Lecture 8 - Cognitive Deficits Following Stroke

Question 1

What cognitive domains may be affected following a stroke?

Answer 1

Attention, memory, executive function, perception/praxis, language.
You may get one area that then impacts another area.

Question 2

What assessments are used for cognitive impairments following stroke?

Answer 2

Mini mental state examination, Montreal cognitive assessment and neuropsychological tests.

Question 3

What is the Mini Mental State Examination (Folstein et al., 1975)?

Answer 3

The MMSE is a brief screening tool that provides a quantitative assessment of cognitive impairment of multiple domains:
- Orientation = ask simple questions e.g. who are you?
- Registration = required to repeat what objects are.
- Attention = count back in 7s for 100 or asked to spell word backwards.
- Recall = asked to recall objects from registration task.
- Language = may be asked to close eyes, or what the time is.
They are then given a score out of 30 with 30 indicating less impairment.

Question 4

What are the strengths of the MMSE?

Answer 4

It is easy to complete, quick and inexpensive.
It also does not require training so can be used widely and it is easy to interpret with the scoring system.

Question 5

What are the limitations of the MMSE?

Answer 5

It lacks sensitivity as it is not very detailed - this means it doesn’t pick out the people who score around the middle who may have major impairments in some areas.
It lacks evaluation of the executive function.
It may be confounded by age, level of education and sociocultural background.
Could be improved with the addition of other tests to improve sensitivity.

Question 6

What is the Montreal Cognitive Assessment?

Answer 6

A battery of tests that measure a range of cognitive domains, it includes tasks such as:
- Clock draw task = have to remember a time on a clock and draw it.
- Picture naming task = asked to name what they see.
- Memory task = given a list of words and asked to recall
- Attention task = given list of letters and told every time the letter A appears, they need to tap.
- Abstraction task = given 2 objects and asked how they are related.
- Language assessment = read a sentence and asked to repeat it (tests comprehension and production) or may be given a letter and asked to name as many words beginning with that letter.

Question 7

What are the strengths of the Montreal Cognitive Assessment?

Answer 7

It is more sensitive than the MMSE as you can see mild impairments in this test.
It is available in multiple languages etc. and is freely accessible.

Question 8

What are limitations of the Montreal Cognitive Assessment?

Answer 8

It is relatively new so not as widely used as MMSE.
The reliability of it has not been thoroughly tested.

Question 9

What is a neuropsychological test?

Answer 9

It is a really comprehensive battery of tests that looks at a wide range of functions with detailed tests:
- Visuospatial memory tests.
- Verbal learning test.
- Wechsler memory scale.
- Delis-Kaplan executive function system.
- Number/letter sequencing.
- Boston naming test.
- Wechsler adult intelligence scale.
- Phonemic/category fluency.

Question 10

What are the strengths of neurological tests?

Answer 10

It is really comprehensive so should be more sensitive.
It looks at a wide range of cognitive domains so if there were any impairments it should find them.

Question 11

What are the limitations of neuropsychological tests?

Answer 11

Because it is very thorough, it is also very time consuming and may cause the patient to get tired which could be a confounding factor.
Or they may have to do it across different days due to tiredness which then causes issues with reliability as you are getting the patient on a different day.
It also needs to be conducted by someone who has been trained.

Question 12

What is unilateral spatial neglect?

Answer 12

It is failure to report, respond, attend or orientate to one side of the body (contralateral side) and comes under the perception, praxis domain.
In unilateral neglect, the parietal lobe is affected which is involved in sensory processing and orientation.
It is more common in patients with right side lesions (42%) than left side (8%). This is because the right side of the brain controls the visual field for both sides so if the lesion was in the left side you would still be able to see both visual fields.

Question 13

How is unilateral spatial neglect assessed?

Answer 13

The line bisection task, clock drawing test and behavioural inattention test.

Question 14

What is the line bisection test?

Answer 14

It consists of 18 horizontal lines drawn on a single piece of paper and patients are required to place a mark on each line that bisects it into 2 equal parts.
If have USN they deviate from the middle because they can’t process the full line.
This test can give some indication of having neglect but it is not a thorough method.

Question 15

What are the strengths of the line bisection test?

Answer 15

It is simple, inexpensive and doesn’t require training.

Question 16

What are the limitations of the line bisection task?

Answer 16

It lacks sensitivity and is not a thorough method for assessing USN.

Question 17

What is the clock drawing test?

Answer 17

It provides a quick assessment of visuospatial and praxis abilities and may detect deficits in both attention and executive dysfunction.
Participants are asked to draw a certain time on a clock and if they have USN this will be difficult as they can’t process the full circle so they won’t draw numbers in the right places.
Scoring is based on if the numbers are in the right place, if they draw the right time on the clock and how much information is missing.

Question 18

What are the strengths of the clock drawing test?

Answer 18

It is easy to administer and inexpensive.
It provides a more complete picture of cognitive function when used with other assessments.
It demonstrates reliability.
It correlates well with other assessments.

Question 19

What are the limitations of the clock drawing test?

Answer 19

It could be confounded by age and education e.g. if don’t know how to tell the time.
It may be affected by motor coordination e.g. if they can’t grip a pen.

Question 20

What is the behavioural inattention test (Wilson et al., 1987)?

Answer 20

It screens for unilateral visual neglect and provides information relevant to its treatment.
It contains multiple tests to look for USN. It contains a conventional section (BITC) (e.g. line crossing, shape copying, line bisection) and a behavioural section (BITB) (e.g. menu/article reading, coin sorting, phone dialling).

Question 21

What are the strengths of the behavioural inattention test?

Answer 21

It is comprehensive and ecologically valid.
It also looks at a wider range of tasks than the clock drawing or line bisection tests.

Question 22

What are the limitations of the behavioural inattention test?

Answer 22

It is time consuming as it looks at a range of tasks.
It is expensive to do.

Question 23

What are the treatments for USN?

Answer 23

There are remedial treatments for USN which aim to get the patients to focus on their affected side, these include visual scanning, computer-based scanning and virtual reality therapy.
If remedial therapy is not appropriate, the patient may be given compensatory treatment to try and make the USN easier to deal with, such as prisms adaptation, limb activation strategies, sensory feedback strategies, and eye patching and hemispatial glasses.

Question 24

How does visual scanning for USN work?

Answer 24

It involves teaching patients to look to the affected side in a consistent manner, they need to be forced to attend to the affected side.
There is evidence that this can improve neglect and therefore function.

Question 25

How does computer-based scanning for USN work?

Answer 25

Participants are given a task which they need to attend to the whole of their environment to do.
It is generally more accessible and cost-effective than the same session under direction if a human therapist. This means it can free up more hospital resources and allow patients to begin and continue rehabilitation as quickly as possible. It can also be used quite quickly compared to one-on-one therapy.

Question 26

How does virtual reality for USN work?

Answer 26

It is similar to computer based therapy but is more engaging. Patient has to engage and attend to environment to move the affect limbs.
Several studies show promising results but it is expensive. The evidence is also quite limited looking at the effectiveness.

Question 27

How does prisms adaptation for USN work?

Answer 27

The prisms affect spatial representation by causing an optical deviation of the visual field.
Patients can have specific prisms made so they can attend to their neglected side and increase their visual field.

Question 28

How to limb activation strategies for USN work?

Answer 28

Intended to increase orientation and attention to the neglected side. If they are encouraged to move their neglected side they are more likely to attend to it. They are given something to help them engage with their neglected side e.g. a tap of their neglected arm every so often. This makes them use that side and increases the brain neural networks linking to that side.
There is evidence that this works but not sure how long the impact lasts.

Question 29

How do sensory feedback strategies for USN work?

Answer 29

Feedback strategies are intended to improve awareness and attention to neglected space - may include auditory or visual feedback. This makes the patient aware of their neglected behaviours and may assist in learning ways to remediate neglect.

Question 30

How does eye patching and hemispatial glasses for USN work?

Answer 30

The eye opposite to the lesion is patched, which forces the patient to use their neglected side more. They have to attend to everything using the neglected eye rather than relying on the non-damaged visual field.

Question 31

What is dyspraxia and apraxia and how do they occur?

Answer 31

These typically occur due to damage to the middle cerebral artery which affects the frontal lobe (motor cortex, language production etc.) and the parietal lobe (sensory processing and orientation).
Dyspraxia = problems with motor coordination - there may be a lack of fluidity or may be hesitant to perform movements.
Apraxia = problems with organising speech - issues with coordination with the muscles involved in speech production, they have to try hard to think about how to produce speech.

Question 32

How is dyspraxia and apraxia assessed?

Answer 32

(Butler, 2002):
Don’t set out to diagnose either of these. It is based on differential diagnosis of what it is not:
- Comprehension deficit.
- Muscle weakness.
- Sensory impairment.
- Tone of abnormality.
- Other movement disorder.

Question 33

What are the treatments/therapy for dyspraxia and apraxia?

Answer 33

Therapy involves teaching compensatory techniques for impairments such as strategy training, sensory stimulation, proprioceptive stimulation and cueing and prompts.

Question 34

How does strategy training for dyspraxia/apraxia work?

Answer 34

Involves repetition of tasks and practice. Patients will usually work with an occupational therapist and plan out an activity or task and keep doing this until they get better e.g. boiling a kettle or making a cup of tea.

Question 35

How does sensory stimulation for dyspraxia/apraxia work?

Answer 35

Stimulation of the nerves in order to encourage a response. It activates the neurons and reactivates the cortical network.

Question 36

How does proprioceptive stimulation for dyspraxia/apraxia work?

Answer 36

Proprioceptive based training (PBT) is based on performing concurrent movements with both unaffected and affected arm with the aim to foster motor recovery.
Involves practicing activities on both sides of the body to activate both hemispheres so they can reconnect and encourage connectivity.

Question 37

How does cueing and prompts for dyspraxia/apraxia work?

Answer 37

Patients are dependent on others to prompt them. They may be prompted by what letter they are looking for or cue for the type of word they are looking for etc.

Question 38

What is aphasia?

Answer 38

It is a language deficit characterised by the loss of ability to communicate either through comprehension or expression. It includes Broca’s (poor expression but good comprehension), Wernicke’s (good expression but poor comprehension) and global (poor expression and poor comprehension).
Patients may struggle to express themselves through spoken word but may use other ways to express themselves e.g. writing or through music or through photos.

Question 39

What therapy is used for aphaisa?

Answer 39

Patients often have a speech and language therapist which involves learning how to produce sounds or help individuals with comprehension.
They may also have group therapy, communication partners, computer-based treatment or constraint-induced aphasia therapy.

Question 40

How does group therapy for aphasia work?

Answer 40

People are placed in a group situation where they interact with one another, this can push people to find ways of communicating. It also encourages people to connect with others and use it as a support network.

Question 41

How does training conversation/communication partners for aphasia work?

Answer 41

It involves training the people who the patients see everyday to be patient and encouraging. This can help with the patients confidence.

Question 42

How does computer-based treatment for aphasia work?

Answer 42

It involves doing practical exercises e.g. pictures and symbols next to a work to help with comprehension. This can be carried out in large groups or can be used at home.

Question 43

How does constraint-induced aphasia therapy work?

Answer 43

Might point to objects or gestures to communicate which can be helpful in the short-term.
But this can stop them from producing speech because they are so reliant on gestures.

Question 44

How many stroke survivors show a cognitive impairment determined by the MMSE?

Answer 44

30% (Sun et al., 2014) but varies depending on countries.

Question 45

What factors have an impact on post-stroke cognitive impairment risk?

Answer 45

Age and education levels. Occupation may also have effects e.g. higher occupations see a more obvious cognitive decline but there’s a higher prevalence of cognitive impairment in manual workers (Sun et al., 2014).
Vascular risk factors such as hypertension, diabetes, smoking etc also increase the risk of cognitive impairment (Sun et al., 2014).

Question 46

What drug treatments are used for cognitive impairment following a stroke?

Answer 46

Cholinesterase inhibitors - studies suggest improvement of cognitive function and daily living e.g. increased activation in prefrontal areas, inferior frontal lobes etc.
Memantine - evidence to show it improves the cognition and behaviour in patients with mild to moderate vascular dementia.
Citicoline - may prevent the cognitive decline after stroke.
Bilobalide - could protect the learning and memory function by inhibiting the apoptosis of neurons.

Question 47

What therapies were suggested to be effective by Cumming et al. (2013)?

Answer 47

rTMS can improve language abilities in patients with chronic non-fluent aphasia. Stimulation modulates and inhibits overactivity.
Prism glasses were found to be effective after an 8 week intervention - improved centre of gravity and some benefits on spatial tasks.