The proposed mechanism of actions of DBS for AD are as diverse as increasing cerebral glucose metabolism [14, 18, 22], “neural hijacking” by resetting theta activity [22], increasing hippocampal acetylcholine release [22], compensating “neuro-chemically for the cholinergic fibres which have already been lost” [58], enhancing neuronal activity [12], increasing nerve growth factor (NGF) release [22], alleviating functional and structural brain circuit aberrations [18] or “normalization” neural oscillations [8, 15]. This evidence concerns the gene NGF and Alzheimer disease.