London, April 19 (IANS): Cancer diagnosis affects cognitive functions among patients even before the initiation of chemotherapy, finds a new study.

A large number of studies have shown that cancer patients very often exhibit mild deficits of attention, memory and other basic cognitive functions.

Recent studies have found symptoms of chemobrain in patients who had not yet embarked on a course of chemotherapy.

"Cancer patients can perceive and experience their condition as a severe trauma. Indeed, many of them develop symptoms of post-traumatic stress disorder, particularly in the early phase after they receive the diagnosis," says Kerstin Hermelink from the Ludwig-Maximilians-Universitaet (LMU) in Munich, Germany.

"Stress has a very considerable influence on cognitive performance and definitely impacts on brain function," Hermelink pointed out.

The research team studied 166 women who had been diagnosed with breast cancer and 60 others in whom screening of the breast had revealed no signs of disease.

The participants were assessed three times during the first year following the diagnosis.

"As we suspected at the outset, the higher failure rate in this test could be linked to post-traumatic stress -- the greater the level of stress, the more errors they made, and statistical analysis confirmed that the correlation was highly significant," Hermelink noted.

The findings appeared in the Journal of the National Cancer Institute.