Transcranial Sonography and DaTSCAN in Early Stage Parkinson's Disease and Essential Tremor
Joana Jesus-Ribeiro1, António Freire, João Sargento-Freitas
1Department of Neurology, Centro Hospitalar e Universitário de Coimbra, University of Coimbra, Coimbra, Portugal.
Background:
The diagnosis of Parkinson's disease (PD) can sometimes be a challenge in the early stages of the disease. Both transcranial sonography (TCS) and DaTSCAN are recommended as auxiliary examinations for the differential diagnosis of PD; however, only few data exist regarding their diagnostic accuracy in the early stage of PD and essential tremor (ET).
Methods:
We evaluated patients with clinically suspected diagnosis of PD at early stages (Hoehn and Yahr ≤2) or ET. All patients underwent DaTSCAN and TCS with a maximum interval of 6 months. Final diagnosis was established after 1-year follow-up.
Results:
From the 63 patients recruited, 3 were excluded due to transcranial insonability and 2 for uncertain clinical diagnosis. The final clinical diagnosis was ET in 44.8% and PD in 55.2%. Compared to clinical diagnosis of PD, TCS had a sensitivity of 87.5% and specificity of 96.2%; DaTSCAN sensitivity was 84.4% and specificity was 96.2%. Both diagnostic tests demonstrated a substantial level of agreement (Cohen's kappa coefficient: 0.83, 95% CI 0.68-0.97, p < 0.001).
Conclusion:
TCS and DaTSCAN have similar diagnostic accuracy for the diagnosis of early stage PD versus ET.
