ppa and semantic dementia l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
PPA and Semantic Dementia PowerPoint Presentation
Download Presentation
PPA and Semantic Dementia

Loading in 2 Seconds...

play fullscreen
1 / 65

PPA and Semantic Dementia - PowerPoint PPT Presentation


  • 400 Views
  • Uploaded on

PPA and Semantic Dementia. Pick’s Disease. Six patients with language impairment and temporal lobe atrophy. Lund-Manchester Criteria Neurology 1998: 51: 1546-1554. Frontotemporal Lobar Degeneration Frontal variant FT dementia Progressive nonfluent dsyphasia Semantic Dementia.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'PPA and Semantic Dementia' - Ava


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
pick s disease
Pick’s Disease
  • Six patients with language impairment and temporal lobe atrophy
lund manchester criteria neurology 1998 51 1546 1554
Lund-Manchester CriteriaNeurology 1998: 51: 1546-1554
  • Frontotemporal Lobar Degeneration
    • Frontal variant FT dementia
    • Progressive nonfluent dsyphasia
    • Semantic Dementia
  • wide range of neuropathological entities
slide4
FvFTD
  • Best viewed in terms of known frontal lobe symptomatology
slide6
Medial frontal-cingulate: apathy (although very common in AD)
  • Dorsolateral: disorders of executive function
distinguishing ftd from ad phonology syntax and grammar well preserved in ad
Distinguishing FTD from ADPhonology,syntax and grammar well preserved in AD
  • Stereotypical behaviours
  • Change in food preferences, Kluver-Bucy like behaviour
  • NPI
  • PPA: phonemic paraphasias are common, rare in AD
    • phonemic or literal paraphasias, in which the response differs from the correct word by one letter or sound, such as saying "shammer" for "hammer."
semantic dementia snowden 1989
Semantic Dementia (Snowden 1989)
  • Semantic memory (Warrington 1975):
  • Term applied to the component of long-term memory which contains the permanent representation of our knowledge about things in the world: facts, concepts and words
  • Culturally shared, acquired early in life.
wernicke s area
Wernicke’s area
  • Gateway for linking the sensory patterns of words to the distributed associations that encode their meaning.
semantic dementia snowden 198910
Semantic Dementia (Snowden 1989)
  • Affects fundamental aspects of language, memory and object recognition.
semantic framework
Semantic Framework

Verbal access

Visual access

Multi-modal semantic system

=“common knowledge”

Sounds, smells, tactile

Actions

Real object use

semantic dementia
Semantic Dementia
  • Progressive anomia, not an aphasia, but a loss of semantic memory.
  • Impaired: naming, word comprehension, object recognition and understanding of concepts.
  • characterized by preserved fluency and impaired language comprehension: “phonologically and syntactically correct”
assessement
Assessement
  • Category fluency
  • Generation of definitions
    • Lion: ” it has little legs and big ears, they sleep a lot, see them in shops”
  • Word-picture matching
  • Famous faces test
  • Normal episodic memory, normal visuospatial skills
slide14
Nature of errorSemantic-type naming errors:initially within-category, “elephant” for hippopotamus, then superordinate “dog” for everything, then “animal”…
  • Profound and complete anomia
  • Circumlocutions and semantic paraphasias
    • semantic paraphasias, in which the wrong word is produced, one that is usually related to the target (eg, "pliers" for "hammer").
slide15
Nature of errorImpaired general knowledge; patients complain of memory loss.
  • “What’s your favourite food?”-
  • ”food, food, I wish I knew what that was”.
  • Patient JL, aged 60, company director:
    • frightened by a snail in his backyard, and thought a goat a strange creature.
slide16
Phonology and syntax striking preserved
  • Surface dyslexia: difficulty reading and spelling irregular words: eg Reading “PINT” to rhyme with flint, mint etc:

Loss of semantic support necessary for correct pronunciation, creating a “phonologically plausible” error( =regularization Error)

sd and memory
SD and memory
  • Can relate details ( in a rather anomic fashion) of recent events, but there is impaired recall of distant life events.
memory what we know
Memory: what we know:
  • Patients with lesions to the hippocampus and related structures show severe impairments to new learning and a temporally limited retrograde amnesia.
slide19
What about patients who may show the converse neuroanatomical lesion (i.e., focal damage to the temporal neocortex sparing the hippocampal system)?
slide20
What about patients who may show the converse neuroanatomical lesion (i.e., focal damage to the temporal neocortex sparing the hippocampal system).
    • show the converse pattern of memory impairment, that is to say, preservation of recent and loss of distant memories.
sd and memory21
SD and memory
  • SD: can relate details ( in a rather anomic fashion) of recent events, but there is impaired recall of distant life events.
  • Alzheimer's disease :more typical temporally graded loss (poor recall of recent memories)
slide22

Amnesic Alzheimer's disease patient with hippocampal

atrophy (H) accompanied by a mild degree of general

neocortical atrophy.

slide23
R. B., who had bilateral lesions limited to the CA1 region of the hippocampus; although he showed a relatively severe anterograde memory impairment, R. B. demonstrated a retrograde amnesia of no more than 1 or 2 years.
slide24

Semantic dementia patient with severe focal atrophy of the left temporal lobe

see arrow, right-hand side of MRI scan) involving the pole, inferior, and middle

temporal gyri with relative sparing of the hippocampal complex (H) and of

the superior temporal gyrus.

slide25
SD
  • In most cases, neuroradiological studies reveal selective damage to the inferolateral temporal gyri(inferior and middle) of one or both temporal lobes, with sparing of the hippocampi, parahippocampal gyri, and subiculum.
  • Note: AD: inferior and middle temporal gyri
disrupted temporal lobe connections in sd mummery cj et al brain 1999 122 61 73
Disrupted temporal lobe connections in SDMummery CJ et al. Brain 1999, 122: 61-73
  • PPT: SEMANTIC TASK VISUAL TASK
  • COW;horse;bear. CUCUMBER:tomato;corn
slide28

SD

: Reduced activity in Left inferior temporal gyrus (BA 37)

: Known for specific naming deficits or anomia

Region is presumed to be structurally intact, but functioning abnormally due to reduced input from anterior temporal lobe.

slide29
Temporal lobe regions engaged during normal speech comprehension Crinion JT et al.Brain, Vol. 126, No. 5, 1193-1201, May 2003
  • Processing of speech is obligatory!
  • Aphasic strokepatients: importance of the posterior temporaland inferior parietal cortex.
  • SD: anterior and ventral temporal lobe cortex may be centralto word comprehension
experiment
Experiment
  • Reversed versions of the narratives, (sameacoustic complexity as forward speech): expected to controlfor early acoustic processing of the speech signal in both leftand right superior temporal cortex.
  • Contrast=speech comprehension
results
Results
  • Comprehension is dependent on anterolateral and ventral lefttemporal regions.
slide33

M. put orange juice in his lasagna and on another occasion, brought the lawnmower up to the bathroom when he was asked for a ladder

slide34

Test: autobiographical information (e.g., an event that occurred at secondary school) across three life periods: childhood, early adulthood, and recent life

Graham KS; Hodges JR. Neuropsychology.1997 Vol. 11, No. 1, 77-89Differentiating the Roles of the Hippocampal Complex and the Neocortex in Long-Term Memory Storage

slide35
The results suggest that the preservation of recently acquired autobiographical memories is restricted to the most recent 5 years, and, in particular, one patient, only from the last 1 1/2 years.
  • Medial temporal lobe structures do not store or index memories for long periods of time, for example, decades.
sd and memory36
SD and memory
  • In contrast to the time-limited role played by the hippocampus, a crucial site for the storage of our knowledge of the world and our past autobiographical experiences is the temporal neocortex.
memory
Memory
  • As direct connections form within the neocortex, remembering the experienced event becomes less dependent on the medial temporal lobe structures and, therefore, more resistant to hippocampal damage.
memory hippocampal function
Memory: Hippocampal Function
  • Hippocampus: does not itself store memories but acts as an orienting system, flagging the need for the neocortex to form a new representation ( Alvarez & Squire, 1994 ).
  • Storage of an experienced event as a process initially reliant on the hippocampal system, before gradual changes in the neocortex allow the memory to be stored permanently
in alzheimer s disease
In Alzheimer’s disease
  • Significant episodic memory impairment due to functional disconnection of hippocampus
in alzheimer s disease40
In Alzheimer’s disease
  • Significant episodic memory impairment due to functional disconnection of hippocampus (transentorhinal & limbic)
  • Even early, may be significant semantic impairment due to temporal neocortex involvement.
  • (NB Category dissasociation: natural vs artefactual)
memory41
Memory
  • Temporal memory system for semantic facts, and medial memory system for episodic memories is an oversimplification.
    • Neuropsychologia 2002
      • Snowden JS, Neary D
      • Relearning of verbal labels in semantic dementia
slide42
Semantic knowledge about the world is more than a static storehouse of words and objects represented by a set of abstract properties. It includes personalised, experience-based knowledge.
slide43
Descriptive information about the meaning of the item:
  • The stimulus picture of a duck was the same type of thing as the china duck ornament in her own conservatory and the same as the ducks that she sees on the pond when she walks in her local park. A line drawing of a rolling-pin was described as the same sort of object as the long glass rolling-pin in her kitchen drawer, which she had used in the past to make pastry to put on the top of pies.
slide44
20 pictures,all of which the patient had consistently failed to name on the pre-test assessments.
  • Recall at 2 weeks and 4 months
slide45
Episodic memories: specific temporal and spatial context.
  • Object information, represented by temporal neocortex, is linked with temporal and spatial information, represented by other brain regions.
  • This linking of (weak) word/object information with (strong) spatial and temporal information that provides the basis for patients' relative preservation of autobiographical memories.
slide46
In semantic dementia the most context-free levels of knowledge (constituting traditional notions of semantic memory) are most compromised.
  • In contrast, patients may retain knowledge tied to specific experiences or routines
slide47
Episodes gradually, over many years, take on the properties of semantic memory (i.e., resemble general knowledge by becoming independent of specific temporal and spatial contexts).
slide48
Butters and Cermak (1986)
    • a detailed case study of a patient with Korsakoff's syndrome,
    • "knowledge of public events and personal experiences from the 1930s and 1940s may be part of semantic memory whereas public and personal happenings from the past decade may still be associated with specific spatial and temporal contexts”
slide49
A more appropriate compartmentalisation might be between context-free (neocortical) and context-bound (medial temporal) memories. The latter is characterised by the drawing together of distinct aspects of information (item, time, space) from distant cortical sites and includes both semantic and episodic characteristics.
slide50
PPA
  • "a slowly progressing aphasic disorder without the additional intellectual and behavioral disturbances of dementia"
  • Memory, judgment, executive function intact.
  • Mesulam, M. M. (1982). Slowly progressive aphasia without generalized dementia. Annals of Neurology, 11, 592-598, and
  • Mesulam, M.M. (2001). Primary Progressive Aphasia. Annals of Neurology, 49, 425-432.
slide51
PPA
  • 1. Insidious onset and gradual progression of word-finding, object-naming, or word comprehension impairments as manifested during spontaneous conversation or as assessed through formal neuropsychological testing of language.
  • 4. Absence of significant apathy, disinhibition, forgetfulness for recent events, visuospatial impairment, visual recognition deficits, or sensorimotor dysfunction within the initial 2 years of illness.
  • 5. Acalculia and ideomotor apraxia can be present even in the first 2 years. Mild constructional deficits and perseveration (eg, as assessed by the go no-go task) are also acceptable as long as neither visuospatial deficits nor disinhibition influence daily living activities.
classification
Classification?
  • Cases of SD often included under PPA “When free of face and object recognition deficits, semantic dementia constitutes a subtype of PPA with poor comprehension of verbal semantics.”
  • Annals of Neurology53, 2003. Pages: 35-49
  • Primary progressive aphasia: PPA and the language network
ppa vs sd
PPA vs SD?
  • “Aphasia in PPA can be fluent”
  • “ there is not a single type of language dysfunction that is pathognomonic for PPA”
  • “the term SD…designates a prominent fluent aphasia with impaired comprehension in the presence of of prominent defects of visual recognition (or perception).
  • But also used to refer to PPA subtype with fluent speech and impaired comprehension
  • Mesulam, M.M. (2001). Primary Progressive Aphasia. Annals of Neurology, 49, 425-432.
slide56

Semantic dementia patient with severe focal atrophy of the left temporal lobe

see arrow, right-hand side of MRI scan) involving the pole, inferior, and middle

temporal gyri with relative sparing of the hippocampal complex (H) and of

the superior temporal gyrus.

ppa vs sd57
PPA vs SD?
  • Hodges:
  • SD is fluent, PPA is not
  • SD deteriorate fast, PPA slow.
  • Primary disorder is verbal, visual component is not obligatory (visuospatial tests are normal)
broca s
Broca’s
  • Generation of articulatory sequences so that thoughts can be turned into statements with correct phonology and syntax.
  • Dysfunction leads to impaired articulation, word order, grammar.
  • Phonology= sound structure
  • Syntax= sentence order and structure
slide59
PPA
  • Anomia is (nearly) universal in PPA
    • “Anomia can emerge with either fluent or non-fluent speech”
  • PPA with agrammatism, frequently impaired fluency, telegraphic speech
  • Rare “lexical lacunes”, which become increasingly common
  • “school? What does school mean?”
slide60
PPA

Comprehension excellent, except for grammatically complex sentences: “ the lion was eaten by the tiger” vs “the tiger ate the lion”

Progress to mutism

slide61

Annals of NeurologyVolume 53, Issue 1, 2003.Pages: 35-49Sreepadma P. Sonty, BA 1, M.-Marsel Mesulam, MD 1 2 3, Cynthia K. Thompson, PhD 1 2 4, Nancy A. Johnson, PhD 1 3, Sandra Weintraub, PhD 1 3, Todd B. Parrish, PhD 1 5, Darren R. Gitelman, MD 1 2 5

  • Sample of PPA patients with impaired word finding but preserved comprehension of conversational speech
annals of neurology volume 53 issue 1 2003 pages 35 49
Annals of NeurologyVolume 53, Issue 1, 2003. Pages: 35-49
  • fMRI.
  • Judgment of pairs of words
  • Phonological task: React if words were homonyms (ie, had identical pronunciation but dissimilar orthography and meaning).
  • Semantic task:React if words in a pair were synonyms (ie, had a very similar meaning but dissimilar orthography and phonology).
annals of neurology volume 53 issue 1 2003 pages 35 4963
Annals of NeurologyVolume 53, Issue 1, 2003. Pages: 35-49
  • PPA patients
  • Activation in fusiform gyrus, precentral gyrus, and intra-parietal sulcus.
  • May be a compensatory spread of language-related neural activity
slide64
Word reading is a highly learned, automatic task.
  • In PPA, this process may lose its automaticity and may become increasingly more dependent on laborious grapheme-to-phoneme transformations, such as those that are necessary for reading unfamiliar pseudowords.
  • .
ppa pathology
PPA Pathology
  • 60% : neuronal loss with gliosis lacking in distinctive histopathological features.
  • 20% : Alzheimer's disease.
    • Some of these patients have an unusual perisylvian and temporal neocortical distribution of neurofibrillary tangles, which occasionally spares medial temporal lobe structures.
  • Another 20% show the tau-positive, intracytoplasmic bodies of Pick's disease.