Epidemiology of psychosis in Parkinson's disease. Independent component analysis of fMRI group studies by self-organizing clustering. Neurology, 5, 331–342.Įsposito, F., Scarabino, T., Hyvarinen, A., Himberg, J., Formisano, E., Comani, S., Tedeschi, G., Goebel, R., Seifritz, E., & Di Salle, F. J., Fenelon, G., Stebbins, G., & Goetz, C. Repeated visual hallucinations in Parkinson's disease as disturbed external/internal perceptions: Focused review and a new integrative model. International Psychogeriatrics, 22, 984–994.ĭiederich, N. The neuropsychiatric inventory-clinician rating scale (NPI-C): Reliability and validity of a revised assessment of neuropsychiatric symptoms in dementia. E., Brodaty, H., Gazdag, G., Cummings, J., & Lyketsos, C. Neuroimage, 34, 177–194.ĭe Medeiros, K., Robert, P., Gauthier, S., Stella, F., Politis, A., Leoutsakos, J., Taragano, F., Kremer, J., Brugnolo, A., Porsteinsson, A. Classification of fMRI independent components using IC-fingerprints and support vector machine classifiers. Movement Disorders, 21, 1899–1907.ĭe Martino, F., Gentile, F., Esposito, F., Balsi, M., Di Salle, F., Goebel, R., & Formisano, E. Effects of rivastigmine in patients with and without visual hallucinations in dementia associated with Parkinson's disease. By using a method that does not need online self-report, we showed that VH in PD patients were associated with functional changes in associative visual cortices, possibly linked with strengthened stability of resting-state networks.īurn, D., Emre, M., McKeith, I., De Deyn, P. Interestingly, the stability of the default-mode network (DMN) was found positively correlated with VH severity (Spearman’s rho = 0.77, p = 0.05). Using a random-effects self-organizing-group ICA, we evidenced increased connectivity in visual networks concomitant to VH, encompassing V2, V3 and the fusiform gyri bilaterally. First, at the individual level, several VH-related components of interest were identified and integrated in a second-level analysis. The phenomenology of VH ranged from visual spots to distorting faces. Data were analyzed in reference to the two-step method, which consists in: (i) a data-driven analysis of per-hallucinatory fMRI data, and (ii) selection of the components of interest based on a post-fMRI interview. Patients were scanned during ON/OFF hallucinatory states and resting-state functional imaging (rs-fMRI) was performed. Patients with severe cognitive decline (MMSE<18) were excluded. Nine PD patients were enrolled because of their frequent and chronic VH (> 10/day). This study aimed to describe the patterns of brain functional changes when VH occur in PD patients. The mechanisms behind this invalidating non-motor symptom remain largely unknown, namely because it is extremely difficult to capture hallucination events.
With disease progression, patients with Parkinson’s disease (PD) may have chronic visual hallucinations (VH).