The diagnostic accuracy of dopamine transporter SPECT imaging to detect nigrostriatal cell loss in patients with Parkinson's disease or clinically uncertain parkinsonism: a systematic review

In specialized movement disorder centers, Parkinson's disease (PD) is wrongly diagnosed in 6 to 25% of cases. To improve the accuracy of the clinical diagnosis, it is necessary to have a reliable and practical reference standard. Dopamine transporter single-photon emission computed tomography (DAT SPECT) imaging might have the potential (high diagnostic accuracy and practical to use) to act as reference standard in detecting nigrostriatal cell loss in patients with (early stage) parkinsonism. We performed a systematic review to evaluate if DAT SPECT imaging can be used as such. Relevant studies were searched in the MEDLINE and EMBASE databases. Studies were selected when they met the following criteria: (1) all patients were adults with a clinical diagnosis of PD or clinically uncertain parkinsonism and (2) the study reported original data. In addition, studies needed to fulfill one of the two following criteria: (1) patients underwent at least one DAT SPECT and had a neuropathological confirmed diagnosis and (2) patients underwent at least two DAT SPECT scans, performed at least 2 years apart. The search identified 1,649 articles. Eight studies fulfilled our selection criteria and were included in this review. There was only one study including patients with diagnostic uncertainty. Sensitivity and specificity of DAT SPECT imaging to detect nigrostriatal cell loss were 98%. The other studies included patients with a diagnosis of PD in whom there was no uncertainty. In these studies, sensitivity was 100%. Our systematic review indicates that DAT SPECT imaging seems to be accurate to detect nigrostriatal cell loss in patients with parkinsonis

The metabolic syndrome in a memory clinic population : Relation with clinical profile and prognosis

Background The metabolic syndrome (MetS) refers to a cluster of cardiovascular risk factors that is associated with an increased risk of cognitive impairment and dementia. It is unclear however, if the presence of the MetS is associated with a particular clinical profile or a different prognosis in patients with cognitive complaints or early dementia. Objectives  To compare 1) the clinical profile and 2) the prognosis of patients attending a memory clinic according to the presence or absence of MetS. Design Longitudinal cohort. Setting Memory clinic. Participants We included and followed 86 consecutive patients (average age of 66.7 (SD 9.7)) from the Amsterdam Dementia Cohort with an MMSE > 22.  Measurements Clinical profile (neuropsychological examination, brain MRI, cerebrospinal fluid (CSF) biomarkers, clinical diagnosis) on an initial standardized diagnostic assessment was compared according to MetS status. Progression to dementia was assessed in initially nondemented patients (subjective complaints n = 40, mild cognitive impairment n = 24, follow-up available in 59).  Results 35 (41%) patients met the MetS criteria. Demographics were similar between patients with or without the MetS. At baseline, diagnosis, cognitive performance, severity of degenerative or vascular abnormalities on MRI, and CSF amyloid and tau levels did not differ between the groups (all p > 0.05). Among nondemented patients, however, MetS was associated with worse performance on executive function, attention & speed and visuoconstructive ability (z-scores, p < 0.05). During a mean follow-up of 3.4 years a similar proportion of patients with (4; 17%) and without (6; 17%) the MetS progressed to dementia (p = 0.45). Conclusion Among nondemented patients presenting at a memory clinic MetS was associated with slightly worse cognitive performance (worse on tasks assessing executive functions, visuo-constructive ability, attention & speed), but conversion rate to dementia was not increased