Time varying effective connectivity for describing brain network changes induced by a memory rehabilitation treatment

Abstract

In clinical practice, cognitive impairment is often observed after stroke. The efficacy of rehabilitative interventions is routinely assessed by means of a neuropsychological test battery. Nowadays, more evidences indicate that the neuroplasticity which occurs after stroke can be better understood by investigating changes in brain networks. In this study we applied advanced methodologies for effective connectivity estimation in combination with graph theory approach, to define EEG derived descriptors of brain networks underlying memory tasks. In particular, we proposed such descriptors to identify substrates of efficacy of a Brain-Computer Interface (BCI) controlled neurofeedback intervention to improve cognitive function after stroke. Electroencephalographic (EEG) data were collected from two stroke patients before and after a neurofeedback-based training for memory deficits. We show that the estimated brain connectivity indices were sensitive to different training intervention outcomes, thus suggesting an effective support to the neuropsychological assessment in the evaluation of the changes induced by the BCI-based cognitive rehabilitative intervention.

Neurofeedback as a Form of Cognitive Rehabilitation Therapy Following Stroke: A Systematic Review

“…Overall, study designs and NFT therapy and training protocols were diverse and heterogeneous in nature. Five of the interventions were case studies [41][42][43][44][45]. Three controlled trials were also included [6,46]; two were non-randomized and non-blinded (experiment 1 n = 32, experiment 2 n = 17) [6], and one was randomized but non-blinded (n = 27) [46].…”

“…15 days to 6 months post-stroke) [6,46]. One study included participants whom bordered the sub-acute/chronic phase [46], another included a sub-acute participant [44]. One study did not indicate time since stroke [44].…”

“…Individuals suffered from various lesions (see Table 1) and exhibited a number of cognitive deficits. NFT interventions directly targeted memory [6,41,44], emotional issues [41,43,45], concentration and distraction issues [41,43,45,46], fatigue and energy deficits [41,43], communication and speech deficits [41,42,45], visual perception deficits [45,46] and motivation [45]. Two patients complained of visual tracking deficits, [41,42] in addition to one of them suffering from tinnitus [41].…”

“…One study included participants whom bordered the sub-acute/chronic phase [46], another included a sub-acute participant [44]. One study did not indicate time since stroke [44]. Participants ranged from 20 to 70 years old [44].…”

“…One study did not indicate time since stroke [44]. Participants ranged from 20 to 70 years old [44]. Individuals suffered from various lesions (see Table 1) and exhibited a number of cognitive deficits.…”