Click here to see the meta data of this asset.

Common types of dementia

 

 

 

Table 10.1 Characteristic features of common types of dementia

 

 

alzheimer's dementia

lewy body dementia (lbd)

vascular dementia

fronto- temporal dementia

Age at onset

(average)

70 – 80

70 – 80

60 – 70

50 – 60

Percentage of dementia

50 – 60%

10 – 20%

10 – 20%

10% (higher proportion in ages < 60)

First symptoms

Short-term memory loss

Slowness, problems with visuospatial tasks

General slowing of cognition, may have depression at onset

Behavioural changes, language changes, apathy

Associated symptoms      

Lack of insight into memory difficulties may be present

early

 

History of

mild cognitive impairment in some individu- als

 

Co-occurring cerebrovas- cular disease common

Parkinsonian symptoms (rigidity, slow- ness, may not have tremor)

 

Hallucinations

(often vi-

sual and non- frightening)

 

Early falls

 

Marked fluctuations in consciousness (can appear drowsy or delirious)

 

Sleep distur- bance (REM sleep disor- der – "act out" dreams)

Registration of events better than recall (more likely to recall when given cues)

 

"Patchy deficits": may have marked deficits in language

with relative preservation in language

 

Pure vascular dementia

less common than mixed vascular and AD

Eating disturbances, (overeating, carbohydrate craving)

 

Disinhibition

 

Loss of insight

 

Impairment

in social skills

 

May be as- sociated with movement disorders or motor neuron disease

 

Family history

Increased risk of AD

Often no fam- ily history

Cardiovas- cular, cere- brovascular disease

Strong fam- ily history in many cases (20 – 40%)

Neurological signs

Absent early on

Parkinsonian symptoms

Many have focal weak- ness, reflex changes

Frontal release signs (grasp, glabel- lar tap, snout reflexes)

Progression

5 – 15 year course Slowly pro- gressive

2 – 3 point decline yearly on MMSE

Rapid progres- sion from on- set to severe symptoms

over few years

Variable "step-wise decline"

Rapidly pro- gressive over few years

 

 

 

·yCharacteristicygradualyonsetywithyprogressiveydecline