Table Of ContentChapter 3
Early Detection of Cognitive Impairment
Dr. William Dalziel
BPSD – Handbook for Family Physicians
BPSD – Handbook for Family Physicians
Chapter Index
Introduction ................................................................................................1
Case Study ..................................................................................................1
The Possible Benefits of “Early” Diagnosis/Treatment of Dementia .... 3
What are the Common Simple Clinical Risk Factors for Dementia? ........................ 5
How do Vascular and Alzheimer’s Pathologies Fit into the Diagnostic Spectrum?
........................................................................................................................................ 7
How Can Physicians Estimate an Elderly Patient’s Risk of Cognitive Impairment?
........................................................................................................................................ 7
Dementia Risk Calculator ............................................................................................. 8
How Can Physicians Quickly Screen for Cognitive Impairment in a Busy Office? . 9
The Case of Mr. AD ....................................................................................9
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Introduction
Early detection of cognitive impairment (CI) can be accomplished by:
1. Screening asymptomatic elderly who are high risk for CI, or by
2. Recognizing early but subtle symptoms of CI (which may be dismissed as normal aging).
In particular, BPSD (behavioural and psychological symptoms of dementia) such as apathy,
irritability, and agitation may be “early warning symptoms” of cognitive impairment. Family
members may find such symptoms quite stressful but may hesitate to bring them to the attention
of the primary care physician.
Case Study
Mr. A.D, an 80 year-old male (in your practice for 35 years) was recently diagnosed as
hypertensive. He is in your office today for BP recheck. With diuretic therapy his BP is now
150/80. He has no memory or cognitive complaints, and no family history of dementia.
Do you already screen this type of patient for cognitive impairment? Is there any value in doing
so?
What do you think is his risk of cognitive impairment?
Dementia now affects approximately 450,000 Canadians. The prevalence of dementia is
8% in those over 65. Therefore, in a typical primary care physician (PCP) practice of
approximately 2,000 patients, there will be 30 – 40 patients with dementia. A 2002 Ontario
College of Family Physician Survey showed 63% of their physicians felt they had less than
15 patients with dementia in their practice. The incidence of new patients with dementia is
approximately 2% per year or an expected 8 – 10 new patients with dementia every year in
an average PCP practice. Do these figures “fit” your practice? Mr. AD’s risk is higher than
8% because of age and the presence of hypertension.
Is the diagnosis of dementia missed? Is dementia under treated?
Studies suggest that approximately 50% of dementia is specifically diagnosed. Of
diagnosed dementia, only 50% get a specific treatment trial with a cholinesterase inhibitor
(CI). Therefore, only 25% of patients with dementia receive a CI trial of therapy. There is
clearly both a diagnostic gap and a treatment gap. (ref: Canadian Study on Health and
Aging + pharmaceutical data bases)
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Dementia
diagnosed
but NOT
Dementia
treated
NOT
diagnose
d Dementia
diagnosed
AND
treated
25% of Canadians have someone in their extended family with Alzheimer’s disease (AD);
52% know someone with AD. . . and the baby boomers are only now turning 60!
The typical ‘presentation’ of CI or early dementia is a relative (spouse or child) or friend
brings someone to the family physician or another healthcare professional and says, ‘I think
she’s having memory problems’. In this scenario, the diagnostic accuracy is 96% for
dementia. However, far more commonly, problems are missed, ignored or denied until a
crisis occurs: obvious loss of executive functions, behaviour problems, superimposed
delirium or a motor vehicle crash. The average delay from first onset of symptoms to
diagnosis (if the diagnosis is made at all) is 2 – 3 years. Dementia is often missed because
of lack of complaints (only 50% sensitive) unless the PCP has a high index of suspicion or
actively screens for CI in high risk elderly.
The usual 2 – 3 year delay in diagnosis means that only 45% of persons with dementia are
diagnosed in the mild stage of the illness, when recognition, treatment and caregiver
support and education can help prevent medical and social problems. Fifty five percent
(55%) are already in the moderate or severe stages of the illness.
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Delay in Diagnosis
45% Mild
45% Moderate
10% Severe
For the many cardiac patients in a PCP practice, there are important clinical implications if
cognitive impairment is not recognized. For example, a hypertensive diabetic patient with
undiagnosed dementia may have trouble understanding instructions, staying on a special diet,
monitoring blood pressure/blood sugars or taking medications properly, even with the use of a
dossette box or compliance pack. Medication errors quickly lead to further complications and
de-stabilization of these medical problems, including a worsening of cognitive difficulties. There
are therefore multiple benefits to early detection of dementia.
The Possible Benefits of “Early” Diagnosis/Treatment of Dementia
Social Medical
• Social/financial planning • Reversible cause/component
• Early caregiver education • Risk factor treatment
• Safety: compliance, driving, • Compliance strategies
cooking
• Treatment of other diseases
• Advance directives planning
• AChEI treatment
• Right/need to know
• Crisis avoidance
• Crisis avoidance
The Canadian Consensus Guidelines on Dementia recommends comprehensive cognitive
assessment for anyone with memory complaints.
Memory Complaints should be evaluated and the individual followed to assess progression (B)
• Complaints should be considered very seriously if confirmed by caregivers / informants.
Cognitive assessment and careful follow-up is recommended (A).
(Patterson: Can J. Neuro Sci 2001; 28 (Suppl. 1) S 3-16).-
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However, if physicians only think of dementia when there are memory or cognitive complaints,
this will mean many dementia diagnoses are delayed or missed. Instead, it may be useful to
widen the concept of early dementia by thinking: A B C D which stands for any unexplained
problems in:
A: Activities of Daily Living, particularly instrumental activities
B: Behaviour: apathy and irritability may pre-date cognitive complaints by up to 1 year
C: Cognition: should be screened/assessed. Continuing the alphabet, one would also include:
D: Driving = tickets, crashes, caregiver concerns re: safety
Clinical Features: ABC
A = ADL’s B = Behaviour
Finances Anger
Shopping Irritability
Driving Apathy
Cooking Depression
Travel Agitation
Laundry
C = Cognition
Forgetfulness
Repetitive questions/stories
Word finding problems
Planning meals/shopping
Misplacing objects/getting lost
Another useful set of behavioural flags for healthcare professionals are the following ‘red
flags’.
Behavioural Flags for Professionals
1. Frequent phone calls.
2. Poor historian, vague, seems “off”.
3. Poor compliance: medications/instructions.
4. Neglected appearance, changes in mood or personality.
5. Word finding difficulty, decreased interaction.
6. Appointments: missing or coming on the wrong day.
7. Confusion: with illness, medications or post-surgery.
8. Weight loss: “dwindles”.
9. Driving: accident, problems (tickets, getting lost).
10. Head turning sign (Turning to caregiver for answer when questioned).
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In summary, relying on patients to report their own cognitive complaints will result in delayed
diagnosis of dementia with important negative clinical consequences. To move diagnosis
earlier, a high index of suspicion (ABC) and appropriate screening of high risk elderly is
necessary.
In fact, screening for an asymptomatic condition is justifiable based on the following criteria, all
of which are met by dementia:
Disease is common: need to ‘create’ a high risk subpopulation.
rd
Disease is costly: dementia = 3 most costly disease in Canada.
Disease can be detected in a practical, efficient method by primary care physicians
(e.g. 2 minute Dementia Screen - see Tool Kit).
Intervention/treatment for disease exists:
Treatment of risk factors.
Treatment with Cholinesterase Inhibitors.
Caregiver education and support.
Perhaps most important is that the use of 3 simple clinical factors (age, family history, and
vascular risk factors detailed below) will easily identify a high risk subpopulation; this ensures
more true positive and fewer false positive screens (higher positive prediction value).
The American Academy of Neurology (Petersen RC. Neurology 2001;56:1132 – 42)
recommended: “General cognitive screening instruments should be considered for the detection
of dementia when used in patient populations with an elevated prevalence of cognitive
impairment due to age or presence of memory dysfunction”.
What are the Common Simple Clinical Risk Factors for Dementia?
The most important risk factor for dementia is age. Both cerebrovascular pathology (vascular
dementia) and neurodegenerative pathology (AD) increase significantly with age (Wolfe PA.
Stroke 1991 (22):312-318). The risk of dementia is 2% at age 65 and doubles every 5 years of
increasing age. Therefore, by age alone Mr. AD at age 80, in the case study has an
approximately 16% chance of cognitive impairment.
st
Family history increases the risk of dementia. For every 1 degree relative (parents, siblings),
the risk of dementia doubles. If both parents have dementia, the risk increases 10 times.
Finally, multiple epidemiological studies have shown vascular risk factors increase the risk of
dementia (each by about 2 times) for each of the 3 commonest subtypes of dementia: AD, VaD
(vascular dementia), and mixed AD with CVD (cerebrovascular disease).
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Figure 1: Emerging View of VaD, AD, and AD with CVD (Cerebrovascular Disease)
VaD AD w/CVD
AD
Pure VaD Mixed AD with CVD Pure AD
Post CVA Intermediate between AD Plaques and
Multi-infarct and VaD in clinical, tangles with no
Subcortical ischemic neuroimaging and prognostic vascular disease
Strategic infarct features
Hypoperfusion
What do epidemiologic studies show with respect to VRFs (Vascular Risk Factors) and
Alzheimer’s disease (AD)?
The Rotterdam study (Breteler MM. Neurology and Aging 2000; 21:153-160.), a longitudinal
study of over 7,000 elderly subjects, confirmed the following risk factors for AD (all of which are
vascular related or reduce cerebral perfusion):
Î Thombotic Episodes/CVA Î Diabetes
Î MI/CAD/PVD Î Atrial fibrillation
Î Hypertension Î Smoking
Î Obesity Î Hyper-homocysteinemia
Neuroimaging studies show that silent brain infarcts more than doubled (Odds Ratio 2.26) the
risk of AD. (Vermeer S. NEJM 2003; 348:1215-1222.) Brain infarcts are common in the elderly
(31% in the Cardiovascular Health study), and are often clinically silent (89% of infarcts).
(Longstreth, W. Arch Neuro 1998; 55:1217-1225.)
Other studies (Skoog, I. Neuroepid 1998; 17:2-9; Seshadri, S. NEJM 2002; 14:476-483) have
reported stroke, coronary heart disease, migraine, peripheral vascular disease, TIA,
hyperlipidemia, high intake of saturated fat, carotid stenosis and coronary bypass surgery.
Particularly important is the association of mid-life hypertension in the development of later life
AD (FINMONICA (Kivipelto, M. Neurology 2001;56:1683-1689) and Honolulu-Asia Aging Study
(Petrovitch, H. Neurolbiol Aging 2000;21:57-62)). Most of these risk factors for AD are also
clearly risk factors for VaD.
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