Author Of 1 Presentation
P0602 - Long-lasting effects of optic neuritis on anatomical and functional visual network patterns (ID 1326)
Abstract
Background
The brain's ability to adapt in response to damage is debated in multiple sclerosis (MS) literature. In a previous work, we have shown that following the acute damage caused to the visual system by an episode of optic neuritis (ON), the functional visual network experiences changes that are associated with the specific neurologic deficit, all within the limits of the underlying disease pathophysiology.
Objectives
To examine whether the changes associated with ON in the structural and functional networks, can still be discerned in progressive MS patients, even years after the acute insult.
Methods
Forty-eight progressive MS patients, with and without prior ON (MS-ON and MS-nON, respectively; nMS-ON = 21, nMS-nON = 27), underwent structural and functional magnetic resonance imaging (MRI), including diffusion tensor imaging (DTI) and resting state fMRI (RS-fMRI). Anatomical and functional visual networks were defined using 50 visual regions-of-interest. Data were analyzed using graph theory-based methods and weighted network metrics were extracted, including density, strength, global and local efficiency, and modularity.
Results
Preliminary results have shown that while no functional metrics were significantly different between the two groups, anatomical global efficiency and density were significantly higher for the MS-nON group, despite no significant difference in lesion load between the groups.
Conclusions
The anatomical networks of the MS-ON group appear to be more damaged than those of the MS-nON group, while the functional networks appear to function to the same degree. Anatomical connectivity seems influenced by the long- standing distal damage to the optic nerve, suggesting trans-synaptic effects. However, despite our previous study having shown possibly-adaptive functional changes in the visual network following acute ON, our current results suggest that even if the MS brain has the ability to respond and adapt to insult in the early stages of the disease, this ability is nullified in progressive patients.