Cognitive Disorders- Dementia Types/Forms Flashcards
Alzheimer’s Disease or Dementia of the Alzheirmer’s Type (DAT)
- most common etiology of dementia
- typically impacts those 65+ years
- can be difficult to diagnose
DAT diagnostic criteria
- build upon the basic criteria for diagnosing dementia
- gradual onset and progressive cognitive deterioration
- cognitive deficits are not due to: other CNS issues, systemic conditions, substance-induced conditions
- cognitive deficits are not due to an axis I disorder (schizophrenia or major depressive disorder)
- diagnosis of AD is presumptive until autopsy or brain biopsy can be completed; focus is on criteria leading to “degree of confidence”
Possible Alzheimer’s Disease
- dementia in the absence of other dementia-producing causes but w/atypical onset, presentation or course
- dementia presenting with another systemic or brain disorder sufficient enough to produce dementia but which is not considered to be the cause of the dementia
- severe progressive decline of a single cognitive function in the absence of another specific cause
Probable Alzheimer’s Disease
- dementia is established by clinical exam documented by mental status examinations and confirmed by neuropsychological tests
- deficits exist in 2+ areas of cognition
- progressive worsening of memory and other cognitive functions has occurred
- no disturbance of consciousness
- onset was b/w 40-90; most often after age 65
- absence of systemic disorders or other brain disease that in of themselves could account for the progressive deficits in memory and cognition
Neuropathology of DAT
- typically begins in areas most related to episodic memory
— (perirhinal cortex, hippocampal complex in temporal lobes and basal forebrain)
- as disease worsens, changes in frontal lobe are noted and working memory is affected
- once disease gets to the temporal and parietal areas, sensory memory becomes impacted
- motor and occipital functions are typically spared
- since motor is not usually affected, speech remains intact
Motor impairments associated with DAT
- motor symptoms can develop as the disease progresses
- typical EPS s/s
— change in muscle tone, cogwheel rigidity, postural instability and difficulty with gait
- the presence of EPS s/s are associated with greater dementia severity
Microscopic Changes with DAT
- microscopic examination of brain tissue, often postmortem reveals the presence of:
— neuritic plaques
— neurofibrillary tangles
— atrophy
— areas of granulovacular degeneration
— amyloid deposits may also be seen in the blood vessels
Neuritic Plaques with DAT
- bits and pieces of degenerating neurons that clump together and have a beta-amyloid core
- beta-amyloid is a protein fragment that has been separated from a larger protein
- disjoined beta-amyloid fragments aggregate and mix with other molecules, neurons and non-nerve cells
- most prevalent in the outer half of the cortex where the number of neuronal connections is largest
Neurofibrillary Tangles and DAT
- disintegrating microtubules
— microtubules are part of the internal structure of healthy neurons
- they break down due to changes in the protein tau (these stabilize the microtubules)
- as they break down they become entangled
- they are a signature morphological sign of AD
DAT and Atrophy
- shrinking of brain tissue
- may not show up on CT if Pt is in the early stages of AD
- better visualization using PET and MRI scans
Granulovacuolar degeneration and DAT
- refers to fluid-filled spaces within cells that contain granular debris
- along with all of the other microscopic changes in the brain facilitate interruption of intercellular communication and thus information processing
DAT Risk Factors
- age
- family history
- less education
- head trauma
- gender
- maternal age
- having two copies of the type 4 allele of apolipoprotein E
- having MCI
Preclinical DAT
- AD occurs many years before a clinical diagnosis is made
- cognitive decline may occur 6y before clinical diagnosis of AD
- preclinical deficits are apparent for both verbal and nonverbal information
- lower scores on measures of memory and abstract reasoning are particularly strong predictors of probable AD
Predictors of disease progression in DAT
- average duration of AD is 8y+
- more rapid decline is associated with:
— early age at onset
— presence of delusions or hallucinations
— presence of EPS s/s
Cognitive/communication effects of DAT
- consistent features of AD include:
— impairment of episodic and working memory
— other executive function declines
- longitudinal studies using the MMSE indicate that the average amount of decline per year is 2-4 points
DAT early stage 1
- lasts from 2-4y
- caregivers report changes with:
— difficulty handling finances
— memory problems
— concentration problems
— difficulty w/complex tasks
— forgetting the location of objects
— decreased awareness of recent events
- mental status: disoriented for time
- motor function: good, ambulatory
- memory: problems w/episodic memory and working memory
DAT early stage 2
- basic ADLs: can complete basic ADLs
- MMSE: 16-24 points (Mini mental status exam)
- linguistic skills:
— fluent speech
— spelling/grammar errors are common in written language
— increased number of empty words (thing, it)
— anomia
— vocabulary shrinks
— difficulty with sarcasm and understanding jokes
DAT Middle Stage 1
- 4-10y post diagnosis
- MMSE: 8-15 points
- mental status: becomes disoriented for place and time
- motor: good, restlessness is common
- memory: episodic memory worsens, pt is easily distractible
- incontinence: mostly bladder
- basic ADLs: can complete w/supervision; managing finances and driving becomes difficult
DAT Middle Stage 2
- linguistic skills:
— fluent speech, but is slower and halting
— use fewer nouns than verbs
— vocabulary continues to decrease
— diminished comprehension of written and spoken language
— anomia
— difficulty repeating phrases
— problems defining words
DAT Late Stage
- MMSE: 0-9 points
- mental status: place, time, person disorientation
- motor: impaired; some pts are non-ambulatory
- incontinence: both bowel and bladder
- basic ADLs: unable to complete
- linguistic skills:
— fluent speech but is slow/halting w/meaningful expression reduced
— some pts are mute; some have palilalia; some have jargon
— reading comprehension is severely impaired
— considerable variability exits among late-stage AD
Vascular Dementia
- VaD
- cerebrovascular disease is the second most common cause of dementia
- more common in men
- caused by disease to the smaller blood vessels of the brain
- median survival time after onset of vascular dementia is 3.3y
- has also been referenced as multi-infarct dementia
- greater risk of morbidity and mortality than AD
Neuropathology of VaD
- defined as the loss of cognitive functions to a degree that interferes w/ADLs resulting from ischemic or hemorrhagic CVD
- type of vascular disease, its location, and the amount of brain damage dictate the clinical presentation of the dementia
Major etiologic subtypes of VaD
- large vessel disease associated w/multiple infarcts in cortex, white matter, and basal ganglia
- small blood vessel disease associated w/multiple infarcts
- multilacunar state
- hypoperfusion in border zones and granular cortical activity
- post-ischemic encephalopathy
Risk Factors for VaD
- more common in males
- incidence/prevalence increases with age
- history of stroke or a first-degree relative w/a history of stroke
- poor life-style choices: dietary habits, lack of exercise, alcohol abuse and smoking
- HTN: single most important risk factor for VaD
- diabetes; 3x more likely to develop stroke-related dementia
Diagnostic criteria for possible VaD
possible VaD:
- dementia
- CVD
- onset of dementia w/in 3 months of stroke
- abrupt deterioration in cognitive functions
Diagnostic criteria for probable VaD
probable VaD:
- dementia
- CVD
- onset of dementia w/in 3 months of stroke
- abrupt deterioration in cognitive functions
- gait disturbance
- falls (unsteadiness)
- urinary symptoms
- personality/mood changes
- absence of other disorders capable of producing dementia
VaD impact on cognition
- no one pattern of cognitive decline
- executive dysfunction is the most common cognitive consequence of CVD whereas memory impairment is typically associated with AD
VaD impact on communication
- communicative function is impacted most in pts with VaD
- will vary depending upon the type of vascular disease
- significant aphasia
- comprehension deficits
- difficulty w/language formulation
- dysarthria
- motor weakness
- changes in pitch, melody, and rate of articulation
Mixed Dementia
- presence of both AD pathology and vascular disease
- produces earlier and more severe cognitive impairment
- shorter length of survival
Lewy Body Dementia
- possibly the second most common type of dementia
- first described in 1961
- between 15% and 25% of pts with dementia have diffuse cortical lewy bodies
- lewy body: abnormal aggregation of protein in the cell processes of neurons
- age of onset for LBD is 50-83y
- according to the LBD association, LBD is now considered a spectrum disorder; it now includes:
[1] dementia w/lewy bodies
[2] parkinson’s disease dementia
Diagnostic criteria for lewy body dementia 1
- central feature:
- essential for a diagnosis of possible or probable lewy body dementia
— dementia defined as progressive cognitive decline that interferes w/normal social/occupational functions
— persistent memory impairment is evident w/progression noted
— deficits in attention, executive function, and visuospatial ability
Diagnostic criteria for lewy body dementia 2
- core feature:
- two core features are sufficient for a diagnosis of probable lewy body dementia, one for possible lewy body dementia
- fluctuating cognition w/pronounced variations in attention and alertness
- recurrent visual hallucinations that are typically well formed/detailed
- spontaneous features of parkinsonism
Diagnostic criteria for lewy body dementia 3
- suggestive features:
- reference p. 107 for criteria
— REM sleep behavior disorder [pt acts out dreams; not paralyzed]
— severe neuroleptic sensitivity [medication that blocks dopamine receptors]
— low dopamine uptake in the basal ganglia
Diagnostic criteria for lewy body dementia 4
- supportive features:
- commonly present but not proven to have diagnostic specificity
— repeated falls
— transient LOC
— severe autonomic dysfunction
— hallucinations in other modalities
— systematized delusions
— depression
Diagnostic criteria for lewy body dementia 5
- a diagnosis of lewy body dementia is less likely if:
— pt has CVD
— any other illness or disorder can account for the clinical picture
— parkinsonism only appears for the first time at the stage of severe dementia
- lewy body dementia should be:
— diagnosed when dementia occurs before or concurrently w/parkinsonism
- parkinson disease dementia should be:
— used to describe dementia that occurs in the context of well established parkinson’s disease
LBD vs. PD
- fluctuation of cognitive symptoms is a defining feature of lewy body dementia
- 50%+ of pts with lewy body dementia do not respond to treatment w/Ldopa
- in lewy body dementia, dementia signs precede parkinsonism
- in PD, parkinsonism signs usually precede dementia
Cognition and communication LBD
- cognitive impairment is present, severity fluctuates
- hallucinations are present
- sleep disorders, daytime drowsiness, and apathy develop
- aphasia and apraxia may appear in the later stages
- issues arise regarding fluency
- abnormal gait
- slow movements may be present
Frontotemporal Dementia
- describes a clinical syndrome associated with various degenerative conditions
- SLPs are likely to work with pts who have:
— pick’s disease
— primary progressive aphasia
— semantic dementia
Pick’s Disease
- behavioral component
- affects more women than men; usually in their 50s
- disease duration can last from 3-17y
- presence of pick bodies
- secondary to frontal lobe issues, changes in personality are present
- pts demonstrate: poor judgment, are emotionally blunted, compulsively explore their environment, hyperorality, altered dietary preferences, changes in sexual behavior, visual/auditory agnosia
- 78% exhibit repetitive behaviors
Cognitive changes in Pick’s Disease 1
- attention deficits
- executive function issues
- some memory issues as well, however, most pts can track day-to-day events until late in the disease
- there is preservation of visuospatial abilities
Cognitive changes in Pick’s Disease 2
- majority of pts w/pick’s disease do not have aphasia early in the disease
- many do develop communication disorders that take the form of nonfluent aphasia with phonological and articulatory impairments
- agrammatism is also present
- slow speech
Primary progressive aphasia (PPA)
- diagnosis is made for those that demonstrate progressive aphasia in the absence of other cognitive/behavioral problems
- although aphasia may interfere with performance on memory and reasoning tests, the pt w/PPA will have no difficulty recalling day-to-day events or in problem solving
Language characteristics of PPA
- high level of variability
- researchers usually break PPA down into the taxonomies of fluent vs. nonfluent
- kertesa, et al., (2003) examined 67 pts with PPA and found that most were fluent initially but became agrammatic and nonfluent later in the course of the disease
- some prefer to use the term “PPA” only for those individuals who are nonfluent and the term “semantic dementia” for those w/fluent aphasia
- our class will use fluent PPA and nonfluent PPA
Nonfluent PPA
- anomia
- effortful, agrammatic speech that lacks function words
- good comprehension w/the exception of more grammatically complicated sentences
- occasional oral apraxia, neurogenic stuttering, impaired repetition, dyslexia, dysgraphica, and sometimes mutism
Fluent PPA
- anomia
- poor comprehension
- normal articulation
- reading/spelling skills deteriorate
- paraphasias
- some suggest that fluent PPA is synonymous with semantic dementia
Neuropathology of PPA
- left perisylvian atrophy (most common pathology)
- nonfluent PPA: pathology is inferior frontal lobes and anterior temporal lobe
- fluent PPA: pathology is in the parietal lobe and temporal lobe
- pathology is greatest in the left hemisphere
Semantic Dementia
- pts progressively lose their semantic “conceptual” knowledge
- have difficulty understanding the meaning of words, objects, faces, nonverbal sounds, tastes, smells, etc
- nonsemantic aspects of cognition remain intact
- difficulty arises when attempting to attach meaning to perception preserved:
— visuoperceptual and spatial abilities
— nonverbal reasoning
— executive functions
— episodic memory
Language deficits in semantic dementia
- typically complaint is “loss of words”
- verbally fluent w/intact grammar and syntax
- testing reveals anomia (greater for nouns than verbs)
- comprehension deficit for single words and difficulty providing definitions
- occasionally anomia is masked in conversation by circumlocutions
Neuropathology of semantic dementia
- MRI scans reveal bilateral but asymmetric pathology of the temporal lobes w/left hemisphere more affected
