Effect of Age on Substantia Nigra Hyper-echogenicity in Parkinson's Disease Patients and Healthy Controls.

Substantia nigra (SN) hyper-echogenicity (SN+) describes an enlargement (>90th percentile) of the area of echogenicity at the anatomic site of the SN in the midbrain detected by transcranial sonography. This ultrasound sign has proven to be a valuable marker supporting the clinical diagnosis of Parkinson's disease (PD). Although there is considerable variation in the extent of echogenic signals at the anatomic site of the SN among PD patients, previous work suggests that SN+ is a stable marker throughout the course of the disease. The present study focused on two aspects: (i) determining whether SN+ values differ between the sides, mirroring the asymmetric character of the disease; and (ii) determining whether age has an influence on SN echogenicity. This cross-sectional study included 300 PD patients and 200 healthy controls. SN+ was measured planimetrically by transcranial sonography. Echogenicity was analyzed separately for onset and non-onset sides, with onset side defined as the SN contralateral to the side of the body that first manifested PD-related motor impairment. Age of the patients and healthy controls at study time was used for correlation. We found that the onset SN+ contralateral to the side of initial motor symptoms was on average 17.6% larger than its counterpart. However, we also found that contrary to the control group, where an increase in age was associated with an increase in size of SN+, age of PD patients was associated with a decline in size of the onset SN+. Furthermore, SN measured at the onset side of PD patients correlated significantly with patient age and Hoehn and Yahr stage, a scale that grades PD severity, although this was not the case for the non-onset side. The present study indicates that changes in SN echogenicity have a different dynamic depending on the onset side of the disease. The age at study time had a significantly negative effect on the size of onset SN+, the effect on the non-onset side was non-significant. We conclude that for appropriate PD analysis, onset SN+ is a more important marker than the average of both sides of SN. Furthermore, we found that among healthy controls, the size of SN+ increases with age.

Prevalence of depressive symptoms and their association with brainstem raphe echogenicity in patients with Parkinson's disease and non-PD controls.

Despite advances in diagnostics and clinical recognition, depressive symptoms in Parkinson's disease (PD) exceeding normal limits remain effectively untreated. In this study, we report on the prevalence and severity of depressive symptoms as well as their association with brainstem raphe echogenicity in patients with PD and non-PD controls. The study included 266 Estonian PD patients and 168 age- and education-matched controls. Demographic and clinical data was documented. Brainstem raphe (BR) was visualized by transcranial sonography (TCS). The prevalence of depressive symptoms in the patient sample was found to be significantly higher than in controls. BR echogenicity in both patients and controls was directly related to their total BDI score, although we found a significantly greater reduction of BR echogenicity in patients with PD and depressive symptoms compared to depressed non-PD controls. The present results corroborate the hypothesis that morphological alteration of the BR is involved in the pathogenesis of depressive disorders. TCS of BR could be used as a non-invasive biomarker to improve detection of depressive symptoms in early PD stages where clinicians may not recognize affective disturbances in the context of PD phenomena.

Substantia Nigra Hyperechogenicity: Validation of Transcranial Sonography for Parkinson Disease Diagnosis in a Large Estonian Cohort.

OBJECTIVES: Substantia nigra hyperechogenicity is a promising biomarker for Parkinson disease (PD). Substantia nigra hyperechogenicity has previously been established as a useful diagnostic criterion in several European and Asian patient cohorts. However, diagnostic cutoff values for substantia nigra hyperechogenicity remain unknown for most patient populations. This study validated the diagnostic accuracy of substantia nigra hyperechogenicity in a large cohort of patients with PD in Estonia. METHODS: The study included 300 patients with PD from Estonia, representing 10% of the national PD patient population, and 200 healthy control participants. To define the optimal cutoff value in the PD cohort, data from a single assessment versus repetitive assessments by transcranial sonography were compared. With the use of 3 repetitive assessments, the diagnostic accuracy of the data was measured. In addition, calculations for percentile values were used to define substantia nigra hyperechogenicity among controls. RESULTS: Our data showed that the multiassessment approach yielded higher diagnostic accuracy than a single assessment (P = .021). The highest diagnostic accuracy was achieved by using the measurement mean to define substantia nigra hyperechogenicity, which was 0.23 cm(2) (sensitivity, 88.7%; specificity, 92.2%), whereas single measurements detected PD with higher sensitivity (sensitivity, 93.2%; specificity, 85.1%). No significant difference was found between mean and median measurements (P= .18). CONCLUSIONS: This study indicates the diagnostic merit of transcranial sonography in PD diagnosis in an additional population and demonstrates that transcranial sonography of the substantia nigra is a relevant and useful diagnostic tool for patients with PD.