A pastor friend told me about the vicar who was visiting a lady in his local community. After enquiries after her health and the usual niceties, he asked if she ever thought about the ‘hereafter’. ‘Oh yes,’ she answered, ‘often when I get to the top of the stairs I forget what I’ve gone for and ask myself what am I here after?’ Why that happens is described in a study (that I’d forgotten!) while looking for something else - and it throws light on to a helpful tactic in dementia care that can diffuse emotions in the moment.

We’ve all experienced it: the frustration of entering a room and forgetting what we were going to do. Or get. Or find. (Mine is usually ‘find’.)

It’s to do with the way our brains compartmentalise events in memory. Psychology Professor Gabriel Radvansky of the University of Notre Dame suggests that passing through doorways is one of the causes of these memory lapses. ‘Entering or exiting through a doorway serves as an ‘event boundary’ in the mind, which separates episodes of activity and files them away,’ Radvansky explains. ‘Recalling the decision or activity that was made in a different room is difficult because it has been compartmentalized.’

In his experiment Radvansky found that subjects forgot more after walking through a doorway compared to moving the same distance across a room, suggesting that the doorway or ‘event boundary’ impedes one’s ability to retrieve thoughts or decisions made in a different room.

An event boundary also occurs when moving from one context to another. Ravansky mentioned previous research showing that environmental factors affect memory and that information learned in one environment is retrieved better when the retrieval occurs in the same context. We’ve all experienced meeting people who clearly know us, but it takes a sentence or two to move them from the context in which you know them to where you are in the moment. In our book, ‘Dementia from the Inside,’ Dr Jennifer Bute describes how a friend she didn’t recognise when they met in Waitrose gave her several clues from the usual context until ‘the lights went on’ and she remembered who she was.

Understanding Event Boundaries helps explain why taking the person with dementia into another room can help defuse tension. Pamela, a daughter who was looking after her mother with dementia told how her mother insisted on going to see her mother, who was no longer alive. Pam tried several deflections with no effect then said, ‘all right, but let’s check that the gas is turned off and everything in the kitchen is alright.’ They moved from the sitting room into the kitchen where Pam suggested they have a cup of tea and a biscuit and her mother settled happily, all thoughts of visiting her mother gone.