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Parkinson’s Disease
Volume 2016, Article ID 5430920, 5 pages
Clinical Study

Freezing of Gait in Parkinson’s Disease Is Associated with Reduced 6-[18F]Fluoro-L-m-tyrosine Uptake in the Locus Coeruleus

1Division of Neurology, Saitama Medical Center, Jichi Medical University, Saitama 330-8503, Japan
2Utsunomiya Central Clinic, Tochigi 321-0112, Japan
3Division of Neurology, Jichi Medical University, Tochigi 329-0498, Japan

Received 3 November 2015; Revised 22 January 2016; Accepted 31 January 2016

Academic Editor: Olga L. Lopatina

Copyright © 2016 Sayaka Asari Ono 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 (FOG) is a common disorder in Parkinson’s disease (PD) and could be attributed to a reduction in brain noradrenaline. The aim of this study was to determine the relationship between aromatic L-amino acid decarboxylase (AADC) activity in the locus coeruleus (LC) and FOG in PD using high-resolution positron emission tomography with an AADC tracer, 6-[18F]fluoro-L-m-tyrosine (FMT). We assessed 40 patients with PD and 11 age-matched healthy individuals. PD was diagnosed based on the UK Brain Bank criteria by two movement disorder experts. FOG was directly observed by the clinician and assessed using a patient questionnaire. FMT uptake in the LC, caudate, and putamen was analyzed using PMOD software on coregistered magnetic resonance images. FOG was present in 30 patients. The severity of FOG correlated with the decrease of FMT uptake in the LC regardless of disease duration and the severity of other motor impairments, indicating dysfunction of the noradrenergic network in FOG.