Language and CognitionColombo June 2011

Day 10 Dementia

Definitions

• ‘Dementia is the general term given to neuropsychological syndromes characterised by acquired cognitive impairment in multiple spheres but without impaired consciousness’ (Brandt and Rich 1995)

• ‘The development of multiple cognitive deficits, including memory impairment and at least one of the following cognitive disturbances – aphasia, apraxia, agnosia or a disturbance of executive functioning’ (The American Psychiatric Association 1994)

Prevalence

• 15% of the population over 65: some form of dementia (Cummings and Benson 1992).

• 47% of people over 85 affected (Evans et al 1989)

• Alzheimer’s Disease (AD) is the largest single cause of dementia

• Other causes:– Multi Infarct Dementia, Parkinson’s disease, Pick’s

disease, Huntingdon’s Chorea and Creutzfeldt-Jacobs Disease.

Neurobiological changes in Alzheimer’s Disease

• Morris and Worsley 2003:• Gross atrophy with widening sulci and ventricular

enlargement; the frontoparietal region and temporal lobes are most affected

• Widely distributed senile or neuritic plaques in the cortex, hippocampus and some sub-cortical structures

• Neurofibrillary tangles; affecting most areas but particularly in the hippocampus, amygdala and parahipppocampal gyri.

• These changes can only be identified definitively at autopsy. Therefore only probable AD can be diagnosed during the person’s lifetime.

• Significant variation in symptoms between people

Clinical Signs of Dementia of Alzheimer’s Type (DAT)

Early Stage

Mild forgetfulness

Misplaced objects

Some disorientation in unfamiliar places

Anomia for proper & low freq vocabulary

Circumlocution

Repetitive discourse

Affect changes

Anxiety and depression

Mid Stage

Hazardous everyday memory problems

Disorientation in familiar places

Visuo spatial deficits

Severe word finding problems with semantic errors

Poor comprehension

Difficulties with complex sentences

Apathy & sleep disturbance

Late Stage

Severe memory problems

Poor recognition of familiar people

Wandering

Bizarre behaviours

Little/no spontaneous speech

Very poor comprehension

Echolalia

Stereotyped utterances

Primitive reflexes

Incontinence

Dysphagia

Word finding in DAT: Evidence of Semantic Impairment

Hodges et al (1992)• Significant relationship between naming and

comprehension – items that induced naming failures also induced comprehension failure

• Grosser tasks, like sorting into unrelated categories, were preserved

Are all naming problems semantic?

Mary (Funnell 1992)• 2 year history of DAT• Memory impairment• Visuo spatial difficulties• Dyscalculia• Severe anomia even with high frequency words

(9/30 on Graded Naming Test)

Initial Comprehension Testing

•Word to picture matching–(BVPS; PALPA) 99%

•Semantic questions–(‘does a rabbit have fur?’) 100%

Demonstrates understanding of low frequency words like ‘bovine’ and ‘prestigious’

Impairment in accessing lexical phonologies2 years later: Rapid decline on comprehension and semantic tasks

Word to picture matching over time

0

5

10

15

20

25

30

35

40

45

1 2 3 4 5 6

Correct

Semantic errors

Unrelated

Syntax in DAT

• Syntactic skills often better preserved than semantic

• Speech still displays syntactic structure, at least in the early stages– ‘The picture incorporates a certain amount of coming

and going and cheating and doing the things in the world’ (Kempler 1995)

• Relative success on syntactic tasks

HCEM (Whitaker 1976)

• Age 59• Familial dementia• Diffuse atrophy (frontal and temporal lobes) and

ventricular dilation• Living in nursing home• Supported in all aspects of self care• Disoriented for time, place and person• Wandering behaviour• ‘indolent, apathetic and totally non-communicative’

HCEM (Whitaker 1976)

Naming• Virtually impossible• Some semantic errors

Comprehension• Untestable on single word, sentence level and non verbal tasks• Unable to carry out requests (such as removal of chewing gum)

Repetition• Almost all output is echolalia

HW Do you like coffee?HCEM Do you like coffee?

HCEM (Whitaker 1976)

SyntaxDemonstrated through repetition task

• HW Can you told the time?• HCEM Can you tell the time?

• HW She likes eat• HCEM She likes to eat

• HW There are two book on the table• HCEM There are few books on the table

Writing in DAT

• Writing to dictation may be relatively well preserved• Surface dysgraphia as semantic/lexical routes failing

–Regular words > Irregular wordsArgues for sublexical, PGC writing

Note that patterns are variable and can show phonological dysgraphia or combination (Luzzatti et al 2003)

Auditory Analysis

AIL VIL

Visual Analysis

POL OOL

Semantics

Picture Analysis

Picture Recognition

Buffer Buffer

Speech Writing

Speech Writing

GPC

PGC

Pictures/Objects

The role of executive control: Funnell and Hodges 1996

• MCR• Farmer’s wife• 2 year history of deteriorating speech and memory• ‘My mind goes blank when I’m doing things’• Family report everyday memory problems (forgetting

tasks and messages)• Speech increasingly sparse, with unfinished sentences

MCR: Funnell and Hodges 1996

Impaired on executive tasks• Card Sorting• Stroop task

Card Sorting

Task: sort by one criteria (colour); then switch to a different criteria (symbol)

Problem: continued to sort by first criteria, even when given very explicit feedback by tester

Stroop Task

RED

• Read word (good)

• Name colour (very poor)

Interim Conclusions

• MCR shows evidence of executive impairment

• Does this underpin her poor word finding?

Language Testing

Good performance on:• Word to picture matching

• Semantic verification– Is a salmon a tree (category)– Does a mouse have a beak (feature)

• Picture naming (51/55)

Category Naming

• Named significantly less than controls

• Big discrepancy between (near normal) picture naming and impaired category naming

• Responsive to semantic prompts

• Therefore: impaired ability to initiate/generate ideas

Conclusions

• MCR shows relatively intact semantic processing

• MCR has an executive impairment

• Her language difficulties relate to this, she cannot sustain plans, eg to generate a large number of items in category naming

• Tasks that impose minimal executive demands (such as picture naming) are still relatively intact

Focal Degenerative Diseases

Progressive language impairment as in DAT but:

• Intact day to day memory – live independently until late in disease

• Good non verbal problem solving (Ravens matrices)

• Good visuo-spatial abilities– Can navigate round familiar environments– Can do visual tasks like copying pictures

Focal Degenerative Diseases

Progressive Non FluentAphasia • Non fluent speech• Dyspraxia• Poor word finding with

effortful word search• Phonological errors• Good comprehension• Impaired syntax

Semantic Dementia• Fluent speech• Normal articulation• Empty speech lacking

content words• No effortful word

searches• Semantic errors (not

phon.)• Impaired lexical

comprehension• Retained syntax

Focal Degenerative Diseases

• Different patterns of impairment reflect different regions of damage– Non fluent progressive aphasia damage to

perisylvian language regions of left hemisphere

– SD progressive damage to anterior temporal lobes

Speech in Semantic Dementia (Garrard and Hodges 1999)

‘Oh gosh, this seems to be, oh come on try to remember the name: I know what they are ‘cause there’s three of these, so it not the two and three. The one which er … some of them will be in Britain because you know with our stuff in Britain some of them are also outside Britain, some of them are also in Britain as well. What d’you call them again because N’s son no not son brother he’s one of these as well’ (naming soldier)

Fluent, syntactically structured, but few content words

Naming in Semantic Dementia

• Within category substitutions (window/door)• Overuse of superordinate substitutions (e.g.

“animal”)• Frequent exemplar labels (eg all animals named

as ‘dog’)• Item consistency, items failed in one test will be

failed in the next

Lexical Comprehension in Semantic Dementia

• Impaired performance• Initially close semantic errors• Later deny knowledge of word• Item consistency• May show category effects

Reading and Repetition in Semantic Dementia

• Typically surface dyslexia• Poor comprehension of written words• Good repetition and reading aloud

• Performance reflects impaired central semantics with better performance on peripheral language tasks

Auditory Analysis

AIL VIL

Visual Analysis

POL OOL

Semantics

Picture Analysis

Picture Recognition

Buffer Buffer

Speech Writing

Speech Writing

GPC

PGC

Pictures/Objects

Non verbal abilities in Semantic Dementia

Pictures• Copying • Drawing from memory x• Categorisation x

Episodic memory – striking preservation in SD (not in DAT)• Recall events in life • Remember appointments • Rarely get lost in familiar surroundings• Although early/long term memories may be impaired

(STM impaired in DAT)

Autobiographical Effects on Language

‘I help reverend Jones by putting the chalice back in the vestry’

(Snowden et al 1994)

Is autobiographical experience (Episodic Memory) sustaining vocabulary?

Further research by Snowden suggests yes.

Therapy?

DM (Graham et al 2001)• Self initiated practice with vocabulary

– List words together with definitions– Cover words and attempt to recall

Outcomes• Practised words are named well (in fluency task)• Control words are not named well • When controls are practised naming improves

But ..

• Learnt categories are poorly maintained• Learning is entirely rote (words are recalled in the same

order as the list in notebook)• Learning is without understanding (able to name

‘dalmatian’ but has no idea what it is)• Practice becomes obsessive and needs increasing input

in order to be maintained (7 – 8 hours per day)

See Heredia et al 2009 for a more recent example of therapy

Practical Help (Snowden et al 2000)

• Sustain person in familiar environment for as long as possible

• Help person sustain rich and varied life style• Minimise opportunities for dangerous semantic

errors (no bleach in bathroom)• Follow strict routine (familiar food packets will be

recognised, unfamiliar ones will not)• Only train concepts within meaningful context

(example of lemon in gin and tonic)• Use rehearsal to sustain concepts