Controlling a Prosthesis With a Brain-Computer Interface
A brain-computer interface (BCI) that uses surface scalp electrodes can help a patient control a lower-extremity prosthesis and thus improve his or her daily life, researchers reported.
A BCI allows a person to control a computer using his or her thoughts. The person is trained to use a specific thought such as flexing a knee for control. The thought generates electrical activity in the nerve cells and brainwaves. A chip can be implanted in the brain to monitor electrical activity, or electrodes can be placed on the scalp to monitor brainwaves. In people with paralysis or amputation, a BCI can help control the movement of muscles, limbs, and prosthetics.
"In general, using a prosthesis is an unnatural act that requires training [and] extra effort and can have a certain amount of awkwardness to it," said Douglas P. Murphy, MD, Associate Professor of Physical Medicine and Rehabilitation at Virginia Commonwealth University in Richmond. Dr. Murphy and colleagues sought to establish the feasibility of manipulating a prosthetic knee with a BCI. The use of a prosthesis can be difficult when climbing stairs or ramps, for example. The goal of all prosthetic research is to establish the same ease, comfort, and ability that the patient had with his or her natural leg, and controlling a prosthesis with thought is a big step in that direction, said Dr. Murphy.
Dr. Murphy's team worked with a person whose leg had been amputated above the knee (ie, a transfemoral amputee). Using surface scalp electrodes to transmit brainwave data to a computer software program, the participant learned how to activate a knee-unlocking switch through mental imaging. Surface scalp electrodes transmitted brainwave data to a software program that was keyed to activate the switch when the event-related desynchronization (ERD) in the EEG recording reached a certain threshold.
"In our first attempt at using BCI with a lower extremity prosthesis, we wanted to test a simple system before moving on to more complicated ones to test the feasibility of the concept," said Dr. Murphy. "Thus, we chose control of the simplest prosthetic knee, which is the manual locking knee. When locked, the knee is rigid and straight, and when unlocked, the knee swings freely. Someone with an above-knee amputation would have to physically unlock the knee to sit and could lock or unlock in standing or walking, depending on his or her needs. We were interested to see if our participant could literally think his way to unlocking his prosthetic."
The participant learned to activate the knee-unlocking switch on his prosthesis that turned on a motor and unlocked his prosthetic knee. He walked up and down parallel bars while demonstrating his ability to unlock the knee to swing his leg and to sit down. Throughout the study, the participant was able to successfully unlock his knee between 50% and 100% of the time, and he responded to a questionnaire about his reactions to using the BCI with his prosthesis.
"The ultimate goal of this research is to provide the individual with a prosthesis that more easily and more successfully meets his or her needs for movement and walking," said Dr. Murphy. "The system should be comfortable [and] easy to use and serve useful purposes. The patient's subjective experience should reflect these goals. Our subject gave a good example of how this system could help him. He likes to hike with his children. Sometimes he is carrying his daughter and coming down a hill. With BCI control, he could adjust his prosthesis for descending the hill easily. This is the type of daily life activity we believe can be improved with BCI."
Based on this study, the BCI-controlled prosthesis would give patients a hands-free system of control, as well as a prosthesis that is responsive to more of their needs and takes less energy to use in complex environments. This system is in the early stages of development, and research is continuing.
College Students Take Longer to Recover From a Concussion
College students take significantly more time to recover from a concussion than the general national average of seven to 14 days, investigators reported.
The Centers for Disease Control and Prevention estimates that between 1.6 million and 3.8 million concussions occur in the United States each year. On average, a person takes seven to 14 days to recover from a concussion. "This duration is in the pediatric and sports-specific populations, however. No prior study has evaluated the outcome of concussions in a collegiate student population," said Prakash Jayabalan, MD, PhD, Assistant Professor of Physical Medicine and Rehabilitation at Northwestern University Feinberg School of Medicine in Chicago. "This population is unique in that it is heterogeneous in individual sporting activity (varsity vs club sports vs recreational activity), and students can have relatively high academic demands placed on them.
"The pivotal consensus statement on concussion in sport from the Fourth International Conference on Concussions advocates for cognitive rest. Yet maintaining a period of cognitive rest in collegiate students is particularly challenging due to the academic rigors of their schooling. Therefore, our research team wanted to determine if recovery time for patients in a college setting is different from those people outside of that setting," said Dr. Jayabalan.
To answer this question, Dr. Jayabalan and colleagues reviewed the medical charts of 128 students who were seen for concussion during the 2014-2015 academic year. They included subjects aged 18 or older at evaluation and enrolled as full-time students. Subjects were diagnosed with a concussion using the consensus statement on Concussion in Sport from the Zurich Guidelines. The investigators excluded subjects not examined within the first seven days after injury, those who did not complain of concussion-related symptoms on initial examination, those who did not complete the Standardized Concussion Assessment Tool, and those who did not provide a specific date of injury or date of symptom resolution.
On average, the students were age 20, and the population was 53.1% female. Forty-four students were varsity athletes, 33 played club sports, 34 played recreational sports, and 17 did not engage in regular physical activity or did not report their activity level.
The average duration of concussion symptoms for all subjects was 17.89 days. Dr. Jayabalan's team found that varsity athletes experienced a shorter duration of concussion symptoms (mean, 11.5 days), compared with club athletes (mean, 18.61 days) and recreational athletes (mean, 22.59 days). This difference could result from the higher amount of medical support student athletes receive, said Dr. Jayabalan. Concussions that were related to sports were shorter in duration (mean, 14.96 days), compared with those that were sustained during nonsporting activity (mean, 21.75 days).
Female students took longer to recover, compared with men (20.79 days vs 14.60 days). People with seizure disorders or prior concussions were more likely to have symptoms that lasted longer than 28 days. Finally, graduate students took two weeks longer to recover, compared with undergraduates (31 days vs 16 days), although the number of graduate students with concussion was relatively small in this study.
"This is the first cross-sectional study reporting the outcome of concussions at a collegiate institution," said Dr. Jayabalan. University students who sustain a concussion need improved resources, he added. "The findings in our study highlight the difficulty in treating collegiate students with concussions, due to both the academic rigors of institutions and the differing needs of student populations. The study also provides insight into at-risk subsets of the student population. Factors such as level of sport, year in school, athlete versus nonathlete, premorbid conditions, and gender may affect outcome, and this needs to be an important consideration for the physician managing concussed college students."
As a next step, the research team plans to implement resources for students with concussion and assess their effect on recovery.
Day of Hospital Admission May Affect Outcome of Head Trauma
Older adults who are admitted to the hospital with head trauma during the weekend have a 14% increased risk of dying, compared with those admitted on a weekday, according to researchers.
Weekend hospital admission is associated with higher instances of death in cardiovascular emergencies and stroke, but the effect of weekend admissions on patients with head trauma is not well defined. Researchers from the University of Texas Southwestern Medical School, Johns Hopkins University School of Medicine, and the Johns Hopkins Bloomberg School of Public Health used data from the 2006, 2007, and 2008 Nationwide Inpatient Sample—a large, publicly available dataset that contains a sampling of data for seven million hospital stays each year—to determine whether older adults admitted to the hospital for head trauma during the weekend were at a higher mortality risk than those admitted during the week.
"Older adults are some of the most vulnerable members of our society, and multiple studies point to differences in outcomes for older adult patients. After seeing the weekend trend in other areas, we wanted to see if a similar pattern existed for older adult patients suffering traumatic head injuries," said Salman Hirani, MD, a second-year resident in the department of rehabilitation medicine at Icahn School of Medicine at Mount Sinai in New York City.
The team identified 38,675 patients with head injury in the sample who met their criteria, which included serious and severe head injuries, based on the Abbreviated Injury Scale (AIS). Individuals between ages 65 and 89 with head AIS equal to 3 or 4 and no other region score less than 3 were included. The researchers calculated Individual Charlson comorbidity scores and excluded individuals with missing mortality, sex, or insurance data. Dr. Hirani and colleagues used Wilcoxon rank sum and Student t-tests to compare demographics, length of stay, and total charges for weekday versus weekend admissions. The χ2 tests compared sex and head injury severity. The investigators used logistic regression to model mortality, adjusting for age, sex, injury severity, comorbidity, and insurance status.
From the initial group, the researchers identified 9,937 patients (25.6%) who were admitted during the weekend. The average age of patients admitted during the weekend and those admitted on weekdays was 78. Weekend patients had fewer additional injuries and coexisting diseases outside of head trauma, compared with those admitted during the week (mean Charlson, 1.07 vs 1.14). Weekend patients also had lower head injury severity (58.3% vs 60.8% of weekday patients had an AIS of 4). Weekend patients were also predominantly female, when compared with weekday patients (52% vs 50%).
The median length of stay in the hospital was one day shorter for weekend patients (four days vs five days), said Dr. Hirani. In addition, the investigators found no significant differences in the charges incurred during each patient's stay. The average charge for weekend patients was $27,128 per patient per stay, compared with $27,703 per patient per stay for weekday patients.
Where the groups differed was in the percentage of patients who did not survive their injuries. Proportional mortality was higher among weekend patients (9.3% vs 8.4%). After the researchers adjusted the data, weekend patients had a 14% increased risk of death, compared with weekday patients. For patients that survive their hospital stay, long term morbidity and functional capacity is not noted in the literature, said Dr. Hirani. Early rehabilitation intervention has been shown to reduce morbidity in such patients and could be critical for patients' long-term survival, he added.
"Overall, weekend patients were less severely injured, had fewer coexisting diseases and conditions, and generated the same amount of charges for their care as weekday patients, yet they experienced a greater likelihood of death," says Dr. Hirani. "While we are not sure of the exact reason for this [result], we can continue to investigate and encourage hospitals to take a look at their own outcomes in order to put into place policies that would improve survival for older adults with traumatic brain injuries. Ultimately, we know that Level I trauma centers do not exhibit this weekend effect. It may then be important for an older adult with a traumatic brain injury, especially those occurring over the weekend, to be admitted to or transferred to a Level I trauma center or a facility with full-time staffing around the clock, as these patients may require closer observation."
What Are the Long-Term Effects of Traumatic Brain Injury?
Many parents whose children have had a traumatic brain injury (TBI) want to know what their children will be like 10 years after the injury. Research is beginning to indicate answers to this question.
Investigators from Cincinnati Children's Hospital have conducted research on the long-term effects of TBI. They currently have data for an average of seven years after injury. Patients with mild to moderate brain injuries are two times more likely to have developed attention problems, and those with severe injuries are five times more likely to develop secondary ADHD. These researchers are also finding that the family environment influences the development of these attention problems.
Parenting and the home environment exert a powerful influence on recovery. Children with severe TBI in optimal environments may show few effects of their injuries, while children with milder injuries from disadvantaged or chaotic homes often demonstrate persistent problems, according to the data.
Early family response may be particularly important for long-term outcomes, suggesting that working to promote effective parenting may be an important early intervention. Certain skills that can affect social functioning, such as speed of information processing, inhibition, and reasoning, show greater long-term effects. Many children do well in the long term after brain injury, and most do not have across-the-board deficits.
More than 630,000 children and teenagers in the United States are treated in emergency rooms for TBI each year. But predictors of recovery following TBI are unclear. These environmental factors include family functioning, parenting practices, home environment, and socioeconomic status. Researchers at Cincinnati Children's hospital are working to identify genes that affect recovery after TBI and to understand how these genes may interact with environmental factors to influence recovery.
The investigators will be collecting salivary DNA samples from more than 330 children participating in the Approaches and Decisions in Acute Pediatric TBI Trial. The primary outcome will be global functioning at 3, 6, and 12 months post injury, and secondary outcomes will include a comprehensive assessment of cognitive and behavioral functioning at 12 months post injury. This project will provide information to inform individualized prognosis and treatment plans.