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Biomedical subjects

B G Batchelor

Publications and source records attributed to B G Batchelor.

5 recordsLinked to original sources
PubMed1992

New acuity test for toddlers.

Preferential looking is the technique of choice for measuring visual acuity in infants and young children. Most workers agree that the toddler age group, 1 to 3 years, is the most difficult to test. This is because of their short attention span and restlessness, but mostly because they find the grating target used in the test, frankly boring. The concept of the vanishing optotype chart offers alternative test targets, while utilizing the technique of preferential looking. We have designed a test which comprises a familiar shape (house, car etc.) on the upper or lower part of a neutral grey card. The shape is computer generated, and designed to fade completely when beyond the resolution limit. Acuity is determined by the width of the white lines making up the shape. As with conventional preferential looking, the observer notes the child's eye movements to determine the position of the target shape. Although picture naming is not required, the shapes help to maintain the child's interest in the test. The test is quick, and is successful with the toddler age group and older patients with intellectual impairment.

Child, Preschool↗
PubMed1979

Visual and computer-assisted assessment of the EEG in epilepsy of late onset.

A study was made of 275 patients presenting with suspected epilepsy after the age of 20 years. In 122 it was concluded that the attacks were non-epileptic. In 60 others cerebral pathology was found. If the EEG was visibly abnormal the risk of cerebral pathology was 8 times greater than when the record was normal. The EEGs were also assessed by an automatic pattern recognition technique, which classified them as abnormal by reference to a control population of 300 volunteers. 90% of EEGs from patients with pathology were classified as abnormal and, conversely, 86% of patients with abnormal records (as assessed by the automatic analysis) had pathology.

Adult↗
PubMed1978

Computer-assisted interpretation of clinical EEGs.

A multivariate pattern recognition technique has been developed, to distinguish the EEGs of patients with cerebral pathology from those of normal controls and to localize any abnormalities detected. Two methods of feature extraction have been used, power spectral density and slope descriptor analysis, together with various types of feature compression. These techniques have been evaluated on EEGs from 63 patients with proven pathology. Spectral analysis proved more reliable than slope descriptor analysis and predicted the site of cerebral pathology more accurately than did visual assessment of the EEGs. This apparent improvement over the diagnostic reliability of visual analysis in considered to justify further development and evaluation of this technique.

Adult↗
PubMed1977

A study of mail survey method.

A major disadvantage of the mail survey in medical research is non-response, which may introduce bias. This study measured the effect of two simple factors on the response rate to a questionnaire concerning headache and migraine in a survey of 2,508 electors. The two factors were the class of postage and the colour of envelopes used; neither was found to have a significant effect. It was concluded that cheaper mailing methods are not likely to jeopardise response.

Color↗