Prosopagnosia (face blindness) may be temporarily improved following inhalation of the hormone oxytocin.
This is the finding of research led by Dr Sarah Bate and Dr Rachel Bennetts of the Centre for Face Processing Disorders at Bournemouth University that will be presented today, Friday 6 September, at the British Psychological Society’s Joint Cognitive and Developmental annual conference at the University of Reading.
Dr Bate explained: “Prosopagnosia is characterised by a severe impairment in face recognition, whereby a person cannot identify the faces of their family or friends, or even their own face”
The researchers tested twenty adults (10 with prosopagnosia and 10 control participants). Each participant visited the laboratory on two occasions, approximately two weeks apart. On one visit they inhaled the oxytocin nasal spray, and on the other visit they inhaled the placebo spray. The two sprays were prepared by an external pharmaceutical company in identical bottles, and neither the participants nor the researchers knew the identity of the sprays until the data had been analysed.
Regardless of which spray the person inhaled, the testing sessions had an identical format. Participants inhaled the spray, then sat quietly for 45 minutes to allow the spray to take effect. They then participated in two face processing tests: one testing their ability to remember faces and the other testing their ability to match faces of the same identity.
The researchers found that the participants with prosopagnosia achieved higher scores on both face processing tests in the oxytocin condition. Interestingly, no improvement was observed in the control participants, suggesting the hormone may be more effective in those with impaired face recognition systems.
The initial ten participants with prosopagnosia had a developmental form of the condition. Individuals with developmental prosopagnosia have never experienced brain damage, and this form of face blindness is thought to be very common, affecting one in 50 people. Much more rarely, people can acquire prosopagnosia following a brain injury. At a later date, the researchers had the opportunity to test one person with acquired prosopagnosia, and also observed a large improvement following oxytocin inhalation in this individual.
Dr Bate said: “This study provides the first evidence that oxytocin may be used to temporarily improve face recognition in people with either developmental or acquired prosopagnosia. The effects of the hormone are thought to last 2-3 hours, and it may be that the nasal spray can be used to improve face recognition on a special occasion. However, much more research needs to be carried out, as we don’t currently know whether there are benefits or risks associated with longer-term inhalation of the hormone.”