Biomedical subjects

K A Bayles

Publications and source records attributed to K A Bayles.

At least 19 recordsLinked to original sources

PubMed1996

Change in cognitive function in idiopathic Parkinson disease.

OBJECTIVE: To study the effects of Parkinson disease (PD) on cognitive function by determining the frequency and amount of change in Mini-Mental State Examination (MMSE) performance. DESIGN: During a 4-year period, 77 patients with idiopathic PD and 43 normal elders were administered a neuropsychological test battery twice at 2 years apart. RESULTS: A 4-point score difference on the MMSE was the amount that was statistically calculated to be a significant difference at the .05 probability level. Using this metric, 17 (22%) patients with PD had a change in their MMSE performance during a 2-year period. Fifteen individuals performed poorer, and 2 individuals improved. Using the same metric, no normal subjects changed in their MMSE performance. The groups of patients with PD who had a change and did not have a change in their MMSE performance were not characterized by significant differences in their years of education, duration of illness, age at onset, age at test time 1, estimated premorbid intelligence, Hamilton Psychiatric Rating Scale for Depression score at test time I, or Unified Parkinson's Disease Rating Scale score. The singular difference was the higher frequency of change that was found in subjects who were taking dopamine agonists at the second test time. CONCLUSION: A change in cognitive function in patients with PD, as measured by a change of 4 points or more in their MMSE performance, was observed in only 22% of a sample of 77 patients with idiopathic PD during a 2-year period.

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PubMed1996

Category and attribute knowledge deterioration in Alzheimer's disease.

A prevalent theory regarding the deterioration of semantic memory in Alzheimer's disease is that it is a bottom-up process. If this is true, performance on tests of attribute knowledge should decline more rapidly than performance on tests of categorical knowledge as dementia severity increases. In the present study, a convincing pattern of findings to either support or reject the theory failed to emerge. This raised questions regarding the ability to separate attribute and categorical knowledge, and whether one can be tested without influence of the other. Questions also were raised regarding the additional cognitive processes needed to complete tasks of semantic memory.

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PubMed1996

Phrase repetition in Alzheimer's disease: effect of meaning and length.

Repetition ability depends in part on the intactness of semantic memory. If the conceptual contents of semantic memory are lost as a function of Alzheimer's disease (AD) pathology, meaningfulness of stimuli should have progressively less effect on the ability to repeat as the disease worsens. This study was designed to evaluate the effects of meaningfulness and length of phrasal stimuli on repetition ability in mild and moderate AD patients and normal elderly subjects. Fifty-seven AD patients and 52 normal subjects were given six- and nine-syllable phrases that were meaningful, improbable in meaning, or meaningless. Cross-sectional and longitudinal data analyses were conducted and results failed to confirm a performance pattern consistent with a semantic memory loss theory. Meaningless nine-syllable phrases were those most difficult to repeat for moderate as well as mild AD patients and normal controls.

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PubMed1996

Cross-sectional analysis of Alzheimer disease effects on oral discourse in a picture description task.

To examine the relation of dementia severity to the quality and quantity of oral discourse of individuals with Alzheimer disease (AD), a picture description task was administered to elicit oral discourse samples from 63 AD subjects, five individuals with very mild cognitive impairment, and 52 normal controls. Eight measures of discourse were used: total words, information units, conciseness, circumlocutions, frustrations, aborted phrases, revisions, and ideational repetitions. Information units, which decreased with increased dementia severity, proved to be the best measure for evaluating the effects of AD on oral descriptive discourse. The conciseness index also decreased with increased dementia severity, and a significantly greater proportion of AD discourse samples contained ideational repetitions. Circumlocutions and frustrations rarely occurred, and although the discourse of AD subjects was more likely to contain an aborted phrase, the frequency of aborted phrases did not vary by stage of dementia. Revisions were commonly observed in the discourse of both normal controls and AD subjects and did not differentiate the two groups.

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PubMed1996

Use of the Arizona Battery for Communication Disorders of Dementia in the UK.

The Arizona Battery for Communication Disorders of Dementia (ABCD) (Bayles & Tomoeda, 1993) was given to groups of young and old normal subjects and to subjects with moderate Alzheimer's disease in the UK. Very few significant differences were found between their raw scores and those of the original standardisation sample in the USA, which makes the ABCD an appropriate test to use in the UK. Although some subjects commented on several of the test stimuli, cultural differences in pictures and vocabulary did not produce notable effects on test performance and so alterations to test materials are not required for the test to be used in the UK.

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PubMed1993

Memory impairment and executive control in individuals with stroke-induced aphasia.

The purpose of this study was to examine memory abilities of aphasic individuals in relation to site of neurological lesion. Fourteen individuals with stroke-induced aphasia (7 with anterior lesions; 7 with posterior lesions) and 14 demographically matched control subjects were given selected tests of short-term memory (STM) and long-term memory (LTM). Stroke patients were impaired relative to control subjects on tests of verbal memory, with greater impairment of LTM associated with anterior lesions and greater impairment of STM associated with posterior lesions. Verbal memory performance did not correlate highly with language ability, and did not appear to be simply a consequence of language impairment. Executive control deficits were postulated as explanatory of the LTM impairment associated with anterior lesions.

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PubMed1993

Generative naming in Parkinson disease patients.

The generative naming ability (verbal fluency) of 88 idiopathic Parkinson disease (PD) patients was evaluated and compared to that of 21 Alzheimer disease (AD) patients and 43 normal age- and education-matched normal control subjects. The PD patients were classified according to whether they scored within the normal range on the Mini-Mental State Examination (MMSE), a score of 27 or higher, or in the abnormal range, a score of 26 or lower. Semantic and letter generative naming tasks were administered to assess verbal fluency. Results of the study provide evidence that letter category naming is inherently more difficult than semantic category naming; that age significantly affects generative naming; that PD patients with normal MMSE scores were significantly inferior to normal control subjects in generative naming even after the effects of age and mental status are controlled; that PD patients with non-normal MMSE scores performed like AD patients after controlling for the effects of age and mental status; and, that ideational perseveration is the most common type of error response for all subject groups.

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PubMed1993

Longitudinal effects of Alzheimer disease on discourse production.

As part of a 5-year study of the longitudinal effects of Alzheimer disease (AD) on language, discourse samples from three patients diagnosed with AD and three matched normal controls were analyzed. A picture-description task was used to elicit comparable samples of discourse. Subjects were asked to describe the "Easter Morning" picture by Norman Rockwell. Samples were tape recorded, transcribed, and scored using eight measures of discourse production. These measures successfully quantified the changes in quantity and quality observed in the discourse of AD patients over time. Results revealed remarkably similar patterns, adding a longitudinal dimension to the growing body of knowledge of the effects of AD on discourse production.

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PubMed1992

Relation of linguistic communication abilities of Alzheimer's patients to stage of disease.

A battery of linguistic communication (L-C) tasks was administered to 152 Alzheimer's disease patients in different stages of the disease and 60 normal elders. Subject performance data are used to construct a profile of L-C deficits by disease stage, as determined by ratings on the Global Deterioration Scale. Specification also is made of the L-C tasks on which mild Alzheimer's patients perform like normal elders, the relative difficulty of various L-C processes, the disease stage in which the greatest change occurs in L-C functions, and the degree of variation in L-C for individuals at a particular level of dementia severity.

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PubMed1992

Confrontation naming in Alzheimer's patients: relation to disease severity.

Reports of Alzheimer's disease patients in whom naming performance is disproportionate to other cognitive performances raise questions about the stage model, or dementia-severity level, for predicting naming performance. Thus, dementia severity as defined by Global Deterioration Scale ratings, Mini-Mental State Examination scores, and combinations of them was evaluated as a predictor of naming performance in 102 Alzheimer's patients and was found to account for approximately 1/3 of performance variability. Additional contributions from age at onset, duration, family history, and gender were negligible. Therefore, naming ability can be argued to have a subcomponent that is not subsumed by overall cognitive ability.

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PubMed1992

Acquired mutism: physiopathy and assessment.

The speechless patient presents a unique challenge to the clinician working with neurologically impaired adults. Acquired speechlessness, or mutism, has been associated with a variety of clinical states and syndromes after damage to central and peripheral nervous system structures. The intent of this paper is to summarize the reported states and syndromes associated with acquired mutism (eg, persistent vegetative state, akinesia), and to organize this information in a framework for clinical assessment of the speechless patient. For the purpose of discussion, speech production is divided into five interrelated processes: arousal; cognitive processing; affect and drive; motor initiation, planning, programming, and coordination; and execution of movement. Disorders characterized by mutism are classified according to the process or processes of speech production that primarily are affected. Each subtype of acquired mutism is characterized by a cluster of neurologic signs, which has been incorporated into a decision-making framework for use in a clinical setting.

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PubMed1991

Age at onset of Alzheimer's disease. Relation to language dysfunction.

A later age at onset of Alzheimer's disease (AD) was found to be related to diminished language performance in 86 patients with probable AD. A hierarchical linear model was constructed to assess effects of age at onset and disease duration on the performance of patients with AD on four language tasks (naming, reading, auditory comprehension, and writing to dictation) after controlling for disease severity. Results of univariate analysis, in which the dependent variable was the averaged language task performances, revealed a significant effect for age at onset of AD, but not for disease duration. To assess the possibility that the relationship between the age at onset of AD and language performance reflects effects of normal aging, the language tasks were given to 33 normal subjects of similar ages who scored perfectly on dementia severity measures. A convincing relationship was not found between test score and age.

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PubMed1991

Caregiver report of prevalence and appearance order of linguistic symptoms in Alzheimer's patients.

We interviewed primary caregivers of 99 Alzheimer's disease patients about the existence and appearance order of linguistic symptoms in a longitudinal study of disease effects on communication. The most prevalent linguistic symptom was difficulty finding the correct word and the least prevalent was increased talkativeness. The prevalence of linguistic symptoms was strongly correlated with order of symptom appearance, with difficulty writing a meaningful letter appearing first and word finding difficulty appearing second. Based on caregiver perceptions, symptom prevalence and order of appearance are specified and discussed in relation to onset of nonlinguistic memory deficit, dementia severity, and performance on a linguistic communication test battery.

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PubMed1990

Speech rate and syntactic complexity effects on the auditory comprehension of Alzheimer patients.

The purpose of this investigation was to examine the effects of speech rate and syntactic complexity on the auditory language comprehension of individuals with presumptive Alzheimer's disease, compared to healthy elderly controls. Three presentation rates and command statements of increasing syntactic complexity were used. Although rate of presentation did not significantly affect comprehension in either group, both groups demonstrated increased difficulty with stimuli of greater syntactic complexity, with Alzheimer's patients performing significantly poorer at all levels.

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PubMed1990

Response consistency on a semantic memory task in persons with dementia of the Alzheimer type.

The purpose of this investigation was to determine the test-retest response consistency rate on a semantic memory task in persons with dementia of the Alzheimer type (DAT). Ten mildly and 13 moderately impaired DAT subjects and 14 normal controls matched for age, years of education, and estimated IQ participated in this study. The Peabody Picture Vocabulary Test (PPVT) was administered twice to each subject with a 7-day intertest interval. The mild and moderate DAT subjects responded inconsistently to significantly more PPVT items than normal controls. When the effects of guessing were considered, moderate DAT subjects gave significantly more inconsistent PPVT responses than normal controls and mild DAT subjects showed a trend toward giving more inconsistent responses. These results substantiate the conclusion that the impairment of specific conceptual knowledge in DAT subjects cannot be reliably measured with a single administration of a semantic memory task such as the PPVT.

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PubMed1990

Naming and categorical knowledge in Alzheimer's disease: the process of semantic memory deterioration.

Semantic memory deterioration in Alzheimer's disease (AD) has been theorized to proceed from a loss of object attribute knowledge to a loss of category knowledge. The theory is based on the belief that naming is a computational process requiring object attribute knowledge. It is strengthened by reports that AD patients misname by giving category information and perform poorer on tests of attribute than category knowledge. The purpose of this study was to test the theory's validity by administering naming and category knowledge tasks to AD and normal elderly control subjects. Results revealed a theoretically unexpected outcome, that is, naming became easier relative to the recall and recognition of category information.

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PubMed1990

Delayed recall deficits in aphasic stroke patients: evidence of Alzheimer's dementia?

In a comparative study of the performance of patients with Alzheimer's disease (AD), aphasia resulting from stroke, and normal elders on a variety of neuropsychological tasks, 3 aphasic patients performed similarly to AD patients in the delayed recall of verbal material. The memory deficit of these aphasic patients raised the question of incipient dementia because memory impairment is the hallmark characteristic of AD. However, when the performance profiles of the aphasic patients on all four memory measures administered in the study were compared to those of AD patients, differences made the presence of dementia unlikely. Nonetheless, the possibility remained that a deficit in delayed free recall might be the primordial symptom of dementia. Therefore, the four memory tasks were readministered to the 3 aphasic patients 2 years later, and intergroup performance comparisons again were made. The performance profiles of the aphasic patients obtained 2 years later were superior to and distinct from the AD patients, confirming the absence of dementia at Test Time 1.

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PubMed1990

Language and Parkinson disease.

Previously published reports of deficits in linguistically oriented tasks were reviewed for both demented and nondemented Parkinson disease (PD) patients in a discussion of the question of whether PD affects language. Additionally, to illustrate the methodological problems inherent in evaluating linguistic competence, the performance on four linguistically oriented tasks of 12 PD patients who scored 8 or better on the Mental Status Questionnaire was compared to that of 32 age- and education-matched control subjects. These tasks, from which a composite variable representing performance was formed, were oral object description, story retelling, the Peabody Picture Vocabulary Test, and the Similarities subtest of the Wechsler Adult Intelligence Scale (WAIS), a test of verbal associative reasoning. After controlling for the effects of disease severity, a significant effect was observed for the presence of PD. However, when the additional effects of performance on the Block Design subtest of the WAIS were controlled, the PD effect was of borderline significance. These results typify those in the literature, that is, whereas nondemented PD patients can be demonstrated to perform significantly more poorly on linguistically oriented tasks, the performance deficit cannot be conclusively demonstrated to result from a language deficit per se.

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