title: Vagus nerve stimulation…25 years later! What do we know about the effects on cognition?
abstract: VNS therapy was delivered to patients for the first time in 1988. After 25 years, insight in the antiepileptic and antidepressant mechanism of action of VNS has grown steadily. The effects on cognition and especially memory remain controversial. This review provides an elaborate overview of studies addressing cognition and describes potential underlying mechanisms for the reported effects. Short-term VNS has an effect on verbal memory recognition when administered at the correct timing and dosage. Chronic VNS resulted into a positive effect on the cognitive status in an Alzheimer population. Positive effect of chronic VNS in epilepsy or depression patients on global cognitive functioning are less convincing. Neither do the results reveal a negative effect which has major implications for chronic treatment of neurology patients. A cascade of neurochemical processes put in motion by changes in NE concentrations in reaction to stimulation of the vagal nerve may underlie the VNS-induced effects on cognition and memory. In Alzheimer pathology, NE may act as an anti-inflammatory agent on brainstem nuclei.
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. Electronic address: Kristl.Vonck@UGent.be.
authors.forename: Kristl
authors.initials: K
authors.lastname: Vonck
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. Electronic address: Robrecht.Raedt@UGent.be.
authors.forename: Robrecht
authors.initials: R
authors.lastname: Raedt
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. Electronic address: Joke.Naulaerts@UGent.be.
authors.forename: Joke
authors.initials: J
authors.lastname: Naulaerts
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. Electronic address: Ferderick.DeVogelaere@UGent.be.
authors.forename: Frederick
authors.initials: F
authors.lastname: De Vogelaere
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. Electronic address: Evert.Thiery@scarlet.be.
authors.forename: Evert
authors.initials: E
authors.lastname: Thiery
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. Electronic address: Dirk.VanRoost@UGent.be.
authors.forename: Dirk
authors.initials: D
authors.lastname: Van Roost
authors.affiliation: Epilepsy Centre Kempenhaeghe, Postbus 61, 5590 AB Heeze, The Netherlands; Maastricht University Medical Centre, P.O. Box 616, 6200 MD Maastricht, The Netherlands. Electronic address: AldenkampB@Kempenhaeghe.nl.
authors.forename: Bert
authors.initials: B
authors.lastname: Aldenkamp
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. Electronic address: Marijke.Miatton@UGent.be.
authors.forename: Marijke
authors.initials: M
authors.lastname: Miatton
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium; Epilepsy Centre Kempenhaeghe, Postbus 61, 5590 AB Heeze, The Netherlands. Electronic address: Paul.Boon@UGent.be.
authors.forename: Paul
authors.initials: P
authors.lastname: Boon
mesh_terms: D000544:Alzheimer Disease / Q000503:physiopathology / Q000523:psychology / Q000628:therapy; D000818:Animals; D001921:Brain / Q000503:physiopathology; D003071:Cognition / Q000502:physiology*; D006801:Humans; D008568:Memory; D055536:Vagus Nerve Stimulation / Q000379:methods*
keywords: Alzheimer's disease; Cognitive functioning; Depression; Epilepsy; Locus coeruleus; Memory; Norepinephrine; Quality of life; Vagus nerve stimulation