Diffusion tensor and volumetric magnetic resonance imaging using an MR-compatible hand-induced robotic device suggests training-induced neuroplasticity in patients with chronic stroke

Abstract

Stroke is the third leading cause of mortality and a frequent cause of long-term adult impairment. Improved strategies to enhance motor function in individuals with chronic disability from stroke are thus required. Post-stroke therapy may improve rehabilitation and reduce long-term disability; however, objective methods for evaluating the specific impact of rehabilitation are rare. Brain imaging studies on patients with chronic stroke have shown evidence for reorganization of areas showing functional plasticity after a stroke. In this study, we hypothesized that brain mapping using a novel magnetic resonance (MR)-compatible hand device in conjunction with state-of-the-art magnetic resonance imaging (MRI) can serve as a novel biomarker for brain plasticity induced by rehabilitative motor training in patients with chronic stroke. This hypothesis is based on the premises that robotic devices, by stimulating brain plasticity, can assist in restoring movement compromised by stroke-induced pathological changes in the brain and that these changes can then be monitored by advanced MRI. We serially examined 15 healthy controls and 4 patients with chronic stroke. We employed a combination of diffusion tensor imaging (DTI) and volumetric MRI using a 3-tesla (3T) MRI system using a 12-channel Siemens Tim coil and a novel MR-compatible hand-induced robotic device. DTI data revealed that the number of fibers and the average tract length significantly increased after 8 weeks of hand training by 110% and 64%, respectively (p<0.001). New corticospinal tract (CST) fibers projecting progressively closer to the motor cortex appeared during training. Volumetric data analysis showed a statistically significant increase in the cortical thickness of the ventral postcentral gyrus areas of patients after training relative to pre-training cortical thickness (p<0.001). We suggest that rehabilitation is possible for a longer period of time after stroke than previously thought, showing that structural plasticity is possible even after 6 months due to retained neuroplasticity. Our study is an example of personalized medicine using advanced neuroimaging methods in conjunction with robotics in the molecular medicine era.

Changes in Structural Connectivity Following a Cognitive Intervention in Children With Traumatic Brain Injury

“…Conventional DTI has been found to be sensitive to WM alterations after training or intervention in both HC and various patient populations. 19 Training length varied widely, from 2 to 8 weeks 19,[52][53][54][55] to up to 3 to 6 months, 56,57 with posttraining functional improvement found in a number of domains, including reasoning, memory, and learning. Taken together, these studies suggest that short-term training is often practical and effective in triggering brain structural reorganization.…”

Muscle, functional and cognitive adaptations after flywheel resistance training in stroke patients: a pilot randomized controlled trial

“…Given that flywheel RE requires the trainee to accommodate to ECC overload, and acceleration and deceleration, this exercise paradigm would likely prompt substantial adaptations at the cortical level. Although the mechanisms dictating exercise-induced cognitive adaptations are largely unknown, the cortical neuroplasticity reported after RE training in individuals with stroke [ 23 ], and the higher activity in specific cortical areas induced by ECC-based RE [ 22 ] may play a role in such adaptations.…”

Capturing neuroplastic changes after bimanual intensive rehabilitation in children with unilateral spastic cerebral palsy: A combined DTI, TMS and fMRI pilot study

“…DTI measurements of CST dysgenesis are strongly related to the manual dexterity of a child with USCP ( Bleyenheuft, Grandin, Cosnard, Olivier, & Thonnard, 2007 ), but does not appear to be predictive of the potential for improvement in these children ( Friel, Kuo, Carmel, Rowny, & Gordon, 2014 ). DTI is also hypothesized to be sensitive to changes after motor learning in children with USCP since changes in DTI have been detected after learning in different contexts ( Imfeld, Oechslin, Meyer, Loenneker, & Jancke, 2009 ; Lazaridou et al, 2013 ; Li, Wang, Hu, Liang, & Chen, 2013 ).…”