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International Journal of Alzheimer’s Disease
Volume 2011, Article ID 263817, 9 pages
http://dx.doi.org/10.4061/2011/263817
Review Article

Transcranial Magnetic Stimulation Studies in Alzheimer's Disease

1Department of Neurology, University Campus Bio-Medico of Rome, 00128 Rome, Italy
2Department of Rehabilitation, University Campus Bio-Medico of Rome, 00128 Rome, Italy
3Department of Neuroscience, University of Pisa, 56126 Pisa, Italy
4Department of Clinical Neurophysiology, University of Eastern Finland, 70210 Kuopio, Finland

Received 30 December 2010; Revised 11 April 2011; Accepted 5 May 2011

Academic Editor: Giuseppe Curcio

Copyright © 2011 Andrea Guerra et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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.