Posts Tagged noninvasive
A new meta-analysis of existing studies shows that a technique called repetitive transcranial magnetic stimulation might be a useful tool to help stroke survivors regain the ability to walk independently.
Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation technique; magnetic coils are placed on a person’s scalp, and short electromagnetic pulses are delivered to specific brain areas through the coil.
Although these pulses only cause an almost imperceptible “knocking or tapping” sensation for the patient undergoing the procedure, they reach into the brain, triggering electric currents that stimulate neurons.
rTMS has mainly been used to treat psychosis, depression, anxiety, and other mood disorders with a fair degree of success. In a recent study, more than one third of people living with auditory verbal hallucinations — a marker of schizophrenia — reported a reduction in their symptoms following the procedure.
But researchers have also been delving into the potential that the technique has for improving life after stroke. Four years ago, for instance, a team of researchers at The Ohio State University Wexner Medical Center in Columbus used rTMS to improve arm movement in people who had experienced a stroke, and more studies have explored this therapeutic potential since.
Now, a team of researchers — jointly led by Dr. Chengqi He, of Sichuan University in the People’s Republic of China, and Shasha Li, of Massachusetts General Hospital and Harvard Medical School, both in Boston, MA — set out to review these studies.
Dr. He and colleagues wanted to see if the technique improved motor skills for people who had stroke; to do so, the researchers examined the impact rTMS has on walking speed, balance, and other key factors for post-stroke rehabilitation.
The findings were published in the American Journal of Physical Medicine & Rehabilitation, the official journal of the Association of Academic Physiatrists.
rTMS ‘significantly improves walking speed’
Dr. He and team reviewed nine studies of rTMS — including five randomized controlled trials — which were published between 2012 and 2017.
The people who participated in these studies had either had an ischemic stroke — that is, a stroke caused by a blood clot in one of the brain’s arteries — or a hemorrhagic stroke — that is, one caused by bleeding within the brain.
Of the nine studies, six included data on the walking speed of 139 stroke survivors. The researchers carried out a pooled analysis of these studies, and the results revealed that rTMS “significantly improves walking speed.”
This improvement was greater among people who received stimulation on the same side of the brain that the stroke occurred. By contrast, those who received rTMS on the opposite side did not see any improvement.
Other key health outcomes for stroke survivors such as balance, motor function, or brain responsiveness did not show any improvement as a result of rTMS.
In the United States, it is estimated that almost 800,000 people annually have a stroke, which makes the condition a leading cause of long-term disability in the country. More than half of the seniors who survived a stroke have reduced mobility as a result.
Although the review shows that rTMS is a promising strategy for restoring independent walking, the authors say that more research is needed. Dr. He and colleagues conclude:
“Future studies with larger sample sizes and an adequate follow-up period are required to further investigate the effects of rTMS on lower limb function and its relationship with changes in cortical excitability with the help of functional neuroimaging techniques.”
[BLOG POST] Brain Computer Interfaces (That Translate Human Thought To Direct Action): Their Evolution And Future
In the last few years, we have read quite a bit about how technology has allowed our brain to control devices or objects around us without the use of limbs. (If you haven’t, you can read about some examples here, here, and here). Futurism.com, a great website that posts about how human potential can be maximized, has this infographic that explains the basics of Brain Computer Interfaces – the use of technology to translate human thoughts into machine commands. We are seeing the use of BCI more and more with prosthetic limbs but where does it end? Will we able to upload our memories straight from our brain to the cloud in the future? Sky is the limit when it comes to innovation through technology.
Read this infographic to know the types of Brain-Computer Interfaces, their origin, what they have in store for us in the future, and how they can bridge the gap between disabled and able-bodied. Text version of infographic is right below the image.
Imagine a world where machines can be controlled by thought alone. This is the promise of brain-computer interfaces (BCIs) – using computers to decode and translate human thoughts into machine commands. Here’s a look at the evolution of BCI technology, its current state, and future prospects.
Invasive: Signal-transmitting devices are implanted directly in the brain’s gray matter. This method produces the highest quality signals, but scar tissue build up can cause signal degradation.
Partially Invasive: Devices are implanted within the skull but not within the brain tissues. Produce higher quality signals than noninvasive techniques by circumventing the skull’s dampening effect on transmissions, and has less risk of scar tissue buildup.
Noninvasive: Involves simple wearables that register the EM transmissions of neurons, with no expensive or dangerous surgery needed. This technique is certainly easier, but suffers from poor resolution caused by the skull’s interference with signals.
A Short History of BCI
1924: German neuroscientist Hans Berger discovers neuroelectrical activity using electroencephalography (EEG).
1970: The Defense Advanced Research Projects Agency (DARPA) begins to explore the potential BCI applications of EEG technology.
1998: First brain implant produces high quality signals.
2005: A monkey’s brain is successfully used to control a robotic arm.
2014: Direct brain-to-brain communication achieved by transmitting EEG signals over the internet.
Types of Noninvasive BCI
- Eye movement and pupil size oscillation
- Magnetic resonance imaging and magnetoencephalography
Applications of BCI
- Direct mental control of prosthetic limbs.
- Neurogaming – interaction within video game and virtual reality environments without the need for clumsy interface.
- Synthetic telepathy – the establishment of a direct mental connection or communications pathway between minds.
- The use of BCI in tele-robotics will allow human operators to directly “link” with robotic machines. – granting us a new way to explore aliens worlds, handle dangerous materials, and perform remote surgery.
- A wealth of new possibilities for interfacing with computers opens up – including linking to the internet, uploading memories to the cloud, etc.
It will effectively erase the divide between the disabled and the able-bodied.
National Academy of Engineering, Techradar, Brain Vision UK, PLOS ONE
This infographic was originally posted on futurism.com.
Transcranial magnetic stimulation (TMS) is a noninvasive procedure that uses magnetic fields to stimulate nerve cells in the brain to improve symptoms of depression. TMS is typically used when other depression treatments haven’t been effective.
How it works
During a TMS session, an electromagnetic coil is placed against your scalp near your forehead. The electromagnet painlessly delivers a magnetic pulse that stimulates nerve cells in the region of your brain involved in mood control and depression. And it may activate regions of the brain that have decreased activity in people with depression.
Though the biology of why rTMS works isn’t completely understood, the stimulation appears to affect how this part of the brain is working, which in turn seems to ease depression symptoms and improve mood.
Treatment for depression involves delivering repetitive magnetic pulses, so it’s called repetitive TMS or rTMS.
Spasticity, Second Edition: Diagnosis and Management
Allison Brashear, MD
[ARTICLE] The feasibility of a brain-computer interface functional electrical stimulation system for the restoration of overground walking after paraplegia – Full text HTML
Background: Direct brain control of overground walking in those with paraplegia due to spinal cord injury (SCI) has not been achieved. Invasive brain-computer interfaces (BCIs) may provide a permanent solution to this problem by directly linking the brain to lower extremity prostheses. To justify the pursuit of such invasive systems, the feasibility of BCI controlled overground walking should first be established in a noninvasive manner. To accomplish this goal, we developed an electroencephalogram (EEG)-based BCI to control a functional electrical stimulation (FES) system for overground walking and assessed its performance in an individual with paraplegia due to SCI.
Methods: An individual with SCI (T6 AIS B) was recruited for the study and was trained to operate an EEG-based BCI system using an attempted walking/idling control strategy. He also underwent muscle reconditioning to facilitate standing and overground walking with a commercial FES system. Subsequently, the BCI and FES systems were integrated and the participant engaged in several real-time walking tests using the BCI-FES system. This was done in both a suspended, off-the-ground condition, and an overground walking condition. BCI states, gyroscope, laser distance meter, and video recording data were used to assess the BCI performance.
Results: During the course of 19 weeks, the participant performed 30 real-time, BCI-FES controlled overground walking tests, and demonstrated the ability to purposefully operate the BCI-FES system by following verbal cues. Based on the comparison between the ground truth and decoded BCI states, he achieved information transfer rates >3 bit/s and correlations >0.9. No adverse events directly related to the study were observed.
Conclusion: This proof-of-concept study demonstrates for the first time that restoring brain-controlled overground walking after paraplegia due to SCI is feasible. Further studies are warranted to establish the generalizability of these results in a population of individuals with paraplegia due to SCI. If this noninvasive system is successfully tested in population studies, the pursuit of permanent, invasive BCI walking prostheses may be justified. In addition, a simplified version of the current system may be explored as a noninvasive neurorehabilitative therapy in those with incomplete motor SCI.
[REVIEW] Transcranial Direct Current Stimulation: From Basic Research on Psychological Processes to Rehabilitation – Full Text PDF
Transcranial direct current stimulation (tDCS) is an “old/new” noninvasive brain modulation technique that has gained increasing popularity and relevance in psychology and neuroscience. The contemporary tDCS procedure is effective and painless. It was shown to modulate motor performance and several sensory and cognitive functions. It can be used to study cortical organization and clarify brain-behavior relationships.
Using tDCS for rehabilitation is a promising strategy, and numerous publications suggest that it can be used alone or combined to augment the outcomes of behavioral training and pharmacological interventions. Compared with other brain modulation techniques, it has the advantage of being noninvasive and safe, with easy and effective placebo controls. Its efficacy, low cost, and ease of use make tDCS a very convenient tool for researchers in developing countries.
This review introduces tDCS to a new audience and seeks to inspire future investigations in the field. We highlight work that illustrates the main concepts and applications of tDCS as a basic research and rehabilitation tool.