TNF and Cognitive impairment: For outcome measurements, brain water content was calculated in 12 studies [8, 22–29, 32, 38], blood–brain barrier permeability was measured in seven studies [24, 25, 27–29, 35, 38], cognitive impairment was evaluated in two trials [37, 39], the TNF-α level was detected in three studies [8, 19, 29] and the NO level was detected in two studies [19, 34].