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Description
Inherited Retinal Dystrophies (IRDs) are a group of genetically inherited disorders marked by the gradual degeneration of photoreceptors and leading to progressive vision loss. As retinal degeneration advances, compensatory changes may emerge across sensory, neural, motor, and psychological domains. The extent to which IRDs shape cortical responsiveness and the mechanisms underlying adaptive coping remain only partially understood. This study aims to investigate the adaptative mechanisms associated with IRDs through a multimodal approach.
A group of patients diagnosed with IRDs underwent a series of neurophysiological assessments through electroencephalography (EEG) and its combination with transcranial magnetic stimulation (TMS). Residual visual responsiveness was evaluated using steady-state visual evoked potentials (SSVEPs) induced by 12 Hz flickering high-contrast checkerboard stimuli. TMS-evoked potentials (TEPs), elicited by stimulating the left or right visual cortex while recording EEG, were used to assess cortical excitability and reactivity, with particular attention to both local responses and the propagation of activity across functionally connected brain networks.
Preliminary results revealed preserved but attenuated SSVEP responses in IRD patients, with altered scalp topographies, suggesting diminished signal strength and reduced spatial specificity. TMS-EEG data indicated altered evoked activity patterns following visual cortex stimulation, pointing to reorganization within the affected cortical circuits.
These findings suggest that the employed techniques are sensitive to residual cortical activity in visual areas, which appear to remain partially responsive despite peripheral degeneration and may be involved in compensatory neural dynamics. The observed plasticity highlights the brain’s capacity to adapt to sensory loss and underscores the importance of integrating neurophysiological assessments.
