Dementia is a late complication of Parkinson’s disease. Dementia and Parkinsonian syndrome can occur at the same time in case of Lewy body dementia.

Dementia observed in Parkinson’s disease is different from the Alzheimer’s dementia.

1-The following signs occur very early and announce dementia:

– the hallucinations (mainly visual or the feeling of the presence beside or behind him)

-the sleep disorders ( vivid nightmares called REM behavior disorders are frequent-more than 90% cases of Lewy Body dementia)

-the daytime sleepiness and the mental slowness. The patient stops to take part in conversations.

2- Over the years, the alertness of the patient becomes variable; one day the patient is very drowsy during the daytime, even nonresponsive and another day he can hold a conversation.It can even fluctuate between morning and afternoon. The concentration and the attention are affected,  and the patient starts falling.

-the patient loses the capacity of executing sequential tasks and also multi-tasking. he does not know anymore how to cook or even to make a cup of tea, how to use the remote control of the TV, how to use the phone for example.

-The memory loss can be mild for many years and respond to cueing; the patient can also recognise people for a long time.

3-The dementia progresses over the years and is associated with loss of mobility, falls, loss of independence, drooling and mutism. The nightmares can become worst or disappeared. The swallowing difficulties exposed the patient to aspiration pneumonia.