PsyDactic - Residency

Psychological versus Neuropsychological Testing

July 11, 2023 T. Ryan O'Leary Episode 36
PsyDactic - Residency
Psychological versus Neuropsychological Testing
Show Notes Transcript

This episode is about how to decide whether to send a patient to get neuropsychological or just psychological testing, and this decision is determined by at least two things.  The first is the question that you are trying to answer.   The second  is, what can the service that I am referring to provide for the patient?  In this episode, I will focus primarily on the first consideration:  the question that you are asking.  As a referring provider, then, it is helpful to know what kinds of tests a psychologist or neuropsychologist can administer, because these are designed to answer very specific questions. 

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Welcome to PsyDactic - Residency Edition.  I am Dr. O’Leary, a 4th year psychiatry resident in the National Capital Region.  This podcast is my own venture.  I hope by having to put together some kind of coherent product, I will increase my own knowledge and competence.  If this podcast helps you as well, then all the better.  I try to report true and up-to-date information to you, the listener, but in the end, everything I say here boils down to my own opinion.  It should not be confused with the opinion of my residency or any other governing body, such as the Defense Health Agency or the US Federal Government. Today I will talk about psychological and neuropsychological testing.  I should warn you that I am not a psychologist.  I hope soon to be a psychiatrist.  It appears likely to me that I will pass my boards and be dubbed a real psychiatrist, but that won’t happen until more than a year from now, if ever.

Many of my patients are confused by the difference between psychology and psychiatry or neuropsychology and neuropsychiatry.  I might say something like, “Psychologists study human behavior and emotions and often conduct research or work in clinics where they are experts in various kinds of psychological testing or psychotherapies.”  There are also many providers, like social workers, who also do therapy, but do not study psychology with the same focus and depth that psychologists do.  Social workers are more experts in the social determinants of health and are fantastic at helping to point clients to resources that can help.  Neuropsychologists are psychologists who also do a fellowship that focuses on the neuroscience of psychology where they learn more specifically the anatomy and functional activities of the brain and the kinds of exams and tests that can reveal these, so that they can identify neurological correlates to help explain what their clients are experiencing.  They might be able to refer a patient to a medical doctor for imaging in order to identify an area of the brain that has been damaged by stroke, seizures, genetic diseases, or physical trauma. Psychiatrists study both neuroscience and medicine, but their focus is more on medicince.  They are medical doctors and they also learn various kinds of therapy.   A psychiatrist's competence with various kinds of therapy tends to rely mostly on their own internal motivation to learn them in addition to the medicine that they learn.  A neuropsychiatrist, like a neuropsychologist, is a psychiatrist who completes an additional fellowship that focuses on neuroscience, especially how medicine or other kinds of therapies affect the brain.  Behavioral health clinics often have many different collaborating kinds of providers and patients are often unclear as to what the credentials are of the providers they are seeing that day.  To be honest, I am also unclear as to what the credentials of many of my colleagues are, especially because every provider tends to focus on the kinds of therapies or treatments that they feel most comfortable with or are attracted to.

Another thing that has been difficult for me to parse in my own mind is what are the differences between psychological and neuropsychological testing.  If I were to try to give a quick one liner, I mights say that neuropsychological testing is concerned more with how the brain is malfunctioning and psychological testing is concerned more with how to measure and predict human behavior when we don’t necessarily have a clear idea about how that behavior is related to brain function.  To put it another way, neuropsychologists are more interested in the neurological correlates of human cognition and psychologists are more interested in predicting and measuring human experience and behavior in general.

I don’t think that anything that I just said is very satisfying, in part because the way we have historically divided behavior from brain function is messy, though understandable, given that the brain is so complex.  In the future, I suspect that psychology and neuropsychology, psychiatry, neuropsychiatry, and neurology will converge on more common understandings of brain function and will be distinguished more by what kinds of services they provide or the kinds of research they conduct then how they conceptualize their patients or subjects.

Go ahead and take a deep breath or another drink of your coffee.  What I am going to focus on for the rest of this episode is how to decide whether to send a patient to get neuropsychological or just psychological testing, and this decision is determined by at least two things.  The first is the question that you are trying to answer.  If you don’t know what the question is, then you should discuss the case with a psychologist and neuropsychologist and see if they have any suggestions for what might be helpful.  The second consideration is, what can the service that I am referring to provide for the patient.  It would be convenient if all clinics out there could provide similar tests, but in actuality, each practice has its own focus and strengths.  Often, referrals will be handled by insurance companies, but in my limited experience, they are not very competent at knowing what is the best place for your patient to go, so it is better to refer to a particular practice or for very specific services so that you don’t waste the patient’s time.

Today, I will focus primarily on the first consideration:  the question that you are asking.  As a referring provider, then, it is helpful to know what kinds of tests a psychologist or neuropsychologist can administer, because these are designed to answer specific questions.  My last episode was concerned primarily with the term validity, and basically, this means that a test is measuring something real and hopefully is only measuring the thing that it is designed to measure and not also measuring other things.  Every test is concerned with one or more constructs.

One of the most common kinds of tests that psychologists administer are tests of personality.  These are given for many different reasons.  Someone may be interested in what kind of career field they might find more rewarding or intuitive for them.  A psychiatrist may suspect that underlying personality traits might be exacerbating a patient's symptoms or contributing to treatment resistance.  A morally rigid person may not be very receptive to cognitive behavioral therapy, which often challenges a person's thoughts and beliefs, although being able to do this may be exactly what the patient needs.  Psychological testing might help predict response to various therapies.   Companies might want to predict which candidates will perform better in certain positions.

It is important to note that the results of these tests cannot really predict the future.  What they do is place the test-taker into a distribution within a population and look to see if this person’s responses on certain items or in aggregate are within one or two standard deviations of the mean.  If they are outside of this range, then they are notably different from most people.  The population may include factors such as age, level of education, sex or gender, racial or ethnic characteristics.  Even if they are not outside of two standard deviations but they have some personality characteristics that can affect their current presentation, these are important to identify.  It can be difficult sometimes, when a psychiatrist suspects a personality disorder, to fit a patient within a single DSM entity.  Personality tests may be able to identify traits that are pathological or nearly pathological within an individual.  Then a psychiatrist may discuss with their patient that they have a personality disorder even though this disorder doesn’t fit cleanly into DSM categories.

These personality inventories may also contain measures of anxiety or depression or obsessiveness, or identify interpersonal styles that can help explaine how the respondent may interact with others.  Their may also be items that estimate a person’s risk of suicide or violence toward others.  Before referring a patient for testing, be sure to let them know that the tests themselves may be long and exhausting.  For some of the longer testing batteries, there are even measures to see if the respondents effort drops off in the last half of the test.

Another helpful tool in many of the tests are items that help estimate whether the individual tends to over or under-report the severity of their symptoms.  I have heard and read the term “cry for help” used when someone is measurably over-reporting, but I’m not sure exactly what that means.  There are patients whose overall distress due to current life circumstances or personality features results in them circling the highest number on every measure because their level of distress appears to short-circuit careful consideration of each test item.  There are also patients who consistently under report symptoms, for whatever reason, be it lack of insight into their dysfunction, lack of familiarity with the words used on the test, or fear that they may be exposed, punished, or limited in their employment if they report accurately.  For people who were raised in families that did not talk about emotions, it may be difficult for them to even conceptualize what sadness or anxiety are.  I have had patients who deny anxiety on screeners and when asked directly about anxiety or worry, but who then report that when they try to sleep they can’t stop thinking about whether what they said might have offended someone, or if they are competent enough, or if their family is safe.

Most personality inventories require a patient to self-report items on a scale.  This is often some kind of Likert scale, where people rate severity of symptoms or agreement with a statement with 5 options scale in various ways.  It may be something like “Not at all like me” to “Very much like me,”  or “Strongly disagree” to “Strongly agree.”  The 3rd or middle option is often something neutral.

There are also tests that a psychologist scores for the patient.  They also require more specialized training by the person administering the test in order to understand what a patient’s responses might mean and how to score them.  Probably the most famous of these tests in the Rorschach Inkblot.  The examiner has to be very careful about how they ask the questions and how the patient’s responses are recorded so that they can be interpreted reliably using a base of possible kinds of answers.  In the Rorschach test, people are shown a standardized set of inkblot cards and respond in a structured way, which includes a chance for the respondent to point to the card and justify their answer.  I don’t have time here to get into specifics, but one of the reasons a patient may be referred for Rorschach testing is to help identify whether they have a thought disorder.  Are their responses related to the shape itself or more internally derived? Do they give logical justifications for why they gave a certain response?  I imagine that something like this might be helpful when a clinician is trying to distinguish between the cluster A personality traits (paranoid, schizoid, or schizotypal) and a psychotic process. Odd or infrequent responses don’t by themselves indicate a thought disorder, but if a patient’s explanations for this don’t make sense to the examiner, then a though disorder is more likely.  There are sub-scales calculated that give scores that help to interpret the results of these tests.

Another more objectively scored test is the Thematic Apperception Test.  This test also uses a set of cards, but instead of inkblots, they have pictures of people who are participating in some kind of social interaction that is designed to be ambiguous.  By that, I mean that the cards can be interpreted in multiple legitimate ways.  The way a person interprets the card determines their scores on various derived measures.  One of these is the Social Cognitions and Object Relations Scale.  The various parts of this scale might reveal features of the respondent such as whether they are able to see others as having complex or even contradictory features (like humans really have), or if they see others as being (for example) all good or all bad.  With so much rich information, a psychologist can then identify things like a person’s level of emotional response, their own interpersonal style and how they may relate to others (including their psychotherapist), whether they see the world as threatening or welcoming.

Aside from exploring the depths of someone’s personality and emotional life, psychological testing is also famous for attempts at measuring intelligence in the form of an intelligence quotient or IQ.  These tests are still widely used today.  I have had people tell me that they took an IQ test online and it showed that they were a super-genius, so this must explain why they don’t relate well to others. This misunderstood genius has fundamentally misunderstood the validity and reliability of the test they took.  I doubt any random IQ test online that someone can self-administer at home is reliable or valid, even if derived from validated tools.

There are some other common misperceptions of IQ tests.  One is that an IQ is a single thing, that it defines a person's overall intelligence.  There are multiple measurements that go into calculating an overall IQ, and these subscores may be very different.  In what is called the Wechsler series, verbal comprehension, perceptual reasoning, working memory, and processing speed all contribute to the overall quotient.  Someone may have a large difference between their verbal and perceptual abilities, and the average of the two may not be very meaningful by itself.  From what I have read, it is expected that all of the components of an IQ should fall within one standard deviation of each other, and if they are outside of this, it should be noted.  Further testing might be necessary.

Another common misconception about an IQ is that it is a permanent, immutable feature of a person.  This is not true.  An IQ can change over time for at least two reasons.  One is that a person's abilities have changed.  They have become more educated or practiced.  The brain is an adaptive organ.  Another reason that an IQ could change is that the group that the individual is compared to changes.  IQ is a normed measure with a mean and standard deviation for the population that it estimates.  If an individual does not change in ability, but they are now in another group with a different mean and standard deviation, then their IQ will change.  A clinical situation in which an IQ may be helpful is in determining if someone has extremely limited abilities or borderline intellectual functioning.  This can have all sorts of prognostic and legal implications (such as whether the person needs a legal guardian) or can help determine what kinds of therapies they can respond to.

I mentioned earlier that one of the objectives of this episode is to distinguish between when a patient needs to be referred to psychological or neuropsychological testing.  There can be a lot of overlap between the two.  Both can be concerned with emotion, cognition, and behavior, with memory and processing speed.  Executive functions can be impaired by many disorders.  In generally, neuropsychologists are concern with a patient population that may have identifiable brain impairments that are due to things like neurodevelopmental disorders, like autism spectrum disorder or ADHD, or with acquired disorders, such as stroke, dementia, multiple sclerosis, traumatic brain injury, autoimmune encephalitis, diffuse hypoxia or diffuse axonal injury, among others.

Neuropsychologists were initially primarily experts in taking a clinical picture and localizing where the dysfunction is in the brain.  They are still experts in this.  However, we now have advanced neuroimaging such as magnetic resonance imaging or MRI (that had good resolution for the soft tissues of the brain), functional MRI (which measure changes in cerebral blood flow patterns), positron emission tomography (which can localize a lesion by finding areas of increased metabolic activity), single-photon emission computerized tomography or SPECT (which is relatively affordable way to localize where a seizure originates), and magnetoencephalography or MEG (that measures the magnetic field created by firing neurons).  A neuropsychologist can use this imaging to help guide what kind of exam or tests they need to perform or can use the clinical picture to recommend what kind of imaging is needed.

In modern times, most of the patients that we will refer for neuropsychological testing will already have a diagnosis.  They may have Huntington’s disease, a frontal lobe injury, a stroke, a history of seizures, ADHD or autism with some associated features that need more investigation.  Testing in these cases can be helpful to establish current levels of dysfunction, other unrecognized defects, and the neuropsychologist can recommend treatments that are tailored to the patient’s current needs.  Patients with acquired issues can be especially difficult.  It would be ideal that a person have had neuropsychological testing before their injury or insult.  That way, the testing could reveal changes in the individual from their premorbid condition.  Tests administered by neuropsychologists are also normed on population data, but just because an individual scores within the normal range, that doesn’t mean that their own abilities have not been compromised.   I can imagine someone who initially had very high processing speed and then scored below average but still within the normal range.  This would represent a large change for them and could result in a loss of ability for them to do things that they could easily do before, or needed some kind of assistance or training to learn new skills to accomplish the same tasks.

Neuropsychological testing expands what basic psychological testing is sensitive for.  IQ for instance, can be very informative for someone who is otherwise normal, but for individuals with specific brain impairments, it is not as helpful.  Neuropsychological testing adds the domains of attention, executive functioning, memory, language abilities, perception and processing of visual information or other sensory modalities, motor function,  and aspects of emotions and personality that are affected by specific pathologies that make regular personality inventories invalid for them.

You may have used a MOCA or Montreal cognitive assessment or a mini-mental status exam in your clinical practice.  These can be used as screening tools for dementia or at times as convenience measures to track whether a patient is worsening.  Tests administered by neuropsychologists are more useful at identifying and measuring very specific neurological abilities or malfunctions.

Sometimes, a patient may be reporting symptoms of poor concentration and attention.  They wonder if they have ADHD.  Adults presenting with concentration and attention issues may have conditions that can also impair concentration and attention, like a TBI, multiple sclerosis, depression, anxiety, or obsessive-compulsive disorder.  Attention can be affected by many things.  A person may have poor short-term or working memory, and this results in needing constant reminders.  Processing visual information may be impaired somehow, which makes it seem like a learner is not paying attention.  It may be difficult for someone to block out other sensory stimuli, and so they are constantly interrupted in their thoughts.  Even in the lack of external stimuli, a person may have difficulty sustaining their attention without being distracted internally.  Neuropsychologists have tests for these things.

I often have difficulty explaining to my patients what executive functions are in their brain because they are so broad.  I often mention that it has to do with the front part of the brain and their ability to sort through important information about their near and distant past, apply it to the present, and plan for the future, but this is very vague.  Neuropsychologists can test for frontal lobe functions by measuring things like social intelligence, which basically means being able to recognize one’s social environment and act appropriately within it.  This may require more than a little emotional regulation or impulse inhibition.  Don’t punch that person in the face.  Instead, remove yourself from the situation.

The frontal lobes are one of the locations that affect our ability to maintain attention, but a lesser known but even more important task is the ability to initiate some kind of behavior.  The frontal lobes help out with that too.  Patients with catatonia often appear stuck, as if they are trying to do something, but just can’t complete the action, or they can’t stop doing or saying something because they can’t switch to or initiate something new.  That’s called perseveration.  This might have something to do with their frontal lobe.  The frontal lobe also helps us to switch away from a focus of attention and then return to it.  One common aspect of ADHD is not only switching attention too frequently, but also not being able to switch attention easily when it is needed.  This is often called hyperfocus and is a deficit in what is called Cognitive Flexibility.  You can’t expect a child with ADHD to respond immediately after they receive a request.  They need some time to process the information and make the switch.  I have heard colloquially people report that because they can multitask (which is actually just task-switching and not multitasking) that they must have ADHD.  The opposite is, in fact, true.  Those with ADHD have a very difficult time, quote, “muli-tasking,” unquote.  They might appear as if they are because they are task switching, but it is not in an efficient or optimal way.

Executive functions are conceptualized as frontal lobe functions, but they require connectivity with other regions of the brain to really exist.  I have mentioned the cortico-striatal-thalamo-cortical tract in the past.  Tracts originating in the DLPFC are necessary for planning and impulse control.  The tracts that include the lateral orbito-frontal circuit are more involved in social intelligence.  There are also systems that process reward and motivation that include the anterior cingulate cortex with connections to the nucleus accumbens.  Particular deficits identified on testing can help locate where the dysfunction is occurring, and might help to target interventions, whether it be therapy, drugs, transcranial magnetic stimulation, or when all else fails deep brain stimulation or gamma-knife radioablation of certain out-of-control tracts.

Personality changes often accompany damage to the frontal lobe.  Traumatic brain injuries and fronto-temporal dementia are classical examples.  These changes are better characterized with neuropsychological testing because they don’t represent the same kind of pathological personality traits that are captured with psychological testing that is normed to a healthy population.

Another aspect of frontal lobe function that neuropsychologists measure is concept formation and reasoning.  This deals with being able to do things like interpret a proverb or apply rules to sorting tasks and being able to change strategies when the rules change.  There may also be tasks that do not require the use of language, but instead require the ability to reason using spatial, abstract, or numerical abilities.  These are the kinds of things that make us able to interact with our physical environment effectively.

Memory is another important construct that neuropsychological tests can parse.  It is far more complex that it appears on the surface.  It is not only anterograde or retrograde memory loss, the former being the inability to form new memories and the latter being the inability to recall previous memories.  We have short-term, working, and long-term memory.  We also encode memories for different sensations differently, and so may have a deficiency in verbal or auditory memory, but not so much in spatial memory.  Neuropsychological testing can identify specific problems and help to localize these.

Language abilities are also a large part of neuropsychological testing.  There are many kinds of aphasia, such as receptive or expressive aphasias, fluent or non fluent aphasias, primary or secondary aphasias, mixed aphasias, primary progressive aphasia.  It is beyond the scope of this episode, but if you are concerned about language abilities, then neuropsychological testing is what you want.

There are also many ways to test the ability of a person to process visual information.  Perceiving visual information is more than just receiving a signal from the optic nerve.  The brain needs to be able to identify what it sees, whether that be an object, a face, or an emotional expression.  It is also critical to be able to have a concept of where something is in space in relationship to the objects around it.  Often neuropsychologists can start with visuoconstructive tests which ask the patient to copy or draw various objects.  It can be simple geometric shapes or far more complex figures that they have to copy.  The MoCA contains a box drawing and a clock drawing test.  If patients fail at construction tests, then other tests can be used to figure out whether the problem is visuospatial or perceptual.

Neuropsychologists can also help provide us with insight regarding a patient’s emotional or behavioral issues.  For patients who seem to be over-reporting their level of dysfunction or who are excessively worried about memory or other cognitive issues, simply knowing that a patient tends to over-report on scales is not so helpful, because it doesn’t test specific functions. Neuropsychiatric testing can provide objective information that can confirm whether the patient’s perception of their deficit matches with a measurement of their deficit.  These tests also have some measures of effort built in, so if a respondent does not appear to be giving their best effort, then this can be reported.

This episode has gotten very long compared to what I normally do.  I try to keep my episodes less than 30 minutes so that they are digestible by the listener, can be finished within a single commute, and stay focussed.  The question that I used to guide this episode was “When will I know whether I should refer a patient for psychological or neuropsychological testing?”

Here are some take-aways for this question.  If you are concerned primarily about diagnostic clarity with regard to symptoms when you feel like personality traits may be confounding affective, psychotic, anxiety, or obsessional traits, or you think that a patient may be systematically over or under-reporting symptoms, then regular psychological testing is going to have a lot of value.  I am not sure when a psychiatry resident would be interested primarily just in a patient’s IQ, then you could refer for IQ testing as well.  IQ testing might be done if a patient has other issues and you want to establish their general ability to understand, agree to, or participate in treatment beyond a single capacity evaluation.

However, you may be interested in IQ, processing speed in particular, or memory function because a patient of yours suddenly finds it difficult to perform certain cognitive tasks after a TBI and you would like to get a baseline to be able to track progress.  In general, if any cognitive, emotional, sensory, or behavioral symptoms appeared or worsened after some kind of acquired injury or illness, neuropsychological testing is the way to go.  A neuropsychologist can also administer any test that a psychologist without a fellowship in neuropsychology can administer, so you are not leaving anything out by going this way.  However, you often don’t need the additional battery of tests that neuropsychologists can provide.

When in doubt, write your question down, and then call a psychologist and ask them what to do.  If you don’t know your question yet, write up a thorough case summary and call a friend.

I want to end this episode by giving you a sense of immense dissatisfaction.  I am going to apologize ahead of time for this, but I think it is important to point out when there are not easy answers to clinical questions. One difficult thing to diagnose is ADHD in an adult.  There are clinical screening instruments like the ASRS or the WURS that can help estimate current symptom burden and past symptoms burden.  Collateral may be contractory.  Quite often someone is coming in when they have reached a point in life when they find it hard juggling so many things, but looking at the past, they seemed to do sufficiently well in school and work before.  We know that highly intelligent individuals may be able to compensate for their ADHD by having fast processing speeds and good memories.  Someone may have been raised in an environment where their parents were extra-involved and so they didn’t see their dysfunction until mom and dad withdrew their constant support.  Or maybe they didn’t learn the skills to organize themselves because mom always did that for them.  Or their school was lower performing and inflated grades, so as to seem to be achieving.  It is tempting to assume that with difficult adult ADHD cases, you can refer for neuropsychological testing and that will give you clarity.  But none of the tests that neuropsychologists or psychologists can add on are specifically designed for diagnosing ADHD.  Even the attention specific tests given by neuropsychologists are not tests for ADHD.  They are tests that can identify certain deficits in attentional capacity, but without a clear clinical picture, prior testing, some insult or injury to explain the results, these tests are not that helpful.  ADHD remains a clinical diagnosis.

I hope this review of what kinds of questions psychological and neuropsychological testing can answer is helpful.  It has helped me to better understand what I am doing when I place a referral.

I am Doctor O’Leary and this has been an episode of PsyDactic - Residency Edition.