Investigating Brain Dysfunction
As our name suggests, the clinical staff at Ormond Neuroscience are hard-nosed scientists who work in accordance with the scientist-practitioner model, applying well researched scientific principles and knowledge to the diagnosis and management of the brain-related problems afflicting a patient. In line with internationally accepted scientific methods, undergoing a neuropsychological assessment at Ormond Neuroscience comprises three types of focused investigations.
Different members of the team contribute to each facet of the examination, each bringing their unique skills to bear on the investigation.
The neuropsychologist, Digby Ormond Brown, inspects the medical evidence that is available. This evidence may shed light on the possible cause of brain dysfunction. Brain scans are usually the primary medical evidence, whether CT scans or MRI scans. 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. If appropriate, you may be referred 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. 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.
And MRI Brain Scans?
Magnetic resonance imaging (MRI) brain scans use a different technology to CT scans. A MRI scanner uses a strong magnetic field to cause all of the protons in your body to align in the same direction. A short pulse of radio waves then knocks them out of alignment, and as they realign a resonant signal is generated, which is used to create an image of the body part being investigated. Simple, eh?
The resolution is higher in a MRI scan, so we can see problems that are not always evident on CT scans. Still, sometimes a CT scan is preferable, for example, when looking for atrophy in a patient with dementia. MRI scans cost a lot more than CT scans.
Signs and Symptoms of Brain Dysfunction
Signs and symptoms of brain dysfunction are critical to understanding and accurately diagnosing the nature of the condition affecting a patient. This is not information that can be obtained by 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. It is of enormous value if collateral information is also available from someone who knows patient well, such as a parent or spouse, and who is able to comment on any changes in their 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 and the neuropsychologist will then ask more detailed questions and clarify the picture.
In order to properly contextualise the information that we obtain during the neuropsychological assessment, we need to know with whom we are dealing, their background, work and so on. To that end, we need to know about:
- 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
Vegetative Signs & Symptoms
- Sleep cycle
- Fatigue and energy levels
- Menstrual cycle
Sensory Signs & Symptoms
Motor Signs & Symptoms
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
- Mood swings
- Temper control
- Impulsive behaviour
Social Signs & Symptoms
- Community involvement
What are Psychometric Tests?
Psychometric tests are carefully designed and scientifically validated measures of different aspects of sensory, motor, cognitive and emotional functioning. The bulk of the measures standardly used for neuropsychological assessment at Ormond Neuroscience tap into cognitive functions, such as memory and reasoning. The particular tests that are selected vary according to the patient and the diagnostic considerations applicable to that patient.
A standard battery of tests provides a general overview of neurocognitive functioning. Depending on those findings, it may be appropriate at a second session to administer additional tests in order to further investigate functioning in a given domain.
Neuropsychological Assessment Protocol
The neuropsychologist decides on the tests that should be used; a psychometrist administers the selected battery of tests. The patient is alone when tested in the laboratory, unless there is some special reason why someone else should be present. The psychometrist will give the patient a break halfway through the testing session.
The laboratory is a comfortable office with a desk and chairs and a computer, and is not a sterile room full of test tubes. The tests come in a variety of formats. For some procedures, the patient simply has to listen and give verbal responses. Other tasks require reading, writing, or drawing. A computer administers some procedures. A standard battery of tests takes approximately three hours to complete, including a 15-minute break.
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. The tests provide objective information about brain function, irrespective of how bright the patient may happen to be. To figure out if the test results are within the normal range, above average, below average, or abnormal, they are compared to a database of normative reference values.
Statistical Significance vs. Clinical Significance
Normative comparisons are statistical and are of somewhat limited utility to neuropsychological assessment because statistical significance is not the same as clinical significance. A problem in your brain may cause a clinically significant impairment of some aspect of cognitive functioning, even if your score on a suitable test is above average.
Imagine you developed a brain tumour that caused damage to neural circuits that impaired your memory. Before you had a photographic memory, but after the tumour your memory deteriorated, and on memory tests you went from 99% to 55%. This is a clinically significant loss of ability, even if your score is still above average.
Ultimately, the neuropsychologist will determine the clinical significance of the findings. Ormond Neuroscience never uses simplistic, mechanical interpretations of test results. (If life was that simple, Digby Ormond-Brown would have been a neurosurgeon!)