Processor Loading Research Articles

Very Early Loading of a Bone-Anchored Hearing System Is Safe.

To investigate the feasibility of early sound processor loading with two separate bone-anchored hearing aid implants 1 to 2 weeks after implantation. Secondary endpoints included registration of any postoperative complications, skin reactions, and any adverse events. Prospective, nonrandomized, noncontrolled, multicenter clinical trial. Tertiary referral center. Sixty adult patients, eligible for bone-anchored hearing aid surgery, were enrolled. Implantation of the bone-anchored hearing aid implants were done using minimally invasive surgery with tissue preservation. Implant stability quotient (ISQ) values were recorded using resonance frequency analysis. Follow-ups were scheduled 5 to 12 days, 4 to 8 weeks, 6 months, and 12 months postoperatively. Differences between the lowest ISQ values (ISQ low) over time were analyzed by paired-samples t test with a significance level of 0.05. Skin and soft tissue reactions were assessed according to Holger's classification. Loading time of the Ponto Wide implant was 11.6 ± 1.4 days (SD) in average (median, 12 d; range, 7-19 d). Loading of the Ponto BHX implant was done 9.7 ± 3.5 days (SD) postoperatively (median, 9 d; range, 5-19 d). The implant stability increased significantly during the 12-month study period with both implants. One Ponto BHX implant was lost. Skin and soft tissue reactions were few in both groups. Across all planned follow-up visits, no skin and soft tissue reactions were observed in 86% (Ponto BHX implant) and 85% (Ponto Wide implant). Very early loading of sound processors after percutaneous bone-anchored hearing system surgery is safe already 1 to 2 weeks postoperatively.

Increasing the accuracy of an analogue-to-digital converter (ADC) with an intermediate voltage-to-frequency conversion

The article proposes an approach to increasing the resolution of integrated analogue-to-digital (ADC) converters with intermediate voltage-to-frequency conversion (VFC). At sampling rate1 kHz was achieved effective number of bits (ENOB) from 12 to 16. In addition, an approach to compensating for the non-linearity of voltage-to-frequency conversion was proposed. Across the range of measured voltages from 100 mV to 8 V, the voltage measurement error comprised no more than ±0.025 %, which corresponds to a five-and-a-half-bit voltmeter. The proposed device was implemented exclusively on mass-produced chips. The six independent ADC channels, implemented on 1316PP1AU VFCs, are serviced by a single 1986VE91 microcontroller, with the processor loading with the task of improving accuracy being no more than 10%.

Patient Preferences in Sound Processor Loading Time After BAHI Surgery.

Objective:Sound processor loading times after bone-anchored hearing implant (BAHI) surgery have gradually decreased over time. This study assessed patient preferences in loading time.Study Design:Prospective patient questionnaire study.Setting:Tertiary referral center.Patients:Patients indicated for BAHI surgery received two questionnaires preoperatively: the validated Glasgow Health Status Inventory (GHSI) and a nonvalidated questionnaire that assessed patient preference for loading time and the rationale behind it. This preference questionnaire was also provided immediately, 7 days and 3 weeks (moment of sound processor loading at our center) postoperatively.Main Outcome Measures:The preoperative and postoperative preferred loading time and the postoperative changes in preference were determined. Correlations between preference and patient-specific variables were assessed.Results:Sixty patients were included. Preoperatively, 70% preferred loading within 1 week after surgery. Of all patients, 43% preferred loading on the day of surgery, mainly motivated by the fast hearing rehabilitation and practical considerations. These preferences were not correlated with the total GHSI score or duration of hearing loss. Directly postoperatively, no change in preference was observed. However, 7 days and 3 weeks after surgery, significantly more patients preferred loading at a later moment. At 7 days and at 3 weeks, 50 and 40% preferred loading within 1 week, and 12.5 and 7.5% preferred loading on the day of surgery, respectively.Conclusion:The preference for the timing of sound processor loading varied among patients and differed pre- and postoperatively. Despite the postoperative decline in patients preferring earlier loading, approximately half of all patients preferred sound processor loading within 1 week after BAHI surgery.

Three-week loading of the 4.5 mm wide titanium implant in bone anchored hearing systems

PurposeThe purpose of this study is to assess implant stability, implant loss, adverse skin reactions and quality of life benefit following surgical implantation and early processor loading (3-weeks post-implantation) of the Oticon Ponto 4.5mm osseointegrated auditory implant. This study also investigates the relationship between the type of post-operative skin reactions and the gender, BMI and medical co-morbidities of participants. Materials/MethodsUsing a prospective, multicenter design, thirty adult patients 18years or older who met medical and audiological candidacy for an osseointegrated auditory bone-anchored hearing device were evaluated. They underwent simultaneous implantation of the Oticon 4.5mm wide implant and a 3.75mm sleeper implant. Sound processor loading occurred at three weeks post-implantation. Implant stability was measured using Radio Frequency Analysis (RFA) at surgery, 1, 3, 6, 12, 26 and 52weeks. The Glasgow Benefit Inventory was used to assess quality of life benefit at 12 and 52weeks following implantation. ResultsThe results show a positive linear trend in implant stability measures in all subjects over time. There have been no implant losses with early 3-week loading. Skin reactions were limited to grade 0 and 1 of the modified Holger's grading scale.Due to the limited incidence of complications, no conclusion can be made regarding the relationship between patient demographic data and soft tissue reaction. ConclusionOur findings confirm the safety and efficacy of early loading of the Oticon 4.5mm wide implant. Participants showed satisfaction with the earlier use of their processor with no added complications after one year post-implantation.

Experience and Outcomes of New Developments in Bone Conduction Hearing Technologies in Children

Objectives: (1) Recognize that percutaneous implant stability in children can be measured using radio frequency analysis (RFA) to generate Implant Stability Quotients (ISQs) and guide sound processor loading. (2) Discuss sound processor loading of the Cochlear BahaÒ (BIA300, BA400) transcutaneous implants at 4-6 weeks in selected children and potential advantages of the transcutaneous ATTRACT implant. Methods: We collected data prospectively on all children undergoing implantable BC implants at surgery and follow up appointments. We aimed to assess implant stability over time in children undergoing 1-stage surgery using RFA measurements and investigate the possible implications for earlier loading following surgery. Our experience and outcomes with the ATTRACT transcutaneous device as part of the controlled market release (3+ cases) will also be reviewed. Results: Nine children underwent 10 BI300 implants with a mean age of 9 years 4 months. 7 children received the BA400 percutaneous device without soft tissue reduction, with a mean age of 7 years 11 months. Using RFA the mean ISQ at surgery for BI300 implants was 60 and the corresponding unadjusted value for BA400 implants was 50. Changes in ISQs over time are discussed, showing the potential for processor loading at 4-6 weeks. Conclusions: Greater implant stability has been demonstrated using the BI300 and BA400 implants, which would subsequently enable early Baha loading. The transcutaneous ATTRACT system potentially offers further improvement in cosmesis and skin inflammation and is likely to have greater acceptance in children with microtia and canal atresia and those who would have previously declined Baha.

Initial experience of a rapid-insertion bone-anchored hearing system: series of 20 consecutive implants.

Objective: The loading of bone-anchored hearing system sound processors usually occurs two to three months after surgical implant. This study examined a new bone-anchored hearing system coupling mechanism that permits loading at two weeks post-implantation without compromising osseointegration. Methods: Twenty implants were implanted into 15 patients. The interval between operation and time of processor loading was recorded, along with the cause of any delay and any late complications. Results: Two patients were fitted with implants at seven and nine weeks. The delay was a result of administrative errors; the patients reported no skin problems. Of the remaining 17 implants, 8 processors were fitted at 2 weeks, 1 at 3 weeks, 4 at 4 weeks, 3 at 7 weeks and 1 at 8 weeks. For those nine implants fitted later than two weeks, the delay was because of incomplete skin healing. Conclusion: The Oticon Medical Xpress system allowed processor loading at two weeks post-operatively, providing skin healing was adequate. Early loading occurred in approximately half of the patients. All patients were fitted within the two to three months traditionally allowed. Prolonged skin healing time was the main reason for the delayed fitting of sound processors.

Stability Measurements of the Baha System in Children

Objectives: Bone conduction implant (eg, Baha®) stability can objectively be measured over time using radio-frequency analysis (RFA). Adult studies suggest that the Cochlear Baha BI300 Implant® may be loaded as soon as the soft tissue wound is healed. We aim to discuss implant stability in children using RFA measurements. Methods: Consecutive children having a Cochlear Baha BI300 Implant had RFA measurements taken peri-operatively, 1 week post-surgery, within 3 months of surgery, and then subsequently at least 3 monthly. RFA measurements were measured at loading of the hearing processor and at 1 week post-loading. Standard practice has been to load the implant at 3-6 months postoperatively. Results: Nine children had 10 Cochlear Baha BI300 implants® (8 unilateral and 1 bilateral) with a mean age of 9 years 4 months (4 years 9 months to 13 years 5 months). The mean time to loading of the hearing processor was 3.3 months (3 to 5 months, n = 9). Mean follow-up was 9 months (6 weeks to 23 months). Peri- and postoperative RFA measurements will be discussed with 6 children having RFAs sufficiently high for hearing processor loading much earlier post-implantation. Implant stability was maintained after loading with the hearing processor. Conclusions: This study indicates that a larger study is warranted to evaluate both the role of sequential RFA measurements in the timings of Baha hearing processor loading and the possibility of loading at 4-6 weeks in selected children. Subsequently RFA measurements may also be used to decide between single- and two-stage surgery.

CFD simulations for prediction of scaling effects in pharmaceutical fluidized bed processors at three scales

Abstract Experimental operation of three fluidized bed processors is compared with CFD simulation results. The capacities of the fluidized bed processors represent two orders of magnitude scale-up. Qualitative fluidization patterns as well as quantitative data are compared with simulated processor operation. The numerical method and simulation approach were found to successfully predict the flow behavior of several different sizes of fluidized beds based solely on material properties, processor loading, inlet air flow rate and fluidized bed process geometry.

Ethnic Disparity in Skin Complications following Bone-Anchored Hearing Aid Implantation

Sound processor loading after implantation of a bone-anchored hearing aid is often delayed by skin-site complications. This study examined the frequency of skin-site complications in various ethnic groups and determined factors that may lead to higher rates of skin-site complications resulting in delayed processor loading. Adult, English-speaking patients who underwent implantation of a bone-anchored hearing aid between 2007 and 2010 were reviewed. Demographic data including ethnicity, tobacco use, diabetes mellitus, immunosuppression, and long-term steroid use were determined. Major and minor skin-site complications and the time to processor loading were recorded. The mean time to processor loading was 9.5 weeks, and the mean follow-up time was 23 months. There were no cases of osseointegration failure. African American patients had a significantly higher rate of major skin-site complications (p < 0.005) and a longer time to processor loading (mean, 17.6 weeks; p < 0.05) than the other ethnic groups. There was no significant difference in minor skin complication rates. There was no correlation between diabetes mellitus, long-term immunosuppression, or tobacco use and skin-site complications. Skin complications can delay processor loading following implantation of a bone-anchored hearing aid. There is a higher rate of major skin-site complications in African American patients, and these often delay processor loading. The risk of skin-site complications is not correlated with smoking, diabetes mellitus, or immunosuppression. An increased risk of skin-site complications is an important consideration for preoperative counseling.

Stability of Osseointegrated Bone Conduction Systems in Children

To obtain objective data of bone conduction implant stability and osseointegration in children; to compare in pediatric subjects the stability and osseointegration of the novel TiOblast-coated implant system (BI300) to the previous generation, as-machined model. Multicenter, controlled, nonrandomized, longitudinal, prospective study. Tertiary referral center. IIIb Ten subjects were enrolled, aged younger than 16 years and without comorbidities that negatively affect osseointegration. All patients were implanted "single stage": 5 received the previous generation, pure titanium fixture (control group), and 5 were implanted the BI300, TiOblast-coated fixture (test group). Measurement of implant stability and osseointegration. Implant stability and osseointegration as measured by means of resonance frequency analysis intraoperatively, at 1 week, 2 weeks, 1 month, and every month till processor loading 6 months after surgery. BI300 is, on average, more stable than the control fixture, both intraoperatively and over time till processor loading. Over the 6 months' follow-up, a stability increase was observed with both models, although it resulted statistically not significant. The BI300 implant system has a greater primary stability as compared with the previous generation model, but its faster osseointegration could not be definitely verified. It is reasonable to assume that the BI300 fixture will enable surgeons to perform single-stage surgery more safely and with a lower failure rate. The possibility of an earlier processor loading remains to be confirmed in a greater sample.

Early Loading After Single‐Stage Bone‐Anchored Implantation in Adults

Classically, processor loading after single-stage bone-anchored implantation (BAI) surgery follows a 3-month osseointegration period. The purpose of this study was to examine audiometric outcomes and postoperative complications in adult patients undergoing single-stage BAI with processor loading at less than 6 weeks postoperatively. Retrospective review. Otology clinic in a tertiary care academic center. A retrospective review was performed of all adult patients (>18 years) undergoing BAI from 2007 to 2010. Sixty-four patients met inclusion criteria. Fifty-five patients had unilateral hearing loss, including single-sided deafness, conductive hearing loss, or mixed hearing loss. Nine patients had bilateral hearing loss. Patients were divided into groups based on time to processor loading (>12 weeks, <12 weeks, <6 weeks). All patients were loaded with the external processor at less than 6 weeks when possible. Preoperative and postoperative audiometric evaluations were performed. There were no cases of osseointegration failure. All groups showed significant improvement in audiometric testing using their BAI (P < .005), and there were no significant differences between patients loaded at less than 12 weeks and those loaded at less than 6 weeks (P > .05). Major skin complications were seen in 9% of subjects and minor complications in 30%. Single-stage BAI implantation with early processor loading is safe and effective in adults. All groups demonstrated significant audiometric benefit that was not affected in patients loaded early. Major and minor skin-site complications frequently delayed processor loading, but there were no cases of osseointegration failure in any group.

Envelope-based amplitude mapping for cochlear implant stimulus

An envelope based amplitude mapping achieves the signal compression required to provide a natural sound level without the high processor loading or waveform alteration. In one embodiment, the output of a family of parallel bandpass filters is processed by an envelope detector, followed by decimation. The resulting reduced data rate envelope is log mapped to produce a scaling factor for the original high data rate bandpass filter output sequence. The resulting scaled signal determines the current level for stimulation of the cochlea for each frequency band, which stimulation achieves a log mapping of the sound amplitude effect similar to natural hearing, while reducing processor load, and preserving waveform shape.

Using intelligent agent templates for dynamic structuring of distributed computer control systems

The development and implementation of a distributed computer control system that uses communication both for structuring and for knowledge and information transfer between agents is described. The agent-centered approach relies on the use of agent templates and interaction rules. This approach results in a distributed computer control system that adapts to changes in operating requirements, and provides improved fault-tolerance over less adaptive distributed controllers. The implemented distributed controller simulates a simple conventional controller, and is used to demonstrate the effect of the approach on system performance. Processor loading and network traffic due to dynamic distributed structuring are shown to be minimal.

Effect of Dynamic Structuring on Distributed Control System Performance

Abstract The performance of a distributed computer control system that uses communication both for structuring and for knowledge and information transfer between agents is discussed. This agent-centred approach relies on the use of agent templates and interaction rules — resulting in a distributed computer control system framework that is able to adapt as operating requirements change. Implementation of a distributed controller, which simulates a simple conventional controller is described. The effect on performance of this approach, both in terms of processor loading and network traffic is shown to be minimal.

Open-loop versus closed-loop control of processor loading

In many processing systems, the goodput (the number of succesfully completed tasks per time unit) may decrease as the offered load increases. Such systems need some form of overload control. We distinguish between open-loop control that limits the number of tasks in the system with a fixed maximum and closed-loop control that rejects new tasks if the observed processor loading is too high. In most control systems closed-loop control performs better than open-loop control. Here we present a remarkable illustration of the converse: we show that higher goodput can be obtained with an open-loop control-law. The results are obtained with a simplified analytical model of a multi-tasking processing system, such as the central processor of a telephone exchange. Compared to open-loop control, closed-loop control is more robust with respect to a change in task idle-time. Under conditions of overload, the mentioned differences between the two types of control law become more pronounced. The computed results are confirmed by the outcome of simulation runs. In the simulations we used a more realistic definition of goodput than was used in the analytical model.

Task assignment with precedence relations in distributed computing systems

Abstract This paper addresses the problem of assigning a task with precedence constraints to a distributed computing system. A cost function considering communication overhead and idle time is adopted to measure the performance of the task assignment. The task assignment in this paper determines not only the assignment of modules but also the sequence of messages transmission to balance processor loading and diminish communication overhead. The search for the optimal task assignment with precedence constraints is known to be NP‐complete [7] in the strong sense. A heuristic algorithm with polynomial time complexity is proposed in order to effectively solve the task assignment problem. The experimental results reveal that the proposed approach is able to obtain a near‐optimal or even the optimal task assignment.

A Graph Matching Approach to Optimal Task Assignment in Distributed Computing Systems Using a Minimax Criterion

A graph matching approach is proposed in this paper for solving the task assignment problem encountered in distributed computing systems. A cost function defined in terms of a single unit, time, is proposed for evaluating the effectiveness of task assignment. This cost function represents the maximum time for a task to complete module execution and communication in all the processors. A new optimization criterion, called the minimax criterion, is also proposed, based on which both minimization of interprocessor communication and balance of processor loading can be achieved. The proposed approach allows various system constraints to be included for consideration. With the proposed cost function and the minimax criterion, optimal task assignment is defined. Graphs are then used to represent the module relationship of a given task and the processor structure of a distributed computing system. Module assignment to system processors is transformed into a type of graph matching, called weak homomorphism. The search of optimal weak homomorphism corresponding to optimal task assignment is next formulated as a state-space search problem. It is then solved by the well-known A* algorithm in artificial intelligence after proper heuristic information for speeding up the search is suggested. An illustrative example and some experimental results are also included to show the effectiveness of the heuristic search.

Design Features of Graphical Displays Used in the Monitoring of Electricity Distribution Systems

Graphical displays have been used to monitor large distribution systems for a number of years. One of the first of these systems was the United Kingdom Central Electricity Generating Board distribution network. This paper discusses the user experience covering hardware, software and operator acceptance features.The design features of a new graphical display are discussed showing the improvements to the design which have been carried out as a result of user comment.These features have resulted in improved operator acceptance and allow greater freedom of display manipulation with the minimum of processor loading and storage.