Power spectral density and coherence analysis of eye disease with and without visual hallucination


Neuroscience Letters, vol.740, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 740
  • Publication Date: 2021
  • Doi Number: 10.1016/j.neulet.2020.135444
  • Journal Name: Neuroscience Letters
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Animal Behavior Abstracts, BIOSIS, CAB Abstracts, Chemical Abstracts Core, EMBASE, MEDLINE, Veterinary Science Database
  • Keywords: Visual Hallucination, Charles Bonnet Syndrome, EEG
  • Istanbul Medipol University Affiliated: Yes


Objectives: Charles Bonnet Syndrome (CBS) is a rare clinical condition which has been defined as complex visual hallucinations (CVH) due to visual loss. This study investigated differences in the EEG power spectral density (PSD) and magnitude-squared coherences between patients with eye disease and hallucinations (VH+), and the control subjects with eye disease without hallucinations (VH-). Methods: 19 scalp channels EEG was recorded in four VH+ (CBS) and four VH- subjects during an eyes-closed resting condition. Artefact-free epochs were analyzed to obtain PSD values in the delta, theta, alpha1, alpha2, beta1, beta2 and gamma frequency bands. Coherence values were calculated through inter-hemispheric and intra-hemispheric electrodes pairs of interest. All subjects were performed with neuropsychological and behavioral assessments to evaluate cognitive functions. Results: The VH + group had increase PSD in theta, beta2 and gamma bands in central, parietal and occipital (O2) areas. The synchronicity was altered particularly in parietal and frontal-parietal regions especially at theta and alpha1 respectively. Conclusions: The aberrant activity in occipital and parietal regions suggest the mechanism of CBS. This is a major electrophysiological study of understanding CBS and visual hallucinations.