. Sensitivity and specificity are affected by the population in which the test is being used - Overlap of cognitive scores (spectrum of disease)

  15. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx x x x x x x x xx x x x x x x x x xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x Specificity = 75% Sensitivity = 62% 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  16. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx x x x x x x x xx x x x x x x x x xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x Specificity = 75% Sensitivity = 75% 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  17. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx x x x x x x x xx x x x x x x x x xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x Specificity = 75% Sensitivity = 87.5% 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  18. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxx x x x x x x x xx x x x x x x x x Specificity = 75% Sensitivity = 100% xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  19. 30 20 10 MOCA or MMSE Scores for persons with normal cognition Scores for persons with dementia xxxx x x x x x x xxx x xx x xxx Specificity = 100% Sensitivity = 100% xx x x x xxxx x x xxx x xxxxxx xx xxx xxxxx xxx x x x xx x 1) Sensitivity= % with disease who are identified as diseased by test (i.e. % of diseased that fall below cut-off score) 2) Specificity= % of normals who are identified as normal by test (i.e. % of normals that score above cut-off) 0

  20. Less overlap – higher combined sensitivity and specificity 0 30 10 20 Greater overlap – lower combined sensitivity and specificity 0 10 20 30

  21. Correct population distribution 0 30 10 20 Incorrect distribution resulting in exaggerated sensitivity and specificity 0 10 20 30

  22. Take Home Message #2 • The sensitivity and specificity depend on the amount of test score overlap between normal and diseased • Sensitivity and specificity depend on sample / population • Since the populations we take care of clinically are different from those in studies • The Sensitivity and Specificity of a test in clinical practice will likely not match that in studies (we cannot know if it does)

  23. Objective 2 Compare and contrast common assessment tools in dementia in terms of their utility, advantages and limitations. • Sensitivity and Specificity are dependent on the test employed

  24. Choosing the right tool for the job For more information on the MOCA go to www.mocatest.org

  25. MOCA validation process • Developed based on clinical intuition of main author (ZN) • Iterative modification based on 5 years of clinical use • Tested on 46 MCI / AD with MMSE > 24 vs. 46 normal • 5 items replaced & weighting adjusted • Clinical distribution • We are now in the stage of validation • Ongoing process • Main dementia / MCI articles to be reviewed.

  26. 3 MOCA Validation Studies in area of Dementia • Nasreddine et al. The Montreal Cognitive Assessment, MOCA: A brief Screening Tool For Mild Cognitive Impairment. Journal of the American Geriatrics Society 2005; 53: 695-699 • Smith et al. The Montreal Cognitive Assessment: validity and Utility in a Memory Clinic Setting. The Canadian Journal of psychiatry 2007; 52; 329-332 • Luis et al. Cross validation of the Montreal Cognitive Assessment in community dwelling older adults residing in the Southern US. International Journal of Geriatric Psychiatry 2008

  27. Nasreddine et al - Results • MOCA (cut-off 25/26) • 90% SENS to detect MCI • 100% SENS to detect AD • MMSE (cut-off 25/26) • 18% SENS to detect MCI • 78% SENS to detect AD • MOCA seems to win on SENS (particularly for MCI)

  28. Nasreddine et al - Results • SPEC = % Normals ≥ 26 (correctly identified as normal • MOCA (cut-off 25/26) • 87% SPEC to normals • Mislabelled 13% as impaired • MMSE (cut-off 25/26) • 100% SPEC to normals • MMSE seems to win on SPECS

  29. Nasreddine – Results (my interpretation) • The results only describe part of the story • If you lowered the MOCA cut-off, its specificity would improve and sensitivity will drop • If you raise the MMSE cut-off, its sensitivity would improve and specificity will drop • SENS / SPEC are very dependent on cut-offsand on populations studied

  30. Tests may have differential sensitivity in different ranges of cognitive decline MOCA MMSE 30 30 Normal 25 MCI 20 Mild dementia 25 15 Moderate dementia 20 10 15 10 Severe dementia 5 5 0 0

  31. Nasreddine et al – recommendations • If patients have cognitive complaints and functional impairment then likely dementia • MMSE first • MOCA if MMSE ≥ 26 (MCI, Mild dementia) • If patients have cognitive complaints but no functional impairment then likely normal or MCI • MOCA first

  32. Screening COST:how to read studies & select tests: Cut-off: Sensitivity and Specificity for any given test are dependent on cut-off score Objective: - screen for MCI & dementia in community (high cut-off) - screen for dementia (not MCI) in community (lower cut-off) - NOT for diagnosis - on inpatient setting can only screen for cognitive impairment (delirium, depression, MCI, dementia) Sample: Sensitivity and Specificity depend on sample / population. Since the populations we take care of clinically are different from those in studies the Sensitivity and Specificity of a test in clinical practice will likely not match that in studies Test Characteristics: Sensitivity and Specificity are dependent on the test employed. MOCA has high sensitivity but low specificity (relative to MMSE)

  33. Objective 3 • Describe an approach to the evaluation of an elderly person with dementia in terms of differential diagnosis of potential cause(s).

  34. 3 Step Approach • Use DSM criteria to: • 1. Rule Out Depression • 2. Rule Out Delirium • 3. Assess for Dementia vs. Mild Cognitive Impairment (MCI)

  35. Step 1 – Rule Out Depression • M Persistent low mood or anhedonia > 2 weeks • S Sleep Impairment • I Interests decreased • G Guilty ruminations / regrets • E Energy decreased • C Concentration decreased • A Appetite decreased • P Psychosomatic complaints / Psychomotor retardation or agitation • S Suicidal ideation (Passive vs. Active)

  36. Step 2 – Rule Out Delirium DeliriumDementia Onset Abrupt Gradual Course Short Long Fluctuation Present Absent Hallucinations Present Absent Attention Impaired Normal LOC Altered Normal Psychomotor Altered Normal It is common for Delirium to be superimposed on Dementia!

  37. This table oversimplifies so let us look at exceptions to the rules as well as the most reliable signs of Delirium

  38. Onset & Duration (exceptions) • Delirium • May have prolonged low grade delirium with chronic ETOH, BDZ, Narcotic, Anticholinergic (e.g. TCA, Ditropan) use • Dementia • Can have rapid onset with strokes or Creutzfeldt-Jakob Disease (see Health Canada CJD website describing rapid progression with changes in balance / mobolity)

  39. Fluctuation • Delirium • New onset unpredictablefluctuation (hour by hour not day by day) • Depression • Predictable diurnal variation (worse in morning) • Dementia • Predictable diurnal variation (worse in afternoon or evening)

  40. Hallucinations • Delirium • Especially if family describe new onsethallucinations • Dementia / Psychiatric Disorders • Long-standing hallucinations • E.g. Lewy Body disease, Psychotic Depression, Bipolar disease

  41. Attention, Concentration, LOC • Delirium • Attention, Concentration and altered Level of Consciousness - LOC (i.e. drowsy, somnolent, slow mentation) • Depression • Can alter Attention, Concentration but not LOC • Dementia • Normal Attention, Concentration, LOC

  42. Patterns of Psychomotor Change in delirium • Hyperactive("wild man!"); 25% • Hypoactive (“out of it!”, “snowed”, “pleasantly confused”); 50% • Mixed delirium (features of both), with reversal of normal day-night cycle (“sundowning”); 25%

  43. Confusion Assessment Method (CAM) • 1. History of acute onset of change in patient’s normal mental status & fluctuating course? • AND • Lack of attention? • AND EITHER • 3. Disorganized thinking? • Altered Level of Consciousness? Sensitivity: 94-100% Specificity: 90-95% Kappa: 0.81 Inouye SK: Ann Intern Med 1990;113(12):941-8 Arch Intern Med. 1995; 155:301

  44. Step 3 - Dementia vs. Mild Cognitive Impairment • Once again employ the DSM criteria – look for a deficit in each of the following categories (5 As + function + progression) base on history, physical examination, cognitive testing: • Amnesia • Aphasia, Apraxia, Agnosia, And Executive dysfunction • Progressive • Impacts on social and / or occupational functioning If do not have 1 deficit in each of 4 categories then have Mild Cognitive Impairment (MCI). Be practical – If MMSE very low (e.g. 20) then Dementia more likely than MCI. 10-15% of persons with MCI progress on to dementia over 5 – 10 years for a total of 60-70% so follow-up is recommended. Amnestic MCI (memory problems) more likely to progress to dementia.

  45. Amnesia – Short-term memory loss • Look for changes from baseline • Repeating questions or stories • Losing items (keys, purse …) • Forgetting details of important events • Trouble recalling names • Mixing up relatives and friends • Increased use of compensatory strategies (lists, calendars, memory cues)

  46. Aphasia (expressive) • Ask if patient has word finding problems (‘words on the tip of their tongue’) • Word searching • Mixing up languages • Losing last language learned first • Patterns • Sudden loss then stable or improving suggests stroke, bleed • Progressive word –finding problems (more frequent and more severe / noticeable) suggests Alzheimer’s • Severe and more pronounced than memory problems suggests stroke, bleed, Semantic Dementia, Primary Progressive Aphasia • Later develop reading and writing difficulty

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