Speech Science Chapter 13

  1. T/F  Computerized Tomography (CT) is an x-ray technique that is sensitive to the density of tissues.
  2. When looking at a CT image, the lighter the image, the ________ (more or less) dense the tissue is.
  3. T/F  CT scans give three-dimensional images of cross sections of selected thicknesses of cortical and subcortical regions of the brain.
  4. Name 2 advantages of CT scanning.
    short imaging times and widespread availability of this technology
  5. List 4 things CT scans can diagnose.
    • tumors
    • cerebrovascular disease
    • head trauma
    • cerebral atrophy
  6. T/F  CT scans are not able to detect calcification and hemorrhages.
  7. This type of brain imaging takes advantage of the cellular basis of human tissue.
    MRI (magnetic resonance imaging)
  8. What percentage of the brain tissue is composed of water?
    over 70%
  9. MRIs look at __________ atoms to gather data.
    hydrogen atoms
  10. The differences in __________ and __________ content of different brain tissues produce the contrasts seen on an MRI.
    water and hydrogen
  11. T/F  MRI uses radiation.
  12. MRI can differentiate between different tissue types. List 3.
    • cerebrospinal fluid
    • grey and white matter
    • vascular structures
  13. T/F MRI takes less time to perform than a CT scan.
    false-it takes longer and it is more expensive.
  14. Not everybody can undergo an MRI. What are some limitations that would prevent a person from having an MRI?
    presence of metal devices in their body-like aneurysm clips, cochlear implants, pacemakers
  15. T/F  fMRI and MRI are based on the same magnetic properties of hydrogen.
  16. fMRI can look at characteristics of ____________ within the brain.
    blood flow
  17. Increase in blood flow to a specific area is known as the ____________________ and it is this response that is measured in an fMRI.
    hemodynamic response
  18. T/F  The fMRI is an indirect measure of brain function because it measures blood flow, not neuronal function.
  19. Name a major advantage of fMRI.
    it is a safe and noninvasive way of measuring a person's brain function changes over time or in different situations.
  20. T/F  An MRI and a fMRI scans can be obtained at the same time allowing structural and functional information to be gathered simultaneously.
  21. Name some disadvantages of fMRI.
    slow process, and the machine is noisy which can interfere with auditory stimuli or speech and language tasks.
  22. This type of test is based on identifying the distribution of an injected or inhaled radioactive substance and a chemical (such as glucose) in a patient's brain.
    PET positron emission tomography
  23. What is the radioactive substance used in a PET scan called?
    a tracer
  24. List 4 commonly used tracers in PET scans.
    oxygen, nitrogen, carbon, and flourine
  25. In a PET scan, areas of the brain that are more active absorb _____ (more or less) of the tracer and areas that are less active absorb _____ (more or less) of the tracer.
    • more active = more tracer
    • less active = less tracer
  26. In index of regional cerebral blood flow (rCBF) is produced with which of the following scans?

    C) PET
  27. T/F  PET scans are useful in determining tissue abnormalities like tumors, and can assess whether they are benign or malignant.
    true-they can also help in determining whether a brain tumor can be surgically removed.
  28. How quickly can a PET scan scan the entire brain?
    it takes about 40 seconds
  29. List some of the disadvantages of PET scans.
    • greater amounts of radiation exposure
    • limited availability of the technology
    • there needs to be more tracers manufactured
    • produces less detailed images tan the CT and MRI
  30. SPECT (single photon emission computerized tomography) is similar to which other test?
    PET, the major difference is that it uses different radioisotopes.
  31. The major disadvantage of SPECT over PET is that it uses __________________ because the isotopes have longer half-lives.
    higher radiation
  32. _______ is a technique used to record electrical potentials generated by the brain.
    EEG (electroencephalograpy)
  33. Current EEG techniques use computers to obtain and analyze data to allow for accurate quantification of information. What are these techniques known as?
    qEEG (quantitative EEG)
  34. This type of EEG is used to measure brain electrical activity in response to some kind of stimulus or task and are measured in terms of their latency and polarity.
    EP (evoked potentials)
  35. qEEGs record brain activity by placing electrodes on what part of the body?
    the scalp
  36. Which neurological disease results from a lack of dopamine in the substantia nigra of the basal nuclei?
    Parkinson's disease
  37. What are the 3 major characteristics of PD?
    • bradykinesia (slowness of movement)
    • rigidity
    • tremor
  38. Which brain imaging technique is useful in determining PD?
    PET scans
  39. Which disease is progressive, affecting both the upper and lower motor neurons?
    Multiple Sclerosis
  40. Which 2 tests are good for monitoring patients with MS?
    MRI and fMRI
  41. Which disease is a progressive disease and has dementia as its hallmark?
  42. Which type of scan is good for identifying people who are at risk for AD?
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Speech Science Chapter 13
brain function measures-chapter 13 speech science