Some Swedish researchers have stated that previous studies about the loss of mental abilities were wrong. The deterioration of our intelligence and our mind capacity starts earlier than we thought before. Some of our most important skills start to deteriorate nearly 15 years before we die.

The tests made to discover this consisted of checking the perceptual speed, spatial ability and verbal functions. All these showed that cognitive skills start to fade long before our death, as Valgeir Thorvaldsson, who worked at the study, said.

Valgeir Thorvaldsson, a psychologist at Gothenburg University in Sweden, added that "Previous studies have showed that the steep decline begins around five years before death. What we could see in our data is that these changes occur much earlier than thought."

The highest mental ability is reached between 35 and 40 years. After this period, a decline is noticed in the mental capacity, which speeds as people approach death. This point is where the acceleration starts together with the loss of mental ability. The study was made during 30 years of observation. 288 men and women from their 70s until their death time were observed as to measure their mental capacities fading.

As Valgeir Thorvaldsson said about the study, "there is substantial acceleration in cognitive decline many years prior to death among individuals without dementia." In the journal of Neurology, he and his colleagues stated that the lack of exercise and other health problems increase the decline.