Jae Jung Lee1, Na-Young Shin2, Yoonju Lee3, Seung-Koo Lee4, Young H Sohn3, Phil Hyu Lee5. 1. Department of Neurology, Inje University College of Medicine, Ilsan Paik Hospital, Goyang, Republic of Korea. 2. Department of Radiology, Ewha Womans University College of Medicine, Seoul, Republic of Korea. 3. Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea. 4. Department of Radiology, Yonsei University College of Medicine, Seoul, Republic of Korea. 5. Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea. Electronic address: phisland@chol.net.
Abstract
OBJECTIVE: To explore the microstructural integrity of the optic nerve and its role as a cognitive predictor in patients with de novo Parkinson's disease (PD) using diffusion tensor image-based magnetic resonance scans. METHODS: We enrolled 82 patients with de novo PD, 36 patients with drug-induced parkinsonism (DIP), and 36 controls. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured on the mid-portion of the intraorbital optic nerve. Using a multivariate analysis of variance with repeated measures, longitudinal changes in cognitive subscores of a comprehensive neuropsychological test were evaluated in PD patients according to optic nerve integrity. RESULTS: The mean FA value in PD was significantly lower (0.552 ± 0.103, p < 0.001) than that in DIP (0.645 ± 0.099) or the controls (0.689 ± 0.089), whereas the mean ADC value was significantly higher in the PD group compared to the DIP or control group (p < 0.001). Optic nerve integrity was not associated with parkinsonian motor severity, striatal dopamine transporter activity, olfaction, or baseline cognitive performance in PD patents. In a longitudinal assessment of cognition in PD, the lower FA group showed significant decline in the performance of Clock Drawing Test (F = 3.39, p = 0.038), but no significant differences in the other cognitive subsets. CONCLUSION: This study demonstrated that microstructural integrity in the optic nerve was distorted in PD patients, and that this nerve integrity might act as a cognitive predictor of visuospatial dysfunction.
OBJECTIVE: To explore the microstructural integrity of the optic nerve and its role as a cognitive predictor in patients with de novo Parkinson's disease (PD) using diffusion tensor image-based magnetic resonance scans. METHODS: We enrolled 82 patients with de novo PD, 36 patients with drug-induced parkinsonism (DIP), and 36 controls. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured on the mid-portion of the intraorbital optic nerve. Using a multivariate analysis of variance with repeated measures, longitudinal changes in cognitive subscores of a comprehensive neuropsychological test were evaluated in PDpatients according to optic nerve integrity. RESULTS: The mean FA value in PD was significantly lower (0.552 ± 0.103, p < 0.001) than that in DIP (0.645 ± 0.099) or the controls (0.689 ± 0.089), whereas the mean ADC value was significantly higher in the PD group compared to the DIP or control group (p < 0.001). Optic nerve integrity was not associated with parkinsonian motor severity, striatal dopamine transporter activity, olfaction, or baseline cognitive performance in PD patents. In a longitudinal assessment of cognition in PD, the lower FA group showed significant decline in the performance of Clock Drawing Test (F = 3.39, p = 0.038), but no significant differences in the other cognitive subsets. CONCLUSION: This study demonstrated that microstructural integrity in the optic nerve was distorted in PDpatients, and that this nerve integrity might act as a cognitive predictor of visuospatial dysfunction.