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Scientific Reports Feb 2016A large number of articles have reported substantia nigra hyperechogenicity in Parkinson's disease (PD) and have assessed the diagnostic accuracy of transcranial... (Meta-Analysis)
Meta-Analysis Review
A large number of articles have reported substantia nigra hyperechogenicity in Parkinson's disease (PD) and have assessed the diagnostic accuracy of transcranial sonography (TCS); however, the conclusions are discrepant. Consequently, this systematic review and meta-analysis aims to consolidate the available observational studies and provide a comprehensive evaluation of the clinical utility of TCS in PD. Totally, 31 studies containing 4,386 participants from 13 countries were included. A random effects model was utilized to pool the effect sizes. Meta-regression and sensitivity analysis were performed to explore potential heterogeneity. Overall diagnostic accuracy of TCS in differentiating PD from normal controls was quite high, with a pooled sensitivity of 0.83 (95% CI: 0.81-0.85) and a pooled specificity of 0.87 (95% CI: 0.85-0.88). The positive likelihood ratio, the negative likelihood ratio and diagnostic odds ratio were calculated 6.94 (95% CI: 5.09-9.48), 0.19 (95% CI: 0.16-0.23), and 42.89 (95% CI: 30.03-61.25) respectively. Our systematic review of the literature and meta-analysis suggest that TCS has high diagnostic accuracy in the diagnosis of PD when compared to healthy control.
Topics: Humans; Parkinson Disease; Publication Bias; ROC Curve; Reproducibility of Results; Substantia Nigra; Ultrasonography, Doppler, Transcranial
PubMed: 26878893
DOI: 10.1038/srep20863 -
Toxicology and Applied Pharmacology Feb 2013Parkinson disease (PD) is a debilitating neurodegenerative motor disorder, with its motor symptoms largely attributable to loss of dopaminergic neurons in the substantia... (Review)
Review
Parkinson disease (PD) is a debilitating neurodegenerative motor disorder, with its motor symptoms largely attributable to loss of dopaminergic neurons in the substantia nigra. The causes of PD remain poorly understood, although environmental toxicants may play etiologic roles. Solvents are widespread neurotoxicants present in the workplace and ambient environment. Case reports of parkinsonism, including PD, have been associated with exposures to various solvents, most notably trichloroethylene (TCE). Animal toxicology studies have been conducted on various organic solvents, with some, including TCE, demonstrating potential for inducing nigral system damage. However, a confirmed animal model of solvent-induced PD has not been developed. Numerous epidemiologic studies have investigated potential links between solvents and PD, yielding mostly null or weak associations. An exception is a recent study of twins indicating possible etiologic relations with TCE and other chlorinated solvents, although findings were based on small numbers, and dose-response gradients were not observed. At present, there is no consistent evidence from either the toxicological or epidemiologic perspective that any specific solvent or class of solvents is a cause of PD. Future toxicological research that addresses mechanisms of nigral damage from TCE and its metabolites, with exposure routes and doses relevant to human exposures, is recommended. Improvements in epidemiologic research, especially with regard to quantitative characterization of long-term exposures to specific solvents, are needed to advance scientific knowledge on this topic.
Topics: Animals; Dopaminergic Neurons; Environmental Exposure; Humans; Parkinson Disease, Secondary; Solvents; Substantia Nigra; Trichloroethylene; Twin Studies as Topic
PubMed: 23220449
DOI: 10.1016/j.taap.2012.11.016