An impairment-specific hip exoskeleton assistance for gait training in subjects with acquired brain injury: a feasibility study.

This study was designed to investigate the feasibility and the potential effects on walking performance of a short gait training with a novel impairment-specific hip assistance (iHA) through a bilateral active pelvis orthosis (APO) in patients with acquired brain injury (ABI). Fourteen subjects capable of independent gait and exhibiting mild-to-moderate gait deficits, due to an ABI, were enrolled. Subjects presenting deficit in hip flexion and/or extension were included and divided into two groups based on the presence (group A, n = 6) or absence (group B, n = 8) of knee hyperextension during stance phase of walking. Two iHA-based profiles were developed for the groups. The protocol included two overground gait training sessions using APO, and two evaluation sessions, pre and post training. Primary outcomes were pre vs. post-training walking distance and steady-state speed in the 6-min walking test. Secondary outcomes were self-selected speed, joint kinematics and kinetics, gait symmetry and forward propulsion, assessed through 3D gait analysis. Following the training, study participants significantly increased the walked distance and average steady-state speed in the 6-min walking tests, both when walking with and without the APO. The increased walked distance surpassed the minimal clinically important difference for groups A and B, (respectively, 42 and 57 m > 34 m). In group A, five out of six subjects had decreased knee hyperextension at the post-training session (on average the peak of the knee extension angle was reduced by 36%). Knee flexion during swing phase increased, by 16% and 31%, for A and B groups respectively. Two-day gait training with APO providing iHA was effective and safe in improving walking performance and knee kinematics in ABI survivors. These preliminary findings suggest that this strategy may be viable for subject-specific post-ABI gait rehabilitation.

Enhancing functional abilities and cognitive integration of the lower limb prosthesis.

Lower limb amputation (LLA) destroys the sensory communication between the brain and the external world during standing and walking. Current prostheses do not restore sensory feedback to amputees, who, relying on very limited haptic information from the stump-socket interaction, are forced to deal with serious issues: the risk of falls, decreased mobility, prosthesis being perceived as an external object (low embodiment), and increased cognitive burden. Poor mobility is one of the causes of eventual device abandonment. Restoring sensory feedback from the missing leg of above-knee (transfemoral) amputees and integrating the sensory feedback into the sensorimotor loop would markedly improve the life of patients. In this study, we developed a leg neuroprosthesis, which provided real-time tactile and emulated proprioceptive feedback to three transfemoral amputees through nerve stimulation. The feedback was exploited in active tasks, which proved that our approach promoted improved mobility, fall prevention, and agility. We also showed increased embodiment of the lower limb prosthesis (LLP), through phantom leg displacement perception and questionnaires, and ease of the cognitive effort during a dual-task paradigm, through electroencephalographic recordings. Our results demonstrate that induced sensory feedback can be integrated at supraspinal levels to restore functional abilities of the missing leg. This work paves the way for further investigations about how the brain interprets different artificial feedback strategies and for the development of fully implantable sensory-enhanced leg neuroprostheses, which could drastically ameliorate life quality in people with disability.

Sensory feedback restoration in leg amputees improves walking speed, metabolic cost and phantom pain.

Conventional leg prostheses do not convey sensory information about motion or interaction with the ground to above-knee amputees, thereby reducing confidence and walking speed in the users that is associated with high mental and physical fatigue1-4. The lack of physiological feedback from the remaining extremity to the brain also contributes to the generation of phantom limb pain from the missing leg5,6. To determine whether neural sensory feedback restoration addresses these issues, we conducted a study with two transfemoral amputees, implanted with four intraneural stimulation electrodes7 in the remaining tibial nerve (ClinicalTrials.gov identifier NCT03350061). Participants were evaluated while using a neuroprosthetic device consisting of a prosthetic leg equipped with foot and knee sensors. These sensors drive neural stimulation, which elicits sensations of knee motion and the sole of the foot touching the ground. We found that walking speed and self-reported confidence increased while mental and physical fatigue decreased for both participants during neural sensory feedback compared to the no stimulation trials. Furthermore, participants exhibited reduced phantom limb pain with neural sensory feedback. The results from these proof-of-concept cases provide the rationale for larger population studies investigating the clinical utility of neuroprostheses that restore sensory feedback.

The Icelandic 16-electrode electrohysterogram database.

External recordings of the electrohysterogram (EHG) can provide new knowledge on uterine electrical activity associated with contractions. Better understanding of the mechanisms underlying labor can contribute to preventing preterm birth which is the main cause of mortality and morbidity in newborns. Promising results using the EHG for labor prediction and other uses in obstetric care are the drivers of this work. This paper presents a database of 122 4-by-4 electrode EHG recordings performed on 45 pregnant women using a standardized recording protocol and a placement guide system. The recordings were performed in Iceland between 2008 and 2010. Of the 45 participants, 32 were measured repeatedly during the same pregnancy and participated in two to seven recordings. Recordings were performed in the third trimester (112 recordings) and during labor (10 recordings). The database includes simultaneously recorded tocographs, annotations of events and obstetric information on participants. The publication of this database enables independent and novel analysis of multi-electrode EHG by the researchers in the field and hopefully development towards new life-saving technology.

A multiscale model of the electrohysterogram the BioModUE_PTL project.

The electrohysterogram (EHG) is a promising means of monitoring pregnancy and of detecting a risk of preterm labor. To improve our understanding of the EHG as well as its relationship with the physiologic phenomena involved in uterine contractility, we plan to model these phenomena in terms of generation and propagation of uterine electrical activity. This activity can be realistically modeled by representing the principal ionic dynamics at the cell level, the propagation of electrical activity at the tissue level and then the way it is reflected on the skin surface through the intervening tissue. We present in this paper the different steps leading to the development and validation of a biophysics based multiscale model of the EHG, going from the cell to the electrical signal measured on the abdomen.

Better pregnancy monitoring using nonlinear correlation analysis of external uterine electromyography.

The objective of this paper is to evaluate the novel method for analyzing the nonlinear correlation of the uterine electromyography (EMG). The application of this method may improve monitoring in pregnancy, labor detection, and preterm labor detection. Uterine EMG signals recorded from a 4 × 4 matrix of electrodes on the subjects' abdomen are used here. The propagation was analyzed using the nonlinear correlation coefficient h(2). Signals from 49 women (36 during pregnancy and 13 in labor) at different gestational age were used. ROC curves were computed to evaluate the potential of three methods to differentiate between 174 contractions recorded during pregnancy and 115 contractions recorded during labor. The results indicate considerably better performance of the nonlinear correlation analysis (area under curve = 0.85) when compared to classical frequency parameters (area under curve = 0.76 and 0.66) in distinguishing labor contractions from normal pregnancy contractions. We conclude that the analysis of the propagation of the uterine electrical activity using the nonlinear correlation coefficient h(2) is a promising way of improving the usefulness of uterine EMG signals for clinical purposes, such as monitoring in pregnancy, labor detection, and prediction of preterm labor.

[Intensive care unit admissions following lobectomy or sublobar resections for non-small cell lung cancer]. / Innlagnir a gjorgaeslu aftir bladnam og fleygskurdi vid lungnakrabbameini.

INTRODUCTION: Following resection for non-small cell lung cancer (NSCLC), patients are usually admitted to the post-anesthesia care unit (PACU)for a few hours before admission to a general ward (GW). However, some patients need ICU-admission, either immediately post-surgery or from the PACU or GW. The aim of this study was to investigate the indications and risk factors for ICU-admission. MATERIAL AND METHODS: A retrospective study of 252 patients who underwent lobectomy, wedge resection or segmentectomy for NSCLC in Iceland during 2001-2010. Data was retrieved from medical records and patients admitted to the ICU compared to patients not admitted. RESULTS: Altogether 21 patients (8%) were admitted to the ICU, median length-of-stay being one day (range 1-68). In 11 cases (52%) the reasons for admission were intraoperative problems, usually hypotension or excessive bleeding. Ten patients were admitted from the GW (n=4) or PACU (n=6), due to hypotension (n=4), heart and/or respiratory failure (n=4) and reoperation for bleeding (n=2). There were three ICU-readmissions. Patients admitted to the ICU were six years older (p=0.004) and more often had chronic obstructive pulmonary disease and/or coronary artery disease. Tumor size, pTNM-stage, length of operation and the ratio of patients receiving TEA (thoracic epidural anaesthesia) were similar between groups. Over two-thirds of the ICU-patients had minor complications and around half had major complications, compared to 30% and 4%, respectively, for controls. CONCLUSION: ICU-admissions are infrequent following non-pneumonectomy lung resections for NSCLC, these patients being older with cardiopulmonary comorbidities. In half of the cases, admission to the ICU directly follows surgery and ICU-readmissions are few.

Resection rate and outcome of pulmonary resections for non-small-cell lung cancer: a nationwide study from Iceland.

BACKGROUND: The proportion of patients with non-small-cell lung cancer (NSCLC) who undergo surgery with curative intent is one measure of effectiveness in treating lung cancer. To the best of our knowledge, surgical resection rate (SRR) for a whole nation has never been reported before. We studied the SRR and surgical outcome of NSCLC patients in Iceland during a recent 15-year period. METHODS: This was a retrospective study of all pulmonary resections performed with curative intent for NSCLC in Iceland from 1994 to 2008. Information was retrieved from medical records and from the Icelandic Cancer Registry. Patient demographics, postoperative tumor, node, metastasis stage, overall survival, and complication rates were compared over three 5-year periods. RESULTS: Of 1530 confirmed cases of NSCLC, 404 were resected, giving an SRR of 26.4%, which did not change significantly during the study period. Minor and major complication rates were 37.4% and 8.7%, respectively. Operative mortality rates were 0.7% for lobectomy, 3.3% for pneumonectomy, and 0% for lesser resection. Five-year survival after all procedures was 40.7% and improved from the first to the last 5-year period (34.8% versus 43.8%, p = 0.04). Five-year survival for stages I and II together was 46.8%, with no significant change in stage distribution between periods. Five-year survival after pneumonectomy was 22.0%, which was significantly lower than for lobectomy (44.6%) and lesser resection (40.7%) (p < 0.005). Unoperated patients had a 5-year survival of 4.8%, as compared to 12.4% for all the NSCLC patients together. CONCLUSION: Compared with most other published studies, the SRR of NSCLC in Iceland is high. Short-term outcome is good, with a low rate of major complications and an operative mortality of only 1.0%. Five-year survival improved significantly over the study period.

[Sublobar resection for non-small cell lung cancer in Iceland]. / Arangur fleyg- og geiraskurda vid lungnakrabbbameini á Islandi.

INTRODUCTION: A sublobar resection is performed on patients with non-small cell lung cancer (NSCLC) who are not candidates for a lobectomy due to reduced pulmonary function or comorbid disease. The aim of this study was to investigate the outcomes of these operations in Iceland. MATERIAL AND METHODS: A retrospective study of all patients with NSCLC who underwent wedge resection or segmentectomy with curative intent during 1994-2008. Data on indication, pathological TNM-stage, complications and overall survival was analyzed. All histological samples were re-evaluated. RESULTS: Forty four patients underwent 42 wedge and 5 segmental resections (age 69.1 yrs, 55.3% female), with 38.3% of cases detected incidentally. The majority of patients (55.3%) had a history of coronary artery disease and 40.4% had chronic obstructive pulmonary disease. Mean operative time was 83 minutes (range 30-131), mean intraoperative bleeding was 260 ml (range 100-650) and median hospital stay was 9 days (range 4-24). Pneumonia (14.9%) and prolonged air leakage (12.8%) were the most common complications. Two patients had major complications and 36.2% stayed in the intensive care unit overnight. No deaths occurred within 30 days of surgery. Adenocarcinoma was the most common histological type (66.7%). Most cases were stage IA/IB (78.7%), 17.0% were stage IIA/IIB and 4.3% were stage IIIA. One and 5 year survival was 85.1% and 40.9% respectively. CONCLUSION: In Iceland, both survival and complication rate after sublobar resection for NSCLC are comparable to results published for lobectomies, even though a higher percentage of patients have underlying cardiopulmonary disease.