Right Hemisphere Brain-damaged Patients Research Articles

Acoustic correlates to idiomatic interpretations in brain-damaged populations

McGill University, Montre´al, CanadaAccepted 8 July 2005Available online 22 August 2005IntroductionAlthough much is known about idiom processing in normal in-dividuals (e.g., Titone & Connine, 1999), some controversial findingshave emerged for brain-damaged patients (e.g., Papagno, Tabossi,Colombo, & Zampetti, 2004), and very few studies have examined therole of prosody in spoken idiom production. In normal subjects, VanLancker, Canter, and Terbeek (1981) have shown that literal produc-tions of potentially idiomatic phrases are longer in duration, exhibitlonger pauses between words, and demonstrate more rapid changes inF0 within words and phrases relative to the same phrases producedwith an idiomatic reading. However, idioms differ with respect to di-mensions like familiarity and compositionality (not heretofore con-trolled) that may influence production, and may be manifest differentlyin productions by brain-damaged populations.With respect to the ability of left- (LHD) and right-hemispherebrain-damaged (RHD) patients to signal idiomatic relative to literalinterpretations through prosodic cues, current theories concerning theneural bases of prosody yield somewhat different predictions (seeBaum & Pell, 1999 for review). According to one perspective, thelinguistic relevance of prosodic cues is critical and intimately linkedwith the prosodic domain or size of prosodic unit, with smaller-sizedunits processed by LH mechanisms and larger units mediated by RHmechanisms (Gandour, et al., 2003). Although idioms are phrase-length units, some studies have suggested that they are initially ac-cessed and stored as lexical units (Titone, Libben, & Romero, 2004;but cf. Papagno et al., 2004). Under this view, it could be hypothesizedthat LHD patients may have difficulty producing the prosodic con-trasts that disambiguate literal from figurative interpretations of idi-oms (assuming a lexical prosodic domain). Further support for thisprediction is based on the suggestion that much of the idiomatic/literalprosodic distinction is carried by temporal cues, with which LHDpatients are known to have difficulty. In contrast, because idioms andtheir literal counterparts are, in fact, phrasal units, one might predictthat RHD patients may be unable to successfully produce the requiredcontrast. To assess these possibilities, following Van Lancker andcolleagues (1981), a set of literally plausible idiomatic expressions (e.g.,‘he kicked the bucket’, but not ‘he was on cloud nine’) were embedded inbiasing contexts that disambiguated the intended meaning as literal oridiomatic. Speakers were instructed to explicitly contrast the targetsentences as clearly as possible to convey the intended interpretation.MethodsSubjectsParticipants included LHD patients, RHD patients, age-matchednon-brain-damaged individuals, and young normal speakers.StimuliThirty-two idioms, following the ‘‘(s)he verbed the noun’’ form,were included as stimuli; these idioms were subgrouped with respectto the semantic decomposability of the verb and the noun (Libben,Borovay, & Titone, 2005) and controlled for dimensions such asfamiliarity and predictability of the idiom-final word. The noun wasrated as highly related to the idiomatic meaning for 8 idioms (Nhigh), the verb was rated as highly related for eight idioms (V high),both the noun and the verb were rated as highly related for eightidioms (NV high), and neither the noun nor the verb was rated asrelated for the final eight idioms (NV low). All idioms were embed-ded in an idiomatic and a literal biasing context and presented tospeakers in a manner such that the interpretive contrast was high-lighted. Subjects were required to read the context sentence silentlyand then produce the idiomatic or literal target sentence for re-cording on digital media.Acoustic analysesMeasures of total utterance duration, number, and length of pausesbetween words within the phrase, and durations of individual wordswithin the phrase were computed, as was mean F0 across the phrase,and the pattern of F0 rises and falls within the phrase.Brain and Language 95 (2005) 223–224www.elsevier.com/locate/b&l

Developing algorithms to enhance the sensitivity of cancellation tests of visuospatial neglect.

We describe a set of algorithms that enhance the sensitivity of cancellation tests used in assessing visuospatial neglect. The algorithms can be readily implemented on a computer and can provide temporal and nontemporal data on strategies used during cancellation. We also present preliminary results from a group of 68 right-hemisphere brain-damaged patients and 12 age-matched control participants, which demonstrate the clinical significance of the measures we have defined.

Distinguishing Lies from Jokes: Theory of Mind Deficits and Discourse Interpretation in Right Hemisphere Brain-Damaged Patients

Right-hemisphere brain damaged (RHD) patients and a normal control group were tested for their ability to infer first- and second-order mental states and to understand the communicative intentions underlying ironic jokes and lies. Subjects listened to stories involving a character who had either a true or a false belief about another character's knowledge. Stories ended either with an ironic joke or a lie by this character. In the joke stories, the speaker knew that the listener knew the truth (a true second-order belief) and did not expect the listener to believe what was said; in the lie stories, the speaker did not know that the listener actually knew the truth (a false second-order belief) and thus did expect the listener to believe what was said. RHD patients performed significantly worse than control subjects on one of two measures of second-order belief, which suggests that the ability to make second-order mental state attributions is fragile and unreliable following right-hemisphere damage. RHD patients in addition performed worse than controls when asked to distinguish lies from jokes, confirming their known difficulties with discourse interpretation. For both groups, the ability to distinguish lies from jokes was strongly correlated with two measures of the ability to attribute correctly second-order beliefs. These results suggest that the fragility of RHD patients' understanding of second-order mental states underlies a portion of their difficulties in discourse comprehension, but that the underlying impairment is not restricted to right hemisphere dysfunction.

The Effects of Right-Hemisphere Brain Damage on Patients' Use of Terms of Personal Reference

Successful communication depends on social as well as linguistic factors. In conversation, for example, a speaker must often refer to another person. Choosing an appropriate term of personal reference requires a speaker to consider several features of the discourse context, including properties of the persons being referred to and what knowledge is shared between the speaker and his or her addressee. In a pair of similar studies, we examined how right-hemisphere brain-damaged (RHD) patients and nonbrain-damaged control subjects use these different kinds of information in choosing formal (e.g., “Mr. Harding”) versus informal (“Oliver”) terms of reference for an absent third person. Stimulus vignettes manipulated three variables: the occupational status of the referent, the speaker's familiarity with the referent (i.e., the degree to which the speaker and referent were personally acquainted), and the addressee's familiarity (i.e., the degree to which the addressee and referent were personally acquainted). Relative to the control subjects, the RHD patients showed decreased use of both familiarity variables when choosing formal over informal labels, but apparently preserved sensitivity to the status variable. These results suggest how decreased use of the knowledge shared between a speaker and addressee disrupts RHD patients' discourse and thus contributes to these patients' aberrant interpersonal behavior. In addition, the results from the second study demonstrated an asymmetry in how female versus male subjects responded to the status manipulation.

Grammatical ambiguity resolution in right hemisphere-damaged patients: Evidence from an insertion task

Abstract We examined the issue of right cerebral hemisphere (RH) participation in sentential syntax processing. A modified version of the Insertion Task of Schneiderman and Saddy 88) was administered to eight right hemisphere brain-damaged (RHD), eight left hemisphere brain-damage (LHD) and 28 right-handed control (CTR) subjects: 28 word/syntagm insertions required role reassignment of a lexical item in the stimulus sentence (Shift); 25 insertions implied only semantic reinterpretation of the sentence (Nonshift). Age, formal education, cognitive proficiency, mood and verbal intelligence were introduced as covariates in the analysis of the outcomes to partial out their influence on performance. The LHD group outperformed the RHD patients on the Shift items, though both scored similarly on other language tasks. The RHD group performed significantly worse only on the Shift items. However, there were no differences between the RHD and CTR Nonshift scores, or between the LHD and CTR Shift scores. Again, the RH...

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 weight 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.

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.

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.

The role of the right hemisphere in processing negative sentences in context

Given a pattern consisting of x1, x2,…, xn similar elements and y1, which is perceived as different from the former, it is more plausible to assert that y is not x rather than to assert that x is not y (Wason, J. verb. Learn verb. Behav.4, 7–11, 1965). In order to appreciate such a difference, the entire set has to be considered. Right-hemisphere brain-damaged patients were submitted to a series of visually presented patterns, each pattern consisting of seven similar items and one dissimilar item. Their task was to complete a statement referring to a single element of each pattern. Statements were either simple affirmative or negative sentences.Errors and reaction times were recorded. Patients with a right-hemisphere injury were found to be insensitive to the plausible-implausible dimension in completing negative sentences.It is hypothesized that right-hemisphere brain-damaged patients are less adequate in this task because they are less capable in putting each element into the visual context.

Effects of left-hand preference on postinjury measures of distal motor ability.

The relationship of preinjury left-hand dominance for motor performance to postinjury distal motor skills following penetrating brain wounds in patients without overt hemiplegia was examined. We studied 13 controls, 13 right-hemisphere brain-damaged patients, and 11 left-hemisphere brain-damaged patients on motor tasks measuring reaction time, strength, and coordination. Our results indicated that no persistent deficits were seen on distal motor tasks in left-handed adults who suffered a penetrating brain wound. These findings are compatible with the relative sparing of persistent neuropsychological deficits in left-handers following brain damage.