Cortical Localization Flashcards
encephalopathy refers to a _________ lesion
encephalopathy refers to a CORTICAL or SUBCORTICAL lesion
myelopathy = _______ lesion
myelopathy = spine lesion
What is the lesion? (what caused it)
VITAMINS D
Vascular Inflammatory Traumatic, Toxic Autoimmune Metabolic, Medication induced Iatrogenic Neoplastic Psychiatric, Seizure Degenerative
importance of lesion localization
- to narrow differential diagnosis
- determine what tests to order
- to determine operative practices (past)
components of a neurological exam
- cognitive exam
- cranial nerve exam
- motor exam, reflex exam
- sensory exam
- cerebellar exam
- other (gait, special tests)
clues that the lesion is cortical
- behavior, personality changes
- language disorders
- visual field deficits in BOTH eyes
- higher cortical sensory deficits
- apraxia (cannot perform learned task)
- neglect
- hemiparesis (PART of side)
- hemiesthesia (PART of side)
- seizure
clues that the lesion is subcortical
- pure motor deficits (whole side)
- pure sensory deficits (whole side)
- movement disorders
- absence of cortical deficits
clues that the lesion is bulbar
- crossed signs (sensory, motor)
- cranial nerve deficits
- vestibular (nausea, vomiting)
- visual field deficits (PCA territory)
- cerebellar signs
- bilateral signs
clues that the lesion is myelopathic (spinal)
- bilateral (not necessarily symmetrical) motor, sensory
- no involvement above neck
- combination of UMN, LMN
- bowel, bladder dysfunction
- autonomic dysfunction
tools to localize cortical
- CST
- ascending sensory tracts
- optic pathways
- language pathways
- special localization syndromes
what to check during a motor exam (voluntary)
- tone
- bulk
- strength
- reflexes
- associated features
UMN signs
- hypertonia
- no atrophy
- weakness
- brisk reflexes
- babinski/myoclonus
LMN signs
- hypotonia
- muscle wasting
- weakness
- depressed reflexes
- fasciculations
clues lesion is motor cortical
- contralateral hemiparesis (not whole side)
- upper motor neuron signs
- cortical deficits (hemisphere specific)
- associated sensory deficits
ascending sensory tracts
- pain
- pinprick
- light touch
- vibration
- proprioception
clues lesion is sensory cortical
- contralateral hemiesthesia (not whole side)
- associated motor deficits
- higher cortical sensory deficits
- –astereognosis
- –2 point discrimination
- –agraphesthesia
astereognosis
- close eyes
- feel object
- determine what it is
agraphesthesia
- close eyes
- scratch # on palm when eyes closed
- determine which #
optic pathway is the only pathway to _____________
optic pathway is the only pathway to CROSS FROM FRONT TO BACK
- great to localize a lesion axially
- different visual fields will help localize
if there is a visual field deficit in one eye only, the problem is ________________
if there is a visual field deficit in one eye only, the problem is ANTERIOR TO THE OPTIC CHIASM
-no need to image the brain
if the patient has “tunnel vision,” the problem is ________________
if the patient has “tunnel vision,” the problem is AT THE OPTIC CHIASM
if there is the same partial visual field deficit in both eyes, the lesion is _______________
if there is the same partial visual field deficit in both eyes, the lesion is POSTERIOR TO THE OPTIC CHIASM (in the cortex)
-image the brain
components of the aphasia examination
- comprehension
- fluency
- repetition
- naming
T/F: we have specialized regions for language/speech and for reading/writing
False. Only have specialized region for language/speech.
-no specialized region for reading/writing or math
If there is a stoke in Broca/Wernicke, no other part of the cortex can take over.
If a stroke causes alexia, another region can theoretically take over
motor aphasia
Broca’s aphasia
-unable to form words
sensory aphasia
Wernicke’s aphasia
- can talk freely, but makes no sense
- no comprehension of what you say or what they are saying
transcortical motor aphasia
-looks like Broca’s aphasia, but CAN repeat
- can repeat
- cannot initate own
transcortical sensory aphasia
-looks like Wernicke’s but can repeat
- can repeat
- cannot understand
global aphasia
- no understanding
- no naming
- no repeating
- no expression
usually due to a larger vessel (proximal occlusion)
conduction aphasia
- arcuate fasciculus
- inability to repeat
propasognosia
- inability to identify faces
- sometimes mistaken for delirium or dementia
conditions that affect the temporal lobe bilaterally
- herpes encephalitis
- seizures
split brain syndrome
- corpus callosum affected
- disconnect between both sides of brain
Due to:
- epilepsy surgery
- tumor
- EtOH abuse
right brain
- emotional
- mathematical
- “big picture”
- nonverbal
- procedural memory
- perceiving
left brain
- verbal
- arithmetical
- perceives details
- declarative memory
- confabulatory
Balint Syndrome
BILATERAL PARIETAL LESIONS
- simultanagnosia: inability to perceive visual field as a whole
- oculomotor apraxia: difficulty fixating the eyes
- optic ataxia: inability to move hand to a specific object using vision
- fail to apprehend all but 1 of simultaneously presented objects at the same location
- –object based, not location based
- –multicolored dots seen if connected by lines
Gerstmann Syndrome
- agraphia
- acalculia
- finger agnosia
- right left confusion
non-dominant parietal signs
- denial of deficits (anosagnosia)
- visual, tactile, auditory extinction
- spatial disorganization
- neglect of left space
simultognosia
- able to name objects all over the picture
- cannot describe what is happening
frontal lobe syndrome signs
-problems with sequences tasks
frontal lobe syndrome signs
- problems with sequences tasks (Stroop test)
- grasp reflexes
- paratonia (Gegenhalten)
- suck and snout reflex
- perseveration
- Luria test (pattern repeat)
orbital frontal signs
- violent
- hypersexual
posterior frontal signs
- apathetic
- akinetic mutism
dorsolateral frontal signs
- executive function loss
- speech problems
We have about _________ neurons, and __% are in the cerebellum
We have about 84 BILLION neurons, and 50% are in the cerebellum
- cerebellum is only 10% of brain mass
- supression, pruning occurs
supression
the cortex (frontal lobe) suppresses infant reflexes that we were born with. only see those reflexes in an adult if the frontal lobe is injured so inhibition of these reflexes is stopped
we are born with _______ neurons, but by adulthood we have ________ neurons
we are born with 160 BILLION neurons, but by adulthood we have 84 BILLION neurons
-due to pruning
Anton syndrome
- bilateral occipital lobe injury
- CORTICAL BLINDNESS
- cannot see, but will flinch when confronted
- confabulation: can see but cannot interpret signal so brain makes something up
- headache, psychosis
-unawareness and denial of cortical blindness
