Investigating the Factor Structure of the Preclinical Alzheimer Cognitive Composite and Cognitive Function Index across Racial/Ethnic, Sex, and Aß Status Groups in the A4 Study.

BACKGROUND: Disparities in Alzheimer's disease (AD) are well-documented among different racial/ethnic groups and between sex/genders. Neuropsychological assessment provides important information about cognitive changes and can offer valuable insights into disparities. However, neuropsychological measures must be comparable across racial/ethnic and sex/gender groups to accurately interpret disparities. OBJECTIVES: To evaluate measurement invariance (equivalence) of the Preclinical Alzheimer Cognitive Composite (PACC) and the Cognitive Function Index across racial/ethnic, sex/gender, and ß-amyloid (Aß) status groups. DESIGN, SETTING, PARTICIPANTS: Cross-sectional analysis of screening data from the Anti-Amyloid in Asymptomatic AD (A4) Study. The study enrolled participants aged 65-85 from sites across the United States, Canada, Australia, and Japan. MEASUREMENTS: Participants completed the PACC and the Cognitive Function Index. Participants classified as cognitively normal also underwent a Positron Emission Tomography (PET) scan to determine Aß status. RESULTS: Participants self-identified as non-Hispanic White (n=5241), non-Hispanic Black (n=267), Asian (n=228), or Hispanic White (n=225) as well as male (n=2885) or female (n=3076). Among those who underwent a PET scan, 3115 were classified as Aß- and 1309 were classified as Aß+. We found support for a one-factor model for both the PACC and Cognitive Function Index across the full sample and in samples stratified by race/ethnicity, sex/gender, and Aß status. The one-factor model of the PACC and Cognitive Function Index demonstrated scalar measurement invariance across racial/ethnic, sex/gender, and Aß status groups. CONCLUSIONS: Our findings suggest that performance on the PACC and Cognitive Function Index can be compared across the racial/ethnic, sex/gender, and Aß status groups examined in this study.

Estrogen receptor variant and hypertension in women.

Eighty-eight women visiting a gynecologist were tested for an estrogen receptor B-variant allele. The women were ethnically and racially homogeneous to a large degree. They were from a suburb of Long Island, and most were white. The 12% incidence of hypertension in women with the estrogen receptor wild-type allele is comparable to the 13-32% incidence in the general population of women aged 55-64 years. However, the 48% incidence of hypertension in women with the estrogen receptor B-variant allele is considerably higher than in the general population of women in this age group. We conclude that the presence of the estrogen receptor B-variant allele might have increased the prevalence of hypertension in the women in this study.

Cone-specific measures of human color vision.

PURPOSE: To describe a new test of color vision (cone-specific contrast sensitivity) and to evaluate its sensitivity in comparison to standard clinical tests. METHODS: Cone-specific colored letter charts were generated by computer and displayed on a color monitor. Each chart consists of colored letters that are most visible at the top but that gradually fade into a gray background. Cone contrast varies systematically on each chart so that letters are visible to only one cone type (L, M, or S cone). Cone-specific letter contrast sensitivity was measured in 30 color normals and 13 subjects with hereditary color deficiency. Values were compared to standard measures of color vision. RESULTS: In color normals, mean log contrast sensitivity was approximately the same on L-cone (1.84 +/- 0.08 log contrast sensitivity) and M-cone (1.87 +/- 0.08) tests but was reduced on the S-cone test (0.89 +/- 0.15) because of the fewer number of S-cones in the human retina. Subjects with red color deficiency showed significantly reduced contrast sensitivity on the L-cone test but normal performance on M- and S-cone tests. Subjects with green color deficiency showed decreased contrast sensitivity limited to the M-cone test. When standardized relative to variability, cone contrast sensitivity identified color deficiency unequivocally in all subjects, whereas FM 100 hue error scores detected 9 of 13 subjects with color deficiency. CONCLUSIONS: Cone-specific contrast sensitivity provides a quantitative measure of normal color vision and indicates both type and severity of color deficiency. It is useful for diagnosing hereditary color deficiency and for monitoring early color vision loss in ocular and systemic disease.

Optical defocus: differential effects on size and contrast letter recognition thresholds.

PURPOSE: To determine if optical defocus produces a greater reduction in visual acuity or small-letter contrast sensitivity. METHODS: Letter charts were used to measure visual acuity and small-letter contrast sensitivity (20/25 Snellen equivalent) as a function of optical defocus. Letter size (acuity) and contrast (contrast sensitivity) were varied in equal logarithmic steps to make the task the same for the two types of measurement. RESULTS: Both visual acuity and contrast sensitivity declined with optical defocus, but the effect was far greater in the contrast domain. However, measurement variability also was greater for contrast sensitivity. After correction for this variability, measurement in the contrast domain still proved to be a more sensitive (1.75x) index of optical defocus. CONCLUSIONS: Small-letter contrast sensitivity is a powerful technique for detecting subtle amounts of optical defocus. This adjunctive approach may be useful when there are small changes in resolution that are not detected by standard measures of visual acuity. Potential applications include evaluating the course of vision in refractive surgery, classification of cataracts, detection of corneal or macular edema, and detection of visual loss in the aging eye. Evaluation of candidates for occupations requiring unique visual abilities also may be enhanced by measuring resolution in the contrast domain.

Nonoptical determinants of aniseikonia.

Interocular differences in apparent size (aniseikonia) are typically associated with interocular differences in refractive error (anisometropia). Aniseikonia is generally thought to reflect disparities in retinal image size that often accompany anisometropia. This assumption was examined with seven highly anisometropic subjects who were tested under conditions in which no substantial retinal image size differences were present. Using a dichoptic size matching task, consistent and large (mean = 22%) aniseikonias were found. Myopic anisometropes exhibit perceptual minification, while hyperopes demonstrate perceptual magnification when using their more ametropic eye. Both ultrasonic and fundus examinations of these subjects indicate that differential retinal growth or stretching is responsible for these findings.

Emmetropization: a vision-dependent phenomenon.

Anomalous visual experience during development has been shown to induce myopia in several species of animals. A retrospective analysis of refractive error among humans subjected to various ocular anomalies that disrupt pattern vision revealed a significant degree of myopia. This result suggests that emmetropization is a vision-dependent phenomenon.

Optical compensation for night myopia based on dark focus and CA/C ratio.

PURPOSE: To determine whether individual differences in dark focus and convergence accommodation to convergence (CA/C) ratio can be used to prescribe the best optical correction for night myopia. METHODS: The best correction for night myopia was obtained by measuring visual acuity and contrast sensitivity across a range of lens powers and luminances. Dark focus was measured with an infrared optometer, and CA/C ratio was measured with an infrared optometer and eyetracker. Only young subjects were used (mean age = 25.4 years). RESULTS: Optimal lens power was significantly correlated with dark focus, regardless of CA/C ratio. However, the slope of the regression line relating lens power to dark focus was steeper for subjects with CA/C ratios less than 0.4 diopters/meter angle (D/MA, n = 7) than for subjects with CA/C ratios greater than 0.4 D/MA (n = 9). The mean CA/C ratio for the entire sample (n = 16) was 0.59 D/MA. The mean optimal lens power and dark focus were -0.79 and 0.74 D, respectively, for the low CA/C group, and -0.60 and 0.91 D, respectively, for the high CA/C group. CONCLUSIONS: Visual performance in night myopia can be optimized by taking into account intersubject differences in dark focus and CA/C ratio. Best visual performance was found with a lens roughly equaling the full dark focus for subjects with low CA/C ratios and half the dark focus for subjects with high CA/C ratios.

Estrogen-receptor polymorphism, spontaneous-abortion, and breast-cancer risk.

In 1988 we identified a polymorphism in the estrogen receptor (ER) gene. The newly identified allele, called B', contains a silent mutation in codon 87, part of the receptor's B domain. Because of the association we previously reported of the B' allele, spontaneous abortion, and estrogen receptor positive breast cancer, we have now performed a preliminary case-control study to estimate the risk of breast cancer in women with the B' allele. Among BB' heterozygotes with ER-positive breast cancers (23 cases, 27 controls), the risk of this type of cancer was strongly related to a history of spontaneous abortion; the age-adjusted odds ratios were 4.1 (95% confidence limits, 0.95-18) after one spontaneous abortion and 9.7 (1.6-61) after two or more spontaneous abortions. No such association was seen for the risk of ER-negative breast cancer in BB' heterozygotes (N=18). Moreover, among BB homozygotes (137 cancer patients, 235 controls), spontaneous abortion was not related to an increased risk of breast cancer, either ER-positive or ER-negative. In BB' patients with ER-positive tumors, receptor concentrations were significantly lower in those who had a history of spontaneous abortion than in those without previous spontaneous abortions. These findings suggest involvement of a functional mutation associated with the B polymorphism, which is either elsewhere in the ER gene region or in a closely linked gene.

Teenagers' awareness of the acquired immunodeficiency syndrome and the impact on their sexual behavior.

One hundred female teenagers attending a teenage pregnancy program were studied to determine the extent of their awareness about acquired immunodeficiency syndrome (AIDS) and the impact of such knowledge on their sexual behavior. Ninety-eight knew that AIDS is a disease, 45 stated that it is fatal, and all knew that it can be transmitted by sexual intercourse. After becoming aware of AIDS, 59 changed their sexual habits, 41 decreased their number of sexual partners, and 13 who had not used condoms started using them. However, only seven obtained more information about their partners' sexual and social histories, and half of those who decreased their number of partners still continued relationships with more than one. The survey showed that the publicity about AIDS has resulted in a favorable change in the sexual practices of these teenagers. However, it also indicated a need for further improvement in specific areas of education, such as the value of obtaining more information about sexual partners, more awareness of the importance of multiple-partner relationships in the spread of AIDS, and more emphasis on the important role of condoms in preventing AIDS virus transmission.

Topical anesthesia for gynecologic procedures.

Topical benzocaine 20% gel was evaluated for its ability to reduce pain associated with several common gynecologic procedures. In the first phase of the investigation, designed to determine the efficacy of the gel, 40 women received it before one or more of five procedures (cervical biopsy, intrauterine device insertion, endocervical curettage, paracervical block, and tenaculum placement). These women reported significantly less pain than 42 control subjects (P less than .05 to P less than .0005). In the second phase of the study, a placebo gel was compared in a blind fashion with 20% benzocaine gel in 63 study subjects and 64 control women undergoing procedures similar to those in the first part of the study. The modal pain rating by both physician and patient was "none" in the study group for all procedures except endocervical curettage, for which the rating was "mild"; ratings were "mild" or "moderate" in the control group. Compliance with respect to keeping follow-up visits was significantly greater in the study group. These data indicate that benzocaine 20% significantly reduces the pain experienced by patients after many gynecologic procedures performed vaginally.

Type IX Ehlers-Danlos syndrome: bladder diverticula with transitional cell carcinoma.

Patients with type IX Ehlers-Danlos syndrome have a tendency for development of diverticulae of the urinary bladder, and these often recur after surgical excision. We report on a patient with this syndrome in whom an extensively infiltrating transitional cell carcinoma developed in a diverticulum. To our knowledge, this is the first reported case of malignancy developing in a patient with type IX Ehlers-Danlos syndrome. The highly aggressive nature of the neoplasm is discussed in relation to the dampened desmoplastic response to the tumor, observed in this patient.

Lightness induction in the S-cone pathway.

Lightness induction is classically regarded as a contrast phenomenon limited to pathways which process luminance information. To determine if lightness induction can also occur in the chromatic domain, this phenomenon was studied with stimuli visible only to the short wavelength sensitive (S)-cones which have post-receptoral connections limited to chromatic pathways. The lightness of an object visible only to S-cones was found to be dependent on the relative intensity of its background in a manner similar to achromatic, luminance stimuli. Less intense (dark) backgrounds made the object appear lighter, while more intense (light) backgrounds made the same object appear darker. These results indicate a commonality among lightness induction effect in the processing of chromatic and luminance information.

Perceptual ambiguity and the short wavelength sensitive visual pathway.

Visual illusions and ambiguous figures are difficult to perceive when presented in a manner which stimulates only chromatic pathways. This perceptual limitation could indicate that these pathways are unable to mediate form perception, or it may reflect the relative visibility of the stimulus, regardless of the pathway utilized. To examine this issue, an ambiguous figure (illusory Necker cube) was presented to the short wavelength sensitive (S) cone pathway which is thought to convey only chromatic signals. Although few observers could recognize the cube when presented in isolation to S cones, the same reduction in recognition was found when the cube was detected by achromatic pathways at a level of visibility comparable to that conveyed by S cones. Our results indicate that for this object recognition task, visibility of the stimulus is the relevant variable, rather than the particular pathway traversed. Prior experience was also found to be important determinant of object recognition.

Visual evoked potentials in three-dimensional color space: correlates of spatio-chromatic processing.

Visual evoked potentials (VEPs) were measured for sinusoidal gratings with spatio-chromatic modulation defined in a three-dimensional color space. The spatio-chromatic modulation of the gratings can be decomposed into contributions from an achromatic luminance varying component, an isoluminant component which modulates only the activities of L cones and M cones, and an isoluminant component corresponding to modulation of only S-cone activity. The emphasis of this report is the nature of VEPs resulting from isoluminant spatio-chromatic modulation. The VEP response was characterized along a number of spatial, temporal, and chromatic stimulus dimensions: contrast, spatial frequency, chromaticity in the isoluminant plane, chrominance/luminance ratio, orientation, and temporal frequency. Isoluminant VEPs resulting from stimuli modulating L and M cones are compared with those from S-cone modulation. When appropriate spatiotemporal conditions are employed, both types produce robust VEPs; however, the S-pathway VEPs show considerably longer latencies than do those from LM-pathway activation. The VEP results are compared to psychophysical and single unit electrophysiological observations. VEP latencies exhibit the lowpass character of psychophysical chromatic contrast sensitivity functions but VEP amplitudes show bandpass tuning along both the S and LM axes. An oblique effect, i.e. shorter latencies for horizontal and vertical gratings than for diagonal, is observed in the isoluminant VEP. S-pathway VEPs are used to demonstrate an electophysiological correlate of transient tritanopia. Normative amplitude and latency data for VEPs from selectivity stimulated chromatic mechanisms provide a baseline for clinical electrodiagnostic applications.

A computerized voiding diary.

OBJECTIVE: To examine a group of subject and control patient's preferences and compliance with regard to the Compu-Void (CV) electronic voiding diary as compared to the written diary (WD) and to compare the two methods with respect to the type of information obtained and whether the order of use of each method influenced results in the subject group. STUDY DESIGN: Thirty-six women between the ages of 20 and 84 with bladder symptoms were compared to a group of 36 age-matched women. RESULTS: In 100% of subjects and 95% of control patients, CV entries exceeded the number made with the WD in voiding events and, in subjects, in incontinence episodes recorded (P < .005 and P < .005, respectively). Over 98% of subjects and over 80% of controls preferred the CV (P < .0005). The order of use of each method in subjects made no significant difference with regard to the volume of information obtained (P < .407), number of leakage events recorded (P < .494) or fluid intake patterns (P < .410). Patients' compliance with each method was not affected by the order of use. CONCLUSION: Our results suggest an increased volume of data and greater patient compliance in reporting bladder symptoms and events using the CV and that the order of use is not important.

The long term benefits of a comprehensive teenage pregnancy program.

A comprehensive program was founded in 1982 to provide adolescents with prenatal and family planning care. The program's impact through its first five years of operation on medical aspects of pregnancy course and fetal outcome will be the subject of a separate report. This study examines subsequent maternal and infant health of the patients attending the program compared to a control group. Four hundred ninety-eight adolescents and their newborns attending the program's mother-baby family planning clinic from 1982 to 1989 (subject group) were compared to ninety-one adolescents and their newborns receiving postpartum family planning and pediatrics clinics from 1980 through 1989 (control group). Seventy-five percent of the subject group regularly attended mother-baby clinic, compared to 18% of the control group attending family planning and pediatric clinics (P less than or equal to .0001). The subject group experienced less maternal and infant morbidity, greater school attendance, graduation, employment, and contraceptive use than the control group (P less than or equal to .0001). Many parameters improved with each program year indicating continued wide acceptance of our program by area adolescents.

Correction of subtle refractive error in aviators.

Optimal visual acuity is a requirement for piloting aircraft in military and civilian settings. While acuity can be corrected with glasses, spectacle wear can limit or even prohibit use of certain devices such as night vision goggles, helmet mounted displays, and/or chemical protective masks. Although current Army policy is directed toward selection of pilots who do not require spectacle correction for acceptable vision, refractive error can become manifest over time, making optical correction necessary. In such cases, contact lenses have been used quite successfully. Another approach is to neglect small amounts of refractive error, provided that vision is at least 20/20 without correction. This report describes visual findings in an aviator who was fitted with a contact lens to correct moderate astigmatism in one eye, while the other eye, with lesser refractive error, was left uncorrected. Advanced methods of testing visual resolution, including high and low contrast visual acuity and small letter contrast sensitivity, were used to compare vision achieved with full spectacle correction to that attained with the habitual, contact lens correction. Although the patient was pleased with his habitual correction, vision was significantly better with full spectacle correction, particularly on the small letter contrast test. Implications of these findings are considered.

Flicker detection through night vision goggles.

Visual performance through night vision goggles (NVG's) is commonly assessed with letter charts or other static displays. Few attempts have been made to evaluate dynamic aspects of vision through NVG's. Such information may be used to better predict human performance and guide the development of improved devices. In this study, contrast thresholds for detection of flickering targets were measured through NVG's across a range of ambient conditions. A comparison of measurements with and without NVG's indicated that flicker detection is limited by the contrast and luminance of the NVG display. The contrast limitation is largely independent of stimulus flicker frequency. Increasing the transfer of static contrast and/or luminance through NVG's will also improve dynamic visual performance.