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Biomedical subjects

S Kemper

Publications and source records attributed to S Kemper.

At least 19 recordsLinked to original sources
PubMed1997

Grammatical abilities in Parkinson's disease: evidence from written sentences.

This study examined the grammatical content of written sentences elicited from 96 Parkinson's patients, 30 Parkinson's with dementia patients and 167 control subjects. Parkinson's patients without dementia or with mild dementia presented no impairments in sentence length, syntactic complexity or amount of information content. Moderately demented Parkinson's patients showed reduced sentence length and information content but normal syntactic complexity. This pattern of results provides evidence that lexical-semantic content is more susceptible to decline than syntactic structure with the progression of dementia in Parkinson's disease.

Aged↗
PubMed1997

Sentence comprehension in Alzheimer's disease: effects of grammatical complexity, speech rate, and repetition.

Caregivers of patients diagnosed with Alzheimer's disease (AD) are often advised to modify their speech to facilitate the patients' sentence comprehension. Three common recommendations are to (a) speak in simple sentences, (b) speak slowly, and (c) repeat one's utterance, using the same words. These three speech modifications were experimentally manipulated in order to investigate their individual and combined effects on sentence comprehension in AD. Fifteen patients with mild to moderate AD and 20 healthy older persons were tested on a sentence comprehension task with sentences varying in terms of (a) degree of grammatical complexity, (b) rate of presentation (normal vs. slow), and (c) form of repetition (verbatim vs. paraphrase). The results indicated a significant decline in sentence comprehension for the AD group. Sentence comprehension improved, however, after the sentence was repeated in either verbatim or parapharsed form. However, the patients' comprehension did not improve for sentences presented at the slow speech rate. This pattern of results is explained via-à-vis the patients' working memory loss. The findings challenge the appropriateness of several clinical recommendations.

Aged↗
PubMed1997

Younger and older adults' on-line processing of syntactically ambiguous sentences.

Off-line studies of younger and older adults' processing of syntactically complex sentences have shown that there is a consistent negative relationship between task performance and working memory for older adults. However, it is not evident from these studies whether working memory affects the immediate syntactic analysis of a sentence, off-line processes, or both. In the current study an online reading paradigm was used to examine the working memory capacity-constrained sentence processing model from M.C. MacDonald, M.A. Just, and P.A. Carpenter (1992). Working memory span, type of syntactic ambiguity (ambiguous vs. unambiguous), and type of syntactic ambiguity resolution (main verb vs. relative clause) interacted to influence younger and older adults' on-line reading times and off-line sentence comprehension.

Adolescent↗
PubMed1997

Metalinguistic judgments in normal aging and Alzheimer's disease.

This study compared sentence acceptability judgments from young and healthy older adults and older adults with dementia due to probable Alzheimer's disease. Two types of sentences were contrasted: one type involved contrasts among verb alternations in which semantic distinctions between verbs regulate the acceptability of phrase structure variations; the second type involved contrasts among directional transformations in which constraints on the movement of noun phrases determine the linear order of main and embedded clauses. The primary findings were that metalinguistic judgments by healthy older adults as well as those with probable Alzheimer's reflected processing demands on working memory. In addition, metalinguistic judgments by adults with probable Alzheimer's reflected the breakdown of semantic information about verbs.

Adolescent↗
PubMed1997

Standardized assessment of psychological well-being and quality-of-life in patients with implanted defibrillators.

The ICD has become a standard treatment for patients with malignant arrhythmias. Despite its benefits it may cause additional discomfort to the patients. Thus, quality-of-life needs to be assessed in these patients. Previous studies have used only small samples or unstandardized measures of quality-of-life that do not allow comparisons with other patient groups. The present study used standardized questionnaires for a cross-sectional assessment of psychological well-being and quality-of-life in ICD patients and to compare them to a similar group of coronary artery disease (CAD) patients without ICD. Overall, quality-of-life did not differ between both groups, ICD patients being less anxious than the CAD group. With increasing numbers of ICD shocks, however, the percentage of psychologically distressed ICD patients rose from 10% to > 50%. Psychologically distressed patients had significantly worse scores on most of the quality-of-life subscales, showed less treatment satisfaction, and more negative attitudes. It is concluded that ICD patients have an acceptable mean quality-of-life and low mean anxiety. However, a relevant subgroup of about 15%, especially patients with frequent shocks, experience psychological distress and reduced quality-of-life and should receive special care.

Adaptation, Psychological↗
PubMed1994

Speech accommodations to dementia.

This study investigated whether spouses would adopt a specialized speech register when communicating with adults with probable Alzheimer's disease. A picture description task was used so that the effectiveness of such speech accommodations could be assessed. The AD subjects did not vary the syntactic complexity, semantic complexity, or content of their descriptions when they were describing individual pictures versus directing their spouse to choose one of four pictures in a barrier task. The spouses' picture descriptions were more complex syntactically and semantically than the AD subjects' and included more highly salient elements. The spouses also varied the complexity and content of their descriptions, reducing syntactic and semantic complexity and increasing references to highly salient picture elements during the barrier task. These accommodations appeared to facilitate the AD subjects' performance on the picture description task.

Aged↗
PubMed1993

On the preservation of syntax in Alzheimer's disease. Evidence from written sentences.

We examined the syntactic complexity of single written sentences elicited from 368 adults undergoing examination for possible Alzheimer's disease. The clause length and composition of the sentences varied with the severity of dementia. The nondemented adults' sentences contained more propositions, main and secondary verbs, and conjunctions than those produced by the mildly and moderately demented adults. Sentence length in clauses, propositional content, and the use of conjunctions and main and secondary verbs discriminated among stages of the severity of the disease. The present results suggest that, while dementia severity affects written linguistic output, such output is, nonetheless, grammatic and coherent.

Aged↗
PubMed1993

Recall and articulation of English and Chinese words by Chinese-English bilinguals.

Three groups of subjects were tested to investigate the effect of language on the relationship between recall span and articulation rate. Native English-speaking monolinguals and native Chinese-speaking monolinguals recalled only English or Chinese words, respectively. Chinese-English bilinguals recalled both English and Chinese words. Articulation rates for English and Chinese monolinguals and Chinese-English bilinguals in each language were also obtained. When recall span was regressed on articulation rate, the slopes for Chinese and English words were significantly different for the Chinese-English bilinguals. This difference was not due to language proficiency but to phonological differences between English and Chinese.

Adult↗
PubMed1992

Adults' reading comprehension: effects of syntactic complexity and working memory.

Two experiments investigated the relationship between working memory and reading comprehension. In the first, college students, 18 to 26 years of age, and adults, 60 to 92 years of age, were given a battery of tests of working memory, a standard timed reading comprehension test, and a reading test designed to explore how syntactic complexity affects comprehension. In a follow-up study, the adults were retested on a modified version of the syntax comprehension text. Age group declines in working memory and reading comprehension were obtained in Experiment I; age group declines in reading rate but not comprehension were obtained in Experiment II. The results suggest that working memory limitations affect elderly adults' ability to process complex syntactic constructions, lowering comprehension in the timed test (Experiment I) and reducing reading rates in the untimed test (Experiment II).

Adolescent↗
PubMed1991

Syntactic complexity and adults' running memory span.

This study investigated age group differences in adults' running memory span for prose. College students and adults 60 to 94 years of age listened to a prose passage that was interrupted occasionally by pauses. At each pause, the adults attempted to recall the immediately preceding text. The pauses followed either two single-clause sentences, a two-clause right-branching sentence, or a two-clause left-branching sentence. There was a significant Age Group x Syntactic Form x Clause Order interaction such that the age group differences in verbatim recall were exacerbated by the effects of syntactic complexity. The elderly recalled 25% fewer words from the first embedded clause of the left-branching sentences than the college students, whereas they recalled only 4% fewer words from the first of two successive single-clause sentences. Performance on the running memory span task was also correlated with two measures of the adults' working memory: forward digit span and backward digit span. The pattern of correlations indicated that working memory limitations determine adults' running memory span for prose and contribute to age-group deficits in comprehension.

Adolescent↗
PubMed1990

Peroxidation-induced perturbations of erythrocyte lipid organization.

Peroxidation of erythrocyte membrane lipids by hydrogen peroxide perturbs the lipid bilayer and increases phagocytosis by macrophages. This study addresses the underlying mechanism of these processes, and in particular the role of malondialdehyde, a major byproduct of lipid peroxidation. When erythrocytes were treated with hydrogen peroxide or ascorbate/iron to generate malondialdehyde, or with malondialdehyde itself, only those cells treated with hydrogen peroxide showed increased phospholipid spacing and enhanced phagocytosis. This result indicates that the alterations observed are unique to hydrogen peroxide treatment, and that malondialdehyde does not play a role in inducing these changes in surface properties. Comparison of adherence to human umbilical vein endothelial cells and phagocytosis showed that increased phagocytosis was not mirrored by enhanced adherence. This result suggests that two different signals may mediate recognition of erythrocytes by macrophages and by endothelial cells.

Cell Adhesion↗
PubMed1990

Adults' word recall and word repetition.

This experiment investigated age group differences in working memory by examining the effects of word length on adults' recall span and repetition rate. College students and adults, 60 to 94 years of age, recalled lists of one-, two-, or three-syllable words and repeated aloud pairs of one-, two- or three-syllable words. Word recall spans and word repetition rates were computed. Main effects of age group and word length were obtained on both measures, although the interactions were not significant. A second analysis examined the relationship between individuals' recall span and their repetition rate. Across all age groups combined, recall span was a linear function of repetition rate and accounted for 25 percent of the variance on the recall task. A reanalysis of the word repetitions revealed that older adults' word durations and inter-word pauses are longer than young adults'.

Adult↗
PubMed1988

Organ blood flow haemodynamics and metabolism of the albacore tuna Thunnus alalunga (Bonnaterre).

Metabolic haemodynamic, and organ blood flow measurements were made in tabled, partially anaesthetized albacore Thunnus alalunga. Heart rates were 115 +/- 9 beats/min: blood pressure 98/75 mm Hg (systolic/diastolic): cardiac output 36.1 +/- 5 (ml/min/kg): oxygen consumption 3.4 +/- 0.7 (ml O2/min/kg) and cardiac contractility (dP/dt) 6342 +/- 822 mm Hg/s. Organ blood flows were measured with radiolabelled microspheres. The red muscle, kidney, and spleen received the highest flows and the white-muscle the least. There was a flow gradient in the white-muscle with the inner portion near the red-muscle receiving the highest flows. Arterial and venous blood gas measurements showed a reverse temperature effect on arterial PO2 and a P50 of 15.9 Torr corrected to 37 degrees C. Red-muscle temperature was 7 degrees C higher than ambient water temperature. These measurements record the albacore's markedly high cardiovascular capability.

Animals↗
PubMed1987

Life-span changes in syntactic complexity.

Adults' diaries were examined for age-related changes in syntactic complexity. The diaries in the longitudinal sample were kept by 8 adults, born between 1856 and 1876, for seven or more decades. The diaries in the cohort-sequential sample were kept by 10 adults born between 1820 and 1829 and recorded during 1860 to 1869 or during 1900 to 1909 and 10 adults born between 1860 and 1869 and recorded during 1900 to 1909 and again in 1940 to 1949. Sentences from the two longest, usable entries from each half-decade were analyzed. The analysis determined the incidence of left- and right-branching embeddings and of coordinate and subordinate phrases and sentence fragments as well as the mean length of sentences in words and in clauses. The analysis revealed an age-related decline in the syntactic complexity of adults' sentences.

Adult↗