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Biomedical subjects

H A Taub

Publications and source records attributed to H A Taub.

At least 19 recordsLinked to original sources

An analysis of symptoms in patients with permanent ventricular pacemakers.

The prevalence and severity of symptoms of the "pacemaker syndrome" were investigated in 64 patients with VVI pacemakers and compared, in the same patients, to a series of control symptoms, unrelated to pacemaker function. Symptoms were also compared in patient groups unlikely to have the "pacemaker syndrome" (atrial fibrillation), most likely to have such symptoms (retrograde atrial activation) and in an intermediate group (competitive paced and sinus rhythms). There was a linear relationship between the frequency and severity of "pacemaker" symptoms and control questions in all groups and no preponderance of "pacemaker" symptoms in any group. The study provides an estimate of the number and severity of symptoms in patients with VVI pacemakers, demonstrates the non-specificity of the "pacemaker syndrome" and shows no evidence of a sub-clinical "pacemaker syndrome" in the patients observed.

Aged

Risks of blood volume changes in hypogonadal men treated with testosterone enanthate for erectile impotence.

Administration of anabolic steroids carries many risks. We present a series of 15 patients with primary hypogonadism who as a group had statistically significant increases in whole body hematocrit and red blood cell volume while on testosterone therapy of 300 mg. intramuscularly every 3 weeks. A small decrease in plasma volume over-all was not significant. Subsequent analyses compared subgroups whose whole body hematocrit during testosterone therapy was either 48% or greater (9) or less than 48% (6). Interaction effects indicated that the subgroups were similar when off testosterone but when on testosterone the former group exhibited an increase in red blood cell volume and a decrease in plasma volume, while the latter group had little change in either measurement. Subsequent to stopping testosterone therapy 2 patients in the whole body hematocrit 48% or greater group suffered strokes and 1 had transient ischemic attacks while on therapy. No one in the whole body hematocrit less than 48% group has had any cerebrovascular symptoms. Clinical implications, as well as cost-effective and practical suggestions for detecting possible dangerous hemoconcentration are discussed.

Aged

Performance of young and older drivers on a static acuity test under photopic and mesopic luminance conditions.

Sixty young (18-25 years) and 91 older volunteers (60-87 years) were tested for static visual acuity under six different luminance levels ranging from 245.5 cd/m2 (photopic) to 0.2 cd/m2 (mesopic). The results showed significant differences in log decimal acuity and in passing a 20/40 acuity criterion score as a function of age and luminance level. There were no differences, however, in comparisons between young subjects and those aged 60-64. It seems, therefore, that when using visual acuity measures, as is done for driver licensing, 65 years is the critical age after which visual acuity becomes significantly poorer under conditions of degraded illumination. The implications for issuing driver's licenses to individuals over age 65 based on standard visual acuity testing are discussed.

Adult

Temporal summation functions for detection of sine-wave gratings in young and older adults.

Temporal summation functions for 0.416 and 7.5 c/deg sinusoidal gratings were measured in young and old observers in order to test the hypothesis of a shift in sensitivity from "transient" to "sustained" channels in the aging visual system. Results failed to support the transient-shift hypothesis. Additional tests showed no age-related changes in temporal summation even within a single channel. When all observers were refracted for the test distance and matched for retinal illuminance, no age-related differences in contrast sensitivity were found.

Adult

Visual information processing speed in hypnotized and nonhypnotized subjects.

Using a backward-masking paradigm with a bias-free and ceiling-free psychophysical task, we tested hypnotized and control subjects for speed of visual information processing. Approximately half of each group received visual imagery suggestions in an attempt to influence attention. Imagery produced no significant differential effect. Although an absence of a hypnotizability-performance relationship was in keeping with findings of a previous study, those subjects in the present study who performed under hypnosis were, as a group, significantly superior to the other subjects in speed of information processing.

Humans

Selective attenuation in brightness for brief stimuli and at low intensities supports age-related transient channel losses.

A brightness estimation experiment was conducted on 10 old (ages 60 to 77) and 10 young (ages 22 to 27) volunteers. Participants were introduced to magnitude estimation by scaling the lengths of line stimuli, after which they dark adapted for 10 minutes. Stimuli for brightness estimation were presented binocularly via a free-viewing system and consisted of circular flashes of 2 degrees. Stimuli covered a 3 log unit range of luminance levels in 0.5 log unit steps, and 3 durations (10, 100, 1000 msec). Linear regression analysis yielded dual-branched functions with a low intensity segment which was significantly steeper in slope than the high intensity segment. The slope for the older group was significantly less steep than that of the younger observers only at the low intensity segment. Findings with respect to stimulus duration showed a significantly attenuated slope for the old as compared to the young group only at 10 msec. The results extend previous threshold results to suprathreshold levels, and are consistent with an hypothesis of a selective loss of transient channels with age.

Adult

Comprehension of informed consent information by young-old through old-old volunteers.

Comprehension of typewritten informed consent information was evaluated for young-old (60-69 years) through old-old (80-89 years) volunteers as a function of years of education (less than 12, 12, and greater than 12), readability of information (low [college level] vs high [7th grade]), and typeface used in the preparation of the materials (Prestige Elite 72, Letter Gothic, and Orator). All volunteers (N = 235) read a typewritten information sheet and retained it for review while answering eight multiple choice questions. Immediate feedback was provided, and a second test was administered if any answers were incorrect. The findings indicated that comprehension varied directly with education and inversely with age. Typeface and age interacted due to age-related differences with the two smaller (Prestige Elite and Letter Gothic), but not with the largest of the typefaces (Orator). These findings suggest that the observed age-related differences may have been due to visual and not cognitive deficits. Readability did not affect performance either by itself or in combination with any other variable.

Age Factors

Older observers have attenuated increment thresholds upon transient backgrounds.

Foveal increment thresholds were measured in young, middle-aged, and older observers. These thresholds, which involved the detection of a small test flash as a function of the intensity of a larger background adapting field (AF), were measured at the instant of onset of the AF (transient condition) and when the eye had been fully light adapted to the AF (steady-state condition). All stimuli were presented to the left eye in a free-viewing system through a 2 mm artificial pupil. For the steady-state condition for all age groups, the functions were similar, but for the transient condition, the slope for the older observers was significantly less steep than that for the younger observers. These findings are consistent with an hypothesis of a selective loss of transient (Y) channels in the aging visual system.

Adult

Informed consent for research. Effects of readability, patient age, and education.

Comprehension of informed consent materials from a study of psychological variables associated with chest pain was evaluated as a function of age (27 to 69 years), education (5 to 20 years), and readability of information [low (college level) versus high (7th grade)]. The potentially confounding effect of memory was eliminated by allowing patients to use the written information sheets to find answers to the multiple choice test. Feedback and a repeat test were provided if any answers were incorrect. The findings indicated that comprehension varied inversely with age and directly with education. It is suggested that while ensuring informed consent may be difficult for all volunteers, it may be a critical problem for elderly patients with low education. The effects of readability were not consistent, suggesting that simplifying informed consent materials by shortening words and sentences may not, by itself, be sufficient to improve comprehension.

Adult

Analgesia for operative dentistry: a comparison of acupuncture and placebo.

Fifty-one volunteer patients participated in a study to evaluate the effectiveness of acupuncture as an analgesic for operative dentistry. For the twenty-six patients randomly assigned to an acupuncture group, needles were inserted through specially designed holders into the Ho-Ku points, located between the first and second metacarpals. An acupuncture pulse generator provided electrical current. For the twenty-five patients in a placebo group, the identical needle and holder arrangement was used. When inserted, however, the needles became embedded in plastic on the undersurface of the holders and did not touch the skin of the patient or receive any electrical stimulation. The patients and dentists were blind to this procedural variation. Analysis of ratings and responses indicated no differences in findings for the acupuncture and placebo procedures, with both having 100% success and high levels of patient acceptance. Since there was no electric current or penetration of the skin in the placebo group, the findings suggest that the successful use of acupuncture for restorative dentistry may be due to psychological and/or placebo effects in combination with a possible diminished need for analgesia because of the modern use of the high-speed drill.

Acupuncture Therapy

Comprehension and memory of prose materials by young and old adults.

Twenty-seven young (X- = 27.3 years) and twenty-seven old (X- = 67.7 years) female volunteers participated in a study of the effect of vocabulary level upon memory and comprehension of prose materials. Comprehension was measured by presenting five multiple choice questions simultaneously with half of the prose passages. Memory was measured with the rest of the materials by presenting questions only after a passage was completed and removed from sight. The results indicated that age-related differences varied inversely with vocabulary levels but did not interact with type of task. No significant differences were found between age groups at the highest vocabulary level. The parallel findings for the two tasks suggest that inadequate comprehension represents one major factor underlying age-related differences in the retention of meaningful materials. A second memory task, not dependent upon accuracy of comprehension, indicated age-related differences at all vocabulary levels. This suggests that old adults may also hve deficits in the ability to maintain in store and/or retrieve meaningful materials.

Adult

Recall of prose as a function of age and input modality.

Three short paragraphs were presented to 18 young (means = 27.6 years) and 18 old (means = 67.2 years) female volunteers to evaluate the effects of three types of input conditions on recall. In the Aloud (combined auditory-visual) condition subjects read the paragraphs aloud, without review, four times (trials), and, after each reading, verbally recalled as much as possible. In the Silent (visual) condition the task was identical except that the paragraph was read silently. In the Review condition subjects also read silently, but were allowed to review the material. The results indicated that, for both age groups, opportunity for review required more reading time and led to significantly better recall than either the silent or aloud conditions, which did not differ. There were no age-related differences in the time used for reading the paragraphs. Further, an Age X Trial interaction indicated that age-related differences in recall were not significant until Trial 3, with the young subjects showing greater increases across trials than the old.

Adult