Attention/Memory Flashcards
Neuroanatomy of attention
Cortex: reticular modulation of ascending sensory info
Focusing attention requires voluntary effort (frontal)
Paralimbic: input adds emotional importance
–> selective attention
Brainstem/basal forebrain cholinergic projections: circuit-tuning
Parietal cortices: shifting from one spatial locus of attention to another
MOCA test
doesn’t test writing/reading
limited naming
attention subtest
Digit span
normally can repeat 5-7 forwards
Divided attention
reverse digit span should be >= foward span-2
Months backwards - better screen in the elderly
Days of week backwards if unable to do months
Spelling “world” backwards (MMSE)
Delirium
prototypical disorder of attention
10-30% of hospitalized patients
may be a presenting feature of undiagnosed medical illness
can be life-threatening
Increased risk of complications
mortality rate of 25% within 6 months of discharge
frequently iatrogenic
under-recognized in nursing homes/hospitalized elderly
Delirium presentation
prominent, fluctuating disturbance of attention
arousal/hallucinations
Common causes of delirium
fever (children esp) infection (pneumonia, bladder, sepsis) R/O meningitis, encephalitis Chemical disturbances/energy failure withdrawa/intoxication Drugs - esp anticholinergic Focal/multifocal lesions Autoimmune processes
Metabolic causes of delirium
hyponatremia uremia hypoglycemia hypoxemia hypercarbia hyperammonemia due to hepatic failure thyroid dysfunctio thiamine deficiency
Drug-related causes of delirium
Withdrawal/intoxication
- alcohol
- benzo
- barbiturates
- other sedatives that increase GABA
Primary/secondary anticholinergics opioids lithium anticonvulsants antiparkisonian agents drugs of abuse
Autoimmune causes of delirium
CNS lupus
paraneoplastic syndromes
Right hemisphere syndromes
Construction apraxia spatial/topographical disorientation Dressing impairment (dressing apraxia) hemi-neglect, anosagnosia emotional indifference language alterations, aprosodias alteration in "pragments" of speech
Hemi-spatial neglect
persistent failure to detect, respond or orient to relevant stimuli, or to initiate appropriate movemetns in a hemispace
unexplained by primary sensory/motor defects
typically L-sided neglect due to R sided lesions
often accompanied by unawareness of deficit (anosognosia)
persistent R-sided neglect is rare - suspect bilateral lesions/unilateral L-side lesion + superimposed encephalopathy
Semantic memory location
inferolateral temporal lobes
Procedural memory locations involved
basal ganglia
cerebellum
supplementary motor area
Working memory neuroanatomy
prefrontal cortex
Verbal/arithmetic: L>R prefrontal/parietal
Visuospatial R>L prefrontal/parietal
Episodic memory test
temporally specific events, personal experiences recent event recall word lists paragraph recall 3 word 3 shape test 3 bedside objects/locations
Episodic memory locations
mesial temporal lobes (hippocampus, parahippocamapal gyrus) fimbria/fornix mamillary bodies mamillothalamic tract anterior thalamic nuclei cingulate gyrus
Agnosia
impaired higher level recognition in presence of preserve elementary perception, memory and general intellect
could be considered a form of semantic memory impairment
Apperceptive visual agnosia
shape/visual form agnosia
shape perception abnormal
worse for geometric figures, pics
seen most often after anoxic damage (esp CO poisoning)
usually involves occipital cortices extensively
Associative visual agnosia
relatively intact perception, but poor recognition
unable to match/describe use by sight
can copy line drawings but not identify
bilateral posterior damage/degeneration involving ventral occipitotemporal areas, esp peri-striate region
Prosopagnosia
loss of facial recognition
usually associated with left hemifield defect
Localization: ventral visual associative areas (medial occipitotemporal cortex)
usually bilateral lesions, right-predominant
Right PCA territory infarct
Colour agnosia
visual association area
occipitotemporal
Tactile agnosia
Parietal sensory association
Auditory agnosia
auditory association cortices
post sup temporal gyrus and connections
Finger agnosia
dominant angular gyrus in inferior parietal lobule
Simultanagnosia
visual association areas
bilateral superior parietal cortex (spatial visual pathway)
Anagnosia
unawareness of neurological deficit/illness
common in hemispatial neglect
seen in other syndromes: fluent aphasia, dementia, cortical blindness (Anton’s syndrome), schizophrenia, mania
Frontal lobe cognitive functions
divided/selective attn retrieval from semantic and episodic memory abstraction analogical reasoning "switching gears" insight judgment, assessment of reward planning/problem solving
Frontal lobe behavioural function
motor activation (apathy) aspects of personality social judgment/demeanor empathy and consideration of rights and feelings of others interest in personal hygiene/grooming
Orbifrontal syndrome
Behavioural variant of frontotemporal dementia, head injury
Disinhibition impulsive behaviour distractible emotional lability, irritable inane euphoria jocularity poor judgment/insight hyperactive/manic-like sexual disinhibition
Dorsolateral frontal syndrome
FTD, frontal lobe infarcts, penetrating head injury Reduce verbal, nonverbal fluency perseveration abstraction impaired retrieval defects poor set shifting poor strategies on copying tasks impaired attention depressed mood
Medial frontal syndrome causes
ACA/MCA borderzone infarcts
ruptured ACA aneurysms
falx meningiomas
hydrocephalus
Medial frontal syndrome presentation
lack of motivation/drive
emotional emptiness/blunting
failure to implement new plans
poor performance and maintenance of output on fluency tasks
decreased motor activity
extreme form: akinetic mutism (no initiation of speech/voluntary movements)
Frontal lobe function tests
verbal fluency
category fluency
nonverbal (design fluency)
