Lec 5: Neurobehavioural variables in clinical assessment

Question 1

what is diaschisis

Answer 1

function loss in a brain area that is anatomically intact due to its connection to a damaged area

Question 2

Example of diaschisis

Answer 2

the symptoms in Parkinson’s disease are caused by disease in a tiny area (substantia nigra), which ultimately affects the function of the basal ganglia, thalamus and neocortex

Question 3

Example of diaschisis

Answer 3

One of the attention hypothesis for spatial neglect proposes that the main problem in neglect is not in the spatial attention system, but rather in the non-spatial, arousal system which si functionally connected with the spatial attention system.
—patients not vigilent, nor realize sth new happening to them in terms of space
symmetric, topographical organisation of the fronto-parietal cortex
lesion in the brain is connected to the spatial system (route) in the brain

Question 4

Give examples of disease variables when predicting the clinical outcome of brain disease

Answer 4

Focal brain disease can have diffuse effects on brain function (swelling/ compression, diaschisis and disconnection)

Brain disease can be covert when the remaining intact areas re-organise to take over the lost function (anatomical and functional plasticity)

Question 5

Give examples of subject variables when predicting the clinical outcome of brain disease

Answer 5

Premorbid competence (cognitive reserve, intelligence)
the effect of emotion on cognition

Question 6

Give examples of generalized deficits due to swelling and brain compression

Answer 6

occur in early stages of an acute brain disease (i.e., stroke or trauma)
resemble the effect of an infection or intoxication 
cognitive impairments
a)memory
b) vigilance
c) executive function
d) intelligence/ reasoning
Emotional impairments 
a) flattening or liability

Question 7

what is disconnection syndromes

Answer 7

function loss in a brain network due to a disorder of the pathways (white matter) between brain areas

disconnection syndromes results from damage to white matter that cuts cortical pathways, disconnecting one or another cortical area from the communcation network of the brain

Question 8

example of disconnection syndrome

Answer 8

interhemispheric disconnection in split brain patients:

using laboratory conditions that restrict stimulation to one hemisphere, information received by the right hemisphere does not transfer across the usual white matter pathway to the left hemisphere that controls the activity of the right hand.

thus, the right hand does not react to the stimulus or it may react to other stimuli directed to the left hemisphere while the left hand responds appropriately

Question 9

what is brain lateralization

Answer 9

asymmetry not in the cortical white matter, it is the asymmetry in brain fibers; thickness of fiber is larger in right hemisphere than left hemisphere

normal people perform line bisection task tend to bisect slightly to the left (because right hemisphere thicker)

Question 10

what is plasticity

Answer 10

reorganization of the brain functional modules

the remaining healthy tissue takes over (some of) the function of the lesioned area

Question 11

puzzling finding of cognitive reserve

Answer 11

completing an education and engaging in hobbies and social activities are associated with decreased risk of developing dementia
more successful agining,
reduced clinical changes in: traumatic brain injuries, Parkinson’s disease(PD), multiple sclerosis (MS), HIV-related dementia
high cognitive reserve can left person normal for long beforethe disease is detected

Question 12

what is cognitive reserve

Answer 12

brain reserve = brain volume, connectivity, number of synapses
brain efficiency and flexibility