Obstructive sleep apnoea (OSA) common among the elderly is a condition where the walls of the throat relax and narrow during sleep stopping breathing and is known to reduce levels of oxygen in the blood. It has also been linked with heart diseases strokes and cancer. A new study suggested that the drop in oxygen may be linked to a shrinking of the brain's temporal lobes and a corresponding decline in memory. Between 30 and 50 per cent of the risk for dementia is due to modifiable factors such as depression high blood pressure obesity and smoking. In recent years researchers