This depends upon the type of dementia. Most lay people think that memory loss is the main symptom of dementia but we all struggle a little with memory which naturally worsens with age and with stress. People with dementia have much more wrong with them than memory loss. For example getting lost in familiar places is worrying for Alzheimer's disease, whereas visual hallucinations and sleep disturbance suggest Lewy Body disease. Dementia is a group of different diseases (like temperature or skin rash) for which there are many symptoms and diagnoses.