Biomedical subjects

B Uttl

Publications and source records attributed to B Uttl.

6 recordsLinked to original sources

PubMed1999

Two periods of processing in the (circum)striate visual cortex as revealed by transcranial magnetic stimulation.

To determine the timing of visual processing in the (circum)striate visual cortex, we examined the effect of single pulse transcranial magnetic stimulation over the occipital pole of healthy subjects who were engaged in a forced-choice visual letter identification task. Single letters, subtending a visual angle of 0.35 degrees, were foveally presented for 10 ms and were immediately followed by a mask. We investigated 30 different delays (d), defined as the time between the onset of the visual stimulus and the onset of the magnetic stimulus, from d = -100 ms to d = +190 ms, and 4 different midsagittal coil positions (x), defined as the distance between the lower edge of the coil and the upper edge of the inion, from x = 1 cm to x = 7 cm. Three out of four subjects showed three distinct delay intervals (dips) at which application of TMS resulted in an impairment of the task. The first dip was centred around d = -50 ms and occurred independently of the coil position; the second dip was centred around d = 0 ms and was elicitable only with the two lowest coil positions; the third dip was centred around d = 100 ms and was also elicitable only with the lower coil positions. In the fourth subject, only the first and the third dip were found. We conclude that there are two distinct periods when the activity in the (circum)striate visual cortex is necessary for the identification of visually presented letters.

Electromagnetic Phenomena↗

PubMed1998

Progressive supranuclear palsy: a survey of the disease course.

BACKGROUND: The most accurate knowledge about progressive supranuclear palsy (PSP) comes from small sample studies that preclude precise estimation of the proportion of PSP patients affected with various symptoms and the examination of factors predicting survival time. OBJECTIVE: To describe the course of PSP in a large clinically diagnosed sample of PSP patients and to identify factors predicting survival time. METHODS: We surveyed the caregivers of 318 living and 119 deceased patients with progressive supranuclear palsy. The main outcome measures were a principal symptom severity questionnaire and a signs and symptoms questionnaire. RESULTS: The estimated age of PSP symptom onset depends critically on how symptom onset is defined, with estimates differing by as much as 1.5 years. Men and women were represented equally (51.6% versus 48.4%) in the living sample, but men formed 61.8% of the deceased sample. Men were diagnosed later than women following symptom onset (33.4 versus 24.1 months) and died earlier following the diagnosis (37.0 versus 47.6 months). Motor and visual symptoms appeared first, followed by emotional and personality problems, cognitive impairment, and sleep changes. Whereas motor symptoms eventually affected almost every patient, emotional/personality and cognitive symptoms did not. The early onset, presence of falls, slowness, and inability to move eyes downward early in the development of the disease predicted survival time. CONCLUSION: PSP is a rapidly progressive disease dominated by motor symptoms, and it affects men more frequently than women.

Affective Symptoms↗

PubMed1998

Caregiving in progressive supranuclear palsy.

BACKGROUND: Basic issues regarding factors influencing progressive supranuclear palsy (PSP) patient caregiver burden remain unresolved, including whether and how disease severity and duration influence caregiver burden. OBJECTIVE: To examine the relation between PSP patient caregiver burden and disease severity, describe the time course of caregiver burden in relation to disease progression, and identify the contribution of other factors (e.g., patient memory and behavioral problems, caregiver gender) to caregiver burden. METHODS: Mail survey of 180 caregivers of PSP patients (living at home and cared for by nonprofessionals) who were members of the Society for Progressive Supranuclear Palsy. The survey included the Burden Interview, an instrument measuring caregiver burden by inquiring how they feel about different aspects and demands of caregiving. RESULTS: Caregiver burden was related to both PSP disease severity (r = 0.40) and disability/need for assistance (r = 0.43). The relation between burden and disease duration was nonlinear, following the same time course as disease severity; the burden increased during the first 18 months postdiagnosis and leveled off thereafter. Women reported more burden than men (caregiver sex delta r2 = 0.05), even after controlling for disease severity and duration (delta r2 = 0.22) and patient gender (delta r2 < 0.01; NS), patient depression (delta r2 = 0.09), and aggressiveness (delta r2 = 0.02). CONCLUSION: Burden in PSP is related to disease severity, disease duration, and caregiver gender (even after controlling for patient's memory, patient depression, and aggression).

Aged↗

PubMed1997

Color-Word Stroop test performance across the adult life span.

In the Color-Word Stroop test (CWST), the basic task is to name the ink color of rows of XXXs, and performance in this condition is compared with performance in naming the ink-color of color words under conditions where word meanings and ink colors mismatch or are incongruent (e.g., the word red printed in green ink). The present study investigated whether Stroop test interference, defined as the cost associated with ink-color naming in the incongruous stimulus condition versus in the basic color-naming condition, provides positive evidence for a kind of processing qualitatively different than that which is required for color naming or for word reading. Does the pattern of age-related differences in Stroop interference force the conclusion that the incongruous condition taps a qualitatively different kind of processing than that required for color naming or for word reading? We gave the CWST to 310 healthy adults. Their performance in each condition of the test replicates and extends previous findings. Structural equation modeling of the data showed a significant, direct link between age and performance in the latent factor associated with the incongruent condition. However, this direct link with age produced a relatively small increase in the model's fit; it amounted to only a .024 increase in the proportion of variance explained in the incongruent condition. In light of this small direct influence due to age, the most parsimonious explanation of our findings is that age effects in Stroop interference are due to age-related slowing (which is also indexed by color naming and by word reading) primarily; the findings do not provide evidence for a qualitatively different kind of processing that declines with age.

Adolescent↗

PubMed1995

Color- and picture-word Stroop tests: performance changes in old age.

The Stroop test comes in different variations, but all of them index performance on a basic task, like color or picture naming, when it is carried out by itself versus when it is performed in the presence of conflicting or incongruent stimuli. The present study examined the hypothesis that Stroop interference--the cost of performing one task in the presence of another--is a general as opposed to a test-specific index of cognitive flexibility. A second goal was to examine changes in Stroop test performance in old age. A group of 129 healthy older adults (> or = 65 years of age) were assessed on the color- and picture-word Stroop test, as well as on a battery of neuropsychological tests. Subjects' performance on each card of both Stroop tests, and various derived (differences and ratios) scores, were used to prepare age-group norms. The use of the norms is illustrated with findings from previous studies. Regression analyses showed age-changes in several aspects of Stroop test performance. Hierarchical multiple regression analyses, and causal modeling showed an age effect on Stroop interference only on the picture-word test but not on the color-word test. Exploratory factor analysis of the Stroop data and the neuropsychological test data revealed different factor loadings for the color- and picture-word test. The combined findings suggest that the color- and picture-word Stroop test measure different cognitive functions, at least in old age.

Aged↗

PubMed1993

Episodic spatial memory in adulthood.

Two experiments examined age-related differences in memory for spatial location information in a museum exhibit (Experiment 1) and in a secretarial office (Experiment 2). In Experiment 1, subjects were the visitors to the exhibit (N = 302, 15-74 years of age), and memory was assessed using a map test. In Experiment 2, subjects were 64 young adults (M = 21.2 years) and 32 older adults (M = 71.2 years), and memory was assessed using both a map test and a relocation test. The relocation test required subjects to replace the to-be-remembered targets where they appeared at study. Experiment 1 showed an age-related decline in spatial memory performance, and it placed the onset of this decline in the sixth decade of life. Experiment 2 showed an age-related decline on both tests, but age effects were smaller on the relocation test than on the map test, and when subjects knew that spatial memory would be tested than when they were not informed.

Adolescent↗