Cerebral Vascular Disease Flashcards
The Three Principle Functions of the Brain
- REGULATE TONE or WAKING
–Brain stem
–If this is not working – patient is comatose
Bilateral injury to brain stem (ascending reticulatinum system knocked out – wakens higher areas of the brain) = coma - OBTAIN , PROCESS and STORE information
- -99% of fibers are interneurons connecting one part of the brain to the other
- -brain is very interactive - PROGRAM, REGULATE, and VERIFY MENTAL ACTIVITY
Brain
Hierarchy of structures
3
PRIMARY AREA (=PROJECTION) receives sensory or produces motor output
- Primary sensory: Where sensory goes first in the brain
- Primary motor: primary area for motor output
SECONDARY AREA (=ASSOCIATION): incoming information is processed or motor programs are prepared
- Areas where info is processed
- Needed for brain function-acknowledge what something is, where, what it is doing
TERTIARY AREA (zones of overlapping): the latest systems of cerebral cortex. Most complex forms of mental activity -------There is more overlap, most complex interactions occur here, Issues occur here
Hemispheric specialization
A. left hemispheric language dominant:
96% of right handed people and 70% of left handed dominant people
B. motor dominance is used to describe hemispheric specialization (dominance usually defined by motor dominance—the side where motor dominance is which is opposite
C. some functions are bilateral, many are dominated by one hemisphere
we can describe by hemisphere or by how they present in extremities:
—right handed person has left hemisphere dominant
—left CVA, right hemi: speech is affected
—if right handed and stroke to right hemisphere-non dominant hemisphere-speech may not be affected at all
people who were left handed used to be forced into right handed and may not have a dominant hemisphere
Clinical Example: Hemispheric Specialization
verbal stimuli come in bilaterally but perceived more strongly in right ear, left hemisphere to process verbal stimuli
Implication?
implication, a patient hard of hearing should receive at least one hearing aide in the RIGHT ear
“left ear advantage” for non verbal stimuli ie music, sounds, other nonverbal input
Primary motor area of Frontal Lobe
o Brodmann’s #4 o Complex, multijoint movements o Voluntary movements o Especially hand control o If only this area of the brain is affected – fine motor movement is gone
Betz Cells
- Come off of primary motor cortex
- Cells that go to (monosynaptically) to the spinal cord level that they innervate
• Only involved in about 50% of movement
–other pathways involvd
FRONTAL LOBE
Primary motor area (brodman 4):
Primary motor area (brodman 4):
posterior part of frontal lobe-
- Complex multijoint movement
- Voluntary movements
- Especially hand control
–rare that only this alone affected but if it is only fine dexterity will be an issue
—primary betz cells (only 50% of movement) come off primary motor cortex and go directly monosynaptically to spinal cord level they innervate and are important motor cells—but they are only in 50% of movement and we have other pathways
FRONTAL LOBE
B. Premotor area:
- Postural sets before movements
- Visually guided movements –strong interaction with cerebellum
- Control eye movements - LESIONS—weakness, spasticity, motor apraxia
[online: Lesions of the premotor cortex lead to slowing of anticipated movements but do not lead to paralaysis
FRONTAL LOBE
C. Frontal eye fields
- Visual tracking, conjugate gaze-motor aspect of vision (vision in occipital lobe but motor aspect of vision is in frontal lobe)
- Coordination of bilateral UE tasks
FRONTAL LOBE
D. Broca’s area
- Motor aspect of speech
- Not needed for controlling mouth or tongue but to FORM WORDS AND SENTENCES -not the muscle activity of speech
- LESIONS:
EXPRESSIVE APHASIA: one word at a time, words stuck on tip of tongue-not form fluency –know what want to say, can move mouth, cannot get it out
FRONTAL LOBE
E. Supplementary Motor area:
small area, midline in the brain, in front of frontal eye field, it is deep
- Initiation of movements
- Planning sequential movements
- Execution of these movements, especially INTERNALLY GENERATED
- LESIONS: poverty? of movement
[online lesion to SMA inhibit the ability to perform complex movements]
Frontal Lobe Areas
A. Primary motor area (brodman 4):
B. Premotor area:
C. Frontal eye fields
D. Broca’s area
E. Supplementary Motor area:
F. All other areas: prefrontal cortex: personality, emotion, self initiation, impact upon others
Frontal lobe syndromes:
Post CVA: TBI etc.: need a separate rehab environment because of the psychological behavioral implications –may be aggressive, sexual advances
A. Dorsolateral lesions: apathy, lack of ability to plan or to sequence
- –Poor memory for verbal information (If left hemisphere L)
- –Or spatial information (if right hemisphere L)
B. Anterior lesion:
- –response inhibition, difficulty with disinhibition, emotional lability, and memory disorders.
- –Impulsiveness, sexual disinhibition, lack of concern for others
ONLINE
LESIONS TO FRONTAL LOBE
Primary motor cortex (area 4): Patient’s fingers lack precise coordination.
Patient cannot precisely contract just one digit or a particular group of digits.
Premotor cortex (lateral area 6): Patient cannot initiate the movement the patient wishes to make. Patient exhibits motor apraxia (defect in motor performance without paralysis) because the selection of a particular movement is impaired.
Supplementary motor area (medial area 6): Patient cannot tie shoe laces (impaired
selection of a particular movement sequence).
Parietal association: Patient has no sock on one foot because of sensory neglect.
Patient has ataxia (inaccurate movements)
Somatosensory cortex: Patient must look to sense where the hand is.
Loss of proprioception results in a reluctance to use affected limb.
FRONTAL LOBE
Dorsolateral lesions
apathy, lack of ability to plan or to sequence
- –Poor memory for verbal information (If left hemisphere L)
- –Or spatial information (if right hemisphere L)
FRONTAL LOBE
Anterior lesion:
- –response inhibition, difficulty with disinhibition, emotional lability, and memory disorders.
- –Impulsiveness, sexual disinhibition, lack of concern for others
PARIETAL LOBE
areas
A. Primary area: localize
Somatosensory areas
B. Secondary areas—interpretation:
C. Association areas: also need PNS to get the cortical sensation
PARIETAL LOBE
primary somatosensory cortical area
Somatosensory areas—brodman 3, 1, 2-posterior to primary motor area: what I feel and where
- Localization of touch, pain, temperature, and pressure
- Texture, shape and size
- Conscious proprioception
(peripheral issue cannot have this)
PARIETAL LOBE
Secondary areas
interpretation: it feels weird but it wont hurt me, interpretation is important (in stroke signals come but they don’t know how to make sense of it vs a peripheral issue)
Interpretation of sensation:
stereognosis
graphesthesia
Association areas:
also need PNS to get the cortical sensation
- Texture, size discrimination
- Same as secondary areas
Parietal Lobe syndromes (deficits if non-dominant right hemisphere is involved)
ie lesion in right hemisphere present with left hemiplegia
A. Left sided neglect:
B. Anosognosia:
C. Alexia:
D. Agraphia
E. Extinction of bilateral simultaneous stimulation
Left sided neglect:
Parietal Lobe syndromes (deficits if non-dominant right hemisphere is involved)
LESION IS IN RIGHT HEMISPHERE–LEFT SIDED NEGLECT (most people dominant in left hemisphere)
lack of recognition of left body parts (don’t know its there, don’t pay attention to it)
- ie hitting the wall on neglected side wheeling down hallway and think wc broken because don’t know hitting wall on that side
- tx: have family visit on that side of them, get them across midline, stand on that side, talk to them from that side because they will hear you, forced use to cross midline
Anosognosia:
Parietal Lobe syndromes (deficits if non-dominant right hemisphere is involved)
unaware of deficit, denial of disability
- They have denial of this deficit
- They are unaware of the deficit
Alexia
Parietal Lobe syndromes (deficits if non-dominant right hemisphere is involved)
inability to read
Agraphia
Parietal Lobe syndromes (deficits if non-dominant right hemisphere is involved)
inability to write
inability to calculate
Extinction of bilateral simultaneous stimulation:
Parietal Lobe syndromes (deficits if non-dominant right hemisphere is involved)
Extinction of bilateral simultaneous stimulation: only perceive stimuli on one side of the body
Stimulate on both sides but they only recognize the touch on the good side
Ideational Apraxia
Parietal Lobe syndromes (deficits if non-dominant right hemisphere is involved)
IDEATIONAL
- Inability to produce or describe motor tasks, patient cannot describe the task, even with cues or when given the object
- The engram cant be tapped for the task
a. Often associated with dementia
b. Gait apraxia
c. Many ADL that cant be performed - Ex: DRESSING APRAXIA: don’t know sequence of putting on a shirt, don’t have motor issue (ie of strength or tone) but they cannot sequence the task
- Ie cant sequence phases of walking in parkinson patient
Ideaomotor Apraxia
Parietal Lobe syndromes (deficits if non-dominant right hemisphere is involved)
(most common)
- Inability to produce on command, purposeful movements
- Patients may be able to describe the task, but cant execute the motor task
- Has the idea but cannot execute serial steps for performance
- Gait apraxia
- Unable to perform many aspects of ADL
Agnosia:
inability to process one or more forms of the sensory information
—could also be a deficit and have difficulty with tactile cues (other cues they have)
—we want to at first compesate but we want them to relearn the task rather than compensate
1) TACTILE agnosia (asterognosis) (PARIETAL lobe lesion)
2) VISUAL agnosia-OCCIPITAL lobe
a. visual processing
b. putting it all together
c. they can hear it and put it together (ie someone walking down hall and we hear who it is) but not the auditory signal, not the written word
3) AUDITORY agnosia-TEMPORAL lobe
