Quiz 1
Video’s
The description of test scores
How do we describe these test scores:
- Wide variety of standard scores
- To describe the scores, we need to know the mean and standard scores of all the scores
- IQ: mean 100, SD 15
- T score: mean 50, SD 10
- Scaled score: mean 10, SD 3
- Percentile of 60 ⇒ 60% of the population has the same score or lower
- 40% of the population has a higher score
Using the label impaired is not accepted anymore:
- A test score can be low for many reasons besides CNS dysfunction
- Preexisting cognitive limitations
- Low test engagement
- Examiner error
- Situational factors: pain, emotional distress, fatigue
- To determine if the person has cognitive impairments, the neuropsychologist has to interpret the
test scores to the unique patient’s history, and estimate premorbid level
,- Don’t label test score as abnormal, borderline, superior, deficient or impaired ⇒ give some kind of
interpretation
, - Use other labels:
- Extremely high
- Very high
- High average
- Average
- Low average
- Very low
- Extremely low
⇒ They only describe the performance, no interpretation
- Explain performance with descriptive labels ⇒ not the interpretation of score
Strategies for interpreting scores:
- Conservative
- Set a high cut-off to flag a test ⇒ e.g., 2SD below population mean or premorbid ability
level
- Increases specificity but decreases sensitivity ⇒ gives confidence that a lower score
gives true impairment
- Does give chance of missing subtle or mild impairment ⇒ increases false negatives (type
2)
- Liberal:
- Lower cut off to flag bad performance in a test, e.g., 1SD
- Increases sensitivity but decreases specificity ⇒ more sensitive to identify people with a
mild impairment
- Increases false positives (type 1)
- Select strategy based on setting and circumstance
- Select strategy based on:
- Assessment goals
- Conditions under consideration (diagnostic hypotheses)
- E.g., patient with memory problems ⇒ liberal approach to detect MCI/ dementia early
stage ; false negative means treatment delays
- We cannot have different cut offs for different patients within the same disorder
- Consequences of false positives and false negatives
- 1-1.5 SD does not necessarily mean impairment, is common
, How to interpret scores:
- Select strategy
- Perform pattern analysis ⇒ test scores should never be interpreted in isolation
- Integration ⇒ test scores, background, observation
IQ:
IQ above 130 = intellectual giftedness
- IQ cannot predict problems
- Composite scores:
- May obscure selective defects in specific tests
- Specific defects in certain cognitive processes (e.g., attention), would lead to low IQ
scores when other cognitive processes may be intact
- Loss of information: in which tests did the patient show problems?
⇒ Assessment focused on cognitive functions and not composite scores (like IQ)
There is not a unique score that can summarize the cognitive ability of a person
Deficit measurement:
- Current state of patient is compared to standard = comparison standard ⇒ if change has
occurred
- Two general comparative standards:
- Normative comparison standards; includes:
- Species-specific standards
- Species-wide capacities (e.g., normal reflexes)
- Counting change
- Drawing a recognizable person
- Using simple construction tools or cooking utensils
- Population average standards
- Average performance of large sample of individuals of a specific
cognitive or behavioral test
- Normative standard does not provide sufficient information to identify a deficit
within an individual; depends on premorbid functioning
- Individual comparison standards
- Determine if a specific patient score represents deficit or is normal
- Requires an individual’s premorbid level of ability
- Several ways:
- Historical records
- Direct method of deficit
- Requires the availability of premorbid test scores, school
grades
- Sometimes not available or difficult to obtain
- Psychometric methods
- Assess resistant cognitive functions to the effects of
brain dysfunction and aging
- E.g. vocabulary ⇒ correlates with education
- Shipley hartford vocabulary scale =
draw a line under the word with same
meaning (premorbid cognitive ability
assessment)
Video’s
The description of test scores
How do we describe these test scores:
- Wide variety of standard scores
- To describe the scores, we need to know the mean and standard scores of all the scores
- IQ: mean 100, SD 15
- T score: mean 50, SD 10
- Scaled score: mean 10, SD 3
- Percentile of 60 ⇒ 60% of the population has the same score or lower
- 40% of the population has a higher score
Using the label impaired is not accepted anymore:
- A test score can be low for many reasons besides CNS dysfunction
- Preexisting cognitive limitations
- Low test engagement
- Examiner error
- Situational factors: pain, emotional distress, fatigue
- To determine if the person has cognitive impairments, the neuropsychologist has to interpret the
test scores to the unique patient’s history, and estimate premorbid level
,- Don’t label test score as abnormal, borderline, superior, deficient or impaired ⇒ give some kind of
interpretation
, - Use other labels:
- Extremely high
- Very high
- High average
- Average
- Low average
- Very low
- Extremely low
⇒ They only describe the performance, no interpretation
- Explain performance with descriptive labels ⇒ not the interpretation of score
Strategies for interpreting scores:
- Conservative
- Set a high cut-off to flag a test ⇒ e.g., 2SD below population mean or premorbid ability
level
- Increases specificity but decreases sensitivity ⇒ gives confidence that a lower score
gives true impairment
- Does give chance of missing subtle or mild impairment ⇒ increases false negatives (type
2)
- Liberal:
- Lower cut off to flag bad performance in a test, e.g., 1SD
- Increases sensitivity but decreases specificity ⇒ more sensitive to identify people with a
mild impairment
- Increases false positives (type 1)
- Select strategy based on setting and circumstance
- Select strategy based on:
- Assessment goals
- Conditions under consideration (diagnostic hypotheses)
- E.g., patient with memory problems ⇒ liberal approach to detect MCI/ dementia early
stage ; false negative means treatment delays
- We cannot have different cut offs for different patients within the same disorder
- Consequences of false positives and false negatives
- 1-1.5 SD does not necessarily mean impairment, is common
, How to interpret scores:
- Select strategy
- Perform pattern analysis ⇒ test scores should never be interpreted in isolation
- Integration ⇒ test scores, background, observation
IQ:
IQ above 130 = intellectual giftedness
- IQ cannot predict problems
- Composite scores:
- May obscure selective defects in specific tests
- Specific defects in certain cognitive processes (e.g., attention), would lead to low IQ
scores when other cognitive processes may be intact
- Loss of information: in which tests did the patient show problems?
⇒ Assessment focused on cognitive functions and not composite scores (like IQ)
There is not a unique score that can summarize the cognitive ability of a person
Deficit measurement:
- Current state of patient is compared to standard = comparison standard ⇒ if change has
occurred
- Two general comparative standards:
- Normative comparison standards; includes:
- Species-specific standards
- Species-wide capacities (e.g., normal reflexes)
- Counting change
- Drawing a recognizable person
- Using simple construction tools or cooking utensils
- Population average standards
- Average performance of large sample of individuals of a specific
cognitive or behavioral test
- Normative standard does not provide sufficient information to identify a deficit
within an individual; depends on premorbid functioning
- Individual comparison standards
- Determine if a specific patient score represents deficit or is normal
- Requires an individual’s premorbid level of ability
- Several ways:
- Historical records
- Direct method of deficit
- Requires the availability of premorbid test scores, school
grades
- Sometimes not available or difficult to obtain
- Psychometric methods
- Assess resistant cognitive functions to the effects of
brain dysfunction and aging
- E.g. vocabulary ⇒ correlates with education
- Shipley hartford vocabulary scale =
draw a line under the word with same
meaning (premorbid cognitive ability
assessment)
