Brain computer interfaces for neurorehabilitation – its current status as a rehabilitation strategy post-stroke

Abstract

The idea of using brain computer interfaces (BCI) for rehabilitation emerged relatively recently. Basically, BCI for neurorehabilitation involves the recording and decoding of local brain signals generated by the patient, as he/her tries to perform a particular task (even if imperfect), or during a mental imagery task. The main objective is to promote the recruitment of selected brain areas involved and to facilitate neural plasticity. The recorded signal can be used in several ways: (i) to objectify and strengthen motor imagery-based training, by providing the patient feedback on the imagined motor task, for example, in a virtual environment; (ii) to generate a desired motor task via functional electrical stimulation or rehabilitative robotic orthoses attached to the patient's limb – encouraging and optimizing task execution as well as "closing" the disrupted sensorimotor loop by giving the patient the appropriate sensory feedback; (iii) to understand cerebral reorganizations after lesion, in order to influence or even quantify plasticity-induced changes in brain networks. For example, applying cerebral stimulation to re-equilibrate inter-hemispheric imbalance as shown by functional recording of brain activity during movement may help recovery. Its potential usefulness for a patient population has been demonstrated on various levels and its diverseness in interface applications makes it adaptable to a large population. The position and status of these very new rehabilitation systems should now be considered with respect to our current and more or less validated traditional methods, as well as in the light of the wide range of possible brain damage. The heterogeneity in post-damage expression inevitably complicates the decoding of brain signals and thus their use in pathological conditions, asking for controlled clinical trials.

After Stroke Movement Impairments: A Review of Current Technologies for Rehabilitation

“…Nowadays, a large toolbox of training-oriented rehabilitation techniques has been developed, which allows the increase of independence and quality of life of the patients and their families [39]. The recovery of function has been shown to depend on the intensity of therapy, repetition of specified-skilled movements directed toward the motor deficits and rewarded with performance-dependent feedback.…”

Development of a Non-invasive Brain Computer Interface for Neurorehabilitation

“…The main principle behind the use of BCI as a rehabilitation tool is that it can induce cortical plasticity by training through feedback [50], [51], [67]. When subjects are trained to operate a BCI system, visual or other sensory feedback is presented to subjects in real-time.…”

“…Clinicians can monitor the level of attention directed towards the different tasks and the level of inter-hemispheric balance, which is an indicator of stroke recovery [67].…”

Multiple Classifier System for Motor Imagery Task Classification

“…Brain plasticity is the capacity of the brain and the nervous system to reorganize its structure, functions, and connections in response to determined training [24]. This training can be based on the Hebbian learning principle, that asserts that two neurons or groups or neurons may reconnect if they are simultaneously activated, which can occur if they are connected to the same circuit of interconnected neurons [23].…”

“…The application of these systems has presented promising results [24]. Consequently, a functional BCI system for neurorehabilitation can be of primary importance to assist the recovery of the more than 9 million strokes survivors yearly in the world [25].…”