Wing C. Wong

Correlation of Constant Flow Rate with Frequency Spectrum of Respiratory Sounds When Measured at the Trachea

Respiration is one of the critical physiological functions of concern when a patient is under examination or treatment. A clinical relationship between respiratory sounds and gross respiratory pathology was established early in the 19th century by auscultation. It is commonly believed that characteristics of respiratory sounds are related to respiratory flow rate. The objective of this study is to determine the correlation or relationship between spectral composition of respiratory sounds as measured at the trachea and flow rates as measured by pueumotachometer. Respiratory sounds at six contant flow rates were measured with an electronic stethoscope placed at the anterior cervical triangle, inferior to the circoid cartilage. Results indicated that the mean frequency of the power spectrum increases linearly with increase in flow but remains about the same when the flow rate is above 0.75 I/s. In addition, the expiratory spectra have higher mean frequencies than inspiratory spectra.

Synopsis of tracheal sounds

A review is presented of the latest progress in studies of tracheal sounds. In particular, characterization of respiratory and heart-valve sounds to explore and develop automated methods for analysis and diagnosis of pulmonary insufficiency, cardiac, and neurological information is presented. Results from these studies indicate that automated analysis of pulmonary pathology is possible but not without impediments. The mean frequency of respiratory sound spectra is linearly related to respiratory flow rates less than 1 l/s. Respiratory sound spectral estimates are affected by heart-valve sounds, which could adversely affect results of discriminant analysis for patient classification. Static lung volume affects heart-valve sound spectra.<<ETX>>

Ocular Tracking Responses To Pseudorandom Stimuli

Human vestibulo-ocular system is known to be nonlinear, however, linear methods are often used in analyze of ocular tracking results. The sum-of-sinusoids method [l] is used to study linear and nonlinear optokinetic responses of human subjects. Nonlinearity of the ocular system is detected by the occurrence of interaction frequencies in the power spectrum of the processed optokinetic response.

Nonlinear Analysis Of Human Optokinetic Responses

The vestibulo-ocular system has been shown to be a nonlinear system, however, classic linear system analysis method is being used to analyze the results in most vestibular investigations. A sum-of-sinusoids method, capable of revealing linearity as well as nonlinearity, is used to study the optokinetic responses of human subjects. Nonlinearity of the ocular system is detected by the occurrence of interaction frequencies in the power spectrum of the processed optokinetic response.

Comparison Of Nystagmus Analysis Programs

A general review of current literature of analog and digital processes of vestibular and optical k inetic nystagmus reveals little agreement in methods used by various l aboratories. The strategies for detection of saccade (fast phase velocity component of nystagmus) vary between laboratories. Most of the processes have not been evaluated and validated with a standard data base. In short, the problem is a lack of standardization.

Vestibular function tests battery: a proposal for standardization

Several well-known clinical vestibular function test batteries are compared. Procedural differences among five groups in performing elements of the vestibular function test battery are identified. A standard vestibular function test battery is proposed, consisting of the following tests performed in the given order: (1) calibration test, (2) midposition gaze test, (3) lateral gaze test, (4) sinusoidal pursuit test, (5) rapid positioning test, (6) positional test, and (7) caloric test. In addition to changes in test procedures and a specified testing order, the proposal includes modifications of nomenclature and standardization of measuring parameters and quantities.<<ETX>>