Brain Injury Center

Application of Medicine-Engineering in the Rehabilitation of Traumatic Brain Injury-3

Posted on December 15, 2022

Traumatic brain injury (TBI) is gaining more attention because of its higher rates of morbidity and mortality. It is defined as a traumatic structural or physiological disruption of brain function, mainly caused by an external physical force. Though efforts for exploring therapeutic strategies for the rehabilitation of TBI have taken over the past few decades, there is still a lack of effective treatment for it, and the treatment of TBI is far from satisfactory. Meanwhile, the combination of medicine and engineering brings new rehabilitation methods to TBI patients.

Noninvasive Brain Stimulation (NIBS)

In the past few years, the extensive use of noninvasive brain stimulation (NIBS) technology has led to a significant development in our understanding of brain behavioral relationships. As a potential treatment for neurological and psychiatric diseases, including traumatic brain injury, it has also received extensive attention. NIBS mainly includes transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS).

Transcranial Direct Current Stimulation (tDCS)

Transcranial direct current stimulation (tDCS) is one method of NIBS. It can increase or decrease cortical excitability according to different polarities (anode or cathode), regulate synaptic plasticity through long-term inhibition or enhancement, and promote long-term functional recovery. It can provide a safe and noninvasive method for regulating neural excitability during neuro-rehabilitation.

The emergence of posttraumatic disorders of consciousness (DOC) increases the mortality of patients and restricts their rehabilitation. A double-blind RCT study has found that tDCS can effectively improve the consciousness disorder of the people with TBI.

The systematic review of transcranial direct current stimulation (tDCS) effects on the rehabilitation of traumatic brain injury (TBI) also supported that although tDCS has been used in clinical treatment, it still needs further improvement, and the after-effects of tDCS are mostly short lived.

The advantages and disadvantages of transcranial direct current stimulation (tDCS).

Advantages

Relative ease of use and good safety profile
A safe, noninvasive technique
Stimulation was well-tolerated
It is a painless, noninvasive, easily applied, and effective therapy.

Disadvantages

There is an ongoing debate about the precise neurophysiological processes that are stimulated by these techniques
They can only directly affect activity in cortical regions.
Did not focus on possible late-occurring side effects or side
Side effects might be caused by intensified use.
Lack of large-sample clinical trials.

Repeated Transcranial Magnetic Stimulation (rTMS)

rTMS is another non-invasion method to stimulate the human brain. It can influence brain plasticity and cortical reorganization through stimulation-induced changes in neuronal excitability, and the treatment effects of rTMS on cortical excitability depend on the stimulation parameters applied, including the stimulus intensity, frequency, and duration of stimulation.

The low-frequency rTMS (<1 Hz) applied at the motor threshold or slightly suprathreshold intensities result in a suppression of cortical excitability, and high-frequency (≥5 Hz) suprathreshold stimulation will lead to increased cortical excitability.

Disorders in memory and neural behavior are a common sequence of TBI. A study shows that low-field magnetic stimulation (LFMS) improved the cognitive and motor function of TBI mice significantly. The neuroprotective effect of LFMS may be achieved through the regulation of cellular prion protein (PrPc) and/or circadian rhythm-related proteins.

A case report found that rTMS could improve the neural activity, to regulate the neural activity, and/or to facilitate recovery in patients with disturbance of consciousness after TBI. Another study confirmed that high-frequency transcranial magnetic stimulation could reduce the pain scores of patients with TBI and improve quality of life. Headache is another common symptom after TBI; a study to test the effectiveness of rTMS in headache after TBI; the result indicated that rTMS can alleviate the headache symptom and provide a transient mood-enhancing benefit.

Although rTMS has been widely used in the rehabilitation of TBI, there are still a lot of areas that need to improve. There is evidence that rTMS may be led to adverse events such as seizure, so we should consider safety when we use it.

The advantages and disadvantages of Repeated Transcranial Magnetic Stimulation.