Methods of Assessing Function and Dysfunction Flashcards
What are the three main types of assessment?
Behavioural
Anatomical
Functional
What does anatomical assessment typically involve?
Structural neuroimaging
Name four examples of structural neuroimaging.
CT
MRI
DTI
Angiogram
What does functional assessment typically involve?
EEG, Transcranial Magnetic Stimulation and functional neuroimaging.
Name two examples of functional neuroimaging.
PET and fMRI
What’s the first thing you can do to assess vision?
A bedside assessment. Test visual fields of patient.
Describe an example of a patient with attention issues rather than visual field issues.
Neurologist tests attention in each hemifield of a patient using both unilateral stimuli and bilateral stimuli.
Patient has normal vision and is able to attend to stimuli in both visual fields during unilateral stimulation. However, upon bilateral stimulation, the patient only reports the stimulus in his ipsilesional hemifield.
Describe Computed Tomography (CT) and what it is used for.
○ Provide anatomical view of the brain by passing a series of X-ray beams through the head. The images are then developed on sensitive film. This method creates cross-sectional 2-D images that show the structure of the brain, but not its function.
Important for imaging neurological pathology e.g. stroke
Describe Magnetic Resonance Imaging (MRI) and what it is used for.
Provide more detailed anatomical view of the brain than CT.
Depends on the magnetic properties of brain tissue and involves a high powered magnet surrounding the brain. The MRI system goes through the participant’s brain point by point, building a 3-D map of the tissue types. It then integrates all of this information together to create a series of 2-D images that show the structure of the brain, but not its function.
MRI is an important tool for imaging neurological pathology.
What is DTI?
Diffusion Tensor Imaging.
Structural neuroimaging.
Provides a view of white matter tracts (i.e. axons) using an MRI scanner.
Describe Angiography and what it is used for.
Vascular radiology.
Provides an image of the vasculature of the brain.
Allow the size and location of blockages to be evaluated, and are especially valuable in diagnosing abnormalities in blood vessels.
Can be based on different methods (x-ray, computed tomography, magnetic resonance).
How would you use x-ray technology to take an angiogram?
Inject dye into the blood vessels and take an x-ray to give a picture of blood flow through the vessels. the contrast agent allows the blood vessels to show up on film because he x-ray cannot pass through.
Describe Electroencephalography and what it is used for.
Provides a recording of the brain’s electrical activity.
Electrodes are attached to the surface of the scalp.
The signal detected by each electrode is amplified and recorded.
There are predictable EEG patterns associated with different behavioural states
Since normal EEG patterns are consistent across individuals, EEG recordings can detect abnormalities in brain function (e.g. seizure activity).
Describe Transcranial Magnetic Stimulation and what it is used for.
Can be used to test the integrity of motor pathways.
Used in conjunction with EMG which records muscle activity.
For example: the effect of the TMS coil placed over the hand area of the motor cortex can be measured by electromyography electrodes placed over the hand muscles.
Describe Positron Emission Tomography (PET) and what it is used for.
Detects radioactive material.
Participants either inhale or are injected with a radioactive material.
When the material enters the bloodstream, it goes to areas of the brain that are metabolically active.
PET provides a functional view of the brain by measuring regional cerebral blood flow.
Can be used to image neurotransmitter systems.
