Neurobiology of dementias and clinical aspects

Question 1

Dementia is a syndrome, not a disease or even a group of diseases. It includes cognitive impairment. Describe what this looks

Answer 1

The cognitive impairment is progressive, due to brain disease, affects life, occurs in adults (40+) and has multiple domains

Question 2

Impaired cognitive function effects memory, language, visuospatial, executive and social. Give examples for each

What is the clinical relevance of this?

Answer 2

Memory impairment of: recent events, facts & concepts, encoding and retrieval, learning vs forgetting

Language: meaning, word finding, syntax, articulation

Visuaspatial: way finding, hand-eye coordination, arranging objects, copying a drawing

Executive: attention, set-shifting, structured task, working memory

Social: disinhibition, loss of empathy, obsessions, poor self care

Impairment of these functions can be clinically assessed in the examples given

Question 3

What is the epidemiology of Dementia?

Answer 3

7.7 million new cases/annum

Prevalence doubles with every 5 years of increasing age, more than 1/10 people over 85 have dementia

Number of cases expected to double in the next 40 years (from 800k in 2012 to 1.7 million in 2051)

Question 4

Dementia is caused broadly by brain damage, degeneration, and dysfunction.

What non-progressive causes exist?

Answer 4

Acute head injury
Stroke
Meningitis/encephalitis

Question 5

Dementia is caused broadly by brain damage, degeneration, and dysfunction.

Which causes exist which may appear progressive but not damaging to the brain?

Answer 5

Systemic disease (metabolic/endocrine)
Prescribe drugs
Psychiatric illness
Poor sleep
Chronic pain

Question 6

Dementia is caused broadly by brain damage, degeneration, and dysfunction.

Which causes exist which are damaging to the brain but not neurodegenerative?

Answer 6

CVD (Vascular dementia)
Multiple sclerosis
Alcohol
Brain tumours/ Hydrocephalis
HIV
B12 deficiency

Question 7

Dementia is caused broadly by brain damage, degeneration, and dysfunction.

What neurodegenerative causes exist?

Answer 7

Alzheimers disease (COMMONEST CAUSE)
Dementia with Lewy bodies
Fronto-temporal lobar degeneration spectrum
Huntingtons
Creutfeldt-Jakob disease

Question 8

Consider Alzheimers disease as a cause of dementia

What type of brain disease/dysfunction/damage are implicated in disruption of encoding, consolidation and recall

Answer 8

ENCODING (and visuospatial): Many causes

CONSOLIDATION (and attention, depression): Alzheimers, alcohol brain injury

RECALL (and language): Many causes

Question 9

What is the time-framing of sensory, short term and long-term memory?

Answer 9

• Sensory memory occurs instantly after an event. It begins to fade after a few seconds
• Short term memory fades within minutes/hours
• Long-term memory can last between minutes to years

Question 10

Consider Alcohol as a cause of dementia

Answer 10

Thiamine deficiency causes:

WERNICKE’s (delirium, ataxia, eye movements) KORSAKOFF’s (amnesia, confabulation, consolidation errors)

Long term alcohol use:
Not only attention, speed difficulties and ataxia BUT ALSO seizures, head injury, malnutrition, liver disease

Question 11

What does confabulation mean?

Answer 11

a memory error defined as the production of fabricated, distorted, or misinterpreted memories about oneself or the world, without the conscious intention to deceive.

Question 12

What is ataxia?

Answer 12

a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes and abnormalities in eye movements.

Question 13

Consider head injury as a cause of dementia

Which specific parts of memory are affected?

Answer 13

Consolidation (anterograde and retrograde amnesia)

Attention

Executive

Question 14

CLINICAL APPLICATION

Dementia is PROGRESSIVE, INCURABLE and eventually FATAL.

What do we consider in the management of dementia?

Answer 14

• Manage symptoms: working memory aids, cholinesterase inhbitors, behaviour
• Treatment for symptoms e.g. depression, pain, sleep, tumours
• Maintain function: physical and mental activity, diet, vascular RFs
• Prevent complications: e.g. falls, infections, malnutrition
• Do no harm: avoid muscarinics, antipsychotics, sedatives

Question 15

What are the societal costs of dementia?

Answer 15

In 2015, $818 billion expected to increase to $2 trillion.

The costs include direct medical(smallest expense) and social care costs and costs of informal care (largest expense)

Question 16

Explain how public and professional attitudes and understanding affect care

Answer 16

False beliefs such as “Dementia is a norma part of ageing” and “Nothing can be done”, in addition to stigma of dementia prevents discussion

This leads to inactivity in seeking and offering help

Question 17

70-80% of dementia patients receive accurate assessment and diagnosis. When they do, it is:

Answer 17

Early in the illness
Early enough to enable choice
In time to prevent harm
In time to prevent crises

Question 18

How does inaction interfere with effective dementia treatment?

Answer 18

Insidious onset, lack of insight, lack of simple testing and stigma lead to INACTION

Public misconceptions, professional misconceptions and role uncertainty emphasis this INACTION

Ultimately leading to impaired help seeking and impaired help offering

Question 19

Where are we in diagnostics?

Answer 19

• No quick diagnostic test
• No efficient screening test

We can conclude an accurate diagnosis by careful clinical assessment with multi-disciplinary synthesis of history, examination and investigation

We do have tests to help make decisions about diagnosis and sub diagnosis

Question 20

Services for early diagnosis and intervention in demential FOR ALL are important. What does this look like in practice?

Answer 20

• Working for the whole population of people with dementia
• Working in a way that is complementary to existing services
• Service content (good diagnosis, communicate diagnosis well, provide immediate support and care from diagnosis)

Question 21

How do we communicate the diagnosis of dementia well?

Answer 21

• Prepare before
• Deliver the diagnosis sensately to patient and carer
• All time to discuss and patient and carer to ask questions

Question 22

How do promote good brain health?

Answer 22

• Integrate with NCD prevention (tobacco control, salt, alcohol, inactivity, CVRF management)
• Its never too early (education, nutrition, hypetension)
• Its never too late (smoking, diabetes)

Question 23

What does improved quality of care look like?

Answer 23

• Improved community personal support services
• Improving care for carers
• Improved quality of care for dementia in general hospitals
• Improved intermediate care
• Housing support, tele care
• Living well with dementia in care homes
• Improved end of life care