Serum Testosterone and Cognitive Function in Ageing Male: Updating the Evidence.

BACKGROUND Testosterone (T) deficit, either in prepubertal or postpubertal form of hypogonadism, seems to play a key role in impairing cognitive function, including memory, attention, language and visuospatial abilities, especially in elderly men. OBJECTIVE Several studies have recently showed the association between low serum T levels and important cognitive dysfunctions in ageing male as well as in subjects suffering from Alzheimer's disease (AD), mild cognitive impairment (MCI) and even depression, suggesting that T could exert an active neuroprotective role. METHODS By searching PubMed and recent patents (ranging from 2010 to 2015), we identified several observational and intervention studies dealing with T and cognitive function in adult and ageing men. Findings were reviewed, thoroughly examined and, finally, summarized herein. RESULTS Although a large number of studies have been carried out so far, conclusive evidence cannot be drawn, in particular, for cognitive disorders in males. Conversely, T supplementation has been suggested for depressive syndrome in young and ageing men. To date, no clinical data have been carried out on cognitive dysfunctions employing the quoted patents in men. CONCLUSIONS Studies aiming to evaluate the role of serum T and its supplementation in adult and ageing men with T deficiency syndrome need to be encouraged, given that subjects affected by overt hypogonadism, either in prepubertal (i.e. Klinefelter syndrome) or postpubertal forms (chemical castration in subjects affected by prostate cancer), often complain of cognitive dysfunction, and seem to considerably benefit from T replacement therapy.