Neuropsychological Assessment Flashcards
Brain dysfunction can be due to…
▪️Structural lesions
▪️Metabolic problems
▪️Neurochemical/neurotransmitter abnormalities
What model was neuropsychological assessments originally based on?
Localisation of function
What model is neuropsychological assessment now based on and what does this mean?
Functional systems - whilst areas of the brain are still localised to particular functions, there are many systems of linked regions contributing to function, and damage to any of these areas in the system may impair it
What is a neuropsychological assessment?
A systematic, standardised measure of neuropsychological functioning that looks at a range of cognitive domains
How are neuropsychological assessments typically carried out?
Office-based pen and paper tasks
BUT could also be in real-life settings (multiple errands), medical settings (Wada test), or observations
How long does a neuropsychological assessment typically take?
2-3 hours
For which individuals should you be cautious when interpreting assessment results?
Anyone who potentially differs from the standardisation sample (e.g. English is not their first language, different culture, people with particularly low or high premorbid ability)
How are results of assessment typically represented?
▪️Percentiles
▪️Scores (e.g. IQ)
▪️Qualitative aspects may also be informative (e.g. awareness of failure, types of errors made)
What are the two main conceptual approaches to neuropsychological assessment?
▪️Psychometric
▪️Localisation
What is the psychometric approach to assessment?
It is based on statistical analysis and relies on the normal distribution of performance of most cognitive functions - how does the patient compare to this?
This is the most used approach in clinical practice
What is the localisation approach to neuropsychological assessment?
Using assessment to determine the localisation of pathology.
This is used much less due to advances in neuroimaging.
When might neuropsychological assessments still be involved in diagnostics?
As a screening tool in places were scanners are not available such as primary care.
It also may provide an overview if scans are not particularly sensitive to the damage.
What are the two main practical approaches to neuropsychological assessment?
▪️Fixed/diagnostic
▪️Flexible/functional
What is the fixed approach to neuropsychological assessment?
Assessment uses a formal composite battery that consists of a large range of fixed tests with the idea that if a deficit is present, they will likely detect it.
Results are described diagnostically
What are the limitations of a fixed, diagnostic approach?
▪️Very time consuming
▪️Doesn’t consider the impact of deficits on function
What is the flexible approach to neuropsychological assessment?
Hypothesis testing - assessment is based on a question posed by referral, background, condition, everyday functioning etc
Results are described functionally
What is the main limitation of the flexible, functional approach?
Deficits that are not readily apparent may not be assessed
What practical approach is typically take in clinical assessment?
A combination of approaches:
▪️Informal composite battery
▪️Further testing as indicated
Why do we test general intellectual functioning?
To provide context to other skills an abilities
Allows us to compare with premorbid estimates
What assessment is most commonly used to assess general intellectual functioning?
The Weschler Adult Intelligence Scale (WAIS-IV)
What are the four indices of the WAIS-IV?
▪️Verbal comprehension
▪️Working memory
▪️Perceptual reasoning
▪️Processing speed
68% of people score within ___ points above or below ____ in the Weschler intelligence score.
▪️15 points
▪️100
How do we estimate premorbid IQ?
▪️Reading vocabulary (e.g. NART, WTAR)
▪️Tests co-normed against the WAIS-IV (e.g. ToPF)
▪️Reading and demographics (combination - WTAR and ToPF)
How is reading vocabulary used to assess premorbid IQ and why?
Usually test low frequency, irregular words.
Typically correlates well with general/verbal intellectual functioning and is relatively resistent to neurological injury or illness
What are the main issues associated with using reading vocab and IQ for premorbid estimates of functioning?
▪️Use in populations who violate assumptions (e.g. acquired reading/language difficulties, English as a second language)
▪️Focus of neuropsychological assessment is often on cognition, not IQ
▪️Large margins of error
What types of memory are most commonly assessed?
▪️Verbal and non-verbal working memory
▪️Episodic memory - recall and recognition
Also anterograde and retrograde but tests of the latter are rare
What might evidence of material-specific difficulties in working memory suggest?
Lateralisation of damage
What are recall and recognition tasks useful for?
Identifying encoding vs retrieval difficulties