**11. Parkinson's and Alzheimer's diseases**

Numerous studies indicate that *H. pylori* infection is associated with a more rapid development of cognitive and functional deterioration. Furthermore, eradication of *H. pylori* could give an improved disease severity [75–78]. Also, a study by Weller et al. showed that the presence of CagA antibodies is associated with a poorer Parkinson's prognosis [79]. It is proposed that *H. pylori* initiates the destruction of mitochondria and together with antigenic mimicry stimulates Parkinson's disease [72]. Only few studies focus on *H. pylori* and Alzheimer's disease, and they are too preliminary to show a causal or therapeutic association [72, 75].
