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Biomedical subjects

H H Brownell

Publications and source records attributed to H H Brownell.

At least 19 recordsLinked to original sources
PubMed1992

The use of pronoun anaphora and speaker mood in the interpretation of conversational utterances by right hemisphere brain-damaged patients.

Understanding utterances in conversations requires a listener to weigh the disparate pieces of information present in a discourse. In this study, we examined how right hemisphere brain-damaged (RHD) patients and non-brain-damaged control subjects interpreted responses to questions concerning the location of a person (e.g., "Where's Dad?"). Stimulus vignettes included variation on three factors relevant to discourse comprehension: the mood of a speaker, the plausibility of the answer to a question, and whether the answer contained an anaphoric pronoun linking the response to the preceding question. Relative to the control subjects, the RHD patients made greater than normal use of the presence/absence of an anaphoric pronoun in their utterance interpretations, less than normal use of the speaker's mood, and marginally less than normal use of a response's plausibility. These data show how RHD patients rely on their largely intact linguistic abilities when understanding discourse and how their comprehension goes awry due to their reduced appreciation of other essential aspects of natural communication. The discussion focuses on the variable roles of speaker mood, plausibility, and pronoun anaphora in supporting inferences about a speaker's intended meaning and on the selective nature of RHD patients' impairment in this domain.

Affect↗
PubMed1992

Story processing in right-hemisphere brain-damaged patients.

The understanding of stories requires sensitivity to structural aspects of narrative, the emotional content conveyed by the narrative, and the interaction between structural and emotional facets of the story. Right-hemisphere-damaged (RHD) and normal control subjects performed a number of different analytic tasks which probed their competence at story comprehension. Results revealed that RHD subjects perform at a level comparable to that of normal controls with stories that follow a canonical form and that they show few difficulties with structural aspects of narrative. Contrary to expectation, they are strongly influenced by the "interest" level of a story and by other factors that tap emotional sensitivity. Findings are discussed in terms of the processing and arousal mechanisms which may give rise to the observed pattern of difficulties in RHD patients.

Aged↗
PubMed1990

Appreciation of metaphoric alternative word meanings by left and right brain-damaged patients.

Appreciation of metaphoric and nonmetaphoric alternative word meanings was assessed in 19 aphasic, left (LHD) and 15 non-aphasic, right (RHD) hemisphere brain-damaged stroke patients. With the one exception in the aphasic group, all patients were male. In an unspeeded sorting task, subjects responded on the basis of less frequent, alternative meanings of polysemous target words. Targets were either polysemous adjectives (e.g. "warm") having metaphoric alternative meanings (loving) or polysemous nouns (e.g., "pen") having non-metaphoric alternative meanings (writing implement, cage). Both patient groups performed worse overall than a group of nonbrain-damaged control subjects. Relative to the RHD patients, LHD patients showed a spared appreciation of metaphoric alternative meanings. In addition, LHD, but not RHD, patients performed better on metaphoric adjective trials when there was high similarity between a word's dominant and (metaphoric) alternative meaning. The results suggest a pervasive insensitivity of RHD patients to alternative interpretations of linguistic units, and a special role for the intact right hemisphere in lexical-semantic processes related to metaphor comprehension.

Aged↗
PubMed1990

The effects of right hemisphere damage on the pragmatic interpretation of conversational remarks.

The ability to interpret conversational utterances was assessed in a group of 12 male patients with unilateral right hemisphere brain damage (RHD) and 12 non-brain-damaged, age-matched male control subjects. Subjects listened to short vignettes which described both the affective tone of the relationship between a speaker and an actor, and the actor's performance on a task. Each vignette concluded with the speaker characterizing the actor's performance. In half of the items, the speaker's utterance was literally true; in the other half, the utterance was literally false and invited a nonliteral interpretation. Results showed no appreciable differences in the performance of control subjects and RHD patients when interpreting literally true utterances. In contrast, the two groups differed reliably when interpreting the pragmatic intent of nonliteral utterances: Control subjects used information about both the actor's performance and the speaker-actor relationship, while RHD patients demonstrated difficulty in using the information about the speaker-actor relationship. Results have implications for patients' understanding of essential elements of conversations, such as characters' internal states and their intentions in employing different forms of literal and nonliteral language.

Affect↗
PubMed1989

Appreciation of indirect requests by left- and right-brain-damaged patients: the effects of verbal context and conventionality of wording.

Unilaterally right (RHD)- and left (LHD)-hemisphere-damaged patients were tested on their ability to discern the correct, nonliteral interpretation of indirect requests (e.g., "Can you open the door?") embedded in short vignettes and presented without any pictorial support. Each stimulus vignette incorporated two verbal cues--context and conventionality of form--designed to influence interpretations of a critical utterance located at the end of each vignette. Contexts were biased to encourage either the direct, literal reading of critical utterances as a question, or the indirect meaning of the utterance as a request for action. The critical utterances themselves were either high in conventionality (e.g., "Can you ...?") which encouraged an indirect interpretation, or low in conventionality (e.g., "Is it possible for you to ...?") which encouraged a direct interpretation. Results indicated that RHD patients were significantly impaired, relative to controls, in their ability to make judgments based on contextual information. RHD patients performed comparably to the aphasic, LHD group in the use of both context and conventionality. These results replicate earlier findings of disrupted indirect request comprehension by RHD patients tested in pictorially supported paradigms.

Adult↗
PubMed1989

The case against the case against group studies.

We challenge the position that only the analysis of single patients can allow us to infer normal function from impaired performance. We claim that the focus on group vs. single case studies is unprofitable and that a more useful question is how best to form abstractions of relevance to cognitive theory. In this context, we consider issues concerning the category of "agrammatism."

Aphasia↗
PubMed1987

Script knowledge in right hemisphere-damaged and in normal elderly adults.

Right hemisphere brain-damaged (RHD) patients and healthy elderly and younger control subjects were tested on a battery of tasks designed to probe their script knowledge. More specifically, their ability to access and organize script information was assessed under conditions that varied in information-processing demands. For this purpose, two types of script tasks were employed: free response tasks, for which subjects had to structure their own responses, and constrained response tasks, in which subjects had to choose the better of two possible responses. All RHD patients tested had shown impairments on other narrative tasks. Subjects were asked to produce the sequences of steps which comprise two common activities and to provide continuations for segments of scripts (free-response tasks); they also were required to judge script element membership, temporal order, and relative importance (constrained-response tasks). The RHD patients and elderly and control subjects demonstrated a generally preserved knowledge of script information on all tasks. However, because of variability in the response style from the RHD patients and elderly subjects on free-response tasks, individual cases were examined. Several RHD patients' script productions were characterized by tangentiality while other patients showed a tendency to terminate their script productions prematurely. Four of ten elderly subjects produced highly personalized scripts. The relation of performance on these tasks to other documented narrative impairments is considered.

Aged↗
PubMed1986

Inference deficits in right brain-damaged patients.

The inferential reasoning ability of right hemisphere-damaged (RHD) patients was tested by presenting pairs of sentences which were to be treated as single, integrated units. The two sentences treated together made one interpretation likely (a correct inference); one of the sentences in isolation encouraged a different interpretation (an incorrect inference). The position of the misleading sentence was systematically varied. Results showed that, in contrast to normal controls, RHD patients have more trouble answering inference questions, especially those concerning incorrect inferences, than answering questions about the factual content of the passages. Also, RHD patients made significantly more errors when the misleading information was contained in the first rather than in the second sentence; this finding indicates that these patients have difficulty revising previously acquired knowledge in light of new information. These results suggest the impairment of several components of normal discourse processing subsequent to right hemisphere brain damage.

Brain Injuries↗
PubMed1986

Basic and subordinate level naming by agrammatic and fluent aphasic patients.

Agrammatic Broca's and fluent (Wernicke's and anomic) aphasics were asked to name objects depicted in outline drawings as a means of testing their ability to identify and to name objects at the basic (e.g., "chair") and subordinate (e.g., "beach chair") levels. Patients from both groups had difficulty producing subordinate names, but successfully conveyed subordinate level identifications using a variety of compensatory strategies. This report supports a separation of the naming process from the conceptual operations and structures needed to identify objects. In addition, the two aphasic groups used different strategies to circumvent their naming difficulties. Fluent patients sometimes conveyed subordinate level identifications without any mention of a basic name. Agrammatic patients in particular avoided use of pre-posed modifiers in their compensatory responses. The composition of most subordinate terms (modifier plus basic name) is discussed in relation to the normal naming process and how it is disrupted in aphasia.

Aged↗
PubMed1986

Comprehension of humorous and nonhumorous materials by left and right brain-damaged patients.

Right hemisphere-damaged (RHD) and left hemisphere-damaged (LHD) aphasic patients were tested on a nonverbal cartoon completion task that included a humorous (Joke) and a nonhumorous (Story) condition. In both conditions, RHD patients performed worse than LHD patients. More importantly, the qualitative difference between the errors produced by the two groups suggests that right and left hemisphere brain damage impairs different components of narrative ability. RHD patients showed a preserved sensitivity to the surprise element of humor, and a diminished ability to establish coherence. Conversely, LHD patients, when they erred, showed an impaired sensitivity to the surprise element of humor, and a preserved ability to establish coherence by integrating content across parts of a narrative. These results suggest that the observed humor comprehension deficits of RHD patients result specifically from right hemisphere disease and not from brain damage irrespective of locus. The performances of the RHD and LHD patients groups together support a separation of narrative ability from the traditional aspects of language ability typically disrupted in aphasia.

Aphasia↗
PubMed1985

Category differentiation in object recognition: typicality constraints on the basic category advantage.

When people are asked to decide whether an object is in a given category, they generally respond faster when the category is at the basic level (e.g., car) than when it is at the superordinate level (e.g., vehicle) or the subordinate level (e.g., sedan). Basic categories have shorter and more frequent names, are learned earlier, and are usually more highly differentiated than other categories (they are both specific and distinctive), but it is not clear which of these factors is responsible for the faster response to basic categories. In three experiments with natural language categories, we found evidence that objects can be identified fastest as members of differentiated categories, even when such categories have longer names and are learned later than less differentiated categories. Specifically, we argued that atypical subordinate categories (e.g., racing car) are highly differentiated and should therefore be responded to as fast as basic categories in object recognition. The results supported this view and also ruled out the hypothesis that objects are necessarily identified as members of basic categories before further identification. We discuss the implications of these findings for the use of category names as definite descriptions in discourse.

Discrimination Learning↗
PubMed1985

Education provides no protection against Alzheimer's disease.

It has been suggested that educational achievement confers protection against dementia. We examined educational level and age of onset in 28 patients with Alzheimer's disease, and assessed the progression of dementia over a mean period of 28 months using both a measure of neurobehavioral status and an index of functional impairment. No protective effect of education was found in either early- or late-onset dementia.

Alzheimer Disease↗
PubMed1984

Sensitivity to lexical denotation and connotation in brain-damaged patients: a double dissociation?

Sets of words can be grouped in terms of their denotation (cold and warm both refer literally to temperature) or in terms of their connotation (cold and warm connote remoteness and intimacy, respectively). To assess whether these two facets of meaning are dissociable, unilaterally left- and right-hemisphere-damaged patients were presented with word triads and asked to group together the two words that were closest in meaning. Right-hemisphere-damaged patients showed a preserved sensitivity to denotation, and a selective insensitivity to connotative facets of meanings. In contrast, left-hemisphere-damaged patients exhibited a preserved sensitivity to connotation as well as a selective insensitivity to denotative aspects of meanings. Inasmuch as normal control subjects displayed a flexible sensitivity to both denotative and connotative aspects of meaning, the results suggest that unilateral brain damage selectively curtails use of one or the other major aspect of word meaning.

Aged↗
PubMed1983

Surprise but not coherence: sensitivity to verbal humor in right-hemisphere patients.

Verbal humor deficits were investigated in right-hemisphere-damaged patients. It was hypothesized that the appreciation of jokes presupposes two elements: sensitivity to the surprise element entailed in the punch line of a joke and apprehension of the coherence which results when the punch line has been integrated with the body of the joke. The possible dissociation between these elements was tested by asking subjects to select from four alternatives the appropriate ending to a joke. Right-hemisphere patients exhibited a selective attraction to endings which contained an element of surprise but which were not otherwise coherent with the body of the joke. This finding suggests that right-hemisphere patients have difficulty in integrating content across parts of a narrative and confirms the psychological reality of the proposed distinction between the surprise and coherence elements of humor processing.

Adult↗
PubMed1983

Utilization of enzymatically hydrolyzed wood hemicelluloses by microorganisms for production of liquid fuels.

Hemicellulose-derived sugars were obtained from a variety of pretreated wood substrates such as water-soluble fractions from steam-exploded aspen, solvent-extracted aspen, and commercial xylan. These fractions were enzymatically hydrolyzed by commercial enzyme preparations and by the culture filtrates of eight highly cellulolytic fungi. The sugars released were assayed by high-pressure liquid chromatography. Over 30% of the hemicellulose fractions, at a 10% substrate concentration, could be hydrolyzed to monosaccharides. These hemicellulose hydrolysates were used as the substrates for growth of Clostridium acetobutylicum and Klebsiella pneumoniae. Comparatively low butanol values were obtained with C. acetobutylicum, although over 50% of the hemicellulose fraction, at a 1% substrate concentration, could be converted to 2,3-butanediol, ethanol, and acetic acid by K. pneumoniae.

Journal Article↗
PubMed1976

Testing the role of vertical symmetry in letter matching.

A series of experiments tested a recent suggestion that vertical symmetry of a stimulus display can serve as a visual diagnostic for responding "same" in a letter-matching task. The data of chief interest were same reaction times to vertically symmetric (e.g., AA) and asymmetric (e.g., LL) displays, each composed of two side-by-side uppercase letters. Overall, the data argue against subjects' use of vertical symmetry as a diagnostic in dealing with letter pairs. The results were interpreted within the context of recent work on symmetry. In particular, it was suggested that the importance of structural diagnostics in a matching task may be inversely related to the codability of the stimulus elements being compared.

Adolescent↗