The News Minute | September 11, 2014 | 07:00 pm ISTPeople suffering from sleep apnoea have weaker brain blood flow that hurts the brain, says a study.Obstructive sleep apnoea (OSA) is a sleep disorder that occurs when a person's breathing is repeatedly interrupted during sleep, hundreds of times a night."This study brings us closer to understanding what causes the problems in the brain of people with sleep apnoea," said lead researcher for the study Paul Macey from the University of California, Los Angeles (UCLA) School of Nursing in the US.For the study, the researchers measured blood flow in the brain using a non-invasive MRI (magnetic resonance imaging) procedure, which shows the global blood-oxygen level dependent (BOLD) signal."By using this method, we were able to show changes in the amount of oxygenated blood across the whole brain, which could be one of the causes of damage we see in people with sleep apnoea," Macey added.In this study, men and women - with and without obstructive sleep apnoea had their BOLD signals measured during three physical tasks while they were awake.When they looked at the results people with OSA saw a much weaker brain blood flow response in two of the tasks."The difference was because signals from the nerves in the arms and legs had to be processed through the high brain areas controlling sensation and muscle movement, which was slower in people with OSA due to the brain injury," the researchers said.The study also found the problem is greater in women with sleep apnoea, which may explain the worse apnoea-related outcomes in females than males.The study appeared in the journal PLOS ONE.IANS