Search

ObjectiveBrain-computer interface (BCI) technology is attracting increasing interest as a tool for enhancing recovery of motor function after stroke, yet the optimal way to apply this technology is unknown. Here, we studied the immediate and therapeutic effects of BCI-based training to control pre-movement sensorimotor rhythm (SMR) amplitude on robot-assisted finger extension in people with stroke.ApproachEight people with moderate to severe hand impairment due to chronic stroke completed a four-week three-phase protocol during which they practiced finger extension with assistance from the FINGER robotic exoskeleton. In Phase 1, we identified spatiospectral SMR features for each person that correlated with the intent to extend the index and/or middle finger(s). In Phase 2, the participants learned to increase or decrease SMR features given visual feedback, without movement. In Phase 3, the participants were cued to increase or decrease their SMR features, and when successful, were then cued to immediately attempt to extend the finger(s) with robot assistance.Main resultsOf the four participants that achieved SMR control in Phase 2, three initiated finger extensions with a reduced reaction time after decreasing (versus increasing) pre-movement SMR amplitude during Phase 3. Two also extended at least one of their fingers more forcefully after decreasing pre-movement SMR amplitude. Hand function, measured by the box and block test (BBT), improved by 7.3  ±  7.5 blocks versus 3.5  ±  3.1 blocks in those with and without SMR control, respectively. Higher BBT scores at baseline correlated with a larger change in BBT score.SignificanceThese results suggest that learning to control person-specific pre-movement SMR features associated with finger extension can improve finger extension ability after stroke for some individuals. These results merit further investigation in a rehabilitation context.

Competing Interests: Competing interests: J.T.R. is a shareholder, director and employee of Motif Neurotech, Inc. S.L.N. is a director and employee of Forest Neurotech. T.D. is founder and director of Amber Therapeutics, non-exec chairman of Mint Neurotechnologies Ltd. and advisor for Cortec Neuro. N.V. is a shareholder, director and employee of Neurosoft Bioelectronics S.A., a Swiss company building BCIs. M.M.S. is an inventor on patents or patent applications related to neural decoding and stimulation. R.M.F. is a shareholder, director and employee of Kernel. A.L.O. is a scientific advisor for Meta Reality Labs. S.A.S. is a shareholder of Motif Neurotech, and has consulting agreements with Neuropace, Boston Scientific, Zimmer Biomet and Koh Young. A.F. is a shareholder, director and employee of Cognixion Corporation. M.R.A. is a shareholder, director and employee of Paradromics, Inc. C.J.R. is an inventor on intellectual property related to neurotechnology, and a shareholder and member of the scientific advisory board of Motif Neurotech, Inc. S.D.S. is an inventor on patents or patent applications related to BCIs and is an advisor to Sonera. T.G.C. is a shareholder and director of Mint Neurotechnologies, Ltd. M.S. is an inventor on patents or patent applications related to neural decoding and stimulation. C.X. is an inventor on intellectual property related to neurotechnology, and a shareholder of Neuralthread, Inc. J.P.D. is a shareholder and board member of Pathmaker Neurosystems, and an advisor to Neurable and to Beacon Biosignals. All other authors declare no competing interests.

Objective. Finger dexterity, and finger individuation in particular, is crucial for human movement, and disruptions due to brain injury can significantly impact quality of life. Understanding the neurological mechanisms responsible for recovery is vital for effective neurorehabilitation. This study explores the role of two key pathways in finger individuation: the corticospinal (CS) tract from the primary motor cortex and premotor areas, and the subcortical reticulospinal (RS) tract from the brainstem. We aimed to investigate how the cortical-reticular network reorganizes to aid recovery of finger dexterity following lesions in these areas. Approach. To provide a potential biologically plausible answer to this question, we developed an artificial neural network (ANN) to model the interaction between a premotor planning layer, a cortical layer with excitatory and inhibitory CS outputs, and RS outputs controlling finger movements. The ANN was trained to simulate normal finger individuation and strength. A simulated stroke was then applied to the CS area, RS area, or both, and the recovery of finger dexterity was analyzed. Main results. In the intact model, the ANN demonstrated a near-linear relationship between the forces of instructed and uninstructed fingers, resembling human individuation patterns. Post-stroke simulations revealed that lesions in both CS and RS regions led to increased unintended force in uninstructed fingers, immediate weakening of instructed fingers, improved control during early recovery, and increased neural plasticity. Lesions in the CS region alone significantly impaired individuation, while RS lesions affected strength and to a lesser extent, individuation. The model also predicted the impact of stroke severity on finger individuation, highlighting the combined effects of CS and RS lesions. Significance. This model provides insights into the interactive role of cortical and subcortical regions in finger individuation. It suggests that recovery mechanisms involve reorganization of these networks, which may inform neurorehabilitation strategies., (Creative Commons Attribution license.)

The lateral intraparietal cortex (LIP) located within the posterior parietal cortex (PPC) is an important area for the transformation of spatial information into accurate saccadic eye movements. Despite extensive research, we do not fully understand the functional anatomy of intended movement directions within LIP. This is in part due to technical challenges. Electrophysiology recordings can only record from small regions of the PPC, while fMRI and other whole-brain techniques lack sufficient spatiotemporal resolution. Here, we use functional ultrasound imaging (fUSI), an emerging technique with high sensitivity, large spatial coverage, and good spatial resolution, to determine how movement direction is encoded across PPC. We used fUSI to record local changes in cerebral blood volume in PPC as two monkeys performed memory-guided saccades to targets throughout their visual field. We then analyzed the distribution of preferred directional response fields within each coronal plane of PPC. Many subregions within LIP demonstrated strong directional tuning that was consistent across several months to years. These mesoscopic maps revealed a highly heterogenous organization within LIP with many small patches of neighboring cortex encoding different directions. LIP had a rough topography where anterior LIP represented more contralateral upward movements and posterior LIP represented more contralateral downward movements. These results address two fundamental gaps in our understanding of LIP's functional organization: the neighborhood organization of patches and the broader organization across LIP. These findings were achieved by tracking the same LIP populations across many months to years and developing mesoscopic maps of direction specificity previously unattainable with fMRI or electrophysiology methods.

Visualization of human brain activity is crucial for understanding normal and aberrant brain function. Currently available neural activity recording methods are highly invasive, have low sensitivity, and cannot be conducted outside of an operating room. Functional ultrasound imaging (fUSI) is an emerging technique that offers sensitive, large-scale, high-resolution neural imaging; however, fUSI cannot be performed through the adult human skull. Here, we used a polymeric skull replacement material to create an acoustic window compatible with fUSI to monitor adult human brain activity in a single individual. Using an in vitro cerebrovascular phantom to mimic brain vasculature and an in vivo rodent cranial defect model, first, we evaluated the fUSI signal intensity and signal-to-noise ratio through polymethyl methacrylate (PMMA) cranial implants of different thicknesses or a titanium mesh implant. We found that rat brain neural activity could be recorded with high sensitivity through a PMMA implant using a dedicated fUSI pulse sequence. We then designed a custom ultrasound-transparent cranial window implant for an adult patient undergoing reconstructive skull surgery after traumatic brain injury. We showed that fUSI could record brain activity in an awake human outside of the operating room. In a video game "connect the dots" task, we demonstrated mapping and decoding of task-modulated cortical activity in this individual. In a guitar-strumming task, we mapped additional task-specific cortical responses. Our proof-of-principle study shows that fUSI can be used as a high-resolution (200 μm) functional imaging modality for measuring adult human brain activity through an acoustically transparent cranial window.

Brain-machine interfaces (BMIs) enable people living with chronic paralysis to control computers, robots and more with nothing but thought. Existing BMIs have trade-offs across invasiveness, performance, spatial coverage and spatiotemporal resolution. Functional ultrasound (fUS) neuroimaging is an emerging technology that balances these attributes and may complement existing BMI recording technologies. In this study, we use fUS to demonstrate a successful implementation of a closed-loop ultrasonic BMI. We streamed fUS data from the posterior parietal cortex of two rhesus macaque monkeys while they performed eye and hand movements. After training, the monkeys controlled up to eight movement directions using the BMI. We also developed a method for pretraining the BMI using data from previous sessions. This enabled immediate control on subsequent days, even those that occurred months apart, without requiring extensive recalibration. These findings establish the feasibility of ultrasonic BMIs, paving the way for a new class of less-invasive (epidural) interfaces that generalize across extended time periods and promise to restore function to people with neurological impairments., (© 2023. The Author(s).)

Introduction: The human papillomavirus (HPV) causes largely preventable cancers by completing a vaccination series. However, pediatric HPV vaccination rates remain low. Current evidence indicates that integrating five factors creates a high-quality recommendation associated with higher HPV vaccination rates. This quality improvement project aimed to evaluate the impact of an educational intervention to improve the quality of providers' recommendations and subsequent vaccination rates., Method: Using the Squire 2.0 Guidelines, clinical staff were observed during well-child visits (aged 11-12 years) before and after the intervention across three Plan-Do-Study-Act cycles., Results: Thirty-nine encounters with mostly (n = 31; 80%) families of color. The quality of vaccine recommendations was improved after the intervention; however, vaccination rates did not increase for the 39 patients. Providers' delivery approach (presumptive vs. conversational) did increase vaccination rates., Discussion: Providers' delivery style appears to be important when making HPV vaccine recommendations., (Copyright © 2022 National Association of Pediatric Nurse Practitioners. Published by Elsevier Inc. All rights reserved.)

After a neurological injury, people develop abnormal patterns of neural activity that limit motor recovery. Traditional rehabilitation, which concentrates on practicing impaired skills, is seldom fully effective. New targeted neuroplasticity protocols interact with the central nervous system to induce beneficial plasticity in key sites and thereby enable wider beneficial plasticity. They can complement traditional therapy and enhance recovery. However, their development and validation is difficult because many different targeted neuroplasticity protocols are conceivable, and evaluating even one of them is lengthy, laborious, and expensive. Computational models can address this problem by triaging numerous candidate protocols rapidly and effectively. Animal and human empirical testing can then concentrate on the most promising ones. Here, we simulate a neural network of corticospinal neurons that control motoneurons eliciting unilateral finger extension. We use this network to (i) study the mechanisms and patterns of cortical reorganization after a stroke; and (ii) identify and parameterize a targeted neuroplasticity protocol that improves recovery of extension torque. After a simulated stroke, standard training produced abnormal bilateral cortical activation and suboptimal torque recovery. To enhance recovery, we interdigitated standard training with trials in which the network was given feedback only from a targeted population of sub-optimized neurons. Targeting neurons in secondary motor areas on ∼20% of the total trials restored lateralized cortical activation and improved recovery of extension torque. The results illuminate mechanisms underlying suboptimal cortical activity post-stroke; they enable the identification and parameterization of the most promising targeted neuroplasticity protocols. By providing initial guidance, computational models could facilitate and accelerate the realization of new therapies that improve motor recovery., (Published by Oxford University Press on behalf of the Guarantors of Brain 2022.)

New technologies are key to understanding the dynamic activity of neural circuits and systems in the brain. Here, we show that a minimally invasive approach based on ultrasound can be used to detect the neural correlates of movement planning, including directions and effectors. While non-human primates (NHPs) performed memory-guided movements, we used functional ultrasound (fUS) neuroimaging to record changes in cerebral blood volume with 100 μm resolution. We recorded from outside the dura above the posterior parietal cortex, a brain area important for spatial perception, multisensory integration, and movement planning. We then used fUS signals from the delay period before movement to decode the animals' intended direction and effector. Single-trial decoding is a prerequisite to brain-machine interfaces, a key application that could benefit from this technology. These results are a critical step in the development of neuro-recording and brain interface tools that are less invasive, high resolution, and scalable., Competing Interests: Declaration of interests M.T. is a co-founder and shareholder of Iconeus Company, which commercializes ultrasonic neuroimaging scanners. D.M. is now affiliated with T.U. Delft, Netherlands. V.C. is now affiliated with University of California, Riverside., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Classical systems neuroscience positions primary sensory areas as early feed-forward processing stations for refining incoming sensory information. This view may oversimplify their role given extensive bi-directional connectivity with multimodal cortical and subcortical regions. Here we show that single units in human primary somatosensory cortex encode imagined reaches in a cognitive motor task, but not other sensory-motor variables such as movement plans or imagined arm position. A population reference-frame analysis demonstrates coding relative to the cued starting hand location suggesting that imagined reaching movements are encoded relative to imagined limb position. These results imply a potential role for primary somatosensory cortex in cognitive imagery, engagement during motor production in the absence of sensation or expected sensation, and suggest that somatosensory cortex can provide control signals for future neural prosthetic systems.

Purpose: A diagnosis of delirium places a critically ill child at risk of increased morbidity/mortality. Although delirium is common in critically ill children, only 2% of pediatric intensive care units (PICU) screen for delirium. The impediments to screening include knowledge deficits regarding delirium and delirium screening tools. The purpose of this improvement science project was two-fold. The first was to implement delirium screening in a PICU. The second was to evaluate the impact of multifaceted education on PICU nurses' delirium knowledge, self-confidence and attitude towards delirium., Design & Method: A series of three plan-do-study-act cycles (PDSA) were used to implement this practice change. Multifaceted education was provided during the PDSA cycles. Two questionnaires were used to assess for changes in delirium knowledge, self-confidence and attitude towards delirium among PICU nurses. Analysis of variance (ANOVA) was used for data analysis., Results: Forty-two PICU nurses completed a questionnaire measuring delirium knowledge, self-confidence, and attitude during each PDSA cycle. A significant increase in delirium knowledge, self-confidence, and attitude towards delirium was found after education (p = .003; p < .001; p = .036) and 3 months post implementation of delirium screening (p = .023; p < .001; p = .027) as compared to pre-education., Conclusion & Practice Implications: Multifaceted education is a successful tool in improving nurses' knowledge, self-confidence and attitude regarding delirium. The use of PDSA cycles is a practical systematic method to improve quality of care. Improving knowledge, self-confidence and attitude have the potential to mitigate adverse effects of delirium in the critically ill child., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Robotic devices can train strength, coordination, or a combination of both. If a robotic device focuses on coordination, what happens to strength recovery, and vice versa? Understanding this interaction could help optimize robotic training. We developed a computational neurorehabilitation model to gain insight into the interaction between strength and coordination recovery after stroke. In the model, the motor system recovers by optimizing the activity of residual corticospinal cells (focally connected, excitatory and inhibitory) and reticulospinal cells (diffusely connected and excitatory) to achieve a motor task. To do this, the model employs a reinforcement learning algorithm that uses stochastic search based on a reward signal produced by task execution. We simulated two tasks that require strength and coordination: a finger movement task and a bilateral wheelchair propulsion task. We varied the reward signal to value strength versus coordination, determined by a weighting factor. The model predicted a nonlinear relationship between strength and coordination recovery consistent with clinical data obtained for each task. The model also predicted that stroke can cause a competition between strength and coordination recovery, due to a scarcity of focal and inhibitory cells. These results provide a rationale for implementing robotic movement therapy that can adaptively alter the combination of force and coordination training to target desired components of motor recovery.

In this paper, we show that a simple haptic device can accurately guide users through planar hand movements. The device guides the user through skin stretch feedback on the fingerpad of the user's index finger. In an angle matching test evaluating two types of stimuli, users are able to discriminate between eight stimulus directions and match the motion of their hand to the stimulus direction with 10 degree accuracy. In two motion guidance tests, haptic cues effectively guide users' arm motions through the full extent of their reachable workspace. Real-time corrective feedback greatly improves user performance, keeping average user hand motions within 12 mm of the prescribed path and within 4 degree of the indicated directions. Additionally, the paper shows that participants exhibit distorted haptic perceptual responses, finding that the distortion causes a response direction bias, but that appropriate haptic feedback can correct for the effect. Such motion guidance has applications in human-machine interaction, such as upper-extremity rehabilitation.

Objective: To document the characteristics and incidence of serious abnormalities in patients prior to admission to intensive care units., Design and Setting: Prospective follow-up study of all patients admitted to intensive care in three acute-care hospitals., Patients: The study population totalled 551 patients admitted to intensive care: 90 from the general ward, 239 from operating rooms (OR) and 222 from the Emergency Department (ED)., Measurements and Results: Patients from the general wards had greater severity of illness (APACHE II median 21) than those from the OR (15) or ED (19). A greater percentage of patients from the general wards (47.6%) died than from OR (19.3%) and ED (31.5%). Patients from the general wards had a greater number of serious antecedents before admission to intensive care 43 (72%) than those from OR 150 (64.4%) or ED 126 (61.8%). Of the 551 patients 62 had antecedents during the period 8-48 h before admission to intensive care, and 53 had antecedents both within 8 and 48 h before their admission. The most common antecedents during the 8 h before admission were hypotension (n=199), tachycardia (n=73), tachypnoea (n=64), and sudden change in level of consciousness (n=42). Concern was expressed in the clinical notes by attending staff in 70% of patients admitted from the general wards., Conclusions: In over 60% of patients admitted to intensive care potentially life-threatening abnormalities were documented during the 8 h before their admission. This may represent a patient population who could benefit from improved resuscitation and care at an earlier stage.

Background: Recent studies have suggested there are a large number of potentially preventable deaths in Australian hospitals., Aim: This study aimed to document antecedent factors in hospital deaths in an attempt to identify potentially preventative factors., Methods: The study was conducted at three separate acute hospitals. Demographics of all deaths were recorded over a 6-month period as well as antecedent factors present within 0-8 and 8-48 h of all deaths including vital sign abnormalities, cardiorespiratory arrests and admission to intensive care. Separate analysis was performed on 'not for resuscitation' deaths., Results: There were a total of 778 deaths, of which 549 (71%) were 'not for resuscitation'. There were 171 (22%) deaths preceded by arrest and 160 (21%) preceded by admission to intensive care. Of the remaining deaths, 30% had severely abnormal physiological abnormalities documented. This incidence was 50% in the non-do not resuscitate (DNR) subgroup. Concern about the patient's condition was expressed in the patient's notes by attending nursing staff and junior medical staff in approximately one-third of non-DNR deaths. Hypotension (30%) and tachypnoea (17%) were the most common antecedents in the non-DNR deaths., Conclusion: There is a high incidence of serious vital sign abnormalities in the period before potentially preventable hospital deaths. These antecedents may identify patients who would benefit from earlier intervention.

Objectives: To evaluate the effectiveness of a medical emergency team (MET) in reducing the rates of selected adverse events., Design: Cohort comparison study after casemix adjustment., Patients and Setting: All adult (> or = 14 years) patients admitted to three Australian public hospitals from 8 July to 31 December 1996. INTERVENTION STUDIED: At Hospital 1, a medical emergency team (MET) could be called for abnormal physiological parameters or staff concern. Hospitals 2 and 3 had conventional cardiac arrest teams., Main Outcome Measures: Casemix-adjusted rates of cardiac arrest, unanticipated admission to intensive care unit (ICU), death, and the subgroup of deaths where there was no pre-existing "do not resuscitate" (DNR) order documented., Results: There were 1510 adverse events identified among 50 942 admissions. The rate of unanticipated ICU admissions was less at the intervention hospital in total (casemix-adjusted odds ratios: Hospital 1, 1.00; Hospital 2, 1.59 [95% CI, 1.24-2.04]; Hospital 3, 1.73 [95% CI, 1.37-2.16]). There was no significant difference in the rates of cardiac arrest or total deaths between the three hospitals. However, one of the hospitals with a conventional cardiac arrest team had a higher death rate among patients without a DNR order., Conclusions: The MET hospital had fewer unanticipated ICU/HDU admissions, with no increase in in-hospital arrest rate or total death rate. The non-DNR deaths were lower compared with one of the other hospitals; however, we did not adjust for DNR practices. We suggest that the MET concept is worthy of further study.

Background: With the introduction of laparoscopic cholecystectomy (LC) there has been a reduction in the use of operative cholangiography. The practice of selective cholangiography (SC), where the common bile duct (CBD) is imaged only in those patients where the surgeon believes there is a significant risk of CBD stones has contributed to this reduction. Selective cholangiography has been criticized by advocates of routine cholangiography who argue that there will be more CBD stones missed and more CBD injuries., Methods: This prospective study reports the outcome in a series of 457 patients who had LC performed between 1990 and 1992 where cholangiography was used according to a strict protocol relying on clinical history, CBD size and pre-operative liver function tests. There were no CBD injuries. Twenty-nine patients (6.4%) had CBD stones., Results: Follow up by structured questionnaire at 12-24 months detected 6 patients (1.3%) with CBD stones. Three of these 6 patients had cholangiograms. Of the 3 patients with missed stones and no X-ray, 2 were protocol breaches and only 1 patient from 307 (0.3%) with no indication for SC was subsequently found to have a CBD stone., Conclusion: We believe that this study validates a policy of SC.

In a double-blind single-dose study, the analgesic effect of a new ibuprofen-codeine phosphate combination was compared with those of codeine phosphate alone and placebo for the relief of moderate and severe postepisiotomy pain. In the 113 patients studied, combination therapy was superior to codeine phosphate alone and to placebo, the difference between the combination and codeine phosphate alone reaching statistical significance (P less than 0.05) after two hours. The few side effects reported were not of a serious nature.

A number of organic dyes have been found to be capable of desensitizing AgBr phase holograms against printout darkening by the light of an argon ion laser. The greatest lifetime extensions observed to date are approximately 500% and 3300% for 488 nm and 515 nm irradiation, respectively, referred to control samples produced by a bleaching process reported to give high stability. The most successful desensitizing dyes showed negligible absorption of the laser light.