Abstract
Mild parkinsonian features can be observed in patients with essential tremor (ET). Although dopamine transporter (DAT) imaging is usually normal in ET, some studies found mild dopaminergic deficit in ET patients compared to healthy controls (HC). We analyzed clinical and DAT imaging data in ET patients with and without parkinsonian features. Thirty-nine ET patients with and without parkinsonian features and 13 HC underwent detailed examination by a movement disorders neurologist and 123-I ioflupane SPECT. Two independent radiologists “blinded” to the clinical diagnosis analyzed images visually and by semi-quantitative calculation of striatal binding ratios in different volumes of interests. ET patients were divided into pure ET group (no parkinsonian features, n = 22), ET-P [one parkinsonian feature not sufficient for the clinical diagnosis of Parkinson’s disease (PD), n = 9], and ET + PD (two or more parkinsonian features meeting diagnostic criteria for PD, n = 8). As expected, ET + PD patients had the lowest striatal binding ratios. We also found a trend toward slightly lower striatal binding ratios in ET patients ET compared to HC, especially in caudate nucleus. There was no significant correlation between striatal binding ratios, ET severity or duration. Patients with ET and parkinsonian features represent a heterogeneous group that includes ET + PD and ET-P. The latter group shares some clinical features with PD but has no dopaminergic deficit on DAT imaging as determined by visual image interpretation. On the other hand, minimal dopaminergic deficit (as compared to controls) is detected in some ET patients with semi-quantitative image analysis, although the pattern may be different from that of PD.
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References
Antonini A, Isaias IU (2009) Imaging evidence supports a link between essential tremor and Parkinson’s disease. Nucl Med Commun 30:93–94
Bain PG (2009) Dystonic tremor presenting as parkinsonism: long-term follow-up of SWEDDs. Neurology 72:1443–1445
Batla A, Erro R, Stamelou M et al (2014) Patients with scans without evidence of dopaminergic deficit: a long-term follow-up study. Mov Disord 29(14):1820–1825
Benamer TS, Patterson J, Grosset DG et al (2000) Accurate differentiation of parkinsonism and essemtial tremor using visual assessment of [123I]-FP-CIT SPECT imaging: the [123I]-FP-CIT study group. Mov Disord 15:503–510
Benito-Leon J, Louis ED, Bermejo-Pareja F (2009) Risk of incident Parkinson’s disease and parkinsonism in essential tremor: a population based study. J Neurol Neurosurg Psychiatry 80:423–425
Bhalsing KS, Saini J, Pal PK (2013) Understanding the pathophysiology of essential tremor through advanced neuroimaging: a review. J Neurol Sci 335(1–2):9–13
Booij J, Kemp P (2008) Dopamine transporter imaging with [(123)I]FP-CIT SPECT: potential effects of drugs. Eur J Nucl Med Mol Imaging 35:424–438
Coria F, Gimenez Garcia M, Samaranch L, Mora FJ, Sampol Bas C, Pastor P (2012) Nigrostriatal dopaminergic function in subjects with isolated action tremor. Parkinsonism Relat Disord 18:49–53
Doty RL, Shaman P, Kimmelman CP, Dann MS (1984) University of Pennsylvania Smell Identification Test: a rapid quantitative olfactory function test for the clinic. Laryngoscope 94:176–178
Elble R, Comella C, Fahn S et al (2012) Reliability of a new scale for essential tremor. Mov Disord 27(12):1567–1569
Erro R, Schneider SA, Quinn NP, Bhatia KP (2015) What do patients with scans without evidence of dopaminergic deficit (SWEDD) have?. J Neurol Neurosurg Psychiatry, New evidence and continuing controversies. doi:10.1136/jnnp-2014-310256 (Epub ahead of print)
Fekete R, Jankovic J (2011) Revisiting the relationship between essential tremor and Parkinson’s disease. Mov Disord 26:391–398
Gerasimou G, Costa DC, Papanastasiou E et al (2012) SPECT study with I-123-Ioflupane (DaTSCAN) in patients with essential tremor. Is there any correlation with Parkinson’s disease? Ann Nucl Med 26:337–344
Goetz CG, Fahn S, Martinez-Martin P et al (2007) Movement Disorder Society-sponsored revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS): process, format, and clinimetric testing plan. Mov Disord 22(1):41–47
Helmich RC, Toni I, Deuschl G, Bloem BR (2013) The pathophysiology of essential tremor and Parkinson’s tremor. Curr Neurol Neurosci Rep 13(9):378
Hughes AJ, Daniel SE, Kilford L, Lees AJ (1992) Accuracy of clinical diagnosis of idiopathic Parkinson’s disease. A clinico-pathological study of 100 cases. JNNP 55:181–184
Isaias IU, Canesi M, Benti R et al (2008) Striatal dopamine transporter abnormalities in patients with essential tremor. Nucl Med Commun 29:349–353
Isaias IU, Marotta G, Hirano S et al (2010) Imaging essential tremor. Mov Disord 25:679–686
Jankovic J, Schwartz KS, Ondo W (1999) Re-emergent tremor of Parkinson’s disease. J Neurol Neurosurg Psychiatry 67:646–650
Lee MS, Kim YD, Im JH, Kim HJ, Rinne JO, Bhatia KP (1999) 123I-IPT brain SPECT study in essential tremor and Parkinson’s disease. Neurology 52:1422–1426
Louis ED, Levy G, Cote LJ, Mejia H, Fahn S, Marder K (2001) Clinical correlates of action tremor in Parkinson’s disease. Arch Neurol 58:1630–1634
Louis ED, Huang CC, Dyke JP, Long Z, Dydak U (2014) Neuroimaging studies of essential tremor: how well do these studies support/refute the neurodegenerative hypothesis? Tremor Other Hyperkinet Mov 4:235
Marek K, Seibyl J, Eberly S et al (2014) Longitudinal follow-up of SWEDD subjects in the PRECEPT Study. Neurology 82(20):1791–1797
Minen MT, Louis ED (2008) Emergence of Parkinsons disease in essential tremor: a study of the clinical correlates in 53 patients. Mov Disord 23(11):1602–1605
Novellino F, Cherubini A, Chiriaco C et al (2013) Brain iron deposition in essential tremor: a quantitative 3-tesla magnetic resonance imaging study. Mov Disord 28(2):196–200
Prodoehl J, Li H, Planetta PJ et al (2013) Diffusion tensor imaging of Parkinson’s disease, atypical parkinsonism, and essential tremor. Mov Disord 28(13):1816–1822
Schwingenschuh P, Ruge D, Edwards MJ et al (2010) Distinguishing SWEDDs patients with asymmetric resting tremor from Parkinson’s disease: a clinical and electrophysiological study. Mov Disord 25:560–569
Shahed J, Jankovic J (2007) Exploring the relationship between essential tremor and Parkinson’s disease. Parkinsonism Relat Disord 13:67–76
Sixel-Doring F, Liepe K, Mollenhauer B, Trautmann E, Trenkwalder C (2011) The role of 123I-FP-CIT-SPECT in the differential diagnosis of Parkinson and tremor syndromes: a critical assessment of 125 cases. J Neurol 258(12):2147–2154
Sommer U, Humme T, Cormann K et al (2004) Detection of presymptomatic Parkinson’s disease: combining smell tests, transcranial sonography, and SPECT. Mov Disord 19(10):1196–1202
Stockner H, Schwingenschuh P, Djamshidian A et al (2012) Is transcranial sonography useful to distinguish scans without evidence of dopaminergic deficit patients from Parkinson’s disease? Mov Disord 27(9):1180–1183
Thenganatt MA, Jankovic J (2014) Parkinson disease subtypes. JAMA Neurol 71(4):499–504
Yahr MD, Orosz D, Purohit DP (2003) Co-occurrence of essential tremor and Parkinson’s disease: clinical study of a large kindred with autopsy findings. Parkinsonism Relat Disord 9:225–231
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Study was partly funded by GE Healthcare, Princeton, NJ and by a grant from the National Parkinson Foundation in support of the Center of Excellence at Baylor College of Medicine.
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Waln, O., Wu, Y., Perlman, R. et al. Dopamine transporter imaging in essential tremor with and without parkinsonian features. J Neural Transm 122, 1515–1521 (2015). https://doi.org/10.1007/s00702-015-1419-z
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DOI: https://doi.org/10.1007/s00702-015-1419-z