Virtual Physical Coupling of Two Lower-Limb Exoskeletons.

Physical interaction between individuals plays an important role in human motor learning and performance during shared tasks. Using robotic devices, researchers have studied the effects of dyadic haptic interaction mostly focusing on the upper-limb. Developing infrastructure that enables physical interactions between multiple individuals' lower limbs can extend the previous work and facilitate investigation of new dyadic lower-limb rehabilitation schemes. We designed a system to render haptic interactions between two users while they walk in multi-joint lower-limb exoskeletons. Specifically, we developed an infrastructure where desired interaction torques are commanded to the individual lower-limb exoskeletons based on the users' kinematics and the properties of the virtual coupling. In this pilot study, we demonstrated the capacity of the platform to render different haptic properties (e.g., soft and hard), different haptic connection types (e.g., bidirectional and unidirectional), and connections expressed in joint space and in task space. With haptic connection, dyads generated synchronized movement, and the difference between joint angles decreased as the virtual stiffness increased. This is the first study where multi-joint dyadic haptic interactions are created between lower-limb exoskeletons. This platform will be used to investigate effects of haptic interaction on motor learning and task performance during walking, a complex and meaningful task for gait rehabilitation.

Haptic Human-Human Interaction During an Ankle Tracking Task: Effects of Virtual Connection Stiffness.

While treating sensorimotor impairments, a therapist may provide physical assistance by guiding their patient's limb to teach a desired movement. In this scenario, a key aspect is the compliance of the interaction, as the therapist can provide subtle cues or impose a movement as demonstration. One approach to studying these interactions involves haptically connecting two individuals through robotic interfaces. Upper-limb studies have shown that pairs of connected individuals estimate one another's goals during tracking tasks by exchanging haptic information, resulting in improved performance dependent on the ability of one's partner and the stiffness of the virtual connection. In this study, our goal was to investigate whether these findings generalize to the lower limb during an ankle tracking task. Pairs of healthy participants (i.e., dyads) independently tracked target trajectories with and without connections rendered between two ankle robots. We tested the effects of connection stiffness as well as visual noise to manipulate the correlation of tracking errors between partners. In our analysis, we compared changes in task performance across conditions while tracking with and without the connection. We found that tracking improvements while connected increased with connection stiffness, favoring the worse partner in the dyad during hard connections. We modeled the interaction as three springs in series, considering the stiffness of the connection and each partners' ankle, to show that improvements were likely due to a cancellation of random tracking errors between partners. These results suggest a simplified mechanism of improvements compared to what has been reported during upper-limb dyadic tracking.

Effect of Dyadic Haptic Collaboration on Ankle Motor Learning and Task Performance.

Optimizing skill acquisition during novel motor tasks and regaining lost motor functions have been the interest of many researchers over the past few decades. One approach shown to accelerate motor learning involves haptically coupling two individuals through robotic interfaces. Studies have shown that an individual's solo performance during upper-limb tracking tasks may improve after haptically-coupled training with a partner. In this study, our goal was to investigate whether these findings can be translated to lower-limb motor tasks, more specifically, during an ankle position tracking task. Using one-degree-of-freedom ankle movements, pairs of participants (i.e., dyads) tracked target trajectories independently. Participants alternated between tracking trials with and without haptic coupling, achieved by rendering a virtual spring between two ankle rehabilitation robots. In our analysis, we compared changes in task performance across trials while training with and without haptic coupling. The tracking performance of both individuals (i.e., dyadic task performance) improved during haptic coupling, which was likely due to averaging of random errors of the dyadic pair during tracking. However, we found that dyadic haptic coupling did not lead to faster individual learning for the tracking task. These results suggest that haptic coupling between unimpaired individuals may not be an effective method of training ankle movements during a simple, one-degree-of-freedom task.

A versatile system for neuromuscular stimulation and recording in the mouse model using a lightweight magnetically coupled headmount.

Neural stimulation and recording in rodents are common methods to better understand the nervous system and improve the quality of life of individuals who are suffering from neurological disorders (e.g., epilepsy), as well as for permanent reduction of chronic pain in patients with neuropathic pain and spinal-cord injury. This method requires a neural interface (e.g., a headmount) to couple the implanted neural device with instrumentation system. The size and the total weight of such headmounts should be designed in a way to minimize its effect on the movement of the animal. This is a crucial factor in gait, kinematic, and behavioral neuroscience studies of freely moving mice. Here we introduce a lightweight 'snap-in' electro-magnetic headmount that is extremely small, and uses strong neodymium magnetics to enable a reliable connection without sacrificing the lightweight of the device. Additionally, the headmount requires minimal surgical intervention during the implantation, resulting in minimal tissue damage. The device has demonstrated itself to be robust, and successfully provided direct electrical stimulation of nerve and electrical muscle stimulation and recording, as well as powering implanted LEDs for optogenetic use scenarios.

EEG hyperscanning in motor rehabilitation: a position paper.

Studying the human brain during interpersonal interaction allows us to answer many questions related to motor control and cognition. For instance, what happens in the brain when two people walking side by side begin to change their gait and match cadences? Adapted from the neuroimaging techniques used in single-brain measurements, hyperscanning (HS) is a technique used to measure brain activity from two or more individuals simultaneously. Thus far, HS has primarily focused on healthy participants during social interactions in order to characterize inter-brain dynamics. Here, we advocate for expanding the use of this electroencephalography hyperscanning (EEG-HS) technique to rehabilitation paradigms in individuals with neurological diagnoses, namely stroke, spinal cord injury (SCI), Parkinson's disease (PD), and traumatic brain injury (TBI). We claim that EEG-HS in patient populations with impaired motor function is particularly relevant and could provide additional insight on neural dynamics, optimizing rehabilitation strategies for each individual patient. In addition, we discuss future technologies related to EEG-HS that could be developed for use in the clinic as well as technical limitations to be considered in these proposed settings.

Children With Unilateral Cerebral Palsy Utilize More Cortical Resources for Similar Motor Output During Treadmill Gait.

Children with unilateral cerebral palsy (CP) walk independently although with an asymmetrical, more poorly coordinated pattern compared to their peers. While gait biomechanics in unilateral CP and their alteration from those without CP have been well documented, cortical mechanisms underlying gait remain inadequately understood. To the best of our knowledge, this is the first study utilizing electroencephalography (EEG) during treadmill gait in older children with and without CP. Lower limb surface electromyographic (EMG) data were collected and muscle synergy analyses performed to quantify motor output. Our primary goal was to evaluate the relationships between cortical and muscle activation within and across groups and hemispheres to provide novel insights into neural control of gait and how it may be disrupted by an early unilateral brain injury. Participants included 9 children with unilateral CP, mean age 16.0 ± 2.7 years, and 12 with typical development (TD), mean age 14.8 ± 3.0 years. EEG data were collected during a standing baseline and treadmill walking at self-selected speed. EMG of 16 lower limb muscles were also collected bilaterally and synchronized with EEG. No significant group differences were found in synergy number or structure across groups. Six cortical clusters were identified as having gait-related activation and all contained participants from both CP and TD groups; however, the percent of individuals per group appearing in different clusters varied. Notably, the cluster least represented in CP was the non-dominant motor region. Both groups showed mu-band ERD in the motor clusters during gait although sustained beta-band ERD was not evident in TD. The CP group showed greater cortical activation than TD during walking as measured by mu- and beta-ERD in the dominant and non-dominant motor and parietal regions and elevated low gamma-activity in the frontal and parietal areas, a unique finding in CP. CP showed greater bilateral motor EEG-EMG coherence in the gamma-band with the hallucis longus compared to TD. In summary, individuals with CP display increased cortical activation during gait possibly relating to differences in distal motor control of the more affected side. Strategies that iteratively reduce cortical activation while improving selective motor control are needed in CP.

Validation of Practical Tools to Identify Walking Cadence to Reach Moderate Intensity.

It is recommended that adults get at minimum 150 minutes of moderate-to-vigorous physical activity in bouts of 10 minutes or greater every week. Walking cadence (steps per minute) is one easy way to estimate intensity required, however tools that claim to quantify walking intensity via walking cadence have not been validated in adults. We aimed to validate: 1- the accuracy of walking cadence measurement by the Piezo RxD pedometer, Polar Stride Sensor Bluetooth Smart foot pod, and Garmin Ant+ foot pod at different speeds and slopes and 2- the ability of the Piezo RxD to identify bouts of walking at moderate intensity using walking cadence. Inclusion criteria included being aged 19+ and the ability to reach moderate intensity when walking without incline as determined by a treadmill cardiorespiratory fitness test to determine 40% of VO2 reserve. Walking cadence measured from the three tools was compared to a manual count of walking cadence during a series of walking stages at several speeds (2.5-5.5 km/h) and inclines (0-15%). The ability of the Piezo RxD to quantify a 10-minute bout was determined by walking for 12 minutes at 40% of VO2 reserve measured by indirect calorimetry. All correlations between manual walking cadence counts and all devices were significant regardless of speed (r ranging from 0.469 to 0.999; p ≤ 0.05) and slope (r ranging from 0.887 to 0.996; p ≤ 0.05). The Piezo RxD was able to correctly measure a 10-minute bout of walking at moderate intensity for 50 of 51 participants. We found that all walking cadence devices provided accurate measurements of walking cadence. The Piezo RxD is an effective tool to quantify bouts of walking done at a minimum of moderate intensity.

Testing Bioimpedance to Estimate Body Fat Percentage across Different Hip and Waist Circumferences.

Many studies have validated the use of bioimpedance analysis (BIA) to quantify body fat percentage (BF%). However, it is unknown if some model types (i.e., hand to hand, foot to foot, and hand to foot) are differing in their validity depending on hip and waist circumferences. The purpose of this study was to compare the difference in BF% between three BIA models (i.e., hand to hand, foot to foot, and hand to foot) against the Bod Pod across different hip and waist circumferences. A total of 92 people aged 19-72 years were recruited in this study. After following the pretesting procedures recommended for BIA measures, BF% was estimated using three BIA models and the Bod Pod. Hip and waist circumferences were obtained using standard procedures and tertiles were computed. The Bland-Altman was plotted and 1-sample T-test as well as correlation between the average measure and the difference between the two measures was tested. Within the entire sample, across all BIA models, the Bland-Altman analysis showed significant difference compared to 0 and a significant difference for the proportional. However, when stratified by tertiles, the two measurements were only significant for the highest tertiles of hip and waist for all BIA apparatus (all p <0.01) and the proportional bias was nonsignificant for all tertiles and across all BIA apparatus. For the highest tertile of waist and hip, the average difference was between 1.67% and 3.29% compared with the Bod Pod estimation. In conclusion, the three BIA models offer a BF% measurement agreeing with the estimation obtained with the Bod Pod with the exception of people having a greater waist or greater hip.

Matlab software for impedance spectroscopy designed for neuroscience applications.

BACKGROUND: Metal electrodes are a mainstay of neuroscience. Characterization of the electrical impedance properties of these cuffs is important to ensure successful and repeatable fabrication, achieve a target impedance, revise novel designs, and quantify the success or failure of implantation and any potential subsequent damage or encapsulation by scar tissue. NEW METHODS: Impedances are frequently characterized using lumped-parameter circuit models of the electrode-electrolyte interface. Open-source tools to gather and analyze these frequency sweep data are lacking. Here, we present such software, in the form of Matlab code, which includes a GUI. It automatically acquires frequency sweep data and subsequently fits a simplified Randles model to these data, over a user specified frequency range, providing the user with the model parameter estimates. Also, it can measure an unknown impedance of an element over a range of frequencies, as long as an external resistor can be added for the measurements. RESULTS: The tool was tested on five bright platinum nerve cuffs in vitro. The average charge transfer resistance, solution resistance, CPE value, and impedance magnitude were estimated. COMPARISON TO EXISTING METHODS: The measured values of the impedance of cuffs were in agreement with the literature (Wei and Grill, 2009). Variation between cuffs fabricated as consistently as possible amounted to 10% for impedance magnitude and 4° for impedance phase. CONCLUSION: The results show that this low-cost tool can be used to characterize a cuff across different conditions including after implantation. The latter makes it useful for a longer-term study of electrode viability.

Esophageal Cancer.

Esophageal cancer has a poor prognosis and high mortality rate, with an estimated 16,910 new cases and 15,910 deaths projected in 2016 in the United States. Squamous cell carcinoma and adenocarcinoma account for more than 95% of esophageal cancers. Squamous cell carcinoma is more common in nonindustrialized countries, and important risk factors include smoking, alcohol use, and achalasia. Adenocarcinoma is the predominant esophageal cancer in developed nations, and important risk factors include chronic gastroesophageal reflux disease, obesity, and smoking. Dysphagia alone or with unintentional weight loss is the most common presenting symptom, although esophageal cancer is often asymptomatic in early stages. Physicians should have a low threshold for evaluation with endoscopy if any symptoms are present. If cancer is confirmed, integrated positron emission tomography and computed tomography should be used for initial staging. If no distant metastases are found, endoscopic ultrasonography should be performed to determine tumor depth and evaluate for nodal involvement. Localized tumors can be treated with endoscopic mucosal resection, whereas regional tumors are treated with esophagectomy, neoadjuvant chemotherapy, chemoradiotherapy, or a combination of modalities. Nonresectable tumors or tumors with distant metastases are treated with palliative interventions. Specific prevention strategies have not been proven, and there are no recommendations for esophageal cancer screening.

Colorectal cancer screening and surveillance.

Colorectal cancer is the third most common cancer in men and women. The incidence and mortality rate of the disease have been declining over the past two decades because of early detection and treatment. Screening in persons at average risk should begin at 50 years of age; the U.S. Preventive Services Task Force recommends against routine screening after 75 years of age. Options for screening include high-sensitivity fecal occult blood testing annually, flexible sigmoidoscopy every five years with high-sensitivity fecal occult blood testing every three years, or colonoscopy every 10 years. In 2012, the U.S. Multi-Society Task Force on Colorectal Cancer updated its surveillance guidelines to promote the appropriate use of colonoscopy resources and reduce harms from delayed or unnecessary procedures; these guidelines provide recommendations for when to repeat colonoscopy based on findings. Adenomatous and serrated polyps have malignant potential and warrant early surveillance colonoscopy. Patients with one or two tubular adenomas that are smaller than 10 mm should have a repeat colonoscopy in five to 10 years. Repeat colonoscopy at five years is recommended for patients with nondysplastic serrated polyps that are smaller than 10 mm. Patients with three to 10 adenomas found during a single colonoscopy, an adenoma or serrated polyp that is 10 mm or larger, an adenoma with villous features or high-grade dysplasia, a sessile serrated polyp with cytologic dysplasia, or a traditional serrated adenoma are at increased risk of developing advanced neoplasia during surveillance and should have a repeat colonoscopy in three years. More than 10 synchronous adenomas warrant surveillance colonoscopy in less than three years. Colonoscopy may be repeated in 10 years if distal, small (less than 10 mm) hyperplastic polyps are the only finding.

Iron deficiency anemia: evaluation and management.

Iron deficiency is the most common nutritional disorder worldwide and accounts for approximately one-half of anemia cases. The diagnosis of iron deficiency anemia is confirmed by the findings of low iron stores and a hemoglobin level two standard deviations below normal. Women should be screened during pregnancy, and children screened at one year of age. Supplemental iron may be given initially, followed by further workup if the patient is not responsive to therapy. Men and postmenopausal women should not be screened, but should be evaluated with gastrointestinal endoscopy if diagnosed with iron deficiency anemia. The underlying cause should be treated, and oral iron therapy can be initiated to replenish iron stores. Parenteral therapy may be used in patients who cannot tolerate or absorb oral preparations.

Results from a transitional-year program director survey: identifying crucial issues and concerns.

BACKGROUND: Transitional Year (TY) programs meet an important need by preparing residents for specialties that accept individuals after an initial preparatory year. To our knowledge, no surveys to date have been conducted to identify attributes of TY programs and concerns of TY program directors. PURPOSE: The purpose of this study was to review TY program characteristics and identify critical issues and concerns of TY program directors (TYPDs). METHODS: A web-based, 22-question survey was sent to all 114 TYPDs of programs accredited by the Accreditation Council for Graduate Medical Education between January and April 2011. The survey included open-formatted and closed-formatted questions addressing program and institution demographics, program director time, administrative support, satisfaction, and future plans. RESULTS: The survey response rate was 86%. The median age of TY programs was 28 years, with few new programs. More than 80% of TY programs were conducted at community hospitals and university-affiliated community hospitals. Of the responding TYPDs, 17% had served less than 2 years, and 32% had served 10 years or more. Common sponsoring TY programs included internal medicine (88%), general surgery (42%), family medicine (25%), emergency medicine (24%), and pediatrics (18%). Overall, TYPDs were satisfied with their positions. They expressed concerns about inadequate time to complete duties, salary support, and administrative duties assigned to program coordinators. Forty-nine percent of TYPDs reported they planned to leave the position within the next 5 years. CONCLUSIONS: Our survey provides useful information to assist institutions and the graduate medical education community in meeting the needs of TYPDs and strengthening TY programs.

Colonoscopy by a family physician: detecting proximal neoplasia in asymptomatic adults.

PURPOSE: Flexible sigmoidoscopy (FS) is considered an adequate screening test in average risk (AR) patients. The purpose of this study was to determine the diagnostic yield of FS in detecting colonic neoplasia between AR and high risk (HR) patients. METHODS: We present a chart review of 559 outpatient colonoscopies performed by a family physician from September 2003 to October 2007. The prevalence of neoplasia and diagnostic yield of FS was compared between groups. RESULTS: The overall prevalence of neoplasia was 23.1% (AR) and 32.8% (HR); p = 0.02. The prevalence of proximal neoplasia not detectable by FS was 10.2% (AR) and 14.5% (HR); p = 0.16. The diagnostic yield of FS in each group was 56%; FS would have missed 44% of polyps regardless of patient risk. CONCLUSIONS: The high rate of colonic neoplasia not detected by FS (44%) suggests that FS alone is inadequate for screening in AR patients.

Patient satisfaction with family physician colonoscopists.

PURPOSE: assessing patient satisfaction after endoscopy with a standardized survey is recommended by gastrointestinal professional societies. The purpose of this study was to assess both patient satisfaction with colonoscopy performed by family physicians and physicians' technical competence in colonoscopy. METHODS: modified Group Health Association of America 9 surveys were sent to all 230 patients who received a colonoscopy by family physicians at Madigan Army Medical Center from June to December 2007. Responses were graded on a 5-point Likert scale (LS), with a score of ≥ 3 (good to excellent) defined as a favorable response. Procedure reports and medical records were reviewed for all patients, and selected quality indicators were compared with recommended colonoscopy standards. RESULTS: sixty-nine percent of patients responded: 85 men (54%; mean age ± SD, 54.9 ± 5.6 years) and 73 women (46%; mean age ± SD, 54.3 ± 4.3 years). The overall rating of the visit received a favorable response rate of 98% (average LS rating, 4.6). Nearly all patients said they would have the procedure repeated by the same physician (98%) and at the same facility (98%). The overall reach-the-cecum rate was 100%. Adenomas were detected in 22% of women and 36% of men. All polyps measuring <2 cm were removed, and 99% of the procedures had scope withdrawal times of at least 6 minutes. Hemostasis techniques were used for 2 patients after polypectomy. There were no perforations. CONCLUSION: family physicians can perform colonoscopy with a high level of accuracy, safety, and patient satisfaction.

Using a simulated surgical skills station to assess laceration management by surgical and nonsurgical residents.

OBJECTIVE: To assess laceration management performance among surgical and nonsurgical postgraduate year-1 (PGY-1) residents objectively and to test for interval improvement. METHODS: From 2006 to 2008, 106 PGY-1 residents from 10 medical specialties were evaluated with a simulated surgical skills station using pigs' feet before and after internship. Subjects were given 11 minutes to choose the proper suture, prepare and close the wound, and answer laceration management questions. Trainees were classified as surgical (emergency medicine, general surgery, obstetrics and gynecology, orthopedics, and otolaryngology) and nonsurgical (family medicine, internal medicine, neurology, pediatrics, and transitional year). An objective checklist was used to assess performance. RESULTS: A total of 106 PGY-1 residents (age range, 25-44 years; mean, 28.7 years) participated, consisting of 41 surgical (39%) and 65 nonsurgical residents (61%). Surgical group scores improved from 78.4% to 87.7% (P < .001). Nonsurgical scores improved from 67.2% to 73.1% (P < .001). There was similar improvement between groups (surgical, 9.4%; nonsurgical, 5.9%; P  =  .21). Surgical residents outscored nonsurgical residents before (P < .001) and after (P < .001) internship. CONCLUSION: Surgical residents outperformed nonsurgical residents before and after the PGY-1 year with similar score improvements. A simulated surgical skills station can be used to evaluate procedure performance objectively and to test for interval improvement. A simulated surgical skills station may serve as a useful adjunct to apprenticeship in assessing procedure competence.

Transfusion medicine knowledge in Postgraduate Year 1 residents.

BACKGROUND: Transfusion medicine is a complex important subspecialty of pathology. A transfusion carries measurable risks and benefits. Although fellowship training exists in transfusion medicine, the majority of transfusion decisions are made by clinicians without formal training. STUDY DESIGN AND METHODS: A total of 116 recently graduated medical students entering 10 residency programs at a single medical center over 2 years were evaluated using a standardized patient encounter to determine baseline knowledge. Transfusion medicine knowledge was assessed during the encounter by obtaining verbal consent for red blood cell transfusion, answering patient questions, and completing a written quiz. Final performance was scored using a peer-reviewed data collection sheet. RESULTS: Scores ranged from 24.0% to 67.1%. Postgraduate Year 1 (PGY-1) residents graduating from allopathic medical schools had higher scores than those from osteopathic schools (mean, 41.3% vs. 37.5%; p = 0.036). There was no significant difference between PGY-1 residents entering primary care versus surgical specialties (38.2% and 41.6%; p = 0.10). Although not significant, PGY-1 residents with previous transfusion medicine education demonstrated a trend toward better performance than those without prior education (47.0% vs. 43.0%; p = 0.057). A total of 17.2% of PGY-1's could define transfusion-related acute lung injury, 6.0% knew the transfusion transmission rate of human immunodeficiency virus, 5.2% knew the transfusion transmission rate of hepatitis C virus, and 0% knew the indication for blood product irradiation. CONCLUSIONS: Marked knowledge deficits in transfusion medicine were noted. If the results of this study could be reproduced at other training institutions, medical schools may be willing to donate more resources into transfusion medicine education.

Acute coronary syndrome and cardiac arrest: using simulation to assess resident performance and program outcomes.

BACKGROUND: Simulation training has emerged as an effective method of educating residents in cardiac emergencies. Few studies have used emergency simulation scenarios as an outcome measure to identify training deficiencies within residency programs. PURPOSE: The purpose of this study was to evaluate postgraduate year-1 (PGY-1) residents on their ability to manage an acute coronary syndrome and cardiac arrest scenario before and after internship in order to provide outcome data to improve program performance. METHODS: A total of 58 PGY-1 residents from 10 medical specialties were evaluated using a human patient simulator before and after internship. They were given 12 minutes to manage a patient with acute coronary syndrome and ventricular fibrillation due to hyperkalemia. An objective checklist following basic and advanced cardiac life support guidelines was used to assess performance. RESULTS: A total of 58 interns (age, 25 to 44 years [mean, 29.1]; 38 [65.6%] men; 41 [70.7%] allopathic medical school graduates) participated in both the incoming and outgoing examination. Overall chest pain scores increased from a mean of 60.0% to 76.1% (P < .01). Medical knowledge performance improved from 51.1% to 76.1% (P < .01). Systems-based practice performance improved from 40.9% to 71.0% (P < .01). However, patient care performance declined from 93.4% to 80.2% (P < .01). CONCLUSIONS: A simulated acute coronary syndrome and cardiac arrest scenario can evaluate incoming PGY-1 competency performance and test for interval improvement. This assessment tool can measure resident competency performance and evaluate program effectiveness.