Mechanisms of aluminium neurotoxicity in oxidative stress-induced ...

INTRODUCTION
diagnosis was substantially higher in patients diagnosed by experts in movement
disorders (Hughes et al. 2002).
8
In order to improve diagnostic accuracy, revised and more stringent diagnostic
criteria were developed by the UK Parkinson‟s Disease Society Brain Bank (Table 2)
(Hughes et al. 1992b) and the National Institute of Neurological Disorders and Stroke
(NINDS) (Table 3) (Gelb et al. 1999). Nevertheless they still remain controversial as
clinicopathological studies suggest that about 10-20% of PD cases remain as false
positives (Hughes et al. 2001, Litvan et al. 2003).
The problem is that a reliable and easily valid diagnostic test for PD is not yet
available. When there is doubt about the diagnosis or when the patient‟s history or
clinical findings are atypical, sophisticated neuroimaging techniques may be useful to
differentiate PD from other diseases (Piccini and Brooks 2006). Conventional brain
imaging, such as magnetic resonance imaging (MRI) or computarized tomography
(CT), are helpful when normal pressure hydrocephalus or vascular parkinsonism are
suspected (Demirkiran et al. 2001). Sophisticated imaging techniques of the DA
pathways such as positron emission tomography (PET) or single photon emission
computarized tomography (SPECT), can make a distinction of PD from essential
tremor, dystonic tremor, neuroleptic-induced parkinsonism and psychogenic
parkinsonism/postsynaptic forms of parkinsonism in specialised settings (Vingerhoets et
al. 1994, Lee et al. 2000, Winogrodzka et al. 2001, Piccini and Brooks 2006). Although
these promising techniques have become more widely available and easier to use, much
controversy exists (because of the lack of universally accepted neuropathological
criteria for PD) (Clarke and Gutman 2002, Marek et al. 2002, Litvan et al. 2003).
Usefulness for population epidemiological studies is still limited as sensitivity and
resolution of these neuroimaging techniques need to be improved and refined.