lectures Flashcards
(39 cards)
The purpose of neuropsychological assessment is:
- Diagnosis
- Distinguish between different neurological conditions
- Discriminating between psychiatric and neurological symptoms
- Identifying a possible neurological disorder - Patient care and planning
- Identifying cognitive strengths and weaknesses needed for optimal and
- Identifying behavioural alterations careful management of many
- Identifying personality characteristics. disorders - Treatment planning and remediation
- What is the most appropriate cognitive rehabilitation treatment? - Treatment evaluation
- Did the treatment have an effect? - Research
- Forensic neuropsychology
- In the context of claims of injury and loss of functionIn criminal cases (Is there reason to suspect brain dysfunction that contributes to misbehaviour)
Evidence based medicine relies on
(1) clinical judgement,
(2) relevant scientific evidence,
(3) patient values and preferences
Formulating hypothesis and going through the diagnostic cycle is important because it helps you avoid interpretation errors. There are multiple forms of interpretation errors.
- The tendency to rely strongly on some results and to disregard others
- Disregarding the base rate of disorders
= A neuropsychologist who works a lot with patients with Alzheimer’s disease will have the tendency to diagnose Alzheimer’s disease more often - Conformation bias
= Looking for results that support you hypothesis - Thinking that subjective complaints are objective disorders
There are Two classical test approaches in neuropsychological assessment:
- Psychometric approach (Reitan-Halstead testbattery)
o Standardized assessment and scoring
o Uses normative data and cut-off scores per test and for the total test performance
o Quantitative test approach
o Not based on theories about the brain
Each person will be tested and scored exactly the same way. Scoring can be done two ways. - Cut-off scores
You either have an impairment or you don’t. - Calculation impairment index
≤ 0.4 = No impairment, ≥ 0.5 = Impairment, 1 = Severe impairment
There is also criticism on the Reitan-Halstead testbattery.
- it is a-theoretical (not based on theories about the brain)
- the test battery is fixed
- it focuses only on abilities and not on dysfunctions (it gives no insight into the
nature of the problem or directions for rehabilitations) - Behavioural neurological approach (Luria’s behavioural-neurological method)
o No empirical testing of his theory
o No normative data qualification of the symptoms
o No standardization testing hypothesis
o Based on observation
o Flexible test battery which is adjusted to the individual patient
o Qualitative assessment approach
o Does give direction to rehabilitation
After the 2nd world war a large number of patients came home with brain injury. Test batteries were developed on the theory of the brain where attention is regulated by the brain stem, perception by the posterior part of the brain and organization and planning on the anterior part of the brain. It became also known that perception has multiple levels: primary (image), secondary (interpretation), and tertiary (cross modal integration).
Luria’s behavioural-neurological methods consisted of simple tasks to provoke symptoms.
There is criticism on Luria’s behavioural-neurological method as well.
- the theory is strongly focussed on the left hemisphere
- it gives no insight into the severity of disorders (you’re impaired or you’re not)
- no standardization, normative data or data about the reliability and validity of the
tests.
In evidence based medicine, now called Differential diagnostic thinking, you have to..
listen to complaints of patients in a unjudgmental manner
try to cluster down syndromes, symptoms and impairments
be aware of the halo-effect (Assuming that a patient has certain complaints or characteristics which in reality are
But before the assessment takes place you should make a couple of decisions..
- do I use a fixed or flexible test battery
- do I use a quantitative or qualitative approach
- which cognitive domains should be tested, and which tests do I choose for that.
There are some problems however (with tests)
- Neuropsychological tests rarely measure only the function they are supposed to measure. In complex figure of Rey examinees are asked to reproduce a complicated line drawing, first by copying it freehand (recognition), and then drawing from memory (recall). Many different cognitive abilities are needed for a correct performance, and the test therefore permits the evaluation of different functions, such as visuospatial abilities, memory, attention, planning, and working memory (executive functions).
- Tests require intact visual and auditory perception
- Tests always rely partly on attention, memory, executive functions, language and motor skills
- Motivation, mood, speed of information processing, fatigue, etc. can have a significant negative influence
So now you have done all your tests, how do you interpret your results?
An impaired performance can be due to either an impairment in the function the test is supposed to measure, or can be due to disturbing factors
a) Cognitive impairments in other domains than those that measure a test.
b) Emotional disturbances
c) Disturbed visual and/or auditory processing
d) Cultural backgroundThese are important to consider when formulating a hypothesis.
Which test do you choose? Check for:
- Reliability
a. Test/retest reliability, parallel versions, interrater reliability - Validity
a. Ecological validity, construct validity - sensitivity/specificity
- level of difficulty
a. 8 words test vs 15 word test (word test when memory is severely impaired) - quality of normative data (comparison group).
A test should preferably have a high test/retest reliability, high construct validity, good sensitivity, good specificity, detailed normative data, validated parallel versions, limited learning effects, no ceiling effects.
Objective vs subjective assessment.
Objective = performanceon tests
Subjective = Complaints of patient Observation from partner/children Observation of nursing staff Observation during neuropsy. assessment
Ethics
There are different, but overlapping, codes of conduct. The most important point mentioned are
- respect for a person’s rights and dignity
- competence (of the psychologist)
- responsibility
- integrity (being honest and transparent)
Always keep the interest of the patient in mind. The patients should decide themselves whether or not they want a neuropsychological assessment. Patients can terminated the ‘professional relationship’ at any time, without giving a reason. Patients are allowed to read the neuropsychological report. Patient data is confidential and can only be distributed if the patient grants his permission.
The empirical cycle, according to Adriaan de Groot.
- Observation: The collecting and organisation of empirical facts; Forming hypothesis.
- Induction: formulating hypothesis
- Deduction: deducting consequences of hypothesis as testable predictions (operationalisation)
- Testing: testing the new hypothesis with new empirical material
- Evaluation: evaluating the outcome of testing.
Phase 1: Observation. Collect facts and form hypothesis
Get as many facts as possible before the assessment.
- Autobiographical information
- Which problems is the patient experiencing?
- What is the referral question? patient-related information
- Medical History
- Neuroimaging data
- Previous assessments, etc.
- Get information from handbooks or articles about symptoms/syndromes Knowledge
related info
How does a clinician generate hypothesis from all these facts?
- pattern recognition based on knowledge (Example in lecture: chess players showed a phenomenal short term memory for chess positions as long as they fitted in with the known rules. When the pieces were randomly arranges their recall was not better than novice chess players. Relevant clinical experience is extremely important)
- Experienced clinicians are able to recognise a pattern (syndrome) based on minimal amount of facts.
- Clinical view is not just a mystic or irrational ‘gut feeling’; it is based on applicable and accessible knowledge. It is memory based.
- Requires specific and up-to-date knowledge of Clinical Neuropsychology, Neurology, Clinical Psychology, Cognitive Science, etc.
Phase 2. Induction: Formulating hypothesis
Why formulate hypotheses?
1. A hypothesis provides a clear statement of what needs to be investigated. It helps the
clinician to (1) identify the assessment objectives, and (2) identify the key abstract concepts
involves in the assessment.
2. Also, a referral question cannot be answered unless it is reduced to hypothesis form.
A good hypothesis …
Can be tested – verified, corroborated, or falsified
Is not too specific, nor to general
Is a prediction of consequences
Is considered valuable even if proven false
Has no moral or ethical judgement
It is always necessary to formulate multiple hypothesis.
o Null hypothesis: a theory that is being put forward because it is believed to be true or it is to be used as a basis for argument, but has not been proved.
In CN-PSY: the patients behaviour/cognitive functions are normal compared to the norm group.
A Null Hypothesis ‘forces’ a clinician to evaluate the possibility that cognitive functioning is not impaired or that the patients behaviour is normal
o Alternative Hypothesis: a statement of what your assessment is set up to establish.
• Is opposite to the null hypothesis
• Is only considered if the null hypothesis is rejected
• In many cases, the alternative hypothesis turns out to be the conclusion of the clinician.
• Always consider ‘personal’ and ‘environmental’ contributors (loss of partner), not just cognitive function.
In CN-PSY: patients behaviour/cognitive functions are abnormal.
Why is a null-hypothesis necessary?
1. Behaviour may be ‘normal’
2. All clinicians suffer from bias
3. A null-hypothesis ‘forces’ a clinician to evaluate the possibility that cognitive functioning is not impaired or that the patients behaviour is normal
Phase 3. Deduction: Deducting consequences of hypothesis as testable predictions
General considerations:
- neuropsychological assessment is an N=1 experiment
- you know the research question, you have formulated the hypothesis
- think of which results will tell you a hypothesis is true (confirmation)
- think of which results will tell you a hypothesis is false (contradiction)
So if we look at our example, what are the relevant facts to look for? Which facts would be exclusive.
look for test that are discriminating. Test that only score positive in case of dementia, and not for depression od MCI for example. It helps to use a matrix.
Phase 4. Testing: testing the hypothesis
General considerations:
- During interview, observation and testing, new hypotheses may arise
- During interview, observation and testing, some hypothesis may be rejected almost immediately
- Keep your matrix and your predictions in mind! Think twice before changing plans!
- About neuropsychological testing: practice makes perfect.
Phase 5. Evaluation: evaluating the outcome of testing
Stepwise interpretation of the results (9 steps).
(re)integrate all available information and check for completeness.
Sources of information include:
- knowledge of function neuro-anatomy
- knowledge of brain diseases and their consequences for behaviour
- knowledge of psychology, clinical psychology, cognitive psy, and psychopathology
- referral question
- medical file, medical history, current status, neuro-imaging data
- psychosocial history of the patient
- interview with patient and peer
- observation data
- test results
Estimate the validity and reliability of the assessment .
Validity : measure that what you want to measure (you don’t measure your weight with a thermometer.
Reliability: a test should be consequent in the outcome when the input is the same.
A test is never 100% valid. A memory test never measure just memory.
Threats to validity include: sensory impairments, motor impairments, (mild) aphasia, perceptual problems, medication, motivation problems, concentration problems, fatigue, malingering, cultural background (all tests have a norm group of young Caucasian people).
Estimate premorbid functioning
There are ‘hold tests’ which measure crystalized intelligence and remain the same with aging. There are also ‘don’t hold’ tests which measure fluid intelligence and decrease with age.
Premorbid functioning can be estimated with information of previous work, education, and social activities.
Summarise observation and interview data
Calculate the standardized scores out of the raw scores.
It is preferable to recalculate all scores to on type of score (e.g. make it all z-scores or all t-scores). Then calculate your confidence interval and provide a clear legend.
When is a test score abnormal? This can be difficult, because a below average score does not necessarily mean an impairment.
- take the entire test profile into account
- more test will mean a greater difference between highest and lowest scores
- in most people a difference of 3 SDs between two tests is not uncommon.
- differences in aptitude are not always clinically meaningful
- consider premorbid functioning
- consider reliability of test and whether scores are corrected for age, education etc.
Rule of thumb 1 ½ Sd (6th percentile) – 2 Sd (1-2 percentile) below average is abnormal.
Calculate the Standard error of measurement (Sem)
Sem = Sd √(1-reliability)
Calculate confidence interval (test score =20, Sem = 2)
real score lies between (20-2xSem) 16 and (20+2xSem) 24.
Fill in matrix
Compare a priori test profile with real test profile
Make decisions about affirmation and rejection of hypotheses
Summarize results
Go back to the original question. Is there enough evidence to answer the question? Remember you are dealing in probability, not certainty.
Try to formulate the most important findings in 3-4 sentences.
The purpose of psychological reports are to
(1) increase others’ understanding of clients,
(2) communicate interventions in such a way that they are understood, appreciated, and implemented, and
(3) ultimately result in clients manifesting improved functioning.
The structure of a psychological report is as follows:
- Disclaimer
a. For who, for what purpose, for how long (expiry date) - Personal details
a. Name, date of birth, sex, education, handedness, marital status, social situation, test date, tested by.. - Referral question/ purpose of assessment
- Medical history and medication
a. Limit the information to relevant facts. - Interview
a. Keep in mind that you are not observing facts but opinions. Not: the patients memory problems started two years ago. But: according to the patient, his problems started two years ago.
b. Not just report the type of complaint but also the nature, duration, course, and intensity.
c. Differentiate to what the patient tells you and what others tell you. (neither are very reliable) - Observation
a. Only report an observation if it enhances insight into:
i. Premorbid functioning
ii. Current level of functioning
iii. Pattern of disfunction
iv. Inconsistencies
b. Be careful not to overinterpret - Test results
a. It is preferred to report by domain (intellectual functioning, attention/concentration, memory, etc.)
b. Avoid using words as ‘rather’, ‘fairly’, and avoid using jargon. - Summary and conclusions
a. Start with restating the purpose of the assessment
b. Summarize your main findins
i. Limit to what is important
ii. Do not name tests, only cognitive domains
iii. Do not limit this to positive findings (be aware of the conformation bias)
iv. Report serious threats to validity of your assessment (lack of motivation, extreme fatigue, visual impairments)
c. Evaluate your hypotheses, but better not name them explicitly. (e.g. the results do not fit with dementia, but are in line with a mood disorder)
d. If necessary advice further assessment
e. If required, give advice for rehabilitation, intervention or care. Stick to what you know (about behaviour, emotions, cognitive functions) and remember whom you are writing for.
Assessment can be done 4 different ways
- Psychometric neuropsychological tests
- Clinical interviews (unstructured, semi structured, structured)
- Questionnaires (self-report, other reports)
- Observations (during clinical assessment)
Different types of assessment provide different types of information. Therefore all assessments are necessary for an complete picture.
Before the interview it is important to look at the patients record. Here you can find:
1) information of the injury and post-injury records (head injuries, tumours, epilepsy, alcohol abuse),
2) neuroimaging data,
3) psychiatric history (developmental-, psychotic-, affective-, anxiety-, personality disorders)
4) previous assessments
5) previous treatments
6) school records
7) vocational records
8) physical problems
If you are well prepared before the interview, you are able to answer the following questions:
what is the purpose of assessment?
What is the aim, which question will be addressed?
Are you confident your assessment will help to answer this question?
Are you confident your level of expertise is sufficient to answer this question?
you confident your equipment is sophisticated enough to answer this question?
Performing the interview (de stappen)
I. inform the patient about the purpose and content
a. The patient’s reports and behaviour can only be interpreted in a valid fashion if the patient has been informed about purpose, content, and duration of the interview
II. collect biographical information
a. family situation, school situation, vocational situation, socio-economic status, private situation, living situation interests/hobbies, stressors (partner crisis, money)
III. measure the premorbid level of functioning Can only be done in acquired brain
a. look at previous assessments (if there are any) damage
b. school education
c. vocational situation
d. income
e. hobbies and interests
f. family background
g. involve a spouse or parent: These are not necessarily more valid or reliable. But the discrepancy between self- and informant reports are important. This helps yo to evaluate the insight of the patient.
IV. ask for the type and nature of the complaints
a. start with spontaneous self-reported complaints. Continue with more specific questions (how did it start, when, at which intensity). Eventually determine complaints on cognitive/modular level (attention, memory, planning, impulse control etc.)
V. what are the course of the problems (sudden onset, slow progressive onset)
a. are the complaints getting worse, since when, how, etc.
VI. ask for the consequences of the complaints.
a. Do complaints affects daily life functioning
