Size of hippocampus may be linked to early dementia

The size of the part of the brain known as the hippocampus may be linked to future dementia, reveals a thesis from the University of Gothenburg, Sweden.

Mild cognitive impairment, or MCI, is a condition where the cognitive functions are impaired - though not as severely as in dementia - and is a precursor to several types of dementia.

"One of the challenges for the healthcare is identifying which MCI patients have an underlying dementia disorder, which is why we need new tools to detect the early signs of dementia," says Carl Eckerström, a researcher at the Sahlgrenska Academy's Department of Psychiatry and Neurochemistry, and doctor at Sahlgrenska University Hospital's memory clinic.

Atrophy of the hippocampus is common in Alzheimer's disease. The thesis shows that the hippocampus may also be affected in small vessel disease (SIVD) which, along with Alzheimer's, are the two most common types of dementia. SIVD is characterised by damage to the brain's white matter and is considered to be the most important type of vascular dementia in the elderly.

Researchers measured the extent of changes to white matter in 122 MCI patients, and compared this with the size of their hippocampus. The patients were divided into two categories - one group who subsequently developed dementia after two years, and a second group whose clinical status remained unchanged after two years. There was also a group of healthy controls. The results showed that there may be a link between damage to the white matter and a reduction in the size of the hippocampus, which means that damage to the white matter could play a part in a process that leads to hippocampal atrophy.

"I believe that measuring the hippocampus could be a useful clinical instrument for investigating whether a person is in the early stages of dementia, as our findings suggest that the size of the hippocampus is linked to a deterioration in cognitive function and dementia," says Eckerström.