Clinical Differentiation of Major Dementias

Disease Alzheimer's disease Frontotemporal dementia Lewy body dementia Vascular

Early symptoms/Age of onset

Onset typically 65+, risk increases with age

Onset in midlife (average age 58; 40-70)

Onset 60+, more rapid decline

Onset 65+, increases with age and vascular disease risk factors

Cognition/Mental status

Early: Memory loss

Later: Executive and visual spatial deficits, word finding

Two primary variants with different profiles: behavioral (executive function, apathy, disinhibition) and primary progressive aphasia (reduced speech output, semantic memory)

Visual spatial, attention and executive function; relative sparing of memory; fluctuations in cognitive status

Executive function, processing speed, attention; relative sparing of memory

Neuropsychiatry

Early: Normal

Later: Agitation, poor insight, mood, anxiety

Apathy, disinhibition, hyperorality, euphoria, depression, poor judgment/insight

Visual hallucinations, depression, sleep disorder, delusions

Apathy, anxiety, depression

Neurology

May have anosmia

May have vertical gaze palsy, axial rigidity, dystonia, alien hand, or motor neuron disease

Parkinsonism, REM sleep disorder, delirium, Capgras’ syndrome

Usually motor slowing, spasticity; apathy, falls, focal weakness can occur

Imaging

Early: Entorhinal cortex and hippocampal atrophy, or normal

Later: parietal, general atrophy

Frontal, insular, and/or temporal atrophy and hypometabolism; spares posterior parietal lobe

Posterior parietal atrophy

Cortical and/or subcortical infarctions, confluent white matter disease

Source: Harrison’s Neurology in Clinical Medicine and Alzheimer’s Association.