Calvin K. Adams

Improved detection of human breast lesions following experimental training

This study was designed to evaluate the effect of breast examination training with silicone models on the detection of lesions in natural breast tissue. Six women with a total of 13 benign breast lumps were examined by 20 trainees before and after a 20–30 minute training session or a period of unrelated activity. Following the training, percentage of correct detections, duration of examination, and reports of false positives increased. Confidence in correct detections and false positives also increased, although confidence in correct detections was greater than confidence in false positives. The results indicate the effectiveness of the training and suggest a need for a more complex model for training discrimination between normal nodularity and breast lesions.

Lump detection in simulated human breasts

Sixteen observers palpated silicone models of human breasts containing lumps 1.6-12.1 mm in diameter. Detectability depended on the size of the lump, producing a systematic psychometric function. In eight observers who participated in three or more sessions, performance improved with practice, with most improvement occurring within one or two 26-trial sessions. Three-week retention measures disclosed no appreciable decrease in performance, but a significant correlation was found between the number of lumps detected and duration of trial (p < .01). There was no difference in performance between four observers who used their preferred hands and four observers who used their nonpreferred hands. These data establish that examination of breast models for the detection of lumps simulating cancer is a task amenable to experimental analysis.

Effects of certain training parameters on detection of simulated breast cancer.

Forty-two female subjects, constituting 14 groups, palpated a silicone breast model in a lump detection task. Three variables, number of trials (amount of practice), search pattern requirement (restricted vs. unrestricted), and the presence or absence of lumps, were manipulated according to 3 X 2 X 2 design. The effect of all modes of practice on detection performance in posttest 1 was evidenced by an increase in percent of lumps detected and a decrease in detection threshold, but no form of practice was superior to the others. Following posttest 1 a brief search-training procedure was administered to 39 subjects which further lowered detection threshold, increased percent of lumps detected, and increased trial duration in posttest 2. The results indicate the effectiveness of the training procedure for improving detection ability and suggest the need for a more complex model to determine more specifically the effects of the practice models employed.

Fast retinal potential luminosity functions

Abstract The adaptation dependence of high frequency signals (fast retinal potentials or FRPs) was analyzed from measures taken from the human cornea. Narrow band chromatic stimuli were presented to two normal Ss under photopic, mesopic, and scotopic adaption conditions. Signals were recorded in two pass bands, broad band (0.2 Hz–2 kHz) and highpass (50 Hz–2 kHz). Results support two primary conclusions: (1) Fast components (above 50 Hz) recorded from the human cornea were related primarily to photopic mechanisms; (2) Fast components educted by analog filtering techniques gave no indication of being differentially related to any single spectral mechanisms. The relationship between conventional and FRP components are discussed with the mechanisms which may initiate the FRP signal.

Spectral sensitivity of the Sooty mangabey

Purkinje shift and scotopic and photopic spectral sensitivity functions were determined for four Sooty mangabeys and five human controls using a flicker technique in a four-choice discrete trials task. Results-indicate a Purkinje shift similar in magnitude and frequency locus to that of human controls. Scotopic spectral sensitivity was almost identical to that of human controls, although both species showed reduced sensitivity relative to the standard CIE function, -at short wavelengths. Photopic spectral sensitivity disclosed enhanced sensitivity in the blue and reduced sensitivity (0.3–0.4 log units) in the red relative to human controls.

Electroretinographic determination of the spectral sensitivity of the baboon (Papio Anubis)

Abstract As a preliminary investigation of the baboon ( Papio Anubis ) visual system, ERGs were recorded using monochromatic light. The computer-averaging technique was used to enhance the signal-to-noise ratio. Scotopic responses were recorded using discrete flashes 100–200 msec in duration under dark-adapted conditions. B-wave amplitude and implicit time analysis disclosed scotopic sensitivity essentially the same as that of man. Photopic responses were recorded using three procedures: (1) 4 Hz flicker and analysis of the first wave; (2) 20 Hz flicker; and (3) discrete flashes superimposed on continuous white-light adaptation. All three procedures disclosed spectral sensitivity functions similar to that of the peripheral cones of man.

Optokinetic suppression of aberrant vestibular reactions: an observation.

It has long been known that optokinetic nystagmus may be modified by vestibular inputs. We have suppressed an aberrant vestibular response and associated gastrointestinal sensations by use of an optokinetic stimulus simultaneous to the positional stimulus in a patient with paroxysmal positional vertigo. This single subject study utilized several optokinetic conditions, and patterned its stimulus presentations to control for visual fixation and vestibular habituation. Objective recordings of eye movements (ENG) were made simultaneously with subjective evaluation of “dizziness” on a simple magnitude estimation scale.