Démence à corps de Lewy

Description

Dementia with Lewy bodies is a nervous system disorder characterised by a decline in intellectual function (dementia), a group of movement problems known as parkinsonism, visual hallucinations, sudden changes (fluctuations) in behaviour and intellectual ability, and acting out dreams while asleep (REM sleep behaviour disorder). This condition typically affects older adults, most often developing between ages 50 and 85. The life expectancy of individuals with dementia with Lewy bodies varies; people typically survive about 5 to 7 years after they are diagnosed.

REM sleep behaviour disorder may be the first sign of dementia with Lewy bodies. It can occur years before other symptoms appear. Individuals with REM sleep behaviour disorder act out their dreams, talking and moving in their sleep when they should be still. This behaviour becomes less pronounced as dementia with Lewy bodies worsens and additional features develop.

Dementia is often the second major feature to develop in dementia with Lewy bodies. Initially, this intellectual decline may be mild or seem to come and go. In this condition, dementia often leads to impaired ability to perform visual-spatial tasks such as assembling puzzles. Affected individuals may also have poor problem-solving skills (executive functioning), speech difficulties, and reduced inhibitions. Problems with memory typically do not occur until later.

Most people with dementia with Lewy bodies experience visual hallucinations, which often involve people or animals. Fluctuations in behaviour and thought processes (cognition) include sudden changes in attention, unintelligible speech, and brief episodes of altered consciousness that may appear as staring spells.

Parkinsonism is usually the last major feature to develop in people with dementia with Lewy bodies, although it can appear earlier in some individuals. The movement problems typically include tremors, rigidity, unusually slow movement (bradykinesia), and impaired balance and coordination (postural instability). Affected individuals may require walking aids or wheelchair assistance over time.

Individuals with dementia with Lewy bodies may also experience a sharp drop in blood pressure upon standing (orthostatic hypotension), fainting episodes (syncope), reduced sense of smell, increased saliva production and drooling, difficulty controlling the flow of urine (incontinence), or constipation.

Inheritance patterns

The source lists the following possible inheritance patterns: Autosomal dominant. More than one pattern can apply in different cases.

Related genes

• GBA1

• APOE

• SNCA

• SNCB

Other names

Dementia of the Lewy body type

Dementia, Lewy body

Diffuse Lewy body disease

DCL

LBD

Lewy body dementia

Lewy body disease