Intracavernosal pressure characteristics analyzed by power spectral density for identifying the phase of penile erection.

Knowledge of the time course of penile erection is very important to understanding erection physiology. The changes in the intracavernosal pressure (ICP) and the different phases of an erection are pivotal to the ability to produce and maintain a rigid penile erection. This study investigated an objective and low-invasiveness method for identifying different erection phases based on an innovative ICP analysis technique. Blood infuses into the corpora cavernosa and causes the ICP to increase. The ICP usually exhibits tiny oscillations at the frequency of the heartbeat when it increases from diastole to systole. The characteristic oscillation amplitudes corresponding to the period when the full and rigid erection phases begin can be extracted by power spectral density analysis. The reliability and accuracy of the proposed method was verified by the Bland-Altman graphs indicating a good agreement with the existing method that compares the ICP with the arterial pressure. Moreover, all of the intraclass correlation coefficient values were close to 1.00, with the lower limit of the 95% confidence interval exceeding 0.75. The described novel objective and low-invasiveness method can therefore be used for identifying the full and rigid erection phases of the penis in urological investigations during different erection phases.

Industrial wideband noise reduction for hearing aids using a headset with adaptive-feedback active noise cancellation.

High-intensity noises are a health hazard for industrial workers, and hearing protection is necessary to prevent hearing loss. Passive methods, such as ear muffs, are ineffective against low-frequency noise. Moreover, many hearing-impaired workers must wear hearing aids to enable communication at their workplace, and such aids can amplify ambient noise. To overcome this problem, the present study developed a headset equipped with a digital signal processing system to implement adaptive-feedback active noise cancellation (AFANC) to reduce low-frequency noise. The proposed AFANC headset was effective against wideband industrial noise, with a maximum noise spectrum power reduction of 30 dB. Furthermore, when used with a hearing aid, it improved the speech signal-to-noise ratio by up to 14 dB. These results suggest that a headset with AFANC would be useful for hearing protection in workplaces with high levels of low-frequency industrial noise, especially for hearing-impaired workers.

Genetic algorithm for the efficient selection of disyllabic word lists used in Mandarin speech discrimination tests.

Speech audiometric tests have been widely used for advanced hearing diagnoses and in rehabilitation. However, there are no standardised speech tests for more than 90% of the world's population, who do not speak English. A major problem in the design of a speech audiometric test is that the selection of test materials is subject to multiple criteria, and its complexity rises dramatically as the structure of test items changes from phonemic or monosyllabic forms to disyllabic or polysyllabic forms. A genetic algorithm is presented that can automatically select a set of disyllabic words from a large Mandarin corpus. The selection accords with the following principal criteria for the items constituting a speech discrimination test: similarity in structure, familiarity to the subjects, and a phonemically balanced composition. The performance of the genetic algorithm was evaluated by computation of the distance between a target vector, specifying the desired distribution of initial and final syllables and tone patterns for daily disyllabic word usage, and the vector derived by the search results of the algorithm. The use of the genetic algorithm was illustrated by its application to the selection of test lists from two Mandarin corpora. The results showed that, for a given corpus, at least 12 disyllabic word lists with a distance of less than 20 could be generated within 72 h. The genetic algorithm performed an efficient, robust and low-complexity search of the problem space and can be easily modified to adapt to the material selection of other languages.

Rapid prototyping strategy for a surgical data warehouse.

OBJECTIVES: Healthcare processes typically generate an enormous volume of patient information. This information largely represents unexploited knowledge, since current hospital operational systems (e.g., HIS, RIS) are not suitable for knowledge exploitation. Data warehousing provides an attractive method for solving these problems, but the process is very complicated. This study presents a novel strategy for effectively implementing a healthcare data warehouse. METHODS: This study adopted the rapid prototyping (RP) method, which involves intensive interactions. System developers and users were closely linked throughout the life cycle of the system development. The presence of iterative RP loops meant that the system requirements were increasingly integrated and problems were gradually solved, such that the prototype system evolved into the final operational system. RESULTS: The results were analyzed by monitoring the series of iterative RP loops. First a definite workflow for ensuring data completeness was established, taking a patient-oriented viewpoint when collecting the data. Subsequently the system architecture was determined for data retrieval, storage, and manipulation. This architecture also clarifies the relationships among the novel system and legacy systems. Finally, a graphic user interface for data presentation was implemented. CONCLUSIONS: Our results clearly demonstrate the potential for adopting an RP strategy in the successful establishment of a healthcare data warehouse. The strategy can be modified and expanded to provide new services or support new application domains. The design patterns and modular architecture used in the framework will be useful in solving problems in different healthcare domains.

Effects of noise on transient-evoked oto-acoustic emission pass/fail criteria.

This study investigated the effects of noise on typical transient-evoked oto-acoustic emission (TEOAE) pass/fail criteria. Different levels of synthesised noise were added to one TEOAE signal, to determine the relationship between the signal-to-noise ratio (SNR) and typical TEOAE parameters: reproducibility, TEOAE level and corrected TEOAE level. Results showed that, with the same TEOAE signal, if the SNR decreased from 19 dB to -7 dB, the means of estimated reproducibility decreased from 97% to 7%, and the means of estimated TEOAE levels were doubled. Only the means of estimated corrected TEOAE levels were relatively insensitive to SNR. The standard deviations of all TEOAE parameter estimators increased with decreasing SNR. With these results, this study proposed that each typical TEOAE parameter alone should not be taken as the absolute pass/fail criterion. A combination of the corrected TEOAE level and the reproducibility would be better.

Modification of the wavelet method used in transiently evoked otoacoustic emission pass/fail criterion to increase its accuracy.

Transiently evoked otoacoustic emissions (TEOAEs) are widely used in newborn hearing screening programmes for early detection of hearing losses. To increase the accuracy of a TEOAE pass/fail criterion that uses the wavelet method, it was demonstrated that the large estimation variance is a possible reason for the inaccuracy, and a modified wavelet method is proposed to solve the inaccuracy problem. In the modified wavelet method, N paired buffers, instead of only one, were used to store the total 512 subaveraged responses, and then the average of the calculated N cross-correlation coefficients between N pairs of TEOAE signals was taken in the pass/fail criterion. Four sets of 256 synthesised noise and eight sets of 256 synthesised noisy TEOAE signals were tested, and each set was tested 1,000 times. The results showed that the standard deviation of the correlation estimation was greatly reduced by using this average value with N selected as 4. As a result, the total number of single-scale cross-correlation coefficients below 50% decreased from 1281 to 195 for noisy TEOAE signals, and the total number of single-scale cross-correlation coefficients above 50% decreased from 90 to 0 for synthesised noise.

Electrogastrographic characteristics in patients of stomach cancer.

Using a homemade electrogastrography (EGG) system, we studied the characteristics of myoelectrical rhythm in gastric cancer (GC) patients. Based on a short-term Fourier transform, recorded slow waves could be automatically analyzed to obtain the following parameters: dominant frequency/power, percent of normal rhythm (2.4-3.7 cpm), power ratio, etc. Fifty histologically confirmed GC patients (34 men, 16 women) were enrolled before surgical intervention to measure their fasting and postprandial EGG parameters for 30 min. The cancerous parameters of GC patients were then obtained postoperatively. In addition, 46 healthy subjects were enrolled for comparison. When compared to controls, GC patients had the following characteristics: absence of postprandial increase in dominant frequency (GC: 3.04 +/- 0.47 vs 3.07 +/- 0.44 cpm, NS; controls: 3.02 +/- 0.31 vs 3.21 +/- 0.25 cpm, P < 0.001), marked power response after meal (P < 0.05), and obvious power ratio (4.58 +/- 7.38 vs 2.27 +/- 2.05, P < 0.05). Multivariate analysis indicated that advanced GC was the factor responsible for the obvious dominant power enhancement after meal (P < 0.05). Other demographic, clinical, and cancerous factors did not influence EGG parameters. We conclude that apparent arrhythmia is not encountered in GC patients, although they mainly exhibit obvious postprandial power response. Advanced GC is likely responsible for this power enhancement on EGG recording.

Influence of carvedilol on hospitalizations in heart failure: incidence, resource utilization and costs. U.S. Carvedilol Heart Failure Study Group.

BACKGROUND: Carvedilol reduces disease progression in heart failure, but to our knowledge, its effects on hospitalizations and costs have not been evaluated. OBJECTIVES: We examined the effects on hospitalization frequency and costs in the U.S. Carvedilol Heart Failure Trials Program. This program consisted of four concurrent, multicenter, double-blind, placebo-controlled studies involving 1,094 patients with New York Heart Association class II to IV heart failure, which treated patients with placebo or carvedilol for up to 15 months (median, 6.5 months). METHODS: Detailed resource utilization data were collected for all hospitalizations occurring between randomization and the end of follow-up. In-patient care costs were estimated based on observed levels of resource use. RESULTS: Compared with placebo, carvedilol reduced the risk of hospitalization for any reason by 29% (p = 0.009), cardiovascular hospitalizations by 28% (p = 0.034) and heart failure hospitalizations by 38% (p = 0.041). Carvedilol also decreased the mean number of hospitalizations per patient (for cardiovascular reasons 30% [p = 0.02], for heart failure 53% [p = 0.03]). Among hospitalized patients, carvedilol reduced severity of illness during hospital admission, as reflected by shorter length of stay and less frequent use of intensive care. For heart failure hospital admissions, carvedilol decreased mean length of stay by 37% (p = 0.03) and mean number of intensive care unit/coronary care unit days by 83% (p = 0.001), with similar effects on cardiovascular admissions. As a result, estimated inpatient care costs with carvedilol were 57% lower for cardiovascular admissions (p = 0.016) and 81% lower for heart failure admissions (p = 0.022). CONCLUSIONS: Carvedilol added to angiotensin-converting enzyme inhibition reduces hospitalization risk as well as severity of illness and resource utilization during admission in patients with chronic heart failure.

Race and the response to adrenergic blockade with carvedilol in patients with chronic heart failure.

BACKGROUND: The benefits of angiotensin-converting-enzyme inhibitors and beta-blockers may be smaller in black patients than in patients of other races, but it is unknown whether race influences the response to carvedilol in patients with chronic heart failure. METHODS: In the U.S. Carvedilol Heart Failure Trials Program, 217 black and 877 nonblack patients (in New York Heart Association class II, III, or IV and with a left ventricular ejection fraction of no more than 0.35) were randomly assigned to receive placebo or carvedilol (at doses of 6.25 to 50 mg twice daily) for up to 15 months. The effects of carvedilol on ejection fraction, clinical status, and major clinical events were retrospectively compared between black and nonblack patients. RESULTS: As compared with placebo, carvedilol lowered the risk of death from any cause or hospitalization for any reason by 48 percent in black patients and by 30 percent in nonblack patients. Carvedilol reduced the risk of worsening heart failure (heart failure leading to death, hospitalization, or a sustained increase in medication) by 54 percent in black patients and by 51 percent in nonblack patients. The ratios of the relative risks associated with carvedilol for these two outcome variables in black as compared with nonblack patients were 0.74 (95 percent confidence interval, 0.42 to 1.34) and 0.94 (95 percent confidence interval, 0.43 to 2.05), respectively. Carvedilol also improved functional class, ejection fraction, and the patients' and physicians' global assessments in both the black patients and the nonblack patients. For all these measures of outcome and clinical status, carvedilol was superior to placebo within each racial cohort (P<0.05 in all analyses), and there was no significant interaction between race and treatment (P> 0.05 in all analyses). CONCLUSIONS: The benefit of carvedilol was apparent and of similar magnitude in both black and nonblack patients with heart failure.

Real-time display of the stomach slow wave and its parameters in a newly designed electrogastrographic system.

We designed a new three-channel electrogastrographic (EGG) system, which was easily operated on the Windows 95 platform and could automatically provide slow wave parameters. The purpose of the present study was to test its reliability and accuracy in clinical recording. The system included a signal acquisition device assembled on a printed circuit board. Recorded myoelectrical signals were filtered, amplified, digitized, and transmitted via this device into a notebook personal computer (PC). Based on the short-term Fourier transform the software could transfer the time domain of the signal into the frequency domain. Real-time displayed slow wave parameters, including dominant frequency/power, percent of normal frequency (2-4 cpm), instability coefficient in frequency/power, and power ratio, were automatically renewed every 64s. Twenty healthy subjects (M/F, 12/8; age, 23-51 years) were enrolled to measure both fast and postprandial myoelectrical activities for each 30-min recording. Our results indicated that meal ingestion significantly increased dominant frequency (3.15+/-0.20 vs 3.23+/-0.23 cpm; P < 0.05) and power (26.1+/-3.8 vs 28.4+/-3.9 dB; P < 0.05). The power ratio of the meal effect was 2.02+/-2.07. Other parameters, including instability coefficient and percent of normal frequency, remained similar despite food ingestion. This newly designed EGG system is acceptable for clinically measuring gastric myoelectrical activity; the real-time display of many EGG parameters is an advantage with this new system.

Color encoding of the two-dimensional echocardiograms to analyze the echo texture of thickened mitral leaflets.

OBJECTIVE: The visual identification of different brightness of two-dimensional echocardiograms has natural limitations. The aim of this study was to perform a color-encoding technique on the echocardiograms and to evaluate whether the thickened mitral valve due to different etiologies may exhibit different colors and textures. DESIGN: Two-dimensional echocardiograms in parasternal long axis view in late diastole were digitized in 28 patients with thickened mitral valves and 14 age-matched control subjects. These 28 patients included 14 patients with mitral valve prolapse (MVP) and 14 patients with rheumatic change of mitral valve (RMV). The mean gray level of the anterior mitral valve and the skewness of the histogram of gray level distribution of the anterior mitral valve were studied in all cases. RESULTS: A significantly greater mean gray level of mitral valves in patients with RMV (114 +/- 20, p < 0.001) and lesser mean gray level in patients with MVP (49 +/- 12, p = 0.041) compared to that of control subjects (62 +/- 18) were noted. The mitral valves of the echocardiograms of patients with MVP tended to show a blue-to-green color, while those of RMV tended to show a yellow-to-orange color by this image processing system. Significant differences in skewness of the gray level distribution of mitral valves in control vs RMV (p = 0.001), control vs MVP (p = 0.005), and RMV vs MVP (p < 0.001) were also found. CONCLUSION: This study demonstrates that the thickened mitral valves due to MVP and RMV may exhibit different colors and textures. Digital image processing can provide additional information to conventional echocardiograms in characterizing different echo textures of the heart valves.

A novel speech controller for radio amateurs with a vision impairment.

This paper describes a portable speech controller system for persons with a vision impairment to adjust the channel frequency of a radio set via speech commands. The speech commands are recognized on a general-purpose digital signal processor using a hidden Markov model (HMM), and are used to remotely control radio channel changes.

Autostage sperm tracing system for semen evaluation.

To overcome the limitation of the microscope field, the study proposed an autostage sperm tracing system (ASTS), which could trace a particular sperm for a long time and distance. The ASTS was constructed by assembling a commercial microscope, an image frame grabber, a personal computer, and a motorized stage. Its performance was tested by evaluating 6 semen samples and by comparing the evaluation with those of other semen evaluations. The ASTS broke through the limitation of the microscope field and traced a particular sperm as long as possible. It analyzed the sperm track and calculated the motility parameters, such as curvilinear velocity (Vcl), straight-line velocity (Vsl), and linearity (L(in)). The sperm quality was then evaluated in real time, and the user could decide to capture or abandon a particular sperm in the IVF The ASTS enables users to evaluate sperm progression for a long time and to have the global quality of a particular sperm in real time. Its open structure has the flexibility for micromanipulating a semen sample, and has the potential application associated with a modern IVF technique.

A probability-based multivariate statistical algorithm for autofluorescence spectroscopic identification of oral carcinogenesis.

A probability-based multivariate statistical algorithm combining partial least-squares (PLS) and logistic regression was developed to identify the development stages of oral cancer through analysis of autofluorescence spectra of oral tissues. Tissues were taken from a 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis model. Analyses were conducted at various excitation wavelengths, ranging from 280 nm to 400 nm in 20 nm increments, to assess classification performance at different excitations. For each excitation the PLS analysis and logistic regression were combined, on the basis of cross validation, to calculate the posterior probabilities of samples belonging to four stages of cancer development: normal tissues, hyperplasia, dysplasia and early cancers and frankly invasive cancers. Results showed that the 320 nm excitation wavelength optimally classified the cancer development stages: the accuracy rates for identifying samples at that excitation were 91.7%, 83.3%, 66.7% and 83.3% for the four respective stages. The average accuracy rate was 81.3%. These results suggest that the algorithm described in this study might be useful for the detection of human oral cancers.

New system for long-term monitoring of sperm motility: EDTA effect on semen.

Many drugs act as sperm stimulants and are of clinical value for male infertility. Current research deals with the physiological mechanisms of sperm motility/sperm stimulation and how long the effect lasts. For such a study, long-term monitoring of sperm motility becomes essential for traditional semen evaluation. A new system was designed to deal with the microscopic images of semen. Its performance was evaluated by studying the effect of EDTA on sperm motility. EDTA increased sperm curvilinear velocity (Vcl) and straight-line velocity (Vsl) by 31 and 20%. EDTA also prolonged the duration of motility by 68 and 61%, respectively. However, EDTA had less effect on the linearity of forward progression (Lin). The proposed system can analyze semen and does well at monitoring sperm motility for short term and long term. It may be valuable to test the possible role of sperm stimulation for male infertility and assisted reproduction.

Safety and efficacy of carvedilol in severe heart failure. The U.S. Carvedilol Heart Failure Study Group.

BACKGROUND: Many patients remain markedly symptomatic despite optimal current therapy for heart failure. Beta-blockers have often been viewed as contraindicated in this group because of their potential adverse short-term effects on cardiac function. METHODS AND RESULTS: One hundred thirty-one patients with severe congestive heart failure were enrolled into a double-blind, placebo-controlled study of the vasodilating beta-blocker carvedilol. All patients had symptomatic, advanced heart failure while on standard triple therapy, as evidenced by a mean ejection fraction of 0.22, marked reduction in distance traveled in a 6-minute corridor walk test, and severe impairment in quality of life measured by the Minnesota Living With Heart Failure Questionnaire. After a 2-week, open-label test of 6.25 mg twice daily carvedilol, 105 patients were randomized (2:1) to receive either carvedilol (up to 25 mg twice daily, n = 70) or matching placebo (n = 35) for 6 months while background therapy with digoxin, diuretics, and an angiotensin-converting enzyme inhibitor remained constant. Ten patients (8%) did not complete the open-label period because of adverse events and 11.4% in both the carvedilol and placebo groups dropped out in the double-blind phase. The study was terminated early by the Data Safety and Monitoring Board and follow-up evaluation was therefore aborted before the projected number of patients and follow-up time was achieved. Quality of life, which was the primary endpoint, improved similarly in the carvedilol and placebo groups, whereas the global assessment by the physicians and the patient exhibited a better response to carvedilol (P < .05). Hospitalization and mortality rate were too low to evaluate a difference, and exercise time and New York Heart Association classification did not change significantly in response to the drug. Left ventricular ejection fraction rose significantly (+0.09) in the carvedilol group compared with the placebo group (+0.02, P = .004). CONCLUSION: The beta-blocker carvedilol can be safely employed in patients with severe heart failure. Improved left ventricular function with a trend for some improvement in symptoms combined with the experience with the drug in the larger population of less severe patients in this multicenter trial suggests that carvedilol may have a favorable long-term effect in heart failure of diverse severity.

Implementation of a patient-centred and physician-oriented healthcare information system.

Integration of information has enabled expeditious operation in air transfer, banking, shopping, and stock brokerage, but not in healthcare. Existing health information systems (HIS) are concerned too much with departmental performance and charge billing, and neglect the end users--the patients and the physicians. The resultant HIS then has divergent operation to antagonize the physicians, and has fragmented data to the disadvantage of patients. Recognizing the problems and the trend of HIS, this study proposed and implemented a patient-centred and physician-oriented HIS in a Urology clinic. The proposed HIS had patient care as its core, and accurately coded the patient's diagnoses and therapy information. It also offered a friendly environment and complete function for the physician to administrate medical records and to provide healthcare services. The HIS had client/server structure and an open system to protect the hardware investment and the software implementation. It will be the key to success in complete hospital environments.