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Parkinson’s Disease
Volume 2011 (2011), Article ID 746303, 7 pages
Research Article

The On-Freezing Phenomenon: Cognitive and Behavioral Aspects

Medicina Clinica, Ambulatorio Complicanze Internistiche Cerebrali, Dipartimento Universitario Clinici di Scienze Mediche Tecnologiche e Traslazionali, Università degli Studi di Trieste, Ospedale di Cattinara, Strada Fiume 447, 34149 Trieste, Italy

Received 14 November 2010; Revised 6 March 2011; Accepted 20 May 2011

Academic Editor: Irena Rektorova

Copyright © 2011 Rita Moretti 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.


Freezing of gait is a warning sign of Parkinson's disease. One could distinguish off-freezing, which is associated with dopaminergic therapy and to its titration, and it is clinically related to wearing-off phenomenon. Differently, the on-freezing phenomenon seems to be related to a neural disruption of the frontal-parietal-basal ganglia-pontine projections; clinically, it does not respond to therapy modifications or to different drug titration. In a group of patients with on-freezing, we have detected an alteration of focusing attention, an impairment of set-shifting, in addition to poor abstract reasoning and a reduction of planning. These aspects have been even more evident, when compared with the results obtained by a group of PD patients, without freezing.