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Visual display of tongue-palate contact: electropalatography in the assessment and remediation of speech disorders.

The technique of electropalatography (EPG) records the location and timing of tongue contacts with the hard palate during continuous speech. Recent developments in hardware and software design of the Reading electropalatograph are described and applications of the technique in assessment and remediation of a variety of speech disorders are outlined. In assessment, it is shown that EPG can provide insights into possible origins of auditorily perceived errors, and case descriptions illustrate how this information can lead to a more rationalised approach to treatment. In therapy, the provision of real-time visual feedback of tongue movement can be effective in the remediation of certain types of intractable speech problems. Finally, the importance of techniques such as EPG in the objective evaluation of treatment procedures is discussed in the light of the increasing demand for accountability within the speech therapy service.

Adolescent

A method of analysis of the electrical activity of the proximal gastrointestinal tract of the chicken.

The present paper describes a method of recording and analyzing electromyographical (EMG) signals from the digestive tract of the chicken. The EMG signals from the proventriculus, gizzard, and duodenum were recorded after implantation of Ni and Cr electrodes. The amplified EMG signals were digitized using a sampling frequency of 50 samples per second, and numerical data was stored immediately on the hard disk (1 datum = 1 byte). The software designed allowed: 1) detection of spike-bursts with a high accuracy; 2) analysis of maximum amplitude (with a maximum error of 6.7%), mean amplitude, duration, and frequency of the spike-bursts; the time of interval between spike-bursts, and the percentage of activity; 3) integration of the recorded data with a variable time set; and 4) a wave analysis by means of the Fourier algorithm. These methods, already used in EMG studies in mammals, are assembled and adapted for its application in birds.

Animals

Validation of automated systems--system definition.

A Parenteral Drug Association (PDA) Committee on Software Validation was formed about three years ago to address some of the issues associated with validating automated systems, particularly where all, or part, of the automated system is supplied by outside vendors. A Technical Report that describes a process which emphasizes system definition, a comprehensive system specification, system qualification and ongoing evaluation will issue later this year. The concepts described in this document will be consistent with the PMA's System Development Life Cycle approach which is commonly used for computer system validation. The following article has been developed from the System Definition section of this PDA Technical Report.

Computer Systems

Picture archiving and communication systems in the United States.

Picture archiving and communication systems (PACS) are expected to replace film in the years to come. PACS acquire, store, transmit, and display medical images. Although there are several clinical PACS in operation today, there are significant problems slowing their introduction. PACS are limited in spatial and contrast resolution and the workstation's displays present difficulties due to low light levels, slow image presentation, and poorly designed software. Standard interfaces are still lacking for most of the imaging equipment currently in use, making connections to these devices nearly impossible. Cost is a major issue as well. Yet limited implementations, often called mini-PACS, offer advantages such as faster image presentation to radiologists and referring physicians, reduced portable retake rates, the capability for viewing images at home off-hours, and transmission from remote sites. More development is needed for interfaces with the radiology information system and for sophisticated network and image management.

Radiology Information Systems

Computed tomography measurement of acetabular cup anteversion and retroversion in total hip arthroplasty.

In a clinical study conducted between March 1983 and July 1987, computed tomography of the hip was employed with specially designed software in 20 patients after 23 total hip arthroplasties (THAs). Three patients had bilateral THAs. Computed tomography was performed in the routine manner, except that the image was reconstructed utilizing software that eliminated the metallic artifacts. The angle of the acetabular cup is determined on a display console. The cursor is turned on, one pole of the cup is marked, and when the second moving cursor is positioned on the opposite pole, the angle is shown and measured on the console. This technique has been indispensable for accurate measurement of the angle of inclination of the acetabular cup and in treatment planning in patients with a dislocating total hip prosthesis.

Acetabulum

Hematologic values of New Zealand white rabbits determined by automated flow cytometry.

Hematologic values of peripheral blood from normal adult New Zealand White rabbits were determined by five different automated flow cytometers in use in a routine clinical hematology laboratory: Technicon H1, Coulter Counter CC540, Coulter Counter VCS, Sysmex NE8000 and Sysmex R1000. The software designed for human blood analysis was used in all instances without adaptation. The total numbers of white blood cells, red blood cells, reticulocytes and platelets were measured with high precision and accuracy. Except for hemoglobin content, concordance was excellent for all measured and calculated values among the different automated flow cytometers. Determining the white blood cell differential count was more complex. Eosinophils and lymphocytes were quantified reliably by all the automated flow cytometers used. However, the results were rejected by Technicon H1 and Sysmex NE8000 in 50% of the cases. Rabbit basophils were recognized with accuracy by Technicon H1 only. The proportion of polymorphonuclear versus mononuclear white cells was identical when measured with Technicon H1 and Coulter Counter VCS. These results show that the new generation of automated flow cytometers designed for human blood can be used with some limitations for animal studies. They allow the standardization of normal values and comparison of results among or between laboratories. They also introduce new parameters, the value of which is as yet undefined.

Animals

Comparison of bicycle and treadmill radionuclide angiocardiography.

The purpose of this study was to test motion-correction algorithms for initial-transit radionuclide angiocardiograms acquired at rest and during bicycle and treadmill exercise. Treadmill data was spatially reoriented by computer software designed to eliminate motion of a 125I point source simultaneously recorded at a lower energy window. A second algorithm based on left ventricular centroid counts further corrected for motion on all studies. Exercise left ventricular ejection fraction was higher on the treadmill (0.68 +/- 0.07) compared to the bicycle (0.64 +/- 0.08) (p less than 0.0001, r = 0.88). Treadmill exercise also resulted in larger end-diastolic volumes (180 +/- 30 versus 157 +/- 36, p less than 0.0001), stroke volumes (124 +/- 28 versus 101 +/- 29, p less than 0.0001) and cardiac outputs (19.9 +/- 4.6 versus 15.9 +/- 5.0, p less than 0.0001). Similar variances for these hemodynamic measurements suggest that the mean differences observed were physiologic and that error from body motion was effectively corrected by this approach. We conclude that the measurement of left ventricular function during treadmill exercise, when combined with these techniques for correcting motion, is a reasonable alternative to conventional bicycle exercise.

Adult

Using a computerized method to measure 99mTc pertechnetate uptake for the assessment of thyroid function: a clinical validation.

This retrospective study evaluated thyroid function by the 99mTc pertechnetate uptake ratio, using computer software designed in our laboratory. We expected that this measurement could be a precise and accurate index. The following studies were performed on 187 patients: (1) 24-hour radioimmunoassay of serum thyroid hormones, including serum thyroxine, free T4, triiodothyronine, thyrotropin concentrations, and T3 resin uptake; (2) 99mTc pertechnetate thyroid imaging and uptake measurement; and (3) 24-hour 131I thyroid uptake. Based on the clinical findings and the results from the predescribed laboratory tests, we found that: (1) the mean value of the 99mTc pertechnetate thyroid uptake ratio in the euthyroid groups was 2.77 +/- 1.77% (mean +/- SD); (2) the correlation coefficient between the 99mTc pertechnetate thyroid uptakes and the 24-hour 131I uptakes of the euthyroid patients was 0.71; and (3) hyperthyroidism could be distinguished from euthyroid condition easily. By setting the upper limit of euthyroid 99mTc pertechnetate thyroid uptake at 6.31%, the diagnostic sensitivity was 92.9%, specificity 96.1%, and accuracy 95.6% in separating hyperthyroid from euthyroid patients. These values were similar to those determined by the 24-hour 131I uptake measurements. Thus, thyroid function can be evaluated simultaneously with a routine 99mTc pertechnetate thyroid scan. Both the patient time and cost can be saved with this method, since the measurement takes only 25 minutes. Decreased radiation exposure is another advantage of this method over the traditional 131I uptake measurement.

Adolescent

Automated quantitation of immunocytochemically localized estrogen receptors in human breast cancer.

Frozen sections of breast tumor tissue have been stained using an immunoperoxidase [estrogen receptor (ER)-immunocytochemistry] kit incorporating a monoclonal antiserum [H222] to visualize nuclear human ERs. Quantitation of specific staining has been performed by manual procedures using optical microscopy and by a computer-assisted image analysis system (CAS 100). Initial investigations with a test panel of ER-immunocytochemistry-positive tumors revealed a good qualitative agreement between CAS and manual assessments. Reduced variance was, however, observed between quantified ER-immunocytochemistry results from four experienced investigators using the CAS analysis. An extended study confirmed the relationships between CAS and manual methods of assessment. These findings were evident when studies were scored either by assessment of the percentage of positively stained cells (n = 92; r = 0.919; P less than 0.01) or by H-score calculations (n = 92; r = 0.913; P less than 0.01). A good correlation was also found between CAS quantification and the results of an ER enzyme immunoassay of 48 primary breast cancer specimens (r = 0.715; P less than 0.05). In 49 cases it was possible to relate CAS-defined ER status and levels to the subsequent response of patients to endocrine therapy. ER was assessed on specimens obtained prior to commencement of treatments for recurrent breast cancer. Presuming the presence of ER to be a prerequisite for successful therapy, very good correlations between response and both status and levels of positivity were recorded. None of 16 patients with CAS-ER-negative tumors responded to treatment, while 16 of 33 (48.4%) CAS-ER-positive patients achieved an objective response according to International Union Against Cancer criteria. A relationship between response and the degree of CAS-ER positivity was obtained when the CAS score divisions of 0, 1-100, and greater than 100 (response rates, 0, 41, and 64%, respectively) were used. These data demonstrate that automated image analysis offers a reliable, reproducible procedure for quantifying ER in immunocytochemically stained sections. It has potential advantages over manual procedures, providing less opportunity for subjective influences in scoring sections. Future advances in software design should further reduce elements of subjectivity and increase both the speed and reliability of results. We anticipate image analysis becoming a valuable tool in investigations concerning, for example, the influence of heterogeneity of steroid receptor distribution on the rate of recurrence of breast cancer after mastectomy and in the clinical course of the disease.

Breast

Converting the representation of medical data: criteria to code the underlying cause of death.

This study deals with a set of coding directives that were conceived for trained coding clerks and rely upon knowledge of their cultural background. These directives were formalized and adapted for computer use and in this form must rely upon a background of explicit medical knowledge. Medical data on death certificates are an invaluable source of information regarding prevention of major causes of death. These causes are coded and tabulated worldwide by means of the International Classification of Diseases (ICD). The ICD manual issues directives to achieve uniformity of coding throughout the world. The coder is required to trace back the flow of events which caused death and to single out the most significant concept from the statistical point of view. After emphasizing the problems encountered in the formalization, the methodological contribution of this work to the identification of a modular architecture for a system which represents and "reshapes" knowledge from medical documents is presented. Therefore we focus on the features of the two kinds of knowledge that must be supplied to a knowledge-based system, in order to enable it to perform semantic conversions on given medical data, namely: i) generic guidelines; ii) detailed medical knowledge.

Cause of Death

Maryland MIRRORS/II: a connectionist model simulator.

Developing and evaluating connectionist models (also called neural models) is a difficult and time-consuming task. To address this issue, we designed a software system called Maryland MIRRORS/II for the construction of connectionist models in biomedicine and other fields. Maryland MIRRORS/II is distinguished from previous and current related systems by its support of a high-level nonprocedural language, a general-purpose event-handling mechanism, and an indexed library of system resources. These features make Maryland MIRRORS/II a convenient software tool for use in biomedicine. This paper describes Maryland MIRRORS/II and provides a simple example in which it uses error back propagation learning to select the appropriate treatment for a given set of manifestations.

Computer Simulation

Median frequency of the myoelectric signal in cervical paraspinal muscles.

Objective measurements of the function of cervical paraspinal muscles (CPM) are lacking. Changes in the frequency spectrum of the myoelectric (ME) signal have been used in the limb muscles as an objective measurement of muscle function. Based on our previous investigational work on limb muscles, we attempted to measure parameters related to median frequency (MF) of the ME signal to measure localized muscle fatigue in cervical paraspinal muscles in 14 healthy subjects. The ME signals were recorded bilaterally using surface electrodes placed posteriorly at the C3 to C6 level. Sustained isometric neck extensions were performed at 20%, 50%, 80%, and 100% of maximum voluntary contractions (MVC). Initial median frequency (IMF) and slope of the MF during sustained isometric contraction were obtained by analyzing the ME signal using an IBM-XT computer, a laboratory interface system, and custom-designed software. The results indicated that the MF of the CPM behave somewhat differently from limb muscles, and that the CPM are less fatigable than limb muscles. The test-retest reliability, using our system, was found to be high, and data processing showed a variability of 4 to 8Hz. These results imply that neck muscles appear to behave differently at high and low force levels in response to daily functional demand. The MF measurements appear to be a useful objective technique for evaluating muscle function of cervical musculature.

Adult

Quality assurance and precision of dual photon absorptiometry in bone mineral measurement.

Dual photon absorptiometry (DPA) has evolved as a powerful technique in measuring bone mineral density (BMD) to assess osteoporosis and metabolic bone diseases in recent years. We introduced the first installation of DPA instrument into this country in Aug. 1987. Since the comparison among longitudinal BMD values influences the diagnosis, monitoring and medical decision-making, high precision of the system performance and strict quality assurance program are prerequisite for judgment of the difference between two successive measurements. However, the automation and black-box software design of the instrument make users gain very little knowledge how the instruments acquire the long-term system reliability. The first part of this study was designed to establish a standardized procedure to evaluate the long-term quality of the DPA instrument. Our instrument was proved to have stable sensitivity, resolution, accuracy and reproducibility in the four months of study. Three subjects with different BMD levels were scanned to evaluate the intraobserver and interobserver errors in BMD analysis expected in our laboratory (2.2 and 1.6% at 95% confidence level, respectively). The results indicated that reanalyzing the same scan by either of the two observers would produce a BMD precision error within 2.2% at a 95% confidence level. Serial scans of 7 normal volunteers within five weeks were then conducted to evaluate the overall precision of the BMD measurements. Our findings indicated that two scans would be considered as having a real BMD change if they differ by more than 3.3% at a 95% confidence level. There are at least five sets of DPA instruments that have been installed in Taiwan presently.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

A computerized representation of a medical school curriculum: integration of relational and text management software in database design.

We describe the development of a computer-based representation of the medical school curriculum at the University of North Carolina at Chapel Hill (UNC-CH). Over the past seven years the Medical School's Office of Academic Affairs has employed both relational database and text management software to design an integrated curriculum database system. Depending on the function selected--exploring the curriculum, searching through course outlines, retrieving elective descriptions, identifying teaching faculty, or searching for specific topics--either text management or relational database management routines are activated in a manner transparent to the user. Initial evaluation of the system has been positive but highlights the need for a more robust biomedical language for use as a controlled vocabulary to index content. Efforts are now underway, with support from the Association of American Medical Colleges (AAMC), to engage other interested schools in the U.S. and Canada in collaborating on further development of a system.

Abstracting and Indexing

An evaluation of computer aided design of below-knee prosthetic sockets.

Forty-eight below-knee amputees compared sockets designed using CANFIT computer aided design (CAD) software with sockets designed using conventional methods. Each subject was fitted by one prosthetist who used conventional techniques and one who used the CANFIT system to design the socket. Prosthetists alternated design methods for each new subject. The prosthetist using the conventional techniques was allowed up to 2 design attempts and the prosthetist using the CANFIT system was allowed up to 5 design attempts. After 2 design attempts with each method 21% of the subjects preferred the CANFIT design socket. Following up to 5 attempts 54% preferred the CANFIT designed socket. A jury of experts made an assessment of the CANFIT system and of CAD in prosthetics. The jury did not think that the version of the system tested was cost effective but that at the rate that it was improving it would become such within 3 to 5 years. The jury noted that, as well as monetary benefits, CAD presents the possibility of benefits in other areas such as research and teaching. A number of specific suggestions regarding the use and development of CAD in prosthetics were also made.

Artificial Limbs

A new microcomputer software system evaluation paradigm: the medical perspective.

The new fourth-generation software has enormously eased the burden of computing for users, but they have also created a confusing, difficult problem in software evaluation and selection. Therefore it is argued that a sound and complete evaluation paradigm is a key element in an efficient and effective software system design and use process. While much has been written about software evaluation in general, in the medical field, the guidances and recommendations previously provided are too general to be of practical use. Considering also the other weaknesses of conventional evaluation paradigms we have decided to develop a more adequate one which will have a solid theoretical framework, specific guidances, strict and well-defined taxonomic space, and a fair ranking approach. In the present paper we will therefore introduce our new evaluation paradigm and show its applicability in evaluation and selection of medical software systems according to their usability.

Classification

Software for experimental design: the computer program EXCAD.

A computer program (EXCAD) dedicated to the optimization of experimental designs to estimate parameters of a mathematical model, is presented. EXCAD computes D-optimal designs and sequentially augmented designs. D-optimal designs minimize the determinant of the variance-covariance matrix and parameters, thus obtaining the average most accurate estimate of parameters. D-optimal designs have generally as many support points as the number of parameters in the mathematical model, so sample scheduling is minimal, not extensive. Augmented designs add to an original design the point that maximizes the decrement of the determinant of the variance-covariance matrix. The general model, linearly or not linearly parametrized Y = F(X,P), that relates two independent variables and P parameters to different responses may be written in the program, while a set of prewritten models is provided.

Algorithms