text: One possible reason for this conclusion is the rare need for a person to perform at their maximum. There is a difference between typical functioning, that is – the normal level of functioning for daily life, and maximal functioning, that is – what cognitive tests observe as our maximum level of functioning. As the maximum cognitive ability that we are able to achieve decreases, it may not actually affect our daily lives, which only require the normal level.
  Some studies have indicated that childhood hunger might have a protective effect on cognitive decline. One possible explanation is that the onset of age-related changes in the body can be delayed by calorie restriction. Another possible explanation is the selective survival effect, as the study participants who had a childhood with hunger tend to be the healthiest of their era.
  Prognosis
  When a person's level of cognition declines, it is often harder to live in an independent setting and some people have trouble taking care of themselves and the burden on the people caring for them can increase. Some people require supportive healthcare and in some cases institutionalization.
  Research
  The role of light therapy for treating people with cognitive impairment or dementia is not fully understood.