Lec2 Methods for assessing psychological dysfunction Flashcards
what are the aims of assessments
i. Clinical decision making 1. Diagnostic, prognosis, treatment and follow-up ii. Research into disease mechanisms iii. Understanding normal psychological function iv. These aims are interdependent
what are the two comparison standard used in assessments? give an example of each
a) Normative comparison standards use as a baseline the population average i. i.e. Bells or letter test in spatial neglect b) Individual comparison standards use as a baseline individual’s own earlier performance i. i.e. Hamilton or Beck depression scales
Pros and cons of standardised tests (normative comparison standards
Advantages i. Diagnostic value Disadvantages i. collecting control data is laborious ii. the normal distribution may differ depending on the characteristics of the population iii. not all psychological variables are normally distributed iv. not all psychological variables are easy to measure
Rating scales are useful for ______________
Rating scales do not confirm diagnoses. they are used to monitor suspected or diagnosed deficits. they are part of the evaluation and management of disease, and are useful for measuring responses to treatments
Describe the content of Beck Depression scale
21 questions about how the subject has been feeling last week. Each question has a set of at least four possible answer choises ranging in intensity
Pros and cons of rating scales (individual comparison standards?
Advantages 1. Easy and cheap 2. Can be used for variables that are not normally distributed or are difficult to measure Disadvantages 1. Risk of operator error 2. the pitfalls in ‘self-reporting’
What is validity what is perdictive validity? what is ecological validity?
- A valid test measures what it claims to measure 2. Predictive validity a) Does the measure accurately tell you about the future state of the variable being measured? 3. Ecological validity a) How well the measure reflects everyday functioning ?
what is reliability? what is inter-rater reliability? what is test retestreliability? what is parallel test reliability?
- A reliable test produces consistent results on each administration 2. Inter-rater reliability: do two experimenters testing the same subject get the same result? 3. Test-retest reliability: do you get the same result if you test the same subject twice? 4. Parallel test reliability: if you test the construct using different measures, are the results comparable?
what is sensitivity
a sensitive test cna identify correctly the individuals who have a disease. sensitivity = True positive/ (true positive+ false negatives)
what is specificity
a specitfic test can identify correctly the patients who do not have the disease. specificity = true negative/ (true negative +false positive)
what is positive predictive value
the ability to detect a disease given the results of the test useful for clinician depend on sensitivity, specificity, prevalence of the disease in the population positive predictive value = true positives/ (true positive +false positives）
Why we should not use the same diagnostic test in a hospital department and in the general population
what are the costs of a false positive
healthy individual, but test outcome is disease
– unnecessary worry
- costs and side effects of unnecessary treatment
what are the costs of false negative diagnostic
individual who actually have disease, but test outcome is healthy
– failure to treat leading to symptom progression
- social stigma or feelings of guilt
evaluation of genotyping
Advantages of genotyping
diagnostic, predictive, prenatal and even preimplantation testing
Disadvantages of genotyping
Genetic diagnostic is not a simple blood test !
Need for support and counselling, especially if no treatment exists.
Ethical implications especially for prenatal screening ie if the parent does not want to know own genetic status, parents anxious about a minor.
