Assessment and Diagnosis of Dementia

Dr Alison Haddow

Dementia

Dementia is the word used to describe a collection of symptoms which may be caused by a variety of disease processes

Dementia

Multiple brain functions are affected:• Memory• Thinking• Orientation• Comprehension• Calculation• Language• Ability to learn• Judgement

What is Dementia?

• Consciousness is clear• Emotional control may be disturbed• Social behaviour may change• Motivation levels may alter• Personality may be affected

Risk factors for Alzheimer’s Disease

• Age• Sex• Genetic Factors• Education• Vascular factors (cholesterol, hypertension)• Smoking• Head injury• Thyroid disease• Exposure to electromagnetic fields

Risk Factors for Dementia – Genetic (1) • Family History of :

– Dementia (about 40%)– Parkinson’s Disease – Down Syndrome

• Concordance Rate for monozygotic / dizygotic twins is 43 / 8 %

Genetics

• Familial Autosomal Dominant AD, single mutated gene causes the disease in each family member carrying the mutation

• Genes on the chromosome 1, 14 & 21)• Associated with the early-onset form of the disease• < 5% of cases

Gene for Amyloid Precursor protein (APP) is on the long arm of Chromosome 21

Genetics

• Fourth gene associated with Alzheimer’s Disease is Apolipoprotein E gene (ApoE).

• Chromosome 19– People : 1 copy of the gene (E4) have 3 times AD than

people without E4– People : 2 copies of the gene (E4) have 8 times AD than

people without E4

Common but no routine testing

Education

• Many studies show that more highly educated people less likely to develop dementia, especially AD

• ?? Effects of education delaying AD• ?? Intelligence masks AD

Assessment of Dementia

• ? Medical cause of cog. Impairment?• ? Effect of medication• ? Neurological condition causing dementia• ? Treatable condition

Assessment of Dementia

• Clinical history– Medical Hx (inc. vascular )– Medication– Family history

• Detailed history – patient and carer/s– Social Hx; ADL’s

• Mental Statepsych symptomsSleep disorder

Assessment of Dementia

• Cognitive Examination

• MMSE; MOCA; Frontal tests

• Neuropsychology

Investigations

• Blood tests– FBC, U&E’s, LFT’s, Ferritin, folate, Vit B12, TFT’s, Calcium,

Glucose. (VDRL) ? Vit D• Brain imaging

– CT, SPECT, CT/SPECT• ECG; CXR if indicated

*Elevated CSF tau level are associated with AD pathology and can help discriminate AD from other dementia- not done clinically.

Differential Diagnosis• Primary Etiology

– Alzheimer’s dementia– Lewy body dementia– Frontotemporal dementia (Pick’s)

Differential Diagnosis• Secondary Etiology

– Vascular dementia e.g. cva, tia– Infections e.g. Hiv, syphyllis– Inflammatory e.g. SLE– Alcohol– Traumatic e.g. head injury

Differential Diagnosis• Neurodegenerative

– Multiple Sclerosis– Huntington’s Chorea– CJD (prion)– Wilson’s Disease– other

Management of Dementia

• Non pharmacological• Pharmacological

Pharmacological Management

• Cholinesterase inhibitors• NMDA (memantine)• Medications for disruptive behavior: BPSD• Antidepressants for comorbid disorders

Cholinesterase Inhibitors

• Galantamine• Donepezil (Aricept)• Rivastagmine (Exelon) Patch

Kaplan-Meier plot of time to nursing home admission among patients with Alzheimer's disease (A) taking and (B) not taking CEIs.

Lopez O L et al. J Neurol Neurosurg Psychiatry 2002;72:310-314

©2002 by BMJ Publishing Group Ltd

When to Prescribe AChEI’s

• In:– Alzheimer’s disease– Mixed AD & vascular dementia– Lewy Body Dementia– Parkinson’s disease dementia

• At earliest possible opportunity• After a discussion with the person with

dementia and their families

Vascular Dementias• Hypertension• Cerebrovascular disease• Hyperlipedemia• Aspirin/clopidogrel

When to review?

• Post Diagnostic support for one year.

• Information and advice given• Monitor medication

– Compliance– Adverse effects

Non Pharmacological

• Cognitive Stimulation Therapy