Transcript IntroND12 - Haiku Learning

Neurodegenerative diseases
Neurodegeneration: progressive loss of structure or function of neurons,
including death of neurons.
Many diseases such as Parkinson’s, Alzheimer’s, and Huntington’s occur
as a result of neurodegenerative processes. Recent insights put MS on
the map of neurodegenerative disease.
As research progresses, many similarities appear which relate these
diseases to one another on a sub-cellular level. Discovering these
similarities offers hope for therapeutic advances that could ameliorate
many diseases simultaneously.
Neurodegeneration can be found in many different levels of neuronal
circuitry ranging from molecular to systemic.
Neurodegenerative diseases
Systemic level: similarities in terms of localization
Cortical Function –
Basal ganglia -
Higher Functions
Primary Sensori-motor Areas
Behavioral Planning
Working Memory
Affective Processing
Attention
Frontal lobe
General testing of cognitive functions
MINI MENTAL STATE EXAMINATION
Section 1: Orientation
Section 2: Memory (part 1)
Section 3: Attention and calculation
Section 4: Memory (recall- part 2)
Section 5: Language, writing and drawing
MINI MENTAL STATE EXAMINATION
Section 1: Orientation
The first 10 points are gained for giving the correct date and location.
Section 2: Memory (part 1)
The first part of the memory test tests the ability to remember immediately three words.
You will be given the names of three objects to remember - table, ball and pen, for example.
You will then be asked to repeat the three names, scoring 1 point for each object correctly recalled (3
points maximum).
You should try to remember the three items as you will be asked to recall them later in the test.
Section 3: Attention and calculation
The next part of the MMSE tests the ability to concentrate on a tricky task.
Two different tests are used, and the best of the two scores is included in the final score.
You will be asked to count backwards. For example, start at 50 and count backwards by 5. One point
is given for each correct subtraction, with a maximum of 5 points.
You may also be asked to spell a word backwards such as 'lunch'. Again, the maximum score is 5.
MINI MENTAL STATE EXAMINATION
Section 4: Memory (part 2)
You will now be asked to recall the three items from Section 2.
One point is given for each correctly recalled object. Sometimes the person doing the testing will
drop hints!
Section 5: Language, writing and drawing
The final part of the test makes an assessment of spoken and written language, and the ability to
write and copy.
The person being tested is shown two everyday items - a hammer and a crayon, for example - and
asked to name them. You score 1 point for each correct answer.
You will then be asked to say aloud a tongue-twister sentence such as 'Pass the peas please'.
Correctly repeating the sentence gains 1 point. The sentence is always the same, so is worth
practising once you have heard it the first time.
You will then be given a piece of paper, and asked to carry out a three-step process:
'Take this paper in your hand' (1 point);
'Fold it in half' (1 point);
'Place it on this chair' (1 point).
The instruction is given only once, but as with the tongue-twister, the task is always the same.
MINI MENTAL STATE EXAMINATION
Section 5: Language, writing and drawing (continuation)
A card is then shown with an instruction for a simple task - 'Clap your hands'. If you clap your hands
you score 1 point.
The next stage of the test is to write a sentence on a piece of paper. The sentence needs to make
sense. One point is scored for an acceptable sentence.
Examples of acceptable sentences include:
'It's a lovely day today.'
'My name is Roger.'
Finally, your ability to copy a design of two intersecting shapes is assessed. One point is awarded
for correctly copying it. All angles on both figures must be present, and the figures must have one
overlapping angle.
This is the end of the test.
Frontal Lobes
•Largest region of the brain (1/3 of the cortex)
•Lateral, medial, orbitofrontal surfaces
Frontal lobe
•Parietal
•Occipital
•Temporal
•Limbic ->ACC)
•Amigdala
•Hippocampus
•thalamus (MD nucleus)
•Head of Caudate
•Cerebellum
•Hypothalamus, braistem
•Behavioral Planning
•Working Memory
•Affective Processing
•Attention
(Restraint, Initiative, Order -RIO)
Functions of Frontal Association Cortex
+ Motor and Behavioral Planning (perseverations)
+ Speech Production
+ Working memory & attention (dual task)
+ Suppression of Stimulus-bound behavior
babies & demented people cannot suppress urge to urinate in response to a full bladder
+ Inappropriate social behavior (frontal release)
+ Affective Processing (Abulia)
+ Complex task solving
Frontal function must be studied with complex paradigms
(delayed response, Towers, Stroop, WCST)
Signs of Frontal Damage
• Emergence of primitive reflexes, impossible to suppress:
Grasp reflex
Suck reflex
snout reflex
• Perseveration (repetition of one behavior without strategy changing)
• Failure to suppress inappropriate responses to sensory stimuli:
Antisaccade
Failure to suppress blink in response to glabellar tap
• Motor signs:
Motor impersistence
Paratonia
Magnetic gait
Frontal Lobe Disorders
• Vascular
• Tumors
• Abscess
• Frontal Lobe degeneration (Pick’s disease)
• Seizures
• Toxic, metabolic
• Demyelination (MS)
• AD, PD, HD
• Schizophrenia
• Depression
Delayed Response Paradigm
Tower Tests
Wisconsin Card Sorting Test
Other Frontal lobe Tests:
Cognitive Estimate testing
Digit Span
Trail Making test
Verbal fluency
Abstraction
Movement coordination
Functions of Parietal Cortex
- Attention
- Spatial location
- Body image
- Multi-sensory integration
- Transfer of sensory information
to the motor system
Hemineglect:
Deficits of spatial attention following Right parietal lesions
 Inability to attend objects or their own body parts in the left
space
Visual acuity normal
Somatic sensation normal
Motor ability generally preserved, although complex motor
behavior can be abnormal in the left space
Association with anosognosia (denial of illness),
anosodiaphoria (absence of emotional distress for the
deficits), hemisomatoanognosia (denial of the affected part”somebody left an arm in my bed”)
Sensory, motor, sensory-motor and conceptual neglect
Hemineglect:
A prominent role role of the Right parietal cortex
Anatomical evidence
Severe L hn
Minimal R hn
Severe R hn
Hemineglect:
Improvement:
Neglect improves following L caloric vestibular stimulation,
and worsens following R vestibular stimulation.
No modification of neglect is observed after bilateral vestibular
stimulation.
Caloric vestibular stimulation may improve neglect through a
specific effect; bilateral stimulation making the putative
activation bilateral and symmetrical does not affect the lateral
bias of neglect.
Parietal Cortex: Apraxia
Parietal Cortex Disorders
Gerstmann’s Syndrome
1.
2.
3.
4.
5.
Agraphia
Acalculia
Right-left disorientation
Finger agnosia
No confusion
If all symptoms are present -->dominant (left) inferior parietal lobe (angular
gyrus)
Balint’s Syndrome
1.
2.
3.
Simultanagnosia (impaired ability to perceive a scene as a whole: deficit in
visuospatial binding)
Optic ataxia (inability to reach/point under visual guidance; dd: cerebellar
ataxia)
Ocular apraxia (difficulty in directing gaze to peripheral visual field; use of
head movements)
-->bilateral lesions of the dorsolateral parieto-occipital cortex
Temporal Cortex
Agnosias:
Inability to recognize “what”…
PARIETAL
DORSAL STREAM
WHERE
Objects
Faces: prosopagnosia
Language problems
Pulvinar
Retina
LGNd
WHAT
TEMPORAL
VENTRAL STREAM
MEMORY TESTS
Wechsler Memory Scale:
The task is to recall stories and other verbal stimuli.
The test is appropriate for people with ages of 16-74.
VERBAL MEMORY TESTS (presentation of words, digits, nonsense syllables,
sentences that must then be recalled :
California Verbal Learning Test.
Rey Auditory Verbal Learning Test.
Selective Reminding Test.
NON-VERBAL MEMORY TESTS (ability to perceive and retain images of visually
presented geometric figures):
Benton Test of Visual Retention-Revised.
Memory for Designs Test.
Rey-O Complex Figure
More "ecologically valid", or "real world" in nature, using tasks that people must
perform each day such as remembering names and faces when meeting new
people or lists.
NO BRAIN AREA IS AN ISLAND
PARIETAL
DORSAL STREAM
FRONTAL
CONVERGENCE
Pulvinar
Retina
LGNd
WHAT
TEMPORAL
VENTRAL STREAM
Anatomical connectivity
NO BRAIN AREA IS AN ISLAND
Functional connectivity
Frontal lobe Dysfunctions
Either side:
a. Contralateral hemiplegia
b. Euphoria, talkativeness, tendency to joke,lack of tact, loss of initiative
c. Grasp & suck reflex
d. Incontinence
e. impaired planning & execution of complex action sequences
f. perseverations
Right:
a. gross social impairment (loss of insight, dysinhibition, loss of respect for
others, personality changes)
Left:
a. Aphasia (non-fluent, Broca type)
b. Agraphia, possibly with lips and tongue apraxia
c. Apraxia of the left hand
Bilateral:
a. Pseudobulbar palsy (shuffled gait, precarious balance, apraxia of gait, bent
posture)
b. Abulia, akinetic mutism, inability to: sustain attention, solve problems; rigid
thinking, bland affect, labile mood
Occipital lobe
Either side
a. Contralateral homonymous hemianopia (color loss)
b. Unformed allucinations (elementary)
Left (dominant)
a. Right homonymous hemianopia
b. Alexia, color naming problem (splenium, white matter)
c. Visual object agnosia
d. Astereognosia
Right:
a. Left homonymous hemianopia
b. Rarely, visual illusion & allucinations
c. Loss of topographic memory & visual orientation
Bilateral:
a. Cortical blindness,
b. Denial of cortical blindness (Anton’s Syndrome)
c. Achromatopsia
d. Prosapagnosia, simultanagnosia
e. Balint syndrome (inability to: scan peripheral space- intact eye movs-;
grasp -optic ataxia hand/eye incoord.-; vissual inattention)
Parietal lobe
Either side
a. Contralateral sensory syndrome, sensory extinction
b. Mild contralateral hemiparesis, hemiataxia
c. Visual defects
Left (dominant)
a. Aphasia (fluent, conduction aphasia: lesions of inferior parietal lobesupramarginal gyrus)
b. Gerstmann syndrome (R-L body confusion; finger agnosianame/designate fingers; dysgraphia; dyscalculia)
c. Apraxia
d. Astereognosia
Right:
a. Hemineglect
b. Topographic memory loss, visuo-spatial disorders
c. Anosognosia (denial of L hemiparesis, also for frontal, temporal & subcortical lesions),
dressing & constructional apraxia
d. Confusion, tendency to keep eyes closed
Bilateral:
a. Neglect,
b. Visuo-spatial dysperception and disorientation
Temporal lobe
Either side
•
Memory problems, declarative, spatial, including retrieval, formation of new
long-term memories
a. Auditory, visual, olfactory, gustatory allucinations
b. Aggressive, psychotic behavior, emotional changes
c. Time misperception
Left (dominant)
a. Homonimous upper quadrantopia
b. Aphasia (fluent, confabulations, Wernicke’s type)
c. Amusia
d. Impaired comprehension of auditory-presented material
e. Visual agnosia; impaired object perception & recognition
Right:
a. Homonimous upper quadrantopia
b. Impaired judgment of spatial relations
c. Impaired comprehension of visual nonverbal material
d. Agnosia for sounds & some music characteristics
Bilateral:
a. Sham rage
b. Korsakoff syndrome
c. Apathy & placidity
Kluver-Bucy
d. Hypersexuality, hyperorality bulimia
syndrome