Favaretto S, Walter U, Baracchini C, Pompanin S, Bussè C, Zorzi G, Ermani M, Cagnin A. Eur J Neurol. 2016 May 1. doi: 10.1111/ene.13028
Favaretto et al. explored in this study the diagnostic role of transcranial brain parenchyma sonography in detecting specific echogenic alterations of the substantia nigra (SN) in dementia with Lewy bodies (DLB) compared to Alzheimer’s disease (AD).
The authors studied overall 71 subjects with TCS: 22 patients with DLB, 28 with AD and 21 healthy elderly controls. Clinical signs/symptoms with respect to cognitive impairment, extrapyramidal signs, visual hallucinations, fluctuations and rapid eye movement sleep behaviour symptoms were investigated, while TCS assessed SN hyperechogenicity and symmetry.
Interestingly transcranial sonography revealed SN hyperechogenicity in 100% of DLB compared to 50% of AD and 30% of controls, while more than 50% of DLB presented a marked hyperechogenicity compared to only 10% of AD (P<0.0003). DLB had symmetrical SN enlargement, whereas AD were mostly asymmetrical (P = 0.015). A combination of SN echogenic area and asymmetry index had a sensitivity of 88.9% and a specificity of 81.2% in discriminating DLB from AD (positive predictive value 85.7%, negative predictive value 85.7%).
This study highlights the possible differential diagnostic role of transcranial brain parenchyma sonography in dementia with Lewy bodies.