The NHS is giving tips on how to spot dementia when meeting loved ones this week.
Family and friends are today told they can play a vital role in seeing early signs over a Boxing Day lunch.
Forgetting a present is one sign, as is forgetting to put the oven or sprouts on, or cooking things in the wrong order.
New environments or seldom-visited houses could also leave people with early dementia disorientated or confused.
NHS chiefs also ask relatives to look out for people forgetting the names of loved ones to the extent it causes embarrassment.
It comes as hundreds more people will be checked for dementia in a new specialist service being trialled across England.
Care home residents will be proactively assessed through 14 new pilot schemes in seven regions, costing £900,000.
GPs will share a list of care home residents without a dementia diagnosis.
Staff will check to see if those listed have memory problems, before offering them a full face-to-face assessment.
NHS England clinical director for dementia Prof Alistair Burns said: "The pandemic has naturally had an impact on the number of people diagnosed with dementia, with elderly people seeing fewer people to protect themselves from Covid-19.
"The NHS is determined to ensure those who developed dementia during the pandemic are given a diagnosis."
He added: "If you have noticed over the festive period that someone has symptoms, please encourage them to visit their GP for an assessment - the sooner someone is seen the quicker the NHS can support them."
Mark MacDonald, of the Alzheimer's Society, said: "Diagnosing dementia is crucial to unlocking the right care and support.
"We're pleased NHS England is prioritising the diagnosis of people in care homes through this initiative."
Full list of warning signs
The NHS said the following could be signs of dementia over the Christmas period:
- Confusion in a new environment - someone may become disorientated or confused when in a new place.
- Forgetting the names of loved ones to the extent that it causes embarrassment.
- Being at a relative's house where the lay out is unusual could put a person's memory and orientation to the test.
- Forgetting a present.
- Forgetting to switch the oven on, forgetting to put the sprouts on or cooking things in the wrong order.
