Difficulties with planning, insomnia, inability to multitask, and irritability may indicate the development of dementia, neurologist Peter Rabins from Johns Hopkins University told the Daily Mail.

Rabins advises people who are concerned about worsening memory to answer ten questions designed to help assess their cognitive state. First of all, one should reflect on whether they have recently had trouble remembering the names of close acquaintances or carrying out familiar tasks that used to be easy — such as planning a holiday or organising meetings.

The researcher also recommends testing one’s ability to hold multiple tasks in mind. At the start of the test, you choose a number, then answer a few questions, and at the end recall the number after subtracting seven — a technique used to evaluate short-term memory and concentration.

According to Rabins, it is also important to review medications being taken, since some drugs — particularly those used to regulate heart rhythm — can affect cognitive function. Alcohol can produce a similar effect: as people age, their bodies metabolise it more slowly, and prolonged periods of mental fog may be mistaken for symptoms of dementia.

The last set of questions, he explains, concerns changes in personality and emotional state. It is worth noting whether a person has become more irritable or anxious, or has lost interest in previously enjoyable activities. Rabins emphasises that positive answers to such questions should be taken seriously, and that chronic insomnia often appears several years before more obvious signs of dementia.