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
Dry and cold through much of the night with a frost for some by morning. It will turn cloudier during Saturday with a few spots of rain.
Police are warning teenagers are putting their lives at risk by carrying out dangerous stunts on the streets of Northampton.
A dog has died after it was attacked by four other dogs in a Norfolk village.