Neuropsychological Assessment: The brain under a magnifying glass

Investigating Brain Dysfunction

Cartoon of a mad scientist

The clinicians at Ormond Neuroscience are scientists whose work is guided by the scientist-practitioner model. Basically, the idea is to use scientific research to inform how we practice as clinicians. Accordingly, we apply well researched scientific principles and knowledge to the diagnosis and management of the brain-related problems afflicting a patient.  Therefore, our work is consistent with internationally accepted scientific methods and protocols. Consequently, undergoing a neuropsychological assessment at Ormond Neuroscience comprises three types of focused investigations.

  1. Medical evidence.
  2. Signs and symptoms.
  3. Psychometric testing.

Different members of the team contribute to each facet of the examination, each bringing their unique skills to bear on the investigation.

Scrutinizing the Medical Evidence

To start, a neuropsychologist, usually Digby Ormond Brown, inspects the available medical evidence. This includes brain scans, blood test results and other reports because this information may shed light on the possible cause of brain dysfunction.  Of course, brain scans are usually the primary medical evidence, whether CT scans or MRI scans. Importantly, consideration is also given to the findings of other professionals, such as neurologists or psychiatrists.  For example, an EEG (electroencephalogram) may have previously been done.  As you would expect, medical evidence is crucial to accurate neuropsychological assessment.  Furthermore, if appropriate, we may refer you for additional investigations.

What is a CT Brain Scan?

CT scans are also sometimes called CAT scans.  CT stands for computerised tomography. CAT stands for computerised axial tomography.  So, a CT scan is the same as a CAT scan. Tomography refers to any kind of imaging procedure that uses penetrating waves to generate cross-sectional (axial) layered images of the subject.  In the case of CT scans, the penetrating waves are x-rays.

CT scanner
A patient being prepared to undergo investigation in a CT scanner.

And MRI Brain Scans?

Sagittal image from an MRI of the brain
An MRI brain scan. This is a sagittal section through the middle of the brain. Nose on the left, back of the head on the right.

In contrast, magnetic resonance imaging (MRI) brain scans use a different technology to CT scans.  Firstly, an MRI scanner uses a strong magnetic field to cause all of the protons in your body to align in the same direction.  Secondly, a short pulse of radio waves then knocks them out of alignment. Thirdly, as the protons realign a resonant signal is generated, which is used to create an image of the body part being investigated.  Simple, eh?

Since the image resolution is higher in a MRI scan, we can see problems that are not always evident on CT scans.  Nonetheless, sometimes a CT scan is preferable, for example, when looking for atrophy in a patient with dementia.  Unfortunately, MRI scans cost a lot more than CT scans.

Signs and Symptoms of Brain Dysfunction

Signs and symptoms are critical to diagnosis. A symptom is something experienced by patient, like pain in your finger or being forgetful. A sign is something a doctor sees that implies a medical problem. For example, redness of the skin implies inflammation or a white spot on scan might imply a stroke.

Therefore, signs and symptoms are important for understanding and accurately diagnosing the of the condition affecting a patient.  Since symptoms are subjective, they are not information that can be obtained from tests, brain scans or laboratory investigations.  Instead, the patient needs to tell us about their symptoms and in turn we need to ask specific questions. 

Collateral Information

It is of enormous value if collateral information is also available. This comes from someone who knows patient well, such as a parent or spouse. They can comment on changes in the patient’s functioning.

Since the human brain is so complex, we need to canvass multiple areas of functioning in order to perform a thorough neuropsychological assessment.  We use a carefully honed and structured clinical interview that investigates multiple domains, as described below.  Typically, one of the psychometrists at Ormond Neuroscience will obtain the basic information that is required. Then, the neuropsychologist will ask more detailed questions and clarify the picture.

Contextual Information

Obviously, we need to know with whom we are dealing, their background, work and so on.  To that end, we need to know the person’s:

  • Medical history
  • Psychiatric history
  • Level of education
  • Occupational history
  • Social circumstances

Domains of Functioning Relevant to Neuropsychological Assessment

To understand the problems affecting the person, we need to ask questions and obtain information in relation to the following areas:

Medical Signs & Symptoms

  • Current medication
  • Chronic pain
  • Epilepsy
  • Headaches

Vegetative Signs & Symptoms

  • Sleep cycle
  • Fatigue and energy levels
  • Appetite
  • Menstrual cycle

Sensory Signs & Symptoms

  • Vision
  • Hearing
  • Olfaction
  • Taste
  • Touch

Motor Signs & Symptoms

  • Balance
  • Tremors
  • Coordination
  • Handwriting
  • Speech

Cognitive Signs & Symptoms

  • Attention and concentration
  • Long-term memory
  • Short-term memory
  • Visuospatial information processing
  • Expressive abilities
  • Comprehension of language
  • Abstract reasoning and problem-solving
  • Planning and organisation

Affective Signs & Symptoms

  • Depression
  • Anxiety
  • Mood swings
  • Temper control
  • Impulsive behaviour

Social Signs & Symptoms

  • Friendships
  • Community involvement

Psychometric Testing

What are Psychometric Tests?

Psychometric tests measure psychological functions. They are carefully designed and scientifically validated measures of different aspects of human functioning. That includes sensory, motor, cognitive and emotional functioning.  The bulk of the measures we use at Ormond Neuroscience tap into cognitive functions, such as memory and reasoning.  Of course, the specific tests vary according to the patient and the diagnostic considerations.

An example of a psychometric test

A standard battery of tests provides a general overview of neurocognitive functioning.  Depending on those findings, it may be appropriate to administer additional tests. That would be done during a second testing session to further investigate functioning.

Neuropsychological Assessment Protocol

Obviously, the neuropsychologist decides on the tests that should be used. Then, a psychometrist administers the selected battery of tests.  Most of the time, the patient is alone when tested in the laboratory. However, sometimes there is some special reason why someone else should be present.  Testing can take a few hours and as a result, the psychometrist will always give the patient a break halfway through the testing session.

The test laboratory is not a sterile room full of test tubes. Rather, it a comfortable office with a desk and chairs and a computer. We try to keep the room as quiet as possible.

Of course, the tests come in a variety of formats.  Sometimes, the patient simply has to listen and give verbal responses.  Then, there are tasks that require reading, writing, or drawing.  Also, a computer administers some procedures.  Usually, a standard battery of tests with an adult takes approximately three hours to complete, including a 15-minute break. In contrast, testing children takes in the region of four hours. Surely, kids need more breaks!


Normative Comparisons and Neuropsychological Assessment

Graph depicting the normal distribution

Let’s be clear, you don’t pass or fail neuropsychological tests!  The neuropsychological laboratory is not school.  Undergoing a neuropsychological assessment is also not the same as IQ testing.  Moreover, irrespective of how bright the patient may happen to be, the tests provide objective information about brain function. 

As a general rule, we compare test results to Joe Average. Thus, to figure out if the test results are within the normal range or abnormal, we compare to the performance of the average person. To that end, we have a database of normative reference values.

Of vital importance, comparison to the norm, to Joe Average, just provides a convenient reference point. The crucial issue is how the patient’s functioning may have changed compared to some point in the past.

Statistical Significance vs. Clinical Significance in Neuropsychological Assessment

Normative comparisons are statistical. They are of somewhat limited utility to neuropsychological assessment because statistical significance is not the same as clinical significance.  Get this point: A problem in your brain may cause a clinically significant impairment of your functioning, even if your score on test is better than Joe Average’s.

Imagine if something went wrong in your brain and afterwards your photographic memory deteriorated. So, say, on memory tests you went from 99% to 65%. That would be a clinically significant loss of ability, even if your score was still above average.

Consequently, in the end the neuropsychologist determines the clinical significance of the findings.  Moreover, Ormond Neuroscience never uses simplistic, mechanical interpretations of test results. 

To find out more about what to expect during a neuropsychological examination, and what and who to bring along, click here.