title: Transcranial magnetic stimulation studies in Alzheimer's disease.
abstract: Although motor deficits affect patients with Alzheimer's disease (AD) only at later stages, recent studies demonstrated that primary motor cortex is precociously affected by neuronal degeneration. It is conceivable that neuronal loss is compensated by reorganization of the neural circuitries, thereby maintaining motor performances in daily living. Effectively several transcranial magnetic stimulation (TMS) studies have demonstrated that cortical excitability is enhanced in AD and primary motor cortex presents functional reorganization. Although the best hypothesis for the pathogenesis of AD remains the degeneration of cholinergic neurons in specific regions of the basal forebrain, the application of specific TMS protocols pointed out a role of other neurotransmitters. The present paper provides a perspective of the TMS techniques used to study neurophysiological aspects of AD showing also that, based on different patterns of cortical excitability, TMS may be useful in discriminating between physiological and pathological brain aging at least at the group level. Moreover repetitive TMS might become useful in the rehabilitation of AD patients. Finally integrated approaches utilizing TMS together with others neuro-physiological techniques, such as high-density EEG, and structural and functional imaging as well as biological markers are proposed as promising tool for large-scale, low-cost, and noninvasive evaluation of at-risk populations.
authors.affiliation: Department of Neurology, University Campus Bio-Medico of Rome, 00128 Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Guerra
authors.forename: Federica
authors.initials: F
authors.lastname: Assenza
authors.forename: Federica
authors.initials: F
authors.lastname: Bressi
authors.forename: Federica
authors.initials: F
authors.lastname: Scrascia
authors.forename: Marco
authors.initials: M
authors.lastname: Del Duca
authors.forename: Francesca
authors.initials: F
authors.lastname: Ursini
authors.forename: Stefano
authors.initials: S
authors.lastname: Vollaro
authors.forename: Laura
authors.initials: L
authors.lastname: Trotta
authors.forename: Mario
authors.initials: M
authors.lastname: Tombini
authors.forename: Carmelo
authors.initials: C
authors.lastname: Chisari
authors.forename: Florinda
authors.initials: F
authors.lastname: Ferreri