Individual parkinsonian motor signs and striatal dopamine transporter deficiency: a study with [I-123]FP-CIT SPECT

Abstract

IntroductionTotal parkinsonian motor symptom severity correlates with presynaptic striatal dopamine function in patients with Parkinson’s disease. There is a lack of studies that have investigated the associations between parkinsonian motor signs and striatal dopaminergic deficiency in patients with parkinsonism of an unknown origin. Identification of specific motor signs associated with the highest likelihood of striatal dopamine deficiency could aid the differential diagnostics of parkinsonian and tremor syndromes.MethodsIn this cross-sectional clinical and imaging study, detailed motor examinations were performed for 221 patients with parkinsonism or tremor of an unknown origin immediately before dopamine transporter (DAT) [I-123]FP-CIT SPECT imaging. Region-of-interest and voxel-based methods were used to investigate striatal DAT deficiency in relation to individual motor signs.ResultsUpper extremity rigidity and facial expression were the only motor signs that differentiated patients with normal and abnormal striatal DAT function. The presence of any upper extremity rigidity showed the highest likelihood of DAT deficiency (OR 4.79, 95% CI 1.56–14.75, P = 0.006) followed by reduced facial expression (OR 2.14, 95% CI 1.14–4.00, P = 0.018). In patients with DAT deficits, reduced facial expression was associated with DAT deficiency specifically in the caudate nucleus, and increased upper extremity rigidity was associated with DAT loss in the dorsal putamen (FWE-corrected P < 0.05).ConclusionsIncreased upper extremity muscle tone and hypomimia are independently associated with a higher likelihood of striatal hypodopaminergic imaging finding. This information can be used as a factor when the clinical need of auxiliary investigations, such as DAT SPECT, is considered for patients with parkinsonism.Electronic supplementary materialThe online version of this article (10.1007/s00415-019-09202-6) contains supplementary material, which is available to authorized users.

Dopamine transporter binding in symptomatic controls and healthy volunteers: Considerations for neuroimaging trials

“…This calibration procedure has been carried out also in our earlier studies with different samples and systems and device-related difference have been tested in each study (see e.g. Kaasinen et al, 2014 , Mäkinen et al, 2019 , Jaakkola et al, 2019 , Mäkinen et al, 2016 , Jaakkola et al, 2017 ) with no statistically significant differences between systems. Nevertheless, this issue is a major limitation of the study and underlines the need for a replication using other imaging systems.…”

Hypomimia in Parkinson’s disease: an axial sign responsive to levodopa

“…Moreover, data on the impact of hypomimia on quality of life and social well-being of PD patients are limited [5,6]. Finally, although hypomimia seems to be a better predictor of basal ganglia dopaminergic denervation compared with other parkinsonian signs [7], no clear information is available on the effects of levodopa on this clinical feature.…”

Burden of non-motor symptoms in unclear parkinsonism and tremor: A study with [123I]FP-CIT SPECT

“…Furthermore, MDS-UPDRS was developed for PD, and the results concerning other conditions may not reflect motor symptoms as accurately as in PD. We have discussed some of these issues in our earlier report as well [13]. In the interpretation of our results it is also important to note that the study population included patients who were referred for DAT imaging due to diagnostic uncertainty.…”