MIAMI: The size of the brain’s hippocampi is positively associated with how well a person performs in verbal and visuospatial memory tests, according to new research.
Smaller hippocampi may indicate a higher risk of developing Alzheimer’s disease and other types of dementia.
Deep inside the human brain are two seahorse shaped structures known as hippocampi. These structures are important for navigation and for storing and retrieving memories.
In people with dementia, the hippocampi are often the first regions of the brain to suffer damage.
Earlier studies have found an association between the volume (size) of hippocampi and the risk of dementia, but the results have been conflicting.
Also, few studies have included people with mild cognitive impairment (MCI), a condition that often precedes dementia.
In this latest study, researchers recruited 226 people attending memory clinics in the US to take part in their study. Thirty-four participants had Alzheimer’s disease, 95 had MCI, 25 had normal memory (for their age), and the remainder (72) had neurological disorders, including other types of dementia.
The average age of the participants was 68 years, but those with Alzheimer’s disease were significantly older than the participants with normal memory.
All of the participants completed verbal and visuospatial memory tests before undergoing an MRI (magnetic resonance imaging) brain scan. The MRI scans were used to determine the size of the hippocampi.
The researchers found that the size of the hippocampi was positively associated with performance on the memory tests. In other words, people who performed better on the tests tended to have larger hippocampi.
The association between the size of the hippocampi and a person’s performance on the memory tests was stronger for the visuospatial memory test than for the verbal memory test. This suggests that visuospatial memory tests may be a better predictor of dementia than verbal memory tests.