Combined assessment of midbrain hyperechogenicity, hyposmia and motor asymmetry improves diagnostic accuracy in early Parkinson's disease

Evaluation of: Busse K, Heilmann R, Kleinschmidt S et al. Value of combined midbrain sonography, olfactory and motor function assessment in the differential diagnosis of early Parkinson's disease. I. Neurol. Neurosurg. Psychiatr. 83(4), 441-447 (2012). The differential diagnosis of Parkinsonian syndromes can be challenging, particularly in early disease stages, when overlapping clinical signs and symptoms may lead to erroneous classification. However, an early differentiation between Parkinson's disease (PD) and other diseases causing Parkinsonism is crucial for prognostic and therapeutic reasons and is essential for clinical research. In a recent study, Busse et al. investigated the diagnostic utility of a set of tests to improve diagnostic differentiation between PD, essential tremor and other Parkinsonian disorders. The authors studied a total of 632 patients divided into a retrospective (n = 517) and a prospective (n = 115) group. Diagnostic anchors were based on clinical criteria. Combining midbrain hyperechogenicity, hyposmia and motor asymmetry increased specificity and positive predictive value for diagnosis of PD up to 98% at the expense of sensitivity, whereas two features provided 91% sensitivity with 77% specificity. The results of this study further support the diagnostic utility of transcranial sonography in diagnosing PD.