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Biomedical subjects

C Wall

Publications and source records attributed to C Wall.

At least 91 records · Page 5Linked to original sources
PubMed1986

Audit procedures in the National Breast Screening Study: mammography interpretation.

Audit procedures for mammography interpretation in a national breast cancer screening program are described. Agreement between radiologists at five screening centers and a single reference radiologist was evaluated based on mammograms at initial screen in 739 women not known to have breast cancer and 204 breast cancer cases detected at or within a year of initial screen. Kappa statistics, used to measure agreement in the interpretation of mammograms between the reference and center radiologists beyond that attributable to chance, were 0.409 in women not known to have breast cancer, 0.472 in women with diagnosed breast cancer, and 0.493 for all women with p less than .0001 for all three categories. To our knowledge, this is the first report presenting measures of agreement made systematically, simultaneously, and on a continuing basis, during a screening program for quality assurance.

Adult↗
PubMed1985

Otoneurological examination in panic disorder and agoraphobia with panic attacks: a pilot study.

A battery of vestibular and audiological tests was administered to eight patients with panic disorder and 13 patients with agoraphobia and panic attacks, all of whom experienced dizziness during their panic attacks. Positional or spontaneous nystagmus was present in 67% of the subjects. Abnormal responses were found in caloric testing (56%), rotational testing (35%), and posturography (32%). Pure tone audiograms were abnormal in 26% of the subjects and acoustic reflexes were abnormal in 44% of the subjects. Six of eight patients tested had an abnormal brainstem auditory evoked potential. The possible importance of the findings and their implications for further research are discussed.

Adult↗
PubMed1984

Intersubject variability in VOR responses to 0.005-1.0 Hz sinusoidal rotations.

Two alternate hypotheses concerning intersubject variability in normal human VOR responses were tested. Both experimental gain and phase data and linear systems parameter fits to that data supported the hypothesis that individual experimental data points varied in a systematic rather than a random fashion about ensemble mean values. A simple two parameter linear systems model was found to characterize normal data, but there was little or no correlation between the values of these two parameters, i.e., they were independent variables.

Adult↗
PubMed1982

Adaptation to altered support and visual conditions during stance: patients with vestibular deficits.

Patients whose deficits were limited to clinically well qualified vestibular disorders have been exposed to a number of altered support surface and visual environments while standing unsupported. A six-degrees-of-freedom platform employing movable support surfaces for each foot and a movable visual surround deprived patients of normal inputs derived from a fixed level support surface and from an immobile surround. Various tests employing EMG, force, and body movement recording identified quantitative changes in the patients' strategy for the relative weighting of proprioceptive, vestibular, and visual inputs. The most dramatic performance deficit of patients was their inability to suppress the influence of visual and proprioceptive inputs appropriately whenever motions of external surface disturbed the orientation information provided by these inputs. Thus, the more mildly afflicted patients experienced instability not so much because of the loss of vestibular inputs directly to posture but because of their inappropriate responses to proprioceptive inputs and vision. Discussion is centered on the role of vestibular input as an internal reference system for orientation about which adaptive changes in proprioceptive and visual inputs are made.

Humans↗
PubMed1980

Combination v. sequential therapy with melphalan, 5-fluorouracil and methotrexate for advanced ovarian cancer.

The results of a national clinical trial to compare combination and sequential chemotherapy for stage III or IV ovarian cancer are reported. Of the 253 patients from 16 centres across Canada who were admitted to the trial 13 were excluded from the analysis. All the patients were observed for 2 to 5 years from entry into the trial. There were no differences in response to therapy or in survival between the patients treated with melphalan followed by 5-fluorouracil and then by methotrexate in high dosage and the patients treated with the same agents in combination. Patients with minimal residual disease after resection of stage III ovarian cancer had a good prognosis. Other favourable prognostic factors were age (less than 55 years), performance status (90% or 100% on the Karnofsky scale) and histologic grade of the tumour.

Adult↗
PubMed1980

A distributed computer system for hierarchical control of a clinical vestibular laboratory.

A vestibular testing laboratory with five test stations was implemented as a clinical research and testing facility, automating and adapting tests for patients with inner-ear balance disorders. These were designed to quantitate postural control, and eye movement response to rotational, caloric, and visual (optokinetic) stimuli. Microprocessors were used as satellite processors in a star network under hierarchical control of a host minicomputer. All disk storage was controlled by the host, with data transfer from satellites via parallel interfaces. Network software was designed and implemented to be under control of the host in a foreground-background structure. The practical operation of this laboratory required that technicians at each satellite test station initiate, perform, and complete an individual test in dependently of other tests. Examples from two test stations are presented. A 2-year data base of test results provides important multitest correlations for use in diagnostic evaluations.

Computers↗
PubMed1980

Human vestibulo-spinal responses to direct electrical eighth nerve stimulation.

Left-right (y-axis) vestibulo-spinal torque responses were recorded from two of four intramodiolar stimulus electrodes placed for auditory stimulation in one human subject. For both electrodes, shorter (100 msec) stimuli caused either subjective or objective head turning whereas stimuli lasting longer than 0.5 sec caused either subjective or objective body tilt depending upon the electrode stimulated. The two electrodes tested also showed strikingly different auditory and vestibular effects. Stimulation of the remaining two electrodes caused no detectable vestibulo-spinal responses.

Auditory Threshold↗
PubMed1980

Dependence of optokinetic nystagmus characteristics upon recording techniques.

The presence of infrared recording spectacles in the visual field is shown, under certain conditions, to influence human eye movement responses to optokinetic stimulation. Electrooculographic recording of optokinetic nystagmus (OKN) of the "follow" and "stare" type were made in four normal subjects, both with and without infrared spectacles. The ratio of slow phase velocity to target velocity was computed. This measure showed that wearing the spectacles produced no statistically significant change for "follow" but a significant decrement for "stare" OKN. The latter finding suggests that the advantage of more accurate eye movement recording offered by infrared spectacles should be weighed against a possible response decrement most probably caused by a stabilized image in the visual periphery.

Adolescent↗
PubMed1979

Oral administration of BCG as an adjuvant to surgical treatment of carcinoma of the bronchus.

A controlled clinical trial of the value of bacille Calmette--Guérin (BCG) vaccine given orally to patients with resectable carcinoma of the lung was conducted in 18 centres across Canada. A total of 308 patients were included in the analysis, 155 in the BCG group and 153 in the control group. The two groups were similar at the time of admission to the trial. BCG (120 mg) was given orally at weekly intervals for 1 month, every 2 weeks up to 3 months and then every 3 months until the total duration of therapy was 18 months. Over a 3- to 5-year follow-up period after the operation there was no difference in survival between the two groups, the proportion alive at 2 years being 61% in the BCG group and 58% in the control group. There was also no evidence of differences in the time to the detection of recurrent or metastatic disease or in the distribution of such disease. An analysis of prognostic factors confirmed the poor survival associated with histologically confirmed lymph node involvement. It may be concluded that no favourable effect from the oral administration of BCG was demonstrated.

Adjuvants, Immunologic↗