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J C Thornton

Publications and source records attributed to J C Thornton.

96 records · Page 6Linked to original sources
PubMedDate not supplied

Population-based prediction equations for neurobehavioral tests.

Quantitative assessment of neurobehavioral function appraises brain injury from inhaled chemicals. Contemporary predicted values for tests useful in epidemiological studies have been developed with step-wise linear regression. In instances in which age and education do not match those of control groups, these equations assist in the interpretation of results of examinations of individual subjects and pilot studies. In this study, investigators considered brain function tests to be analogous in concept to pulmonary function tests. The authors used the tests to assess 293 adults in three unexposed groups from different areas of the United States. The subjects, who were contacted at random from voter registration rolls, were compensated for their time. The tests included balance, reaction time, strength, hearing, visual performance and cognitive recall, and perceptual motor and memory functions. Regression equations modeled the performance of each test and the influences of demographic factors. The investigators retained all influential factors in the equations. Age was a significant predictor for most tests. Education attainment was not a factor in any of the physiological measures, but it was a determinant in many psychological tests. Prediction equations assist investigators in the quantitative testing of chemically exposed individuals and other brain-injured individuals. The investigators verified the equations against other groups, including additional unexposed populations.

Adolescent↗
PubMedDate not supplied

Protracted neurotoxicity from chlordane sprayed to kill termites.

Over 250 adults and children were exposed to chlordane when the wooden building surfaces and soil around an apartment complex were sprayed in 1987. Two hundred-sixteen adults had neurobehavioral functions measured and completed questionnaires for symptom frequency, mood status, confounding factors, and medical, rheumatic, and respiratory disorders in 1994. Measurements included simple and choice reaction time, balance, blink reflex latency, color vision, cognitive, perceptual motor, memory, and recall functions. We analyzed 216 exposed and 174 referent adults. Age, educational level, weight, height, and gender ratio were similar for the exposed and referent groups. Performance of balance, reaction times, Culture Fair, digit symbol, verbal recall, and trail-making were significantly impaired in exposed persons compared to referents. Mood-state scores were elevated, as were the frequencies of respiratory, neurobehavioral, and rheumatic symptoms. In contrast, long-term memory function was similar in both groups, consistent with its status before exposure. There was no identified bias or confounding factors. Chlordane exposure was associated with protracted impairment of neurophysiological and psychological functions. The central nervous system is the most important target of chlorinated cyclodiene insecticides. Human exposure should be prohibited.

Adolescent↗
PubMedDate not supplied

Lack of correlation of ultrasonographically determined ovarian size with age, ponderal index, and hormonal factors in 45 patients with polycystic ovarian disease.

An ultrasonographic study was performed on 45 patients with polycystic ovarian disease. These patients demonstrated hirsutism, menstrual disturbances, or infertility, as well as an increased LH/FSH ratio and/or evidence of hyperandrogenemia. Ovarian size was not correlated with age, Ponderal Index, serum testosterone, prolactin, androstenedione, dehydroepiandrosterone sulfate or LH/FSH ratio in the 45 subjects studied.

Adolescent↗
PubMedDate not supplied

Mean and instantaneous expiratory flows, FVC and FEV1: prediction equations from a probability sample of Michigan, a large industrial state.

Prediction equations for FVC, FEV1, FEV1/FVC, FEF25-75%, FEF75-85%, FEF50% and FEF75% were modelled for 396 normal non-obese adult lifetime nonsmokers and continuing smokers. Subjects came from a random cross-section of the white population of Michigan, a large industrial state. In both sexes, linear models utilizing age and height were appropriate for FVC, FEV1/FVC and FEV1; flows were better described by logarithmic transformation. These regression equations provided similar predicted values for FVC and FEV1 in nonsmokers to other models in wide use. Previous equations for instantaneous flows have yielded inconsistent predicted values. It is hoped that the present equations will be useful for these measurements. Duration of cigarette smoking was a significant prediction variable for FEV1, FEV1/FVC and mean and instantaneous flows in these normal men, but not in normal women. For FEV1, the effect of each year of smoking was 40% of the effect of ageing.

Adult↗
PubMedDate not supplied

A field method for blink reflex latency R-1 (BRL R-1) and prediction equations for adults and children.

PURPOSE: To develop a field worthy apparatus for blink reflex latency R-1 (BRL R-1), to compare mechanical and electrical stimulation, to define a standardized measurement of BRL R-1, to test a field worthy procedure and to produce population-based prediction equations. METHODS: A special low voltage electromyographic (EMG) recording system was constructed which is uninfluenced by electrical and magnetic field. The supraorbital notches were stimulated mechanically using a small hammer and electrically using a stimulus of 2.0 ms duration and 2-5 mA 13. A computer program was developed which substracts the baseline for all data points and sums R-1 for 10 tests by identifying the noise floor or baseline of the EMG recording and the noise envelope. The beginning of R-1 and R-2 is defined as 2 times the noise amplitude of this envelope. BRL R-1 was compared after tap and after electrical stimulation in 16 subjects. Prediction equations were developed from data of 240 adults and 163 children unexposed to chemicals. RESULTS: Mechanically and electrically elicited mean BRL R-1 in 16 subjects was identical at 12.6 ms on the right and 12.7 ms vs 12.5 on the left. In adults, BRL R-1 depended on age. In children BRL R-1 was age, weight and height dependent. CONCLUSION: BRL R-1 elicited by supraorbital tap is field worthy, computer defined and identical to electrical BRL.

Adolescent↗