Please enable JavaScript.

Coggle requires JavaScript to display documents.

Task 3. Towards the core of the matter (Processing speed as a central…

- - - - Metaphor: assembly line. E.g. Five minutes to complete one product, and the first person takes a lot of time, you can never complete the whole product (more about the external time limit).
      - What is it? Relevant cognitive operations are executed too slowly to be successfully completed in available time
    - - Metaphor : Metaphor “juggler”: many complex activities requires synchronization of time, and some tasks are only able to be completed if you do it in the same speed -as quickly as possible-. It is more about an internal slower mental process.
      - What is it? Slow processing reduces the amount of simultaneously available information needed for higher-level processing. Products of early processing may be lost by the time that later processing is completed. Information decreases in availability over time as function of either decay or displacement. (this results in high rates of error or time-consuming repetitions of critical operations)
      - 1st figure in the task: represents simultaneous process. Functioning of working memory can be seen when activation is above threshold (every peak above threshold = more information you juggle). Every digit has an activation phase, but after a while the activation of that digit decays (first digit will disappear). If the activation is above the threshold, the digit is in the WM. The second vertical line represents the point where the first digit gets below threshold, and therefore disappears. Slowing in the rate of activation, but the decay of the curve remains the same. Activation = keeping active in the working memory the numbers. Amount of numbers you can get in your memory capacity. Older adults will not be able to juggle as many digits as the younger ones (you see two peaks, versus three peaks in a time given).
- - - - Looking at a correlation and see of the two (or more) factors are related. With path analysis you could look at correlations, standardized correlations or explained variance.
  - - - In other words: storage capacity + coordination effectiveness also contribute to age differences, but are themselves influenced by processing efficiency; so processing efficiency seems to be primary factor for age differences in WM.
        
        Method used: path analysis. Paths between age and storage capacity and between coordination effectiveness and WM had low coefficients, so their pathways were deleted.
    - - Again, paths with coefficients less than twice their SD were deleted from initial analysis and analysis repeated with left over paths.
    - - Later evidence that effects of restricted processing time also propagate to more complex forms of processing
- - - - MD: measure of average rate of water diffusion. High values = high rate of diffusion; probably due to poor local wm integrity
      - FA: reflects how direction-specific diffusion of water is. High value = more consistent diffusion orientation; probably due to intact local wm
    - - increase MD both in entire white matter skeleton as well as in specific white matter tracts (genus of corpus callosum, prefrontal wm, thalamic radiations, internal capsule, corona radiata, cingulum), supporting the white matter degeneration hypothesis
      - Anterior-posterior gradient of white matter integrity in corpus callosum (anterior section more susceptible to ageing than posterior)
      - decrease in FA
      - WM integrity differences were found to mediate the age-related reductions in processing speed, but no significant mediation found for episodic memory, visuospatial ability or fluency
      - Conclusion: WM integrity is not a major contributing factor to declining cognitive performance, but only for processing speed
  - - - Hypothesis: slow information processing may underlie reported deficits in cognitive flexibility and divided attention in DAI. Expected: deficits on basic speed or processing tasks (simple RT, Stroop etc.) but not additional deficits regarding attention. Hypothesis confirmed: DAI reveals slower information processing.
    - - The diffuse group was slower than the mixed injury and control groups on basic speed of processing tasks.
      - Impairment seems specific to simple basic speed of processing rather than complex task.
      - The diffuse group’s slower speed of processing was not accounted for by differences in injury severity, age, or time postinjury. Also, this group showed greater recovery over time.