Complex network changes during a virtual reality rehabilitation protocol following stroke: a case study

Abstract

Stroke is one of the main causes of disabilities caused by injuries to the human central nervous system, yielding a wide range of mild to severe impairments that can compromise sensorimotor and cognitive functions. Although rehabilitation protocols may improve function of stroke survivors, patients often reach plateaus while undergoing therapy. Recently, virtual reality (VR) technologies have been paired with traditional rehabilitation aiming to improve function recovery after stroke. Aiming to better understand structural brain changes due to VR rehabilitation protocols, we modeled the brain as a graph and extracted three measures representing the network's topology: degree, clustering coefficient and betweenness centrality (BC). In this single case study, our results indicate that all metrics increased on the ipsilesional hemisphere, while remaining about the same at the contralesional site. Particularly, the number of functional connections increased in the lesion area overtime. In addition, the BC displayed the highest variations, and in brain regions related to the patient's cognitive and motor impairments; hence, we argue that this measure could be regarded as an indicative for brain plasticity mechanisms.

Effects of virtual reality-based motor rehabilitation: a systematic review of fMRI studies

“…The number of rehabilitation sessions was four in one study [33]; about 8-10 in five studies [29,35,36,48,53]; 15-18 in six studies [28,31,32,49,50,54]; 20-24 in six studies [27,30,34,47,52,57]; 36-40 in two studies [37,51]; and 65 in one study [38].…”

“…The frequency adopted was 2 d a week in two studies [33,34]; 3 d a week for four studies [32,37,49,54]; 4 d a week for four studies [29,36,48,53]; and 5 d a week for nine studies [27,28,31,38,47,[50][51][52]57]. Two studies did not mention the frequency [30,35].…”

“…The choice of keywords in this review was based on terms that best represented the topic of our interest. We also included two studies from our research group [33,34]. Out of the 50 collected manuscripts, 28 did not meet the eligibility criteria (see section 2.2) and were excluded.…”

“…• Thirteen with chronic patients: although the definition of the chronic phase as 6 months or longer accommodates all studies, there was a profile variation across chronic cohorts: 6 months or longer [27,29,30,53], 10 months [33,35], 1 year or more [32,52], 2 years [34], range of 1.2-4.8 years [28], and between 3 and 4 years [47,54]. • Four with subacute patients: subacute phase varied among studies from 9 to 85 d [36], up to 3 months [50], and from 1 to 6 months after stroke [31,51].…”

“…Although in many cases specific VR equipment has been developed for rehabilitation purposes (e.g. [27][28][29][30][31][32][33][34][35][36]), some researchers have adapted or directly used already existing off-the-shelf video games [37][38][39], which are usually lower cost and more accessible. In VR rehabilitation, the user receives real-time feedback regarding his/her interaction with the environment and objects within.…”