Evaluating the effects of Bacopa monnieri on cognitive performance and sleep quality of patients with mild cognitive impairment: A triple-blinded, randomized, placebo-controlled trial

•Bacopa monnieri can improve the cognitive performance.•Bacopa mennieri improved some cognition domains, such as attention and verbal fluency, more than others.•Language and attention decline in the early stages of dementia can improve by bacopa mennieri.•Bacopa mennieri with a daily dose of 160 mg did not have a significant effect on improving sleep quality in patients with MCI. Mild cognitive impairment is the middle level of natural cognitive impairment during primary steps of dementia. There are a few studies about improving the cognitive performance and sleep quality in patients with a limited dementia. So, this study was conducted to evaluate the effects of Bacopa monnieri on cognitive performance and sleep quality of patients with mild cognitive impairment. In this study, 62 patients with mild cognitive impairment were categorized into two groups of control and intervention. The intervention group received one pill of 160 mg Bacopa monnieri extract in 2 months, and the control group received a pill containing starch powder. The cognitive impairment and sleep quality was assessed using a questionnaire containing demographic information, Montreal Cognitive Assessment, and the Pittsburg Sleep Quality Index in three time-points of before the study, one months after the intervention and 2 months after the intervention (the end of study). The results showed no statistically significant difference between two groups in all three time-points in overall cognitive performance score and its 6 parameters (P > 0.05). While in the field of attention at the end of the first month (P = 0.033) and the end of the second month (P = 0.004), it was significant difference between the study groups. Also, in the field of verbal fluency at the end of the second month, this difference was significant (P = 0.003). The cognitive performance overall score showed no significant difference between two groups in first (P = 0.939) and second time-points (P = 0.661), although it was significant at third time-point (P = 0.029). There was no statistically significant difference between two groups in all time-points for sleep quality overall score (P > 0.05). The results showed that Bacopa monnieri can improve the cognitive performance overall score and some of its parameters, but it had no effect on sleep quality.