Objective: To evaluate the role of transcranial sonography (TCS) in discriminating between Parkinson’s disease (PD) patients with normal cognition (PDNC), mild cognitive impairment (PD-MCI) and dementia (PDD).

Background: Cognitive impairment and dementia are common in PD, however no stable marker of cognitive dysfunction is available. TCS can evaluate global and focal brain atrophy and has been widely used in the differential diagnosis of parkinsonism.

Methods: 179 consecutive PD patients were recruited in a two-center cross sectional study and underwent a standardized TCS protocol assessing the third ventricle’s width (IIIvw) and substantia nigra (SN) hyperechogenicity. All subjects were evaluated with an extensive motor and cognitive battery. The correlation between TCS measurements and motor/cognitive scores, group differences, and diagnostic power in discriminating between PDNC and PDD were calculated with Spearman correlation, Mann-Whitney U and Fisher’s Exact test, and ROC analyses, respectively.

Results: 179 PD patients entered the study (mean age 66.7 ± 8.8 years, mean disease duration 6.3 ± 4.3 years) and were classified as PDNC (n=109), PD-MCI (n=49) and PDD (n=21). IIIvw correlated with age and cognition, most significantly with tests assessing attentional and executive function (p<0.001) but also with memory and visuoconstructive abilities (p<0.01), and with language (p<0.05) while SN size (as sum of bilateral echogenic areas) did not. There was no correlation with disease duration, UPDRS III or H&Y stages. PDD patients had significantly wider IIIvw than PDNC (p=0.002) while no differences between PD-MCI and PDNC or PDD were observed. There were no group differences in SN size. ROC analyses resulted in age-related IIIvw cut-offs for the prediction of PDD (6.0 and 7.3 mm for subjects < and ≥ 70 years of age, respectively; AUC 0.74 and 0.65, respectively). These cut-offs significantly differentiated PDD from PDNC (p=0.001, OR 5.2, 95%CI 1.9-14.0) and from all patients without dementia (PDNC+PD-MCI; p=0.005, OR 4.0, 95%CI 1.6-10.3).

Conclusions: IIIvw showed a strong correlation with cognitive performance in all domains and is able to differentiate PDD patients from those without dementia with good diagnostic accuracy. Longitudinal studies are warranted to evaluate whether TCS could identify PD patients still without dementia at risk for a rapid cognitive decline.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/transcranial-sonography-and-cognitive-dysfunction-in-parkinsons-disease/