It's thought as many as 50,000 people may be living with dementia in the East - but haven't been diagnosed.
The statistics obtained by the Alzheimer's Society found doctors in some areas are spotting only a third of cases.
It means patients are missing out on the vital support they need.
More top news
Three people have been arrested on suspicion of murder after a man was found dead in Cambridgeshire.
Organisers of the Clacton Airshow have announced the Red Arrows will be returning to the event this summer.
Two men who were arrested in connection with the death of a man in Downham Market eight years ago have been released under investigation.