Dr. Joan Montaner, coordinator of the Neurosciences Area at Vall d’Hebron Institute of Research (VHIR), explained in the Ràdio 4 news bulletin the preliminary results of the first stage of the "http://www.vhir.org/salapremsa/mitjans/mitjans_detall.asp?Idioma=en&mv1=5&mv2=1&mh1=0&mh2=0&mh3=0&mh4=0&ms=0&any=2011&num=320" clinical trial which attempts to determine the frequency of silent strokes, coordinated by Dr. Pilar Delgado.In a sample over 1.000 patients with hypertension and aged between 50 and 70, researchers detected brain injury in the 15 per cent of them. This damage was caused by silent strokes, which are unnoticed and don’t present any clinical manifestations. As patients are not aware of it, they don’t follow any treatment or take any preventive measure. Therefore, the possibility of suffering a second stroke is then multiplied by 3, probably with manifestations of serious conditions, as well as the possibility of suffering some form of dementia is multiplied by 5.Dr. Montaner warned at the public radio that such a high rates are quite alarming because in Barcelona, there could be over 100,000 people suffering silent strokes, without being aware of it. The second stage of the clinical trial will be focused in the common characteristics of people who suffer silent strokes and the validation of the results in more patients. VHIR’s researchers work with the aim of preventing and designing new routine tests that in a future could detect the risk of suffering them. Stroke is the first cause of death in women in Catalonia, and every year hospitals attend more than 13.000 patients: the 10 per cent of them die at the hospital, whereas the 30 per cent suffer a permanent disability.