Scientists have found that the compound epigallocatechin gallate present in green tea, along with a cognitive stimulation protocol, might improve some cognitive domains in individuals with Down's syndrome and may modify the excitability and functional connectivity of their brains.
The findings suggest that participants who had received the treatment had better scores in the visual memory recognition and inhibition tasks, and improvement in adaptive behaviour than those in the control group (placebo and cognitive training).
"This is the first time that a treatment has shown some efficacy in the improvement of some cognitive tasks in persons with this syndrome," said Mara Dierssen from Centre for Genomic Regulation (CRG) in Spain. "It must be made clear that our discovery is not a cure for Down's syndrome and that our results have to be proven in larger populations, but it may be a treatment to improve these individuals' quality of life," she said.
According to the World Health Organisation (WHO), Down's syndrome affects approximately one out of 1,000 persons in the world, and is the most common cause of genetic-origin intellectual disability.
Researchers from CSG and Hospital del Mar Medical Research Institute (IMIM) in Spain focused on the role of a compound called epigallocatechin gallate, which compensates for the excess of function of one of the genes present in chromosome 21 (DYRK1A), involved in cerebral plasticity and certain cognitive functions. The results indicate that individuals treated with epigallocatechin gallate and a cognitive stimulation protocol had score improvements in visual recognition memory, inhibitory control, and adaptive behaviour and that these changes might be correlated with biological changes in their cerebral connectivity.
Researchers studied 84 persons with Down's syndrome aged 16 to 34 years.
"The results suggest that individuals who received treatment with the green tea compound, together with the cognitive stimulation protocol, had better score in their cognitive capacities," said Rafael de la Torre from IMIM. Epigallocatechin gallate was known to inhibit the excess of the DYRK1A gene, and the success achieved in previous studies with mice suggested that the treatment could also work for human beings.
Scientists studied more than the cognitive effects on the study participants. They also conducted neuro-imaging tests to determine whether the improvement was attributable to physical or neurophysiological changes in the brain. "It was surprising to see how the changes are not just cognitive - in the reasoning, learning, memory and attention capacities - but suggest that the functional connectivity of the neurons in the brain was also modified," said de la Torre.
The findings were published in the journal Lancet Neurology.
