Optical coherence tomography to distinguish Parkinson disease versus supranuclear progressive palsy

Abstract

PurposeThe aim of the study was to examine patterns of peripapillary andretinal layer damage as a potential marker of neurodegeneration in Parkinson'sdisease (PD) compared to progressive supranuclear palsy (PSP) with 2 SD‐ OCTdevices.MethodsPeripapillary retinal nerve fiber layer (pRNFL), macular thickness (MT)and ganglion cell layer inner plexiform analysis (GCA) by Cirrus and pRNFL analysis and automaticsingle retinal layers macular segmentation by Spectralis were used to evaluate38 patients with PD and 15 patients with PSP.ResultsMean average and superior RNFL by Cirrus were thicker in PD compared to PSP (p = 0.001). The mean central, superior, supero‐temporal and infero‐temporal RNFL thicknesses by Spectralis were also significantly higher in PD compared to PSP (p < 0.05). Using Cirrus OCT, mean MT and all measurements by GCA were significantly higher in PD compared to PSP (p < 0.002). The AUC was larger for minimum GCIPL (0.912) than for average GCIPL thickness (0.850). A minimum GCIPL thickness cut‐off value of 69 μm, was able to differentiate PSP from PD (Sensitivity: 91.7%; Specificity: 72.7%). Minimum and average GCIPL thicknesses significantly correlated with Hoehn and Yahr score (p < 0.05), and with UPDRS (Unified Parkinson's Disease Rating Scale) (p < 0.005).ConclusionsThedifferential diagnosis of Parkinsonian disorders is clinical one and not alwayseasy, especially at the onset of disease. In thecurrent study, the minimum GCIPL thickness was the most sensitiveparameter to differentiate PD from PSP and it was significantly correlated withneurological score. These findings may facilitate the differential diagnosisand give insight into the degenerative processes of atypical parkinsonian syndromes.