Deep brain stimulation improves electroencephalogram functional connectivity of patients with minimally conscious state

Abstract

Aim: Deep brain stimulation (DBS) is a potential neuromodulatory therapy that enhances recovery from disorders of consciousness, especially minimally conscious state (MCS). This study measured the effects of DBS on the brain and explored the underlying mechanisms of DBS on MCS. Methods: Nine patients with MCS were recruited for this study. The neuromodulation effects of 100 Hz DBS were explored via cross-control experiments. Coma Recovery Scale-Revised (CRS-R) and EEG were recorded, and corresponding functional connectivity and network parameters were calculated. Results: Our results showed that 100 Hz DBS could improve the functional connectivity of the whole, local and local-local brain regions, while no significant change in EEG functional connectivity was observed in sham DBS. The whole brain's network parameters (clustering coefficient, path length, and small world characteristic) were significantly improved. In addition, a significant increase in the CRS-R and functional connectivity of three MCS patients who received 100 Hz DBS for 6 months were observed. Conclusion:This study showed that DBS improved EEG functional connectivity and brain networks, indicating that the long-term use of DBS could improve the level of consciousness of MCS patients.

Dysfunctional connectivity as a neurophysiologic mechanism of disorders of consciousness: a systematic review

“…Several methods have been used to access functional connectivity after stimulation protocols. We can divide them into two categories: (a) non-invasive – which is transcranial magnetic stimulation (TMS), and (b) invasive: spinal cord stimulation (SCS) ( Bai et al, 2017 ), vagus nerve stimulation (VNS), and DBS ( Arnts et al, 2022 ; Dang et al, 2023 ).…”

Long-term functional outcomes improved with deep brain stimulation in patients with disorders of consciousness

“…On the contrary, continuous stimulation will lead to fatigue and decreased nerve excitability of patients, so we adopted the strategy of intermittent stimulation. According to our previous experience that based on several spinal cord stimulation clinical studies, we believe that 15 min on and 15 min off is a very effective strategy 29…”

“…According to our previous experience that based on several spinal cord stimulation clinical studies, we believe that 15 min on and 15 min off is a very effective strategy. 29 We also compared the CRS-R and GOS before and after the patients received DBS, and found that the behaviour and consciousness level of the patients have improved significantly. CRS-R is more detailed in the behavioural improvement among patients with DoC, while GOS is a more feasible score to assess whether the patient emerged from unconsciousness, and the effect of DBS in patients with DoC is consistent.…”

“…Periodic electrical stimulation was administered to the brains of patients. The main source of stimulation was monopolar with a frequency of 100 Hz, 120 μs and 1.0–4.0 V. Stimulation was provided continuously from 08:00 to 20:00 hours with a 15 min on/off cycle (15 mins on, 15 mins off) 29…”

“…The main source of stimulation was monopolar with a frequency of 100 Hz, 120 μs and 1.0-4.0 V. Stimulation was provided continuously from 08:00 to 20:00 hours with a 15 min on/off cycle (15 mins on, 15 mins off). 29 Statistical analysis SPSS V.25 (IBM), Prism V.8 (GraphPad Software, USA) and R V.4.2.1 (USA) were used for statistical analyses. The normality of data distribution was evaluated using the Kolmogorov-Smirnov test.…”