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Biomedical subjects

W E Kumley

Publications and source records attributed to W E Kumley.

6 recordsLinked to original sources

Algorithm for analyses of saccadic eye movements using a digital computer.

An algorithm for digital computer analyses of electro-oculographically recorded saccardic eye movements is presented. From a brief, 4-min recording session detailed statistical information about saccade velocity, accuracy, and delay time can be obtained. Since this data is not significantly altered by practice of motivational factors, it provides a sensitive functional test of the extra-ocular muscles and their brain control system.

Animals

Quantitative analysis of micrographs by computer graphics.

A computer-aided graphical analysis system is presented which can be used to quantify several types of information from micrographs of cross-sectioned peripheral nerves. A simple input consisting of eight points, corresponding to two diameters of each axon and two for each axon plus myelin, is used to compute statistical and numerical estimates of these diameters, the myelin thickness being expressed as a function of axon diameter, and both the spatial position and distribution of nerve fibres within the bundle. The computer programs presented and summarized here describe the procedure for digitizing the input data and the subsequent computations for editing and analysis. The general applicability of this approach for automated analyses of other anatomical areas is also presented.

Axons

Quantitative measurement of saccade amplitude, duration, and velocity.

A method for rapid, accurate measurement of saccade amplitude, duration, and velocity (average and maximum) was developed as a functional test of the extraocular motor system. Recordings were made with a direct-current electro-oculographic system, and data analysis was performed on a laboratory digital computer. Saccade amplitude and duration were found to be linearly correlated in 25 normal subjects, with a mean slope of 2.7 msec per degree over a large amplitude range. In the same subjects, saccade amplitude and velocity (maximum or average) had a nonlinear relationship that was best fit by an exponential equation. The two constants of this equation adequately characterized the relationship between saccade amplitude and velocity and permitted rapid statistical comparison between normal and abnormal subjects.

Electrooculography

Algorithm for the multi-parameter analysis of nystagmus using a digital computer.

A computer program for analyzing nystagmus has been developed and can be used on a small laboratory digital computer. The algorithm accepts digitized data and looks for the minimum and maximum (minmax) points of the nystagmus waveform. These points in turn are used to define seven descriptive parameters of nystagmus, including the amplitude, duration, and velocity of the slow and fast phases, and the frequency. The algorithm uses three user-adjusted criteria for accepting or rejecting minmax points. The treatment of noisy or irregular data can be improved by adjusting the values of these criteria.

Computers

Quantitative measurement of smooth pursuit eye movements.

Smooth pursuit eye movements were quantitatively assessed in 25 normal subjects and 22 patients. A laboratory digital computer was used to compute 200 eye velocity samples per second and to statistically compare these eye velocity measurements for five different object velocities. Of six statistics evaluated, mode eye velocity showed the least variability in normal subjects and was most frequently abnormal in patients. Compared to normal subjects, patients with brain stem degeneration and cerebellar-pontine angle tumors with brain stem compression had significant impairment of smooth pursuit. Patients with peripheral vestibular lesions and C-P angle tumors without brain stem compression did not have impaired smooth pursuit. These preliminary findings suggest that quantitative measurement of pursuit eye velocity can be a sensitive test for brain stem dysfunction.

Adult