AUTHOR=Sasaki Shoichi 

TITLE=High Prevalence of Early Parkinson's Disease in Patients With Subtle Parkinsonian Signs

JOURNAL=Frontiers in Neurology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2021.656679

DOI=10.3389/fneur.2021.656679

ISSN=1664-2295

ABSTRACT=<p><bold>Background:</bold> Little is known about how frequently patients with a Unified Parkinson Disease Rating Scale part III (UPDRS-III) score of 3 or 4, including postural and action tremor, could be classified into early Parkinson's disease (PD).</p><p><bold>Objective:</bold> To examine the prevalence of early PD in patients with subtle parkinsonian signs (rest tremor, postural tremor, and rigidity) without bradykinesia, having a UPDRS-III score of 3 or 4.</p><p><bold>Methods:</bold> Parkinsonism was assessed using UPDRS-III based on both the United Kingdom PD Society Brain Bank criteria and the Movement Disorder Society PD criteria. Ninety patients with a UPDRS-III score of 3 or 4, including postural tremor, were evaluated by <sup>123</sup>I-FP-CIT SPECT (DaTscan), brain MRI, the Mini-Mental State Examination, and smell test. Some patients were additionally examined by <sup>123</sup>I-metaiodobenzylguanidine myocardial scintigraphy or <sup>123</sup>I-N-isopropyl-p-iodoamphetamine SPECT.</p><p><bold>Results:</bold> Seventy-five [mean age (standard deviation): 76.9 (8.1)] out of 90 patients (83.3%) showed abnormal findings on DaTscan imaging: 57 out of 75 (76.0%) showed a reduced specific binding ratio (SBR) accompanied by an egg shape pattern (<italic>n</italic> = 37, 49.3%) or a mixed type pattern (<italic>n</italic> = 14, 18.7%), both reduced SBR and increased asymmetry index (AI) with a normal shape (<italic>n</italic> = 4, 5.3%), and reduced SBR only (<italic>n</italic> = 2, 2.7%); 18 (24.0%) showed an egg shape pattern or a mixed type pattern without reduced SBR. In other words, 69 out of 75 patients (92.0%) showed either an egg shape or a mixed type pattern with or without reduced SBR. All patients were free of dementia, and their olfactory function was significantly impaired compared with controls (<italic>n</italic> = 141) on the odor-stick identification test for Japanese (<italic>p</italic> &lt; 0.0001).</p><p><bold>Conclusions:</bold> The prevalence of patients with subtle parkinsonian signs having a UPDRS-III score of 3 or 4, including postural tremor, is unexpectedly high in daily clinical practice, and most of these patients could be categorized into mild early-stage PD.</p>