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Auditory Prostheses (AP) are widely used electronic devices for patients suffering with severe to profound senosorineural deafness by electrically stimulating the auditory nerve using an electrode array surgically placed in the inner ear. AP mainly contains external Body Worn Speech Processor (BWSP) and internal Implantable Receiver Stimulator (IRS). BWSP receives an external sound or speech and generates encoded speech data bits for transmission to IRS via radio frequency transcutaneous link for excitation of electrode array. After surgical placement electrode array in the inner ear, BWSP should be fine tuned to achieve the 80-100% speech reception abilities of patient by an audiologist. Problem statement: Basic objective of this research was to develop a simple personal computer based user friendly hardware and software interface to fine tune the BWSP to achieve the best possible speech reception abilities of each individual patient. Approach: Tuning process involved several tasks such as identifying the active electrode contacts, determination of detection and pain thresholds of each active electrode and loads these values into BWSP by reprogramming the BWSP. This study contracted with development of easy and simple user friendly hardware and software interface for audiologist to perform post operation tuning procedures. A microcontroller based impedance telemetry with bidirectional RF transceiver was developed as a hardware interface between PC and IRS. The clinical programming software was developed using VB.NET 2008 to perform the postoperative tuning procedures such as (i) impedance measurement, (ii) fitting to determine the threshold and comfort levels for each active electrodes and (iii) reprogramming the speech processor. Results: Simple hardware and software interfaces for audiologist were constructed and tested with laboratory model BWSP and IRS using simulated resistance electrode array. All the functional aspects were tested and results were enumerated. Conclusion: Clinical application software had been developed for AP used in postoperative fitting procedure used by the audiologists. Software is readily available for use after the laboratory model of BWSP and IRS are available as final product. Key words: Cochlear implants, clinical programming, fitting, auditory prosthesis, INTRODUCTION A Cochlear Implant (CI) or auditory prosthesis has recently emerged as clinically acceptable prosthesis for people who suffer from a profound hearing loss (1-8). With the help of modern [...]

This study investigated the use of surface electromyography (EMG) combined with pattern recognition (PR) to identify user locomotion modes. Due to the nonstationary characteristics of leg EMG signals during locomotion, a new phase-dependent EMG PR strategy was proposed for classifying the user's locomotion modes. The variables of the system were studied for accurate classification and timely system response. The developed PR system was tested on EMG data collected from eight able-bodied subjects and two subjects with long transfemoral (TF) amputations while they were walking on different terrains or paths. The results showed reliable classification for the seven tested modes. For eight able-bodied subjects, the average classification errors in the four defined phases using ten electrodes located over the muscles above the knee (simulating EMG from the residual limb of a TF amputee) were 12.4% [+ or -] 5.0%, 6.0% [+ or -] 4.7%, 7.5% [+ or -] 5.1%, and 5.2% [+ or -] 3.7%, respectively. Comparable results were also observed in our pilot study on the subjects with TF amputations. The outcome of this investigation could promote the future design of neural-controlled artificial legs. Index Terms--Electromyography (EMG), neural-machine interface, pattern recognition (PR), prosthesis, targeted muscle reinnervation.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ahj.2008.04.003 Byline: Jason Swindle (a), Thomas E. Burroughs (a), Mark A. Schnitzler (a), Paul J. Hauptman (a)(b) Abstract: The use of implantable cardiac devices in the management of heart failure has increased, but patient selection and inhospital outcomes in clinical practice have not been critically explored. Therefore, we evaluated the inhospital mortality and costs associated with patients with heart failure who received an implantable cardioverter defibrillator, cardiac resynchronization device, or device lead. Author Affiliation: (a) Center for Outcomes Research, Saint Louis University School of Medicine, St Louis, MO (b) Division of Cardiology, Department of Medicine, Saint Louis University School of Medicine, St Louis, MO Article History: Received 7 January 2008; Accepted 3 April 2008 Article Note: (footnote) The study is supported in part by National Institutes of Health RO1-AG021515 (Dr P Hauptman)., Dr Hauptman: Grant support from the National Institutes of Health; local site coinvestigator on the SCD-HeFT trial. Mr Swindle: No relevant financial relationships. Dr Burroughs: No relevant financial relationships. Dr Schnitzler: No relevant financial relationships.

Two experiments were conducted to investigate the effects of ractopamine-HC1 (RAC) and implant strategy or days on feed (DOF) on feedlot performance and expression of [beta]-adrenergic receptors (AR). In Exp. 1, 1,147 feedlot heifers weighing 282 [+ or -]3 kg were used with implant treatments of Revalor-200 (R200) at arrival, or Revalor-IH at arrival with reimplantation with Finaplix-H on d 58 (RF). Ractopamine (0 vs. 200 mg/d) was fed the last 28 d in both experiments. Treatments were randomly assigned to 16 pens. At slaughter, semimembranosus muscle tissue was excised for RNA isolation. Ractopamine administration increased (P < 0.05) ADG, G:F, HCW, and LM; decreased (P < 0.05) 12th rib fat depth; and improved (P < 0.05) yield grade. There was no effect (P > 0.10) on the expression of [[beta].sub.1]AR mRNA; however, there was a tendency (P = 0.10) for RAC feeding to increase [[beta].sub.2]-AR mRNA levels. For [[beta].sub.3]-AR mRNA, there was an implant by RAC interaction (P = 0.05), with RAC numerically increasing [[beta].sub.3]-AR mRNA in heifers implanted with RF, but a decrease (P < 0.05) in expression in heifers implanted with R200. Ractopamine also decreased (P < 0.05) IGF-I mRNA in heifers implanted with RF. In Exp. 2, 2,077 heifers were used to investigate the effects of RAC and DOF. Days on feed were 129, 150, and 170, and RAC was administered the last 28 d. Ractopamine improved (P < 0.05) G:F, but had no other effects (P > 0.05) on performance. Average daily gain decreased (P < 0.05) as DOF increased. Hot carcass weight, LM area, 12th rib fat, G:F, calculated yield grade, and marbling score increased (P < 0.05) and the percentage of KPH fat decreased (P < 0.05) as DOF increased. These data aid in our understanding of the effects of steroidal implants, DOF, and RAC administration in feedlot heifers. Key words: bovine, heifer, ractopamine, skeletal muscle, steroidal implant

The aim of this study was to investigate the feasibility of using external urethral sphincter electromyogram (EMG) ([EUS.sub.EMG]) to detect the onset of detrusor contractions in patients with both neurogenic detrusor overactivity (NDO) and detrusor sphincter dyssynergia (DSD). Detrusor pressure ([P.sub.det]) and [EUS.sub.EMG] was recorded in 23 neurogenic patients during slow artificial bladder filling. The time delay between the onset of a detrusor contraction and the onset of [EUS.sub.EMG] activity was calculated together with the detrusor pressure increase related to this delay. Of 23 patients enrolled, 12 patients showed both NDO and DSD. Of these 12 patients, 10 had a strong correlation between detrusor pressure and [EUS.sub.EMG]. One patient in this group was excluded due to a storage pressure above 30 cm [H.sub.2]O. Two detection methods were applied on the remaining 9 patients. Method 1 was a root mean square (RMS)-integrator with simple thresholding. This approach had a good sensitivity but also a poor specificity (many false-positive detections). Detection method 2 included a kurtosis-based scaling function, which was multiplied to a similar RMS-integrator as used in method 1. Onset detection occurred before [P.sub.det] exceeded 18 cm [H.sub.2]O with both methods. However, method 1 resulted in 14.1 [+ or -] 12.8 false-positive detections during one bladder filling. [P.sub.det] at onset detection was on average 1.0 [+ or -] 1.1 cm[H.sub.2]O higher with detection method 2 but the number of false-positives was reduced by 95.8%. This paper demonstrates the feasibility of using [EUS.sub.EMG] to estimate the onset of a detrusor contraction in selected patients. Index Terms--Electromyography, neural prostheses, neurogenic bladder, spinal cord injury, urinary incontinence.

Byline: Yoshio Kobayashi, Seiki Nagata, Kiyoyuki Eishi, Kiyoharu Nakano, Kunio Miyatake Abstract: Background: Doppler echocardiography is a valuable noninvasive method for evaluating of the occurrence and degree of either prosthetic valve stenosis or regurgitation. By using serial Doppler echocardiographic examination, we evaluated the incidence and the mode of the Carpentier-Edwards pericardial valve (CEPX) dysfunction compared with that of the Ionescu-Shiley valve (IS). Methods and Results: After aortic and/or mitral valve replacement, 80 patients with CEPX and 111 with IS underwent Doppler echocardiography at intervals of at least 2 years after surgery. The average durations of follow-up were 6.1 [+ or -] 2.9 years for patients with CEPX and 7.2 [+ or -] 3.0 years for those with IS. Bioprosthetic valve stenosis was defined as reduced excursion of the bioprosthetic valve leaflets and peak gradient [greater than or equal to]60 mm Hg after aortic valve replacement and mean gradient [greater than or equal to]7 mm Hg after mitral valve replacement. Bioprosthetic valve regurgitation caused by bioprosthetic valve dysfunction was defined as grade [greater than or equal to]3 transvalvular regurgitation. In the aortic position, although there was no significant difference in the actuarial rate of freedom from bioprosthetic valve stenosis between patients with IS and those with CEPX (10 years after surgery, 88% [+ or -] 7% vs 90%, NS), bioprosthetic regurgitation caused by bioprosthetic valve dysfunction occurred less frequently in patients with CEPX than in those with IS (10 years after surgery, 86% vs 54% [+ or -] 9%, p < 0.05). In the mitral position, bioprosthetic valve stenosis occurred more frequently in patients with CEPX than in those with IS (10 years after surgery, 54% [+ or -] 11% vs 72% [+ or -] 8%, p < 0.01). Although grade [greater than or equal to]3 transvalvular bioprosthetic regurgitation occurred later in patients with CEPX than in those with IS, there was no significant difference in the actuarial rate of freedom from that regurgitation between patients with CEPX and those with IS (10 years after surgery, 63% [+ or -] 10% vs 54% [+ or -] 7%, NS). Conclusions: For aortic valve replacement, CEPX has good long-term durability because of the low incidence of bioprosthetic regurgitation. For mitral valve replacement, long-term durability of CEPX is poor, although medium-term durability is satisfactory. (Am Heart J 1998;135:1086-92.) Author Affiliation: Osaka, Japan Article History: Received 5 December 1996; Accepted 4 February 1998 Article Note: (footnote) [star] From the Division of Cardiology, Department of Internal Medicine, and the Division of Cardiovascular Surgery, National Cardiovascular Center., [star][star] Reprint requests: Kunio Miyatake, MD, Division of Cardiology, Department of Internal Medicine, National Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565, Japan., a 4/1/89401

Radio frequency (RF) heating of an implanted spinal fusion stimulator (SpF) during magnetic resonance imaging (MRI) was studied on a full-size human phantom. Heating during MRI scans (GE Signa 4X, 1.5 T) was measured with RF-transparent fiberoptic sensors. With the implant correctly connected, the maximum temperature rises were less than 2 [degrees] C during the 26 min that the scans were at maximum RF power. At the tip of a broken stimulator lead (connecting the SpF generator and its electrodes), the maximum temperature rise was 11-14 [degrees] C. Regular 4-min scans of the spinal cord produced similar temperature rises at the broken tip. After the generator and the leads were removed, heating at the electrode connector tip was less than 1.5 [degrees] C. The control temperature rises at the same locations, without the stimulator, were less than 0.5 [degrees] C. This study shows that spinal fusion stimulator heating is within the Food and Drug Administration safety guideline of 2 [degrees] C. However, if a lead wire is broken, it is unsafe during MRI scans. Radiological examinations will be necessary to ensure the integrity of the implant. Index Terms - Bone fusion, induced current, phantom model, RF energy absorption, thermal effect.

Surgical closure of patent ductus arteriosus may be more effective and less expensive than implanting an occluder device with a catheter. Patent ductus arteriosus is a birth defect characterized by an opening between the aorta and the pulmonary artery. Among 631 children treated for patent ductus arteriosus from 1982 to 1987, 185 had an occluder implanted and 446 had conventional surgical closure. The surgical closure was successful in all cases. The implant procedure was successful in only 86.5% of cases, even after some patients had further surgery. There were fewer significant complications in the surgical closure group. Average costs per patient for the procedures, including hospital care and follow-up, were $8,838 for surgical closure and $11,466 for occluder implantation. The occluder implantation involves more sophisticated and costly technology and has a lower success rate than the standard surgical closure method.

Catheter implantation of an occluder device for closing a patent ductus arteriosus may prove to be an acceptable alternative to surgery. Patent ductus arteriosus is a birth defect characterized by an opening between the aorta and the pulmonary artery. This opening normally closes shortly after birth. In premature infants, closure can sometimes be stimulated with the drug indomethacin. Infants whose ductus arteriosus does not close are at risk of heart failure. Surgical closure of patent ductus arteriosus has been used since 1939. Occluder implantation has been used in Europe since 1982. A study compared the two techniques and concluded that surgical closure was more effective and less costly than occluder implantation. However, the time span of that study may not have been sufficient to judge the success of the occluder implantation technique. The new technique should improve with experience, and costs should drop accordingly.