Common Dementias

  Primary Site of Degeneration/ Dysfunction Profile Diagnosis Communication Behavior

Alzheimer's (AD)


insidious onset; more likely after age 65

progressive course; slow course with plateaus not unusual

can be familial or non-familial

can coexist with other conditions, such as Parkinson's disease

proliferation of neural plaques and neurofibrillary tangles at autopsy

aphasia is common, starting as either fluent on nonfluent; semantic system is most affected; syntax and phonology are affected later

language comprehension deficits, difficulty with topic maintenance, echolalia, lack of meaningful speech, gradual progression to mutism

depression, insomnia, incontinence, delusions, agitation, restlessness, hyperactivity,

disorientation, delusions of persecution, loss of initiative

Multi-infarct Dementia


caused by multiple strokes, some without noticeable clinical signs

symptoms may begin suddenly, often progressing in stepwise fashion after each small stroke

sometimes co-occurs with Alzheimer's disease

vascular disease resulting in damage to areas of the brain due to diminished blood flow

symptoms similar to Alzheimer's disease makes it difficult to make a firm diagnosis

motor speech disorders are prominent; slurred speech

word-retrieval difficulties

difficulty following instructions

depression and mood changes

confusion, problems with short-term memory

wandering or getting lost in familiar places

impaired coordination or balance

Lewy Body (LBD)


periods of normal cognition alternate with abnormal cognition

progressive course, often rapid

presence of Lewy bodies (intraneuronal cytoplasmic inclusions) typically found in the substantia nigra at autopsy

motor speech disorder with hypophonia

disorganized speech

visual and auditory hallucinations

pronounced fluctuations in alertness and attention; periods of delirium (confusion) and daytime drowsiness

Parkinsonian motor symptoms (e.g., rigidity and loss of spontaneous movement)

Frontotemporal Lobar (FTD)

Pick's Disease


insidious onset, more likely before age 65

progressive course, often slow

focal cortical atrophy; degeneration in frontal and temporal lobes

two kinds of neuronal abnormalites: Pick bodies (dense intracellular formation in cytoplasm) and Pick cells (inflated neurons)

reduced speech output; speech is nonfluent

progressive decrease in expressive vocabulary; word-finding problems

reduced spontaneous conversation

echolalia and meaningless repetition of phrases

wide range of behavioral changes, especially frontal lobe variant

executive dysfunction (in frontal variant)

behavioral (personality) changes and disregard for social conventions

uninhibited behavior, including inappropriate social behavior

depression, irritability, mood fluctuations

Frontotemporal Lobar (FTD)

Primary Progressive Aphasia (PPA)


may be caused by a wide variety of underlying diseases

possibly inherent genetic preprogramming

gradual loss of language function in the context of relatively well-preserved memory, visual processing, and personality until the advanced stages

a focal dementia (or focal cortical atrophy syndrome)

structural and physiological abnormalities typically noted only in the left hemisphere language-related cortices (i.e., frontal, parietal, and temporal regions)

symptoms usually begin with word-finding problems and progress to impaired grammar (syntax) and comprehension (sentence processing and semantics)

symptoms associated with impaired speech production can also be present (e.g., dysarthria and apraxia)

activities of daily living, judgment, insight, and behavior are relatively, if not totally, spared

Parkinson's Disease


sporadic; gradual course

average age of onset 60 years, although a juvenile form exists

reported incidence of dementia in patients is variable across studies

impaired dopaminergic system; reduced dopamine levels

degeneration of nuclei; widened sulci; loss of cells from substantia nigra; neurofibrillary tangles and neuritic plaques; presence of Lewy bodies

hypokinetic dysarthria (hypophonia, rapid rate, voice tremor, monopitch, and monoloudness)

naming problems, impaired discourse comprehension

micrographia (writing in extremely small letters)

immobility or slow voluntary movements, diminished facial expression, resting tremors, increased muscle tone, and resistance to movement

disturbed gait and posture

memory problems, confusion, hallucinations, executive dysfunction

apathy, depression, social withdrawal, anxiety

Huntington's Disease


gradual onset

rate of progression and age of onset vary from person to person

inherited (autosomal dominant) neurodegenerative disease; mutation on chromosome 4

genetic test is available for accurate diagnosis

loss of neurons primarily in the basal ganglia

naming difficulties, use of shorter/simpler utterances, grammatical errors, difficulty comprehending subtle aspects of discourse

dysarthria of the hyperkinetic type, including variations in loudness, monopitch, and harsh voice quality

mutism in final stages

excessive complaining, eccentricity, irritability, emotional outbursts, violence, and extreme confusion in final stages

spasmodic, involuntary movement of limbs, neck, and head

impaired memory, attention deficits, slowness with all intellectual activities

Multiple Sclerosis


chronic neurological disease that affects the central nervous system (CNS)

damage to the myelin sheath, caused by inflammation that occurs when the body's own immune cells attack the nervous system

primarily a white matter disease, but may also involve gray matter

dysarthria including unclear articulation, difficulty controlling loudness, poor pitch control

problems comprehending and using language related to cognitive changes

fatigue, vision problems, weakness, gait, balance and coordination problems, pain

dizziness and vertigo

emotional changes, anxiety, depression, cognitive dysfunction

(Hegde, 2006; Johnson & Jacobson, 2007; National Institute of Neurological Disorders and Strokes [NINDS], 2013)

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