RESUMEN
RATIONALE: The potential to improve cognition in older women with estrogen or estrogen/progesterone therapy is currently a matter of intense debate. Only a few studies conducted so far have used electrophysiological indicators of cognitive information processing as outcome measures in randomised placebo controlled studies. OBJECTIVES: This study was undertaken to measure changes in event-related potentials (ERPs) after short (4 weeks) or prolonged (24 weeks) hormone treatment in older women. METHODS: A randomised, double-blind, placebo-controlled study in hysterectomized older women (aged 58-75 years) was performed (n = 51). The participants received orally estradiol (2 mg estradiol valerate), estradiol plus progesterone (100 mg micronized progesterone) or placebo for 24 weeks. Using four different paradigms, early and late ERPs were assessed at baseline and after 4 and 24 weeks of treatment. RESULTS: Strong hormone increases were observed in the two active treatment groups. However, no significant effects on any of the assessed ERPs were observed in either of the two treatment groups. Similar non-significant findings were obtained for reaction time and error rate. CONCLUSIONS: Estradiol or estradiol/progesterone treatment appears to have no strong effects on several ERP markers of information processing in older hysterectomized women. The current negative findings might suggest a reduced sensitivity of the aged brain to gonadal steroids.