This is the commonest cause of dementia which is due to changes within the brain resulting in loss of brain cells and biochemical changes over time. Typically impairment in 'short term' memory is initially noticed by the individual but more often by others who know them well. Impaired attention is also an early feature but this may be subtle and difficult to recognise without formal testing. Problems finding the right words when speaking and other communication issues are also common symptoms. Thinking and problem solving abilities can become more impaired over time. Alzheimer's disease can sometimes present with few typical symptoms as it depends on the area of the brain initially affected by the disease. Reading texts and judging distances may be more problematic . As the condition progresses the entire brain could be significantly affected which makes it harder to differentiate between the various types of dementia.