A woman in her early 40s with congenital
prosopagnosia and
attention deficit hyperactivity disorder observed for the first time sudden and extensive improvement of her face recognition abilities, mental imagery, and sense of navigation after
galactose intake. This effect of
galactose on
prosopagnosia has never been reported before. Even if this effect is restricted to a subform of congenital
prosopagnosia,
galactose might improve the condition of other prosopagnosics. Congenital
prosopagnosia, the inability to recognize other people by their face, has extensive negative impact on everyday life. It has a high prevalence of about 2.5%.
Monosaccharides are known to have a positive impact on cognitive performance. Here, we report the case of a prosopagnosic woman for whom the daily intake of 5 g of
galactose resulted in a remarkable improvement of her lifelong
face blindness, along with improved sense of orientation and more vivid mental imagery. All these improvements vanished after discontinuing
galactose intake. The self-reported effects of
galactose were wide-ranging and remarkably strong but could not be reproduced for 16 other prosopagnosics tested. Indications about heterogeneity within
prosopagnosia have been reported; this could explain the difficulty to find similar effects in other prosopagnosics. Detailed analyses of the effects of
galactose in
prosopagnosia might give more insight into the effects of
galactose on human cognition in general.
Galactose is cheap and easy to obtain, therefore, a systematic test of its positive effects on other cases of congenital
prosopagnosia may be warranted.