@article{fd36674d-d2d5-4829-a181-ef7e77b19b58,
  abstract     = {{<p>IntroductionAlthough transcranial sonography (TCS) assessing hyperechogenic substantia nigra (SN+) as biomarker for Parkinsońs disease (PD) has been introduced elsewhere, the clinical relevance and accuracy in a Swedish population is still unknown.MethodsThis retrospective single-center study included 74 patients with predominantly early-stage parkinsonism at first visit who had been examined by TCS from 2013 to 2017 to determine the SN+ biomarker status in relation to PD, atypical parkinsonian disorders (APS), essential tremor (ET) and vascular/secondary/ unspecified parkinsonism, with the aim of long-term follow-up to confirm the clinical diagnosis. The cut-off value for SN+ was regarded as the 90 % percentile of SN echogenicity in a local healthy cohort (here, 0.23 cm2).ResultsIn 2024, the mean follow-up time was 95 months. Three patients (4 %) without transcranial bone were excluded. SN+ was found in 38/51 patients with finally diagnosed PD and 4/20 patients with other final clinical diagnoses (p &lt; 0.001). Sensitivity was moderate (75 %) whereas specificity and the positive predictive value were higher (80 % and 90 %, respectively). SN area measurements (most abnormal side) were significantly different in PD-patients compared to non-PD patients (n = 63; 0.28 ± 0.09 [95 % CI: 0.25–0.30] cm2 vs. 0.23 ± 0.10 [0.18–0.29] cm2, p 0.035).ConclusionAfter a follow-up of up to 8 years, to maximize diagnostic certainty, our findings support the use of TCS as a valuable add-on tool in PD diagnostics in a Swedish patient population, already in the early stage of disease but not for screening.</p>}},
  author       = {{Stiehm, M. and Nilsson, C. and Skogar and Walter, U.}},
  issn         = {{2590-1125}},
  keywords     = {{Essential tremor; Hyperechogenicity; Movement disorders; Parkinsonism; Parkinsońs disease; Substantia nigra; Transcranial sonography; Ultrasound}},
  language     = {{eng}},
  month        = {{01}},
  publisher    = {{Elsevier}},
  series       = {{Clinical Parkinsonism and Related Disorders}},
  title        = {{The diagnostic value of transcranial sonography in Swedish parkinsonism patients : A retrospective cohort study with long-term follow-up}},
  url          = {{http://dx.doi.org/10.1016/j.prdoa.2025.100411}},
  doi          = {{10.1016/j.prdoa.2025.100411}},
  volume       = {{13}},
  year         = {{2025}},
}