Lecture 1 - Neuropsychological Testing

neurological disorders

structural or functional abnormalities, linked to identifiable brain or nerve damage

psychiatric disorders

affect mood, thought or behaviour, not always tied to clear structural brain abnormalities

neuropsychology

studies brain behaviour relationships, measures and evaluates cognition, emotion and behaviour in people with known or suspected brain disorders and utilizes this info to aid diagnosis, design and evaluation of interventions

what does a neuropsychologist do?

they work in teams with neurologists in hospitals or private setting, they do an assessment to understand the relationship between the cognitive dysfunction and brain abnormalities (case presentation, referral, assessment and report)

what does a neuropsychologist look for during an assessment?

the level of cognitive performance, pattern analysis of cognitive performance and lateral comparisons of sensory and motor functions

what are the two types of assessments used?

fixed approach and hypothesis driven

fixed approach

each patient receives the same combo of tests

hypothesis driven

understand the needs of each patient so the assessment is tailored to the patient/patient specific

what are the main questions asked during an assessment?

understand whether there is a neurological issue, if there are lesions and where they are located in the brain, are there psychiatric symptoms that are causing the cognitive impairment, time course of the problem

what could a short time course indicate?

stroke or epilepsy

what could a long time course indicate?

dementia

neuropsychological tests

tasks designed to test the psychological function associated with brain regions or pathways, it requires systematic administration and scoring procedures, they have to have well-defined normative samples so that a single administration can identify cognitive deficits caused by an injury or neurodegenerative disorder, they are often qualitative in nature so context is important when looking at results

what does normed testing mean?

a normative sample is used as a reference and compared to the subject group when interpreting results

neuropsychological assessment factors

qualitative signs of cognitive deficits, functional neuroanatomy, history, individual differences, culture and language, threats to validity

demographics (assessment)

age, education, gender, SES, employment history and proficiency in the language used for testing

medical history (assessment)

medications, hormonal deficiencies, major surgeries, psychiatric history and course/duration of the illness

hierarchy of assessment

qualitative tool, range of conditions, tasks that are normally easy, level of dysfunction, pattern of similar error, patient performance

qualitative tool

should assess range of functions from basic to more complex

range of conditions

should allow the participants to reveal any deficits pretty easily

tasks used in an assessment

they should be easily achievable for neurotypical individuals at any level

nature of the assessment

it should become more progressively more dynamic to understand differences in ability in the same domain, it should allow the examiner to tease out different components of cognitive domains that are impacted

patient performance

the examiner should be careful not to over or underestimate it

pattern of similar error

this is what allows the examiner to draw a conclusion, allows them to say something about a particular pathway that is impacted

psychological domains

attention, visuo-spatial processing, language, memory and executive function

attention

the ability to focus awareness on a stimulus or task, it is the base for other cognitive functions

attention based tasks

continuous performance task, letter cancellation task, trail making task A & B

what brain region is responsible for attention?

the frontal and parietal lobes

what does an experimenter look for in an attention based assessment?

they assess vigilance/sustained attention or selective attention

continuous performance test

this is used to test sustained attention, the participant responds when they see a particular target and performance is assessed by reaction time and number of hits

selective attention

ability to focus on relevant info while ignoring all other info

stroop test

this is used to test selective attention, colored words are displayed and the person is asked to name the color that is written and not the actual color of the word

visuo-spatial processing

the ability to make sense of the visual world and reproduce what is seen, it involves drawing tasks

rey complex figure task

a drawing task that is used to assess visuo-spatial processing, the participant is shown a complex figure and then is asked to recall it by drawing it from memory

language

the ability to express oneself (oral or written) and comprehend (oral or written) linguistic information, it can range from basic word repetition to comprehension of grammatically complex sentences

semantic fluency

this is a language assessment where the participant is given a category and they have to come up with as many words that fit in that category as fast as possible

what area of the brain is responsible for language?

frontal and temporal lobe

memory tests

these includes immediate, delayed and assessment of long term semantic memories, visual, verbal and motor memories are tested separately

how are memories measured?

with free recall, cued recall and recognition

what area of the brain is responsible for memory?

the medial temporal lobes

California Verbal Learning Test (CVTL)

a memory test where participants are required to read a list of words to a patient and then there is a delay, afterwards they are given a list of words and the food acts as a cue for the semantic category

executive functioning

includes planning, conceptualizing, organizing, evaluating and working memories

what area of the brain is responsible for executive functioning?

the frontal lobe

what tests are used to assess executive functioning?

digit span backwards and wisconsin card sorting task

interpreting test performance

the score is typically out of 100, it requires an appropriate sample and understanding of the test quality so reliability and validity, also have to consider distributions and make sure there is no floor or ceiling effects

distributions

sensitivity and specificity, helps us figure out the criteria we need to choose to differentiate between calculations, they often overlap between healthy and disease populations

comparative sample

most neuropsychological tests have been normed on a normal distribution curve, this is done so you get values for different genders and groups, we have to assume in this case that the patient can be seen as an observation in the population group

comparative sample limitations

the sample comes from a specific geographic area/only includes a certain demographic, the sample size is small and it is outdated (ex; boston naming test was only normed up to 59 yrs old)

CVTL test improvements

the test was modified so the new word list was intended to be easier, with less geographic, cultural and SES bias because it wasn’t based on a research sample, the new one was proven to be better because when participants took both there was an observed strong consistency in raw numerical scores but deviations in numerical scores

reliability

degree to which an assessment produces consistent results over repeated measures, this is determined through evaluation of different types of reliability, its a property of test scores (how we interpret them)

internal reliability

the extent to which the individual items in a test measure the same cognitive domain or construct

test-retest

correlation between scores on a test administered twice, would you score the same or different (if its reliable then you would score the same)

alternate form reliability

correlation between scores on alternate forms of a test, we want it to be as close as possible to the original one, the higher the correlation the higher the reliability of the alternate form

interrater

degree of consensus between raters in scoring a test, we want the raters to score the items similarly

split-half reliability

correlation between scores on a test administered twice, correlate scores between the first and second half of the test

validity

the degree to which a test measures the construct it is intended to measure (ex; if tis an attention test, does it actually assess attention or does it assess some other cognitive function like working memory)

high reliability

scores are clustered

low validity

off target, you can have a valid test that is not reliable

low reliability

scores are scattered, it cant be valid

face validity

how well the test items measure the construct (usually based on a theoretical model)

construct validity

how well the construct is measured, is it measured reliably?

criterion reliability

how well the criterion that is used to draw a line between average and exceptions, how well does it differentiate between groups 

sensitivity

the ability to detect a deficit when a deficit exists, sometimes you can sacrifice specificity for sensitivity in cases that are more serious

true positives

the proportion of people that are positive for a disease that test positive

false positive

the proportion of ppl who are negative who test negative, confirm absence of a disorder when it is absent

floor effect

when a test is too difficult for everyone and ppl’s scores cluster on the lower bound of the scale

ceiling effect

when a test is too easy, shows that higher bound prevents ppl from scoring higher (ex; boston naming test), useful for detecting dementia