Orbitofrontal area.

Dementia with Lewy bodies is the second most common cause of dementia.

Typical symptoms are: More rapid decline in cognitive impairment; visual hallucinations; rapid eye movement (REM) behavior sleep disorder; and early extrapyramidal signs, very sensitive to typical neuroleptics.

Pathology: Lewy bodies in the cerebral cortex and basal ganglia are stained by α-synuclein antibodies.

Chromosome 1: Presenilin 2, presents in <1% cases with onset at age 50 to 60 years.

Chromosome 14: Presenilin 1, presents in 1% to 5% cases with onset between age 30 and 50 years.

Chromosome 19: Apolipoprotein E (APO E), presents in 50% to 60% cases with age at onset 60 and older.

Chromosome 21: Amyloid precursor protein (APP) and β-amyloid, presents in <1% cases with age at onset of 40 to 50 years.

APP and PS genes are obligate factors, while APO E gene is a risk factor.

Cholinesterase inhibitors: Donepezil (Aricept), rivastigmine (Exelon), galanthamine (Razadyne).

N-methyl-D-aspartate (NMDA) antagonist: Memantine (Namenda).

Nonsteroidal anti-inflammatory drugs, estrogen replacement, and cholesterol-lowering medications were proposed for preventive treatment, but none proved effective in controlled studies.

Aβ vaccinations, γ secretase inhibitors, and stem cell implantation are experimental therapies under investigation.

Age.

Family history.

APO E-4 gene, mutation in presenilin gene, and amyloid peptide precursor gene.

Mild to moderate risk factors: Female gender, head trauma, myocardial infarction, low education level.

Stepwise progression of deficits.

Pseudobulbar palsy.

Focal sensorimotor abnormalities.

A variety of psychiatric symptoms that result from lesions in a frontal lobe.

Orbitofrontal syndrome: Disinhibition; impulsiveness; behaviors that are profane, irascible, and irresponsible.

Medial frontal syndrome: Apathy.

Left frontal syndrome: Depression.

Right frontal syndrome: Mania.