Impaired Cognition Flashcards
Define retrograde amnesia
Loss of memory from before damaging incident
Assoc diecephallic regions
Define anterograde amnesia
Inability to create new memories
Associate with hippocampal damage
What causes amnesia
Stroke, ABI, TBI, alcohol
What is korsakoff syndrome
Amnesia due to long term excessive alcohol consumption - thiamine deficiency due to malnutrition and alcohol cause impairment in regions that require thiamine ie lesions in limbic system/thalamus/diecephallic structures
leads to confabulation, disordered eye and limb movement, retrograde/anterograde amnesia and enlarged ventricles
What is the limbic system
Interconnecting structures in the brain
ie thalamus, cc, fornix, hyp, hipp, amygdala, olfactory bulb
Biomaterial of korsakoff S
Vitamin b1 deficiency
Thalamus impairment - acts as relay centre for forming and maintaining episodic memory
Enlarged ventricles that fill with CSF
Define hemispatial neglect
Attentional deficit where failt to respond or orient to stimuli in contralesional side of space
More common in left hemispace as right hemisphere modulate attention
thought to be due to impairment in gradient of attention between two hemispheres - right more dominant across visual field and left specific to right spatial attention
Define contralesional
Opposite side of lesion
Define ipsilesional
Same side of brain lesion
Define hemianopia
Visual deficit that means cannot see/process info on one side of space
Braine regions assoc with hemispatial neglect
Tempo paretial junction
Intraparetial sulcus
Supramarginal gyrus
Symptoms of neglect
Deficit in body representation
Don’t incorporate what don’t perceive & ignore
Anosognosia - unaware of disorder
Representational neglect - have info but ignore it (piazzo del duomo)
Extinction - when there is two competing stimuli, one extinguished
allesthia - see stimulus on left but report seeing on right
Tests for hemispatial neglect
visual search task
line bisection
drawing tasks (visual or representational)
Treatment of hemispatial neglect
Cognitive training Scan training Neck muscle vibrations Mental imagery training Video feedback training
Problems with hemispatial treatments
Improvement is transient and short lived
Describe prism adaptation treatment
Wear prism goggles that shift visual field 10 degrees
Ask to reach for targets whilst wearing - realligns the visual and proprioceptive frame ‘peas magic shift’
causes after effect - neglect slower to realign to vision so show reduction in neglect symptoms for longer - limited feedback/attention
Prism adaptation improvements rosette 1998
subjective shift to midline
Improvement on : line bisection, line cancellation, copying drawings, memory drawing and reading as well as wheel chair navigation
last for at least 2 hours
Prism adaptation lasting effects pisella et al
Found to last up to 5 weeks
But limit of 10 weeks
What other problems can arise from pre frontal lobe damage
impaired executive function Inertia Perseveration Disinhibition Deficient self awareness Inflexibility
Define intertia
Problems starting
Apathetic and unresponsive - superior medial damage
Ie only eat when food in front of them
Define perseveration
Prolongation or continuation of act/action sequence - can’t break sequence
Dorsolateral lesions
Define disinhibition
Impulsivity - don’t inhibit behaviours
Aggressive outbursts, promiscuity, poor decisions
Orbital frontal cortex
Define deficient self awareness
Inability to perceive performance errors and failure to appreciate impact on others
Don’t respond normally to emotional or social reinforcers
Orbital cortex and related limbic systems
Define inflexibility
Concrete attitude
Can’t plan or sustain goal directed behaviours
Define amnesia
Impairment to encoding or storage processes in memory due to disease or accident
Retrograde or anterograde
patient HM
anterograde amnesia following procedure to remove bilateral medial temporal lobe in epilepsy procedure
also remove hippocampus and amygdala
minler 1962 Patient HM
gave repeated procedural tasks
ie draw line between two outlines or draw a 5 point star in mirror
not recall doing procedures but show sig improvement in speed and accuracy
- dissoc between motor and knowledge base learning
kopelman 2014 temp lobe amnesia vs korsakoff
Both syndromes show ‘core’ features of an anterograde amnesic syndrome; but retrograde amnesia more extensive (going back many years or decades) in the Korsakoff syndrome.
spontaneous confabulation occurs more commonly in the Korsakoff syndrome
amnesia forget more rapidly but korsakoff more influenced by proactive interference
These differences are attributed to the greater prevalence of frontal atrophy and frontal damage in Korsakoff cases.
proactive interference
previously learned material hinders subsequent learning.
retroactive interference
new material interferes with old memory/learning
Thelma (parkin 1996)
neglect patient fail to notice stimuli to the left side of space unless important
behtman et al 1997 hemispatial neglext
each hemisphere accounts for contralateral attention of space
hemispatial show similar eye saccased across left and right hemispace as controls - take into account both sides just don’t attend to one
baylis driver and rafal 1993 hemispatial neglect and extinction
extinction paradigm - two pens or 1 pen and 1 comb
extinction of 2nd pen in first condition but recognise comb in second - ignore unnecessary/irrelevant info
Bisiach and Luzzatti 1978 hemispatial and representational neglect
two neglect patients describe imagined perspective of piazza del duomo
omit descriptions on left but report when from a diff perspective - have the info but ignore
visual search task for neglect
cancel or identify target numbers or letters in a display of similar stimuli or distractors
neglect fail to identify targets to the left
line bisection task for neglect
bisect centre of the line
fail to account for left to bisect to the right of the centre
drawing tasks for neglect
visual - copy
representational - from memory
omit details to the left/squeeze to the right
marshall and halligan 1988 neglect
burning house
which would you prefer to live
neglect say one with non burning window
laduras paladine and cubelin 1998 priming and neglect
present patients with word/non word on neglect side then letter dring
letter string is word/non word linked or not to word seen on neglect side
faster to respond to word linking to that prev see but fail to explicitly report seeing the word
luaute et al 2006 neural basis of prism adaptation
improvement correlated with neural activity in right cerebellum (assoc with control of visuospatial output), left thalamus, left temporal occ cortex, right posterior parietal crtex and left medial temp lobe
increased efficiency in visual stimuli recognition and greater implications of ventral “what” region
what is executive function
set of cognitive processes – including attentional control, inhibitory control, working memory, and cognitive flexibility, as well as reasoning, problem solving, and planning – that are necessary for the cognitive control of behavior: selecting and successfully monitoring behaviors
assoc with frontal lobes
Phineas gage
explosion during ork
tamping iron in skull
heat courterise wound
“not gage anymore” - change in personality, become unreliable, unpredictable disrespectful and lacked social skills
damasio graborski and trank et al 1994 Phineas gage
estimate trajectory of rod using neuroimaging on skull
impaired orbitofrontal cortex and anterior medial areas
all assoc with exec functioning
