Attention

Decreased

Decreased

Memory

Prominent memory impairment

Recognition deficits >recall

Retrieval and recall deficits >recognition

Less severe intellectual and memory dysfunction

Language

Prominent deficits with aphasia and agnosia

Decreased verbal fluency without anomia

Dysarthria may be present

Executive function

Varies with course

Poor and disproportionately affected

Cognition

Impaired judgment, abstraction, and calculation

Impaired problem solving and decision making

Emotion

Absent early in disease

Tendency to minimize deficits

Psychosis/agitation later in course

Apathy

Prominent affective changes with depressed mood/affective lability

Motivation

Alert, attentive, ambulatory

Decreased with bradyphrenia (slowed mental processing)

Motor abnormalities

Lack prominent signs

Preserved motor function, gait, and posture

Apraxia

Prominent with gait abnormalities

Tremor, tics, dystonia, extrapyramidal symptoms may be present

Visuospatial skills

Present

Later in disease

Examples

Alzheimer type Frontotemporal Creutzfeldt-Jakob disease

Dementias due to HIV, Parkinson disease, Huntington disease, multiple sclerosis

Course

Insidious onset and steady progression

Earlier age (<65)

Insidious onset and slow progression

Presenting symptoms

Memory loss with poor insight

Impaired functioning in independent activities such as driving to unfamiliar places and financial management

Personality changes

Social and personal disinhibition

Affective blunting

Loss of insight

Cognitive deficits

Memory impairment

Language disturbance

Impaired executive functioning

Apraxia and agnosia

Intact visuospatial skills

Severe impairment in executive functions

Progressive expressive aphasia and mutism later in course

Mood/personality disturbances

Mood

Depression common, especially in mild cases

Anxiety

Affective lability

Agitation with worsening of illness

Personality

Disinhibition common

Apathy and agitation increase as illness progresses

Mood

Prominent depression

Suicidality

Anxiety

Personality

Severe apathy and disinhibition (e.g., sexually and aggressive)

Psychotic/behavioral disturbances

Psychosis

Delusions: persecutory, theft themes common

Visual hallucinations common

Behavioral

Increasing agitation (e.g., wandering, pacing) as disease progresses

Verbal and physical aggression often accompanies psychosis

Psychosis

Bizarre delusions

Behavioral

Poor social and interpersonal regulation and awareness

Stereotyped and impulsive behavior

Severe compulsions (e.g., hyperorality)

Somatic preoccupation

Motor abnormalities

Not prominent early in disease

Visuospatial difficulties (e.g., constructional apraxia)

Frontal lobe release reflexes early in course

Akinesia/bradykinesia, ataxia, perseveration of movements, rigidity, and tremor late in course

Neuropathology

Neuritic plaques consisting of beta-amyloid protein deposits

Neurofibrillary tangles consisting of hyperphosphorylated tau

Loss of neurons in the nucleus basalis of Meynert

Frontal and anterior temporal lobe atrophy

Abnormal function of the cytoskeletal protein tau

Pick disease: presence of massed argentophilic inclusion-containing neurons (Pick’s bodies)

Special considerations

Typical decline in MMSE scores in DAT is 2-4 points per year

Risk factors include family history, limited cognitive reserve, increased age, female, smoking, never married, Down syndrome, apolipoprotein E (APOE) e4 allele, history of head trauma

Higher educational attainment/increased cognitive reserve is protective

May be misdiagnosed as substance use, hypomania, personality disorders, and/or schizophrenia