Biomedical subjects

Stéphane Laframboise

Publications and source records attributed to Stéphane Laframboise.

2 recordsLinked to original sources

PubMed2006

Effect of aging on stereoscopic interocular correlation.

PURPOSE: This study was designed to evaluate the minimum interocular correlation (IOC) needed by the visual system to correctly perceive a static stereoscopic stimulus as a function of normal aging. It was also our goal to evaluate the feasibility of clinical charts testing this aspect of visual perception. METHODS: Stereoscopic IOC threshold was determined in 100 normal observers (average age +/- standard deviation, 45.7 +/- 20.4 years) drawn from a clinical population between the ages of 10 and 85. We used partially correlated red-green random dot stereograms (RDS) displaying flat, square surfaces at 360 arcsec of either crossed or uncrossed disparity. RESULTS: Older observers needed a higher binocular correlation to perceive the stereoscopic stimuli when compared with the younger groups. There is a slight increase in the threshold value of the individuals in the 45- to 64-year-old group and a further effect on the observers over 65 years of age. Data did not reveal any effects of gender, near point phoria, or fixation disparity on IOC thresholds. CONCLUSIONS: Normal aging produces a statistically significant deficit in binocular correlation processing. This process is marginally correlated with stereo acuity measures even when stereoacuity floor effects are factored out. Although further experiments directly comparing stereoacuity and IOC are necessary and more refining is required to obtain optimum parameters, clinical stereoscopic IOC test charts appear feasible and may not assess the same processes as stereoacuity charts.

Adolescent↗

PubMedDate not supplied

Use of CA-125 and ultrasound in high-risk women.

Our objective was a retrospective study reporting on ovarian cancer screening in a high-risk female population using both CA-125 and ultrasound over a 7-year period. We used risk estimates of carrying a BRCA mutation that were based on family history. Subjects were screened with CA-125 and ultrasound every 6 months. Each of 311 high-risk subjects had between 1 and 17 screening visits. Overall, 33 of 1209 (2.7%) CA-125 results were abnormal (>35 U/ml); 226 of 1342 (17%) ultrasounds were abnormal, with abnormalities ranging from benign appearing cystic changes to more ominous patterns. Since entry into the program, 29 subjects (9%) have undergone surgery. In 20 of these, the preoperative screening was normal; in six, only the ultrasound was abnormal, and in two, only the CA-125 was abnormal (46-91 U/ml). In only one subject undergoing surgery were both serial CA-125 levels (52-91 U/ml) and ultrasound abnormal. In 7 years of screening, one patient (0.3%) has been diagnosed with ovarian cancer (stage IA, grade 1 endometrioid adenocarcinoma). Overall, 31 (10%) subjects have completed BRCA testing. We conclude that despite screening results comparable to other studies, the detection of only one ovarian cancer over 7 years is lower than expected. Explanations for this observation are discussed. Despite the limitations of CA-125 and ultrasound, we continue to recommend these screening modalities for high-risk women. At the present time, they offer the best opportunity to detect ovarian cancers early. With increasing knowledge of BRCA testing, more women may benefit from this testing in assessing their personal risk.

Adult↗