Longitudinal follow-up of SWEDD subjects in the PRECEPT Study
ABSTRACT To compare the clinical and imaging characteristics of those PRECEPT (Parkinson Research Examination of CEP-1347 Trial) subjects with a scan without evidence of dopaminergic deficit (SWEDD) to those with dopamine transporter (DAT) deficit scans at study baseline and during a 22-month follow-up.
Baseline (n = 799) and 22-month follow-up (n = 701) [(123)I] β-CIT SPECT scans were acquired. The percent change in [(123)I] β-CIT striatal binding ratio, the percentage of subjects requiring dopaminergic therapy, the change in Unified Parkinson's Disease Rating Scale (UPDRS) score, and the PRECEPT Study investigators' diagnosis at study termination were compared between SWEDD and DAT deficit subjects.
SWEDD subjects (n = 91) compared with DAT deficit subjects (n = 708) showed reduced UPDRS score at baseline (18.7 [SD 8.5] vs 25.5 [SD 10.5], p < 0.05) and minimal change in both [(123)I] β-CIT striatal binding ratio (-0.2% [SD 12.2] vs -8.5% [SD 11.9], p < 0.0001) and UPDRS score (0.5 [SD 6.9] vs 10.5 [SD 8.9], p < 0.0001) at follow-up assessments. At PRECEPT termination, the diagnosis by study investigators was changed from Parkinson disease (PD) to other disorders not associated with DAT deficit in 44% (95% confidence interval 34.2, 54.7) of SWEDD subjects compared with 3.6% (95% confidence interval 2.3, 5.1) of DAT deficit subjects.
These results indicate that subjects identified as having a SWEDD, with DAT imaging within the normal range, have minimal evidence of clinical or imaging PD progression. These data strongly suggest that SWEDD subjects are unlikely to have idiopathic PD.
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ABSTRACT: Dopaminergic brain imaging might aid early diagnosis of Parkinson disease (PD), but some patients with mild symptoms show no evidence of dopaminergic dysfunction at baseline, and apparently do not progress. Although some of these patients may have been misdiagnosed, others continue to fulfil PD diagnostic criteria despite normal follow-up brain scans.Nature Reviews Neurology 07/2014; 10(8). DOI:10.1038/nrneurol.2014.123
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ABSTRACT: The clinical diagnosis of Parkinson's Disease (PD) is not supported by Single Photon Emission Computed Tomography (SPECT) using dopamine transporter radioligand in 4-15 % of patients. It has been hypothesized that this phenomenon, named "Scans Without Evidence of Dopaminergic Deficiency" (SWEDD), may be an adult-onset dystonia. We investigated the hypothesis that these patients might be affected by Dopa-Responsive Dystonia (DRD). We enrolled eleven unrelated patients (8 F and 3 M) with clinical parkinsonism and normal [(123)I]FP-CIT SPECT. The GTP-cyclohydrolase1 (GCH1) gene was sequenced in all patients; urine biopterin and neopterin analysis was carried out in nine and oral phenylalanine (Phe) loading in seven. Neurological examination showed bradykinesia and resting/postural tremor in all patients, and rigidity in ten, suggesting a clinical diagnosis of PD. We detected mild dystonic signs in eight cases. In particular, five of them presented cranial dyskinesias. No mutation of the GCH1 gene was found. The results of the urine biopterin and neopterin analysis and the oral Phe loading did not reveal biochemical abnormalities suggestive of reduced GCH1 activity. We confirm that some clinical features, namely the presence of focal or segmental dystonia, suggest an adult-onset dystonia in SWEDD cases. However, we exclude DRD caused by GCH1 gene mutations in the present series.Journal of Neurology 09/2014; 261(11). DOI:10.1007/s00415-014-7477-6
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ABSTRACT: The purpose of this study is to evaluate the relative risk of abnormal dopamine transporter (DAT) imaging for subjects with and without hyposmia and the feasibility of acquiring a large, community-based, 2-tiered biomarker assessment strategy to detect prodromal Parkinson disease (PD).Neurology 10/2014; 83(19). DOI:10.1212/WNL.0000000000000960