Clinicoradiological comparisons between vascular parkinsonism and Parkinson\'s disease

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JNNP Online First, published on June 10, 2015 as 10.1136/jnnp-2015-311155

LETTER

Clinicoradiological comparisons between vascular parkinsonism and Parkinson’s disease Dear Editor; We have closely read the paper by Cardoso Vale et al,1 aimed at comparing the clinical and radiological features between patients with Parkinson’s disease (PD) and those with vascular parkinsonism (VP). The article seeks to provide key clinical data that may help in the definition and distinction of these illnesses. To accomplish this, the authors performed a large body of assessments on a small sample of patients. We would like to make some comments on the rationale of the evaluations that were carried out; because, in our view, the authors’ approach on the assessment of the groups of patients was sometimes made under inaccurate concepts and there is a need for clarification. It is well known that pure VP without evidence for nigral Lewy body pathology may occur as a distinct clinicopathological entity, but the presence of age-associated white matter lesions (WMLs) in idiopathic PD is also a frequent circumstance.2 Actually, imaging studies have shown that WMLs are present in 30–55% of patients with PD.3 Following this scenario, it could also be that acute infarctions unmask or worsen an incipient idiopathic PD not previously noticed by the patient or relatives, and the authors left this unmentioned. For these cases, the presence of premotor and nonmotor symptoms is a very useful tool for disclosing possible PD cases and we are surprised that this issue was not taken into account or discussed in the article, as olfactory function has been shown to be preserved in VP.4 Along these lines, an olfactometry test would have been helpful as well. The authors also highlight the presence of risk factors for stroke and white matter disease, such as hypertension, as a way of differentiating between the disorders; however, we do not think that this issue

adds any diagnostic accuracy because the reported prevalence of hypertension and other comorbidities (coronary artery disease and diabetes mellitus) in PD is not that different from those in the general population when matched with ambulatory patients as controls.5 Concerning diagnosis, VP can sometimes be difficult to differentiate from the postural instability and gait disorder (PIGD) subtype of idiopathic PD, which manifests in more cognitive impairment when compared with VP.6 However, consensus on diagnostic criteria is lacking. It is important to note that in the criteria of Zijlmans et al,7 which are the most common criteria utilised for diagnosis and are employed in this article, very few scenarios of patients with mixed pathological findings of PD and coexisting white matter ischaemia and/or lacunar infarcts in the basal ganglia were included. These situations are likely to present and progress differently from those with VP alone. Regarding the scales used for making comparisons between the groups, it is important to take into account that Hoehn and Yahr is quite appropriate for the assessment of PD progression. However, in VP, a HY stage of 2 or 3 at disease onset due to the presence of gait abnormalities or axial involvement does not actually reflect progression but, rather, suggests the mode of the presentation of the disorder. In addition, some of the assessments in PD and VP cases were performed in the OFF and ON conditions. This is quite easy to understand for the PD group, as the wearing off phenomena is one of the most frequent motor complications in patients with PD, but it is not the same for VP. The intake of a levodopa dose does not necessarily imply the occurrence of a subsequent ON motor state unless it is followed by positive clinical changes in motor performance. Therefore, it is difficult to understand what the authors mean by ON and OFF periods in patients with VP. In future studies, it would be pertinent to determine the differences in the clinical and image studies, including DaT SPECT, between VP and PIGD groups, as well as to

PostScript

search for distinguishing biomarkers, since this is a real challenge in clinical practice and these studies are underdeveloped. In conclusion, for research purposes, it is important to consider that WMLs and stroke can coexist in idiopathic PD; and, to date, the presence of clinical and epidemiological features alone are not sufficient in differentiating VP from PD. Michel Saenz Farret, Maria Graciela Cersosimo, Carolina Candelaria Ramirez Gomez, Federico Micheli Hospital de Clínicas “José de San Martín”, Parkinson and Movement Disorders Program, Buenos Aires University, Buenos Aires, Argentina Correspondence to Dr Federico E Micheli, Parkinson’s Disease and Movement Disorders Program, Hospital de Clínicas José de San Martín, University of Buenos Aires, Buones Aires 1631, Argentina; fmicheli@fibertel.com.ar Competing interests None declared. Patient consent Obtained. Provenance and peer review Not commissioned; internally peer reviewed. To cite Farret MS, Cersosimo M G, Ramirez Gomez C C, et al. J Neurol Neurosurg Psychiatry Published Online First: [ please include Day Month Year] doi:10.1136/jnnp-2015-311155 Received 28 April 2015 Accepted 4 May 2015 J Neurol Neurosurg Psychiatry 2015;0:1. doi:10.1136/jnnp-2015-311155

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Cardoso Vale T, Caramelli P, Cardoso F. Clinicoradiological comparison between vascular parkinsonism and Parkinson’s disease. J Neurol Neurosurg Psychiatry 2015;86:547–53. Bohnen NI, Albin RL. White matter lesions in Parkinson disease. Nat Rev Neurol 2011;7:229–36. Sohn YH, Kim JS. The influence of white matter hyperintensities on the clinical features of Parkinson’s disease. Yonsei Med J 1998;39:50–5. Katzenschlager R, Zijlmans J, Evans A, et al. Olfactory function distinguishes vascular parkinsonism from Parkinson’s disease. J Neurol Neurosurg Psychiatry 2004;75:1749–52. Nataraj A, Rajput AH. Parkinson’s disease, stroke, and related epidemiology. Mov Disord 2005;20:1476–80. Jankovic J, McDermott M, Carter J, et al. Variable expression of Parkinson’s disease: a base-line analysis of the DATATOP cohort. Neurology 1990;41:1529–34. Zijlmans JCM, Daniel SE, Hughes AJ, et al. Clinicopathological investigation of vascular parkinsonism, including clinical criteria for diagnosis. Mov Disord 2004;19:630–40.

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Clinicoradiological comparisons between vascular parkinsonism and Parkinson's disease Michel Saenz Farret, Maria Graciela Cersosimo, Carolina Candelaria Ramirez Gomez and Federico Micheli J Neurol Neurosurg Psychiatry published online June 10, 2015

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