Clinical Outcome of Patients with Poor-Grade Aneurysmal Subarachnoid Hemorrhage with Bundled Treatments: A Propensity Score-Matched Analysis.

BACKGROUND: Poor-grade aneurysmal subarachnoid hemorrhage (aSAH), defined as Hunt and Hess (HH) grades IV and V, is a challenging disease because of its high mortality and poor functional outcomes. The effectiveness of bundled treatments has been demonstrated in critical diseases. Therefore, poor-grade aSAH bundled treatments have been established. This study aims to evaluate whether bundled treatments can improve long-term outcomes and mortality in patients with poor-grade aSAH. METHODS: This is a comparative study using historical control from 2008 to 2022. Bundled treatments were introduced in 2017. We compared the rate of favorable outcomes (modified Rankin Scale score 0-2) at 6 months and mortality before and after the introduction of the bundled treatments. To eliminate confounding bias, the propensity score matching method was used. RESULTS: A total of 90 consecutive patients were evaluated. Forty-three patients received bundled treatments, and 47 patients received conventional care. The proportion of patients with HH grade V was higher in the bundle treatment group (41.9% vs. 27.7%). Conversely, the proportion of patients with fixed pupils on the initial examination was higher in the conventional group (30.2% vs. 38.3%). After 1:1 propensity score matching, 31 pairs were allocated to each group. The proportion of patients with 6-month favorable functional outcomes was significantly higher in the bundled treatments group (46.4% vs. 20.7%, p = 0.04). The 6-month mortality rate was 14.3% in the bundled treatments group and 27.3% in the conventional group (p = 0.01). Bundled treatments (odd ratio 14.6 [95% confidence interval 2.1-100.0], p < 0.01) and the presence of an initial pupil reflex (odd ratio 12.0 [95% confidence interval 1.4-104.6], p = 0.02) were significantly associated with a 6-month favorable functional outcome. CONCLUSIONS: The bundled treatments improve 6-month functional outcome and mortality in patients with poor-grade aSAH.

Significant Reduction in External Ventricular Drain-Related Infections After Introducing a Novel Bundle Protocol: A Before and After Trial.

BACKGROUND: External ventricular drain (EVD)-related infection (ERI) is a serious complication in neurosurgical patients. The estimated ERI rates range from 5 to 20 cases per 1,000 EVD catheter days. The pathophysiology of ERI is similar to central line-associated bloodstream infections (CLABSIs) stemming from skin-derived bacterial colonization. The use of bundle management can reduce CLABSI rates. Due to the pathogenic similarities between infections related to the two devices, we developed and evaluated the effectiveness of an ERI-bundle protocol based on CLABSI bundles. METHODS: From November 2016 to November 2021, we conducted a study to evaluate the effectiveness of an ERI-bundle protocol. This study adopted a before-and-after trial, comparing the ERI rates for the 2 years before and 3 years after the introduction of the newly developed ERI-bundle protocol. We also analyzed the contributing factors to ERI using logistic regression analysis. RESULTS: A total of 183 patients with 2,381 days of catheter use were analyzed. The ERI rate decreased significantly after the ERI-bundle protocol from 16.7% (14 of 84; 14.35 per 1,000 catheter days) to 4.0% (4 of 99; 3.21 per 1,000 catheter days) (P = 0.004). CONCLUSION: Introduction of the ERI-bundle protocol was very effective in reducing ERI.

The Outcomes of Endoscopic Suturectomy in Syndromic Craniosynostosis.

OBJECTIVE: Endoscopic suturectomy is a widely practiced surgical option for infants with craniosynostosis. But the efficacy and safety of the procedure remain unclear in syndromic patients. This study aims to evaluate the efficacy and safety of endoscopic suturectomy for patients with syndromic craniosynostosis. METHODS: From January 2013 to December 2020, 242 patients underwent endoscopic suturectomy at our institution. The surgical outcome was determined to be favorable or unfavorable based upon the necessity of an additional cranial surgery upon the last follow-up. First, we analyzed the outcomes of 26 syndromic craniosynostosis patients who have followed up for over a year. Second, we compared the outcomes between the syndromic (N=12) and nonsyndromic (N=11) patients with bilateral coronal synostosis who have followed up for over a year. RESULTS: Twenty-three out of 26 syndromic craniosynostosis patients (88%) showed favorable outcomes without significant complications. In the analysis for bilateral coronal synostosis patients, 11 of 12 syndromic patients (92%) presented favorable outcomes, and all nonsyndromic patients showed favorable outcomes. No significant differences were observed in various anthropometric indices (cranial index, intracranial volume, anterior cranial height, anterior cranial base length, and cranial height-length index) and surgical outcomes between syndromic and nonsyndromic groups. CONCLUSIONS: Endoscopic suturectomy has the potential to be a surgical option for syndromic craniosynostosis. Even for patients with unfavorable outcomes, endoscopic suturectomy could serve as a bridge treatment for infants to counter cranial deformation before additional extensive surgery.

Retained medullary cord and terminal myelocystocele as a spectrum: case report.

The caudal portion of the spinal cord, the medullary cord, is formed by secondary neurulation. One of the distinctive features of secondary neurulation compared to primary neurulation is that the medullary cord normally degenerates into a filum in humans. Various anomalies have been known to originate from degenerating process errors. One anomaly is terminal myelocystocele (TMCC), which is a closed spinal dysraphism with an elongated caudal spinal cord. The terminal part is filled with cerebrospinal fluid (CSF) and protrudes into the dorsal extradural space. Another anomaly is the retained medullary cord (RMC), which is a nonfunctioning cord-like structure extending to the cul-de-sac. In a 1-month-old boy, we identified an RMC with cystic dilatation of the caudal end extending to the epidural space at the very bottom of the cul-de-sac, resembling a degenerating terminal balloon, which is an essential feature of TMCC. Hence, this case may be considered an intermediate form between TMCC and RMC. This case provides clinical evidence that TMCC and RMC share the same pathoembryogenic origin, namely, failure of the regression phase of secondary neurulation.

Myelomeningocele as an anomaly of secondary neurulation.

PURPOSE: Myelomeningocele (MMC) is the representative entity of open neural tube defects resulting from an error during primary neurulation. However, cases of MMC in the region of the secondary neural tube (below the junction of S1 and S2 vertebrae) are sometimes encountered. We aimed to analyze the clinical features of atypical "low-lying" MMC in comparison to the typical MMC and suggest possible pathoembryogenesis. METHODS: From 1986 to 2020, 95 MMC patients were treated in our institute. A retrospective review of the radiological and clinical information was performed. We defined "low-lying" MMCs as those with fascia or lamina defects below the S1-2 interspinous ligament. RESULTS: Thirty-one out of the 95 MMC patients were identified as having low-lying MMC. The percentage of low-lying MMC within the entire MMC group increased dramatically (19% from 1990 to 1999 and 48% from 2000 to 2020). Thirty-nine percent of the low-lying MMCs were associated with hydrocephalus, and 36% showed the Chiari malformation. Clean intermittent catheterization was being performed by 52% of the patients and 46% had a motor weakness. The proportions of hydrocephalus, neurological symptoms, and the number of related procedures in the low-lying MMC were substantially lower than the typical MMC in our cohort and the literature. CONCLUSIONS: We present cases of atypical MMC occurring in the region of secondary neurulation. These cases provide clues that secondary neurulation may lead to open neural defects. Future experiments with animal models supporting what we have seen in the clinics will greatly enhance the understanding of the developmental process of neurulation and the corresponding anomalies.

The stability of multifocal ventriculoperitoneal shunts with Y-connections.

PURPOSE: Multifocal ventriculoperitoneal shunts with Y-connections (MVPS with Ys) are widely used in many centers when neuroendoscopic procedures on entrapped ventricles are not feasible; however, their use is not frequent. This study aimed to confirm the stability of an MVPS with Y and, for the first time, identify the factors that influence stability. METHODS: We studied 33 consecutive patients who underwent initial conversion to MVPS with Ys. The one-year overall shunt survival rate was calculated and compared with the historical outcome of single ventriculoperitoneal shunts (VPSs). The factors influencing the one-year overall shunt survival rate were also investigated. The one-year survival rate for proximal catheters in each location was further investigated, and the rates were compared among locations. The factors affecting proximal catheter survival were determined. RESULTS: The one-year overall shunt survival rate of MVPS with Y was 70%, which was not much different from that of previously reported single VPSs, including our institution. We found no significant factor influencing overall shunt survival, but when an additional catheter was inserted into the fourth ventricle, the survival rate was exceptionally low at 40% (p = 0.21). When we investigated the one-year survival rate of each proximal catheter, we found that the location of the proximal catheter showed a certain trend toward significance (p = 0.07), especially in the case of the fourth ventricle, which had the lowest survival rate at 57% and an odds ratio of 15.64 (p = 0.013) in multivariate analysis. However, when the catheter was sufficiently inserted parallel to the brain stem using navigation, the survival was relatively well maintained (1,995 to 2,547 days). CONCLUSIONS: The stability of MVPS with Y was similar to that of single VPSs. However, the malfunction rate of the proximal catheter inserted at the fourth ventricle in the Y-connection was higher than that at other locations. The transcerebellar vertical approach or transtentorial approach parallel to the brain stem may decrease the malfunction rate.

Wearable hip-assist robot modulates cortical activation during gait in stroke patients: a functional near-infrared spectroscopy study.

BACKGROUND: Gait dysfunction is common in post-stroke patients as a result of impairment in cerebral gait mechanism. Powered robotic exoskeletons are promising tools to maximize neural recovery by delivering repetitive walking practice. OBJECTIVES: The purpose of this study was to investigate the modulating effect of the Gait Enhancing and Motivating System-Hip (GEMS-H) on cortical activation during gait in patients with chronic stroke. METHODS: Twenty chronic stroke patients performed treadmill walking at a self-selected speed either with assistance of GEMS-H (GEMS-H) or without assistance of GEMS-H (NoGEMS-H). Changes in oxygenated hemoglobin (oxyHb) concentration in the bilateral primary sensorimotor cortex (SMC), premotor cortices (PMC), supplemental motor areas (SMA), and prefrontal cortices (PFC) were recorded using functional near infrared spectroscopy. RESULTS: Walking with the GEMS-H promoted symmetrical SMC activation, with more activation in the affected hemisphere than in NoGEMS-H conditions. GEMS-H also decreased oxyHb concentration in the late phase over the ipsilesional SMC and bilateral SMA (P < 0.05). CONCLUSIONS: The results of the present study reveal that the GEMS-H promoted more SMC activation and a balanced activation pattern that helped to restore gait function. Less activation in the late phase over SMC and SMA during gait with GEMS-H indicates that GEMS-H reduces the cortical participation of stroke gait by producing rhythmic hip flexion and extension movement and allows a more coordinate and efficient gait patterns. Trial registration NCT03048968. Registered 06 Feb 2017.

Range Sensor-Based Efficient Obstacle Avoidance through Selective Decision-Making.

In this paper, we address a collision avoidance method for mobile robots. Many conventional obstacle avoidance methods have been focused solely on avoiding obstacles. However, this can cause instability when passing through a narrow passage, and can also generate zig-zag motions. We define two strategies for obstacle avoidance, known as Entry mode and Bypass mode. Entry mode is a pattern for passing through the gap between obstacles, while Bypass mode is a pattern for making a detour around obstacles safely. With these two modes, we propose an efficient obstacle avoidance method based on the Expanded Guide Circle (EGC) method with selective decision-making. The simulation and experiment results show the validity of the proposed method.

Compact Hip-Force Sensor for a Gait-Assistance Exoskeleton System.

In this paper, we propose a compact force sensor system for a hip-mounted exoskeleton for seniors with difficulties in walking due to muscle weakness. It senses and monitors the delivered force and power of the exoskeleton for motion control and taking urgent safety action. Two FSR (force-sensitive resistors) sensors are used to measure the assistance force when the user is walking. The sensor system directly measures the interaction force between the exoskeleton and the lower limb of the user instead of a previously reported force-sensing method, which estimated the hip assistance force from the current of the motor and lookup tables. Furthermore, the sensor system has the advantage of generating torque in the walking-assistant actuator based on directly measuring the hip-assistance force. Thus, the gait-assistance exoskeleton system can control the delivered power and torque to the user. The force sensing structure is designed to decouple the force caused by hip motion from other directional forces to the sensor so as to only measure that force. We confirmed that the hip-assistance force could be measured with the proposed prototype compact force sensor attached to a thigh frame through an experiment with a real system.

Caudal Agenesis: Classification Based on the Pathoembryogenesis of the Spinal Cord.

BACKGROUND AND OBJECTIVES: Caudal agenesis (CA) is a congenital disease characterized by lower vertebral bone defects. Previous classifications for CA were based on the levels of bony defects or the conus medullaris. We created a new pathoembryogenic classification that takes into account the level of conus, considering both its shape and filum. We evaluated its accuracy in reflecting the neurological status and the need for untethering. METHODS: Patients with radiologic studies available on our institute's electronic image view system between 1985 and 2019 were reviewed. Our classification categorized patients with CA into 3 groups: the failure of formation (a conus level > L1 or normal level conus with a blunt shape), the failure of regression (a conus level < L3 or normal level conus with a thickened filum or a filar lipoma), and the normal (a normal level conus without specific abnormalities). We analyzed which of the following 3 classifications better reflects the neurological status and the probability of recommending untethering: classifications based on (1) bony defect level, (2) conus level, and (3) pathoembryogenic mechanism. RESULTS: A total of 89 patients were included in this study. The pathoembryogenic classification revealed more significant differences in motor or sensory deficits compared with other classifications (failure of formation: 42%; failure of regression: 16%; and normal: 0%, P = .039). In addition, the pathoembryogenic classification emerged as a significant or suggestive predictive factor for motor and sensory deficits (motor: odds ratio 11.66, P = .007; sensory: odds ratio 5.44, P = .066). Notably, only the pathoembryogenic classification exhibited a significant difference in the probabilities of recommending untethering between groups (failure of formation: 42%; failure of regression: 81%; and normal 12%, P < .001). CONCLUSION: The correlation between bony classification and spinal cord abnormalities was exaggerated. Our new pathoembryogenic classification was valuable in prognosticating neurological status and identifying the patient group more likely to require untethering among patients with CA.

Intracranial Pressure Monitoring for Acute Brain Injured Patients: When, How, What Should We Monitor.

While there is no level I recommendation for intracranial pressure (ICP) monitoring, it is typically indicated for patients with severe traumatic brain injury (TBI) with a Glasgow Coma Scale (GCS) score of 3-8 (class II). Even for moderate TBI patients with GCS 9-12, ICP monitoring should be considered for risk of increased ICP. The impact of ICP monitoring on patient outcomes is still not well-established, but recent studies reported a reduction of early mortality (class III) in TBI patients. There is no standard protocol for the application of ICP monitoring. In cases where cerebrospinal fluid drainage is required, an external ventricular drain is commonly used. In other cases, parenchymal ICP monitoring devices are generally employed. Subdural or non-invasive forms are not suitable for ICP monitoring. The mean value of ICP is the parameter recommended for observation in many guidelines. In TBI, values above 22 mmHg are associated with increased mortality. However, recent studies proposed various parameters including cumulative time with ICP above 20 mmHg (pressure-time dose), pressure reactivity index, ICP waveform characteristics (pulse amplitude of ICP, mean ICP wave amplitude), and the compensatory reserve of the brain (reserve-amplitude-pressure), which are useful in predicting patient outcomes and guiding treatment. Further research is required for validation of these parameters compared to simple ICP monitoring.

Protein Requirement Changes According to the Treatment Application in Neurocritical Patients.

Objective: Exploring protein requirements for critically ill patients has become prominent. On the other hand, considering the significant impact of coma therapy and targeted temperature management (TTM) on the brain as well as systemic metabolisms, protein requirements may plausibly be changed by treatment application. However, there is currently no research on protein requirements following the application of these treatments. Therefore, the aim of this study is to elucidate changes in patients' protein requirements during the application of TTM and coma therapy. Methods: This study is a retrospective analysis of prospectively collected data from March 2019 to May 2022. Among the patients admitted to the intensive care unit, those receiving coma therapy and TTM were included. The patient's treatment period was divided into two phases (Phase 1: application and maintenance of coma therapy and TTM; Phase 2: tapering and cessation of treatment). In assessing protein requirements, the Urine Urea Nitrogen (UUN) method was employed to estimate the nitrogen balance, offering insight into protein utilization within the body. The patient's protein requirement for each phase was defined as the amount of protein required to achieve a nitrogen balance within ±5, based on the 24-hour collection of UUN. Changes in protein requirements between phases were analyzed. Results: Out of 195 patients, 107 patients with a total of 214 UUN values were included. The mean protein requirement for the entire treatment period was 1.84 ± 0.62 g/kg/day, which is higher than the generally recommended protein supply of 1.2 g/kg/day. As the treatment was tapered, there was a statistically significant increase in the protein requirement from 1.49 ± 0.42 to 2.18 ± 0.60 in phase 2 (p < 0.001). Conclusion: Our study revealed a total average protein requirement of 1.84 ± 0.62g during the treatment period, which falls within the upper range of the preexisting guidelines. Nevertheless, a notable deviation emerged when analyzing the treatment application period separately. Hence, it is recommended to incorporate considerations for the type and timing of treatment, extending beyond the current guideline, which solely accounts for the 'severity by disease.

Clinical Outcome of Endoscopic Procedure in Patients with Shunt Malfunction.

OBJECTIVE: The goal of this study was to analyze the clinical outcomes of endoscopic third ventriculostomy (ETV) and endoscopic septostomy when shunt malfunction occurs in a patient who has previously undergone placement of a ventriculoperitoneal shunt. METHODS: From 2001 to 2020 at Seoul National University Children's Hospital, patients who underwent ETV or endoscopic septostomy for shunt malfunction were retrospectively analyzed. Initial diagnosis (etiology of hydrocephalus), age at first shunt insertion, age at endoscopic procedure, magnetic resonance or computed tomography image, subsequent shunting data, and follow-up period were included. RESULTS: Thirty-six patients were included in this retrospective study. Twenty-nine patients, 18 males and 11 females, with shunt malfunction underwent ETV. At the time of shunting, the age ranged from 1 day to 15.4 years (mean, 2.4 years). The mean age at the time of ETV was 13.1 years (range, 0.7 to 29.6 years). Nineteen patients remained shunt revision free. The 5-year shunt revisionfree survival rate was 69% (95% confidence interval [CI], 0.54-0.88). Seven patients, three males and four females, with shunt malfunction underwent endoscopic septostomy. At the time of shunting, the age ranged from 0.2 to 12 years (mean, 3.9 years). The mean age at the time of endoscopic septostomy was 11.9 years (range, 0.5 to 29.5 years). Four patients remained free of shunt revision or addition. The 5-year shunt revision-free survival rate was 57% (95% CI, 0.3-1.0). There were no complications associated with the endoscopic procedures. CONCLUSION: The results of our study demonstrate that ETV or endoscopic septostomy can be effective and safe in patients with shunt malfunction.

Growth patterns of young achondroplasia patients in Korea and predictability of neurosurgical procedures.

BACKGROUND: Achondroplasia is an autosomal dominant disorder mainly affecting bony growth, typically resulting in markedly short stature. From a neurosurgical viewpoint, patients sometimes develop spinal cord compression at the narrowed foramen magnum and hydrocephalus. This study aims to construct growth references for height, weight, and head circumference (HC) of young achondroplasia patients in Korea and to evaluate the predictability of the necessity and timing of neurosurgical procedures through growth patterns. METHODS: Growth data were collected from achondroplasia patients who visited our institution between January 2002 and August 2022. First, we constructed percentile growth curves of height, weight, and HC for the patients under 3 years of age with the generalized additive model for location, scale, and shape (GAMLSS). Second, the growth patterns of the patients with hydrocephalus who underwent neurosurgical procedures such as foramen magnum decompression (FMD) and ventriculoperitoneal (VP) shunt were analyzed. RESULTS: There were 125 achondroplasia patients, including 67 males and 58 females. Among 125 patients, 46 underwent FMD, and 5 underwent VP shunt. As short stature and macrocephaly were typical characteristics of achondroplasia, the height of achondroplasia was lower than that of the general population, and HC in achondroplasia showed accelerated growth postnatally. There were no significant changes in HC in hydrocephalus patients before they underwent neurosurgical procedures. The influence of hydrocephalus on the growth patterns of HC in achondroplasia seemed insignificant. CONCLUSION: Growth references for height, weight, and HC in young achondroplasia patients were constructed. It is the first report of growth patterns of achondroplasia in Korea. Unlike other pediatric patients, the diagnosis of hydrocephalus and the necessity of neurosurgical procedures are hard to be predicted with HC in achondroplasia. Neuroimaging should be considered for achondroplasia patients with neurological symptoms.

Optimizing Mannitol Use in Managing Increased Intracranial Pressure: A Comprehensive Review of Recent Research and Clinical Experiences.

Mannitol, derived from mannose sugar, is crucial in treating patients with elevated intracranial pressure (ICP). Its dehydrating properties at the cellular and tissue levels increase plasma osmotic pressure, which is studied for its potential to reduce ICP through osmotic diuresis. While clinical guidelines support mannitol use in these cases, the best approach for its application continues to be debated. Important aspects needing further investigation include: 1) bolus administration versus continuous infusion, 2) ICP-based dosing versus scheduled bolus, 3) identifying the optimal infusion rate, 4) determining the appropriate dosage, 5) establishing fluid replacement plans for urinary loss, and 6) selecting monitoring techniques and thresholds to assess effectiveness and ensure safety. Due to the lack of adequate high-quality prospective research data, a comprehensive review of recent studies and clinical trials is crucial. This assessment aims to bridge the knowledge gap, improve understanding of effective mannitol use in elevated ICP patients, and provide insights for future research. In conclusion, this review aspires to contribute to the ongoing discourse on mannitol application. By integrating the latest findings, this review will offer valuable insights into the function of mannitol in decreasing ICP, thereby informing better therapeutic approaches and enhancing patient outcomes.

The Unique Relationship between Neuro-Critical Care and Critical Illness-Related Corticosteroid Insufficiency : Implications for Neurosurgeons in Neuro-Critical Care.

The brain houses vital hormonal regulatory structures such as the hypothalamus and pituitary gland, which may confer unique susceptibilities to critical illness-related corticosteroid insufficiency (CIRCI) in patients with neurological disorders. In addition, the frequent use of steroids for therapeutic purposes in various neurological conditions may lead to the development of steroid insufficiency. This abstract aims to highlight the significance of understanding these relationships in the context of patient care and management for physicians. Neurological disorders may predispose patients to CIRCI due to the role of the brain in hormonal regulation. Early recognition of CIRCI in the context of neurological diseases is essential to ensure prompt and appropriate intervention. Moreover, the frequent use of steroids for treating neurological conditions can contribute to the development of steroid insufficiency, further complicating the clinical picture. Physicians must be aware of these unique interactions and be prepared to evaluate and manage patients with CIRCI and steroid insufficiency in the context of neurological disorders. This includes timely diagnosis, appropriate steroid administration, and careful monitoring for potential adverse effects. A comprehensive understanding of the interplay between neurological disease, CIRCI, and steroid insufficiency is critical for optimizing patient care and outcomes in this complex patient population.

The Unique Relationship between Neuro-Critical Care and Critical Illness-Related Corticosteroid Insufficiency : Implications for Neurosurgeons in Neuro-Critical Care.

The brain houses vital hormonal regulatory structures such as the hypothalamus and pituitary gland, which may confer unique susceptibilities to critical illness-related corticosteroid insufficiency (CIRCI) in patients with neurological disorders. In addition, the frequent use of steroids for therapeutic purposes in various neurological conditions may lead to the development of steroid insufficiency. This abstract aims to highlight the significance of understanding these relationships in the context of patient care and management for physicians. Neurological disorders may predispose patients to CIRCI due to the role of the brain in hormonal regulation. Early recognition of CIRCI in the context of neurological diseases is essential to ensure prompt and appropriate intervention. Moreover, the frequent use of steroids for treating neurological conditions can contribute to the development of steroid insufficiency, further complicating the clinical picture. Physicians must be aware of these unique interactions and be prepared to evaluate and manage patients with CIRCI and steroid insufficiency in the context of neurological disorders. This includes timely diagnosis, appropriate steroid administration, and careful monitoring for potential adverse effects. A comprehensive understanding of the interplay between neurological disease, CIRCI, and steroid insufficiency is critical for optimizing patient care and outcomes in this complex patient population.

Supra-threshold vibration applied to the foot soles enhances jump height under maximum effort.

Previous studies have shown that absence or reduction of cutaneous sensory feedback can diminish human motor performance under maximum effort. However, it has not been explored whether any appropriate intervention in the cutaneous sensory input can augment the output motor performance, particularly in motor tasks such as jumping that involve the kinematic chain of the entire body. Using shoes with active vibrating insoles, we applied mechanical vibration to the soles of 20 young and healthy adults and evaluated the change in the jump height and muscle activation using within-participants repeated measures. The noise-like vibration having an amplitude of 130% of the sensory threshold of each participant led to an average increase of 0.38 cm in the jump height (p = 0.008) and activation of the rectus femoris of the dominant leg (p = 0.011). These results indicate that application of a properly designed cutaneous stimulus to the soles, the distal end effectors of motor tasks, can augment the output performance by involving the prime movers distant from the end effector.

Application of vibration to the soles reduces minimum toe clearance variability during walking.

Minimum toe clearance (MTC) is an important indicator of the risk of tripping. Aging and neuromuscular diseases often decrease MTC height and increase its variability, leading to a higher risk of tripping. Previous studies have developed visual feedback-based gait training systems to modify MTC. However, these systems are bulky and expensive, and the effects of the training continue only for a short time. We paid attention to the efficacy of vibration in decreasing the variability of gait parameters, and hypothesized that proper vibration applied to soles can reduce the MTC variability. Using shoes embedded with active vibrating insoles, we assessed the efficacy of both sub- and supra-threshold vibration in affecting MTC distribution. Experiment results with 17 young and healthy adults showed that vibration applied throughout the walking task with constant intensity of 130% of sensory threshold significantly decreased MTC variability, whereas sub-threshold vibration yielded no significant effect. These results demonstrate that a properly designed tactile sensory input which is controlled and delivered by a simple wearable device, the active insole, can reduce the MTC variability during walking.