Tiantan Hospital: Study on the mechanism of spinal cord stimulation

Scientific research has always been the leading force in the development of our department.
We have always adhered to clinical-oriented medical research.
The transformation and application of medical cutting-edge technologies has always been the top priority of our department
.

As early as 2010, our department has carried out research on wake-up procedures including Deep Brain Stimulation (DBS), Spinal Cord Stimulation (SCS), and Vagus Nerve Stimulation (VNS).

Adhere to clinically-oriented medical research, cutting-edge medical technology

 

 1.
Spinal cord electrical stimulation can change the frontal δ and γ band EEG activity in patients with microconsciousness

1.
Spinal cord electrical stimulation can change the frontal δ and γ band EEG activity in patients with microconsciousness

 

 

In this study, we included 11 microconscious patients undergoing chronic SCS treatment
.

Each patient underwent a total of six experiments with a treatment interval of at least two days

 

Figure 1 Experimental paradigm

Figure 1 Experimental paradigm

 

The EEG recorded in each patient's six experiments includes 10 minutes before stimulation, 20 minutes in the on-state, and 10 minutes after stimulation
.

Calculate relative spectral energy, coherence, coherence matrix SI value and bispectral coherence to evaluate changes in EEG

The results show that, under the stimulation of SCS at 5 Hz and 70 Hz, the relative spectral energy of the Gamma band in the frontal lobe region increases while the relative spectral energy of delta decreases
.

In addition, through the calculation of the coherence and the estimated value of S, it is found that the frontal lobe's delta and the synchronization of the Gamma band have also changed significantly

 

 

Figure 2 The relative relative spectral energy changes of Delta and Gamma of the frontal lobe before and after stimulation

Figure 2 The relative relative spectral energy changes of Delta and Gamma of the frontal lobe before and after stimulation

 

 

 

Figure 3 Delta-Gamma coherence changes of the frontal lobe before and after different stimulation frequencies

Figure 3 Delta-Gamma coherence changes of the frontal lobe before and after different stimulation frequencies

Figure 4 The Delta-Delta and Delta-Gamma bispectral coherence of the frontal lobe before and after different stimulation frequencies

Figure 4 The Delta-Delta and Delta-Gamma bispectral coherence of the frontal lobe before and after different stimulation frequencies

 

2.
Frontal lobe γ band (30–45 Hz) connectivity changes in microconscious patients receiving spinal cord electrical stimulation

2.
Frontal lobe γ band (30–45 Hz) connectivity changes in microconscious patients receiving spinal cord electrical stimulation

 Spinal cord electrical stimulation has been widely used clinically as an effective means of awakening consciousness, but its internal mechanism is still not completely clear.
This study further explored the effects of spinal cord electrical stimulation on patients with micro-consciousness after the previous study The influence of the brain network
.

 

 We insert the stimulation electrode into the epidural space of the cervical spine and place it at the C2-C4 level
.

The stimulation parameters are voltage 3V, pulse width 210μs, frequency 70HZ, and each stimulation lasts for 20 minutes

The results of the study directly indicate that SCS can effectively intervene in cortical γ activities.
Intervention measures include direct overall effects (changes in frontal-parietal and frontal-occipital connectivity and changes in brain network characteristics) and long-lasting local effects (frontal cortex).
Internal connectivity continues to change)
.

The above results provide further evidence to support the key role of the frontal cortex in the SCS effect

The key role of the frontal lobe region in changing the connectivity with SCS stimulation prompted us to propose the frontal cortex as a relay station in the SCS modulation pathway
.

SCS changes the frontal cortex through the thalamus-cortex connection, and then spreads to other areas through the connection with the cerebral cortex to affect the cerebral cortex

 

 

 

(A) The functional connectivity of the patient's gamma band before, during and after SCS stimulation
.

  

(B) The paired t-test was used to compare the functional connectivity of patients at different stages (On-SCS and Pre-SCS, Post-SCS and On-SCS, and Post-SCS and Pre-SCS)
.

The thick red arrow indicates a significant increase, the thin red arrow indicates no significant increase, and the blue arrow indicates a significant decrease
.
  

(C) The upper figure shows the electrode with a significant change in connectivity, and the lower figure shows the key electrode with a significant change in connectivity in the t-test (at least three electrodes with a significant change in connectivity are defined as key electrodes)
.
The red line indicates a significant increase in connectivity, and the blue line indicates a significant decrease in connectivity
.
Red dots indicate electrodes with significantly increased connectivity, and blue dots indicate electrodes with significantly reduced connectivity
.

3.
The effect of spinal cord stimulation interval on patients with impaired consciousness: a preliminary functional near-infrared brain imaging study

3.
The effect of spinal cord stimulation interval on patients with impaired consciousness: a preliminary functional near-infrared brain imaging study

 

 

 

Inter-stimulation interval (ISI) is the length of time to remain stationary after each stimulation cycle.
This parameter is to prevent excessive fatigue and continuous over-stimulation from causing damage to neurons
.
In fact, Huettel et al.
found in 2004 that the length of the interval between consecutive stimuli greatly affects the responsiveness and durability of neurons
.
Therefore, this study aims to study the effect of SCS stimulation interval on patients with impaired consciousness
.

We insert the stimulation electrode into the epidural space of the cervical spine and place it at the C2-C4 level
.
The stimulation parameters are voltage 1-5V, pulse width 210μs, frequency 70HZ, and each stimulation lasts 30s
.

According to three different settings for three experiments, each experiment is switched alternately and repeated four times
.
The stimulation interval ISI is 2min (short time), 3min (medium time) and 5min (long time)
.
The three different ISIs are displayed in pseudo-random order
.
Between each experiment, provide patients with a 30-minute rest time to avoid superimposing effects
.

 

 

 

Figure 5 Experimental paradigm

Figure 5 Experimental paradigm Figure 5 Experimental paradigm

   The results showed that during stimulation and 30s after stimulation, total hemoglobin (HbT) was significantly increased in the prefrontal cortex; while 30s after the stimulation was turned off, HbT returned to the baseline level; however, this phenomenon was not observed in the occipital cortex
.
Therefore, it is believed that short stimulation (30s) causes significant changes in cerebral blood volume, especially in the prefrontal cortex, which is an important area of ​​the consciousness system
.
By comparing the average of the first and last interval responses in each stage, it was found that a shorter ISI can improve blood volume in the prefrontal cortex, and it is more significant in patients with a good prognosis
.
The results of the study suggest that ISI may be an important factor affecting the prognosis of SCS, laying a foundation for further quantitative evaluation of the efficacy of neuromodulation
.

   

(Written by: Zhuang Yutong)

(Written by: Zhuang Yutong) Leave a message here