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[The personality of patients with Broca's aphasias].
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Communicative effectiveness in Broca's aphasia.
The purpose of this study was to investigate communicative effectiveness in aphasia. Five patients with Broca's aphasia and five neurologically normal subjects participated in referential communication and spontaneous conversation tasks. Performance on the referential tasks was used to derive measures of communication success, learning, and efficiency. A representative sample of utterances from the referential tasks and 100 utterances from the spontaneous conversation task also were analyzed to determine the frequency of operationally defined errors in speech, lexical access, grammar, content, discourse, and use. Results suggest that patients with Broca's aphasia retain communicative effectiveness in the presence of significant speech and language deficits and experimentally imposed constraints on the use of visual and gestural communication modalities.
Proper and common nouns: form class judgments in Broca's aphasia.
Studies of agrammatic Broca's aphasics' comprehension of sentences containing articles have demonstrated profound deficits. It has not been clear whether the impairments are due to an inability to isolate the article in the stream of speech, or to difficulty in the construction and/or interpretation of various syntactic, semantic, or pragmatic levels of representation. This paper reports three experiments on Broca's aphasics' ability to distinguish between common nouns (e.g., "a rose") and proper nouns (e.g., "Rose"). This grammatical form class decision is signaled by the presence or absence of an article, and is represented at the lexical node level of linguistic analysis. The three experiments demonstrated that Broca's aphasics point to pictures representing classes of objects when asked to point to "the X" and point to pictures representing unique individuals when asked to point to "X". Thus, they were shown to be able to use the presence or absence of an article to determine lexical category. Their performance was especially accurate in an oral language context which was highly redundant and in a written language context where patients themselves could control the rate of information flow. They were quantitatively impaired, relative to controls, in a third study, which made higher information processing demands. Moreover, in this third study nonsense syllables preceding the noun which are phonologically similar to a known article were much more likely to evoke the misclassification of its noun as common than were phonologically distinct nonsense syllables. These data indicate that Broca's aphasics indeed have some difficulty isolating the article in the stream of speech. Nevertheless, detailed analyses of aphasics' performance revealed their ability to distinguish between common nouns and proper nouns even under these demanding conditions. Taken together, the three studies show that insofar as agrammatic patients are able to keep track of the presence or absence of articles, they can make a grammatical decision at the lexical node level of linguistic analysis. We conclude, then, that agrammatic Broca's aphasics are particularly impaired in the use of articles to construct and/or interpret phrasal constituents.
[Broca's area and Broca's aphasia: based on the observations of two cases with the lesions involving Broca's area].
Recently, the relation between Broca's area and Broca's aphasia has come into notice again. We investigated two right-handed patients without Broca's aphasia in spite of the presence of lesions involving Broca's area after hemorrhagic infarction. In addition, the clinical findings, the clinical courses and the sites of lesions of two cases were quite similar as follows. They showed no motor deficits and no other abnormal neurological findings from the beginning of the strokes. From the near muteness in the initial stage, speech began to improve gradually. And then, they demonstrated so called transcortical motor aphasia. Namely, repetition and reading aloud were excellent and articulations were normal without phonetic disintegration and dysprosody in contrast to the sparse and limited spontaneous speech. Comprehension was well preserved. Anomia was present and the ability to generate word lists was so poor that, for instance, only two animal names were listed in one minute. Mild to moderate agraphia was present. Agrammatism and buccofacial apraxia were not associated. Afterwards, the two patients showed rapid amelioration. About one month later after the stroke, only a slight difficulty in word finding and mild agraphia remained. In both cases, the lesions confined predominantly to the cortical and subcortical areas in the left posterior part of both the third and the second frontal gyri were confirmed by computerized tomography. According to the evidence from our two cases and to the literature, it may be concluded that the lesion restricted to the posterior part of the third and second frontal gyri in the dominant hemisphere produces a subtype of transcortical motor aphasia and that the lesion restricted to the posterior part of the third frontal gyrus (Broca's area) does not lead to phonetic disintegration.
Understanding ambiguous words in sentence contexts: electrophysiological evidence for delayed contextual selection in Broca's aphasia.
This study investigates whether spoken sentence comprehension deficits in Broca's aphasics results from their inability to access the subordinate meaning of ambiguous words (e.g. bank), or alternatively, from a delay in their selection of the contextually appropriate meaning. Twelve Broca's aphasics and twelve elderly controls were presented with lexical ambiguities in three context conditions, each followed by the same target words. In the concordant condition, the sentence context biased the meaning of the sentence-final ambiguous word that was related to the target. In the discordant condition, the sentence context biased the meaning of the sentence-final ambiguous word that was incompatible with the target. In the unrelated condition, the sentence-final word was unambiguous and unrelated to the target. The task of the subjects was to listen attentively to the stimuli. The activational status of the ambiguous sentence-final words was inferred from the amplitude of the N400 to the targets at two inter-stimulus intervals (ISIs) (100 ms and 1250 ms). At the short ISI, the Broca's aphasics showed clear evidence of activation of the subordinate meaning. In contrast to elderly controls, however, the Broca's aphasics were not successful at selecting the appropriate meaning of the ambiguity in the short ISI version of the experiment. But at the long ISI, in accordance with the performance of the elderly controls, the patients were able to successfully complete the contextual selection process. These results indicate that Broca's aphasics are delayed in the process of contextual selection. It is argued that this finding of delayed selection is compatible with the idea that comprehension deficits in Broca's aphasia result from a delay in the process of integrating lexical information.
Alexia in recent and late Broca's aphasia.
The hypothesis was tested that alexia associated with Broca's aphasia may often be a residual receptive disorder of a broader picture of global aphasia. It was found that alexia does tend to be associated, as expected, to the long-standing Broca's aphasias more often than to the recent ones. However, the CT scan failed to disclose larger and more posterior lesions in Broca's alexic than in Broca's non-alexic patients.
[Evaluation of central speech disorders using objective criteria: a psychophysiologic contribution to the discussion of the neural plasticity hypothesis].
Examinations of aphasic patients by using cognitive tasks were based on the hypothesis that semantically evoked potentials correlate to the processing of information in the different speech processing of information in the different speech processing areas. It was found that patients with Broca aphasia generated synchronization potentials in the Wernicke area in contrast to Wernicke patients. We suppose a correlation between the timing in sensorial speech processing areas and the generation of synchronization potentials.
Compensatory articulation in Broca's aphasia.
Thirteen patients clinically diagnosed as Broca's aphasics, were administered a vowel bite block task to ascertain their on-line compensatory articulation ability. Formant frequencies for F1 and F2 were obtained from a pitch-synchronous spectral analysis of digitized vowel waveforms. Bite block/i/productions were consistently characterized by higher F1 and lower F2 frequencies compared to normal vowel productions. Undershooting of tongue elevation and fronting explains this result. No consistent pattern of "off-target" productions were found for/a/tokens. A multiple correlation analysis among clinically derived quantitative measures (BDAE score, oral and verbal apraxia), experimentally derived measures (bite block performance, articulatory reaction time), and neurological measures (brain lesion volume) was highly successful despite a relatively small sample size. Compensatory articulation was significantly related to both oral apraxia scores (r = -.70) and the BDAE total score (r = -.51). A multiple regression analysis nearly reached statistical significance (p = .11) in predicting bite block performance, with oral apraxia the most powerful predictor variable. Descriptive accounts of loci of brain lesion vis-à-vis compensatory articulation ability are given to delimit brain areas thought to possibly mediate this articulatory adaptive skill. Preliminary speculation supports the notion that an intact Area 44 is a prerequisite for successful compensatory ability.
Functional magnetic resonance imaging to word generation task in a patient with Broca's aphasia.
We describe the findings of functional magnetic resonance imaging (fMRI) in a patient with Broca's aphasia. The patient was a 45-year-old, right-handed woman who developed Broca's aphasia after infarction in the left frontal lobe. The first fMRI showed no signals in the left frontal lobe during verbal tasks, 2 weeks after the onset of infarction. Four weeks later, when the patient's symptom had improved, the second fMRI showed some increase in the fMRI signals in the left frontal lobe. Seven months later, she had completely recovered the ability to speak. The last fMRI then showed that the increment in signal activity in the left frontal lobe during verbal tasks had recovered to the level seen in normal subjects. There was a good correlation between the increase in task-related signals in Broca's area and the recovery of language function. Our findings show that fMRI has can be important in assessing cognitive functions in patients with Broca's aphasia.
Broca's aphasia, verbs and the mental lexicon.
Verb production is notoriously difficult for individuals with Broca's aphasia, both at the word and at the sentence level. An intriguing question is at which level in the speech production these problems arise. The aim of the present study is to identify the functional locus of the impairment that results in verb production deficits in Broca's aphasia. Levelt's (1989) model is used as a theoretical framework for this study. Two experiments have been conducted, one on verb movement and one on verbs with alternating transitivity. The results suggest that the functional impairment in Broca's aphasia should be located in Levelt's "grammatical encoder."
Controversies about CP: a comparison of language acquisition and language impairments in Broca's aphasia.
In both language acquisition research and the study of language impairments in Broca's aphasia there is an ongoing debate whether or not phrase-structure representations contain the Complementizer Phrase (CP) layer. To shed some light on this debate, I will provide data on German child language and on German agrammatic Broca's aphasia. Analyses of subordinate clauses, wh-questions, and verb placement indicate that early child grammars do not generate the CP layer yet, whereas the ability to project the CP layer is retained in agrammatism.
Dichotic ear preference for C-V-C words in Wernicke's and Broca's aphasias.
A dichotic listening task was administered to subjects with a relatively distinct Broca's aphasia, subjects with a relatively distinct Wernicke's aphasia, and normal subjects. The dichotic stimuli consisted of C-V-C words differing in initial consonant only. Subjects were instructed to respond only to the stimulus of which they were most sure by pointing to a picture representing the dichotic stimuli or foils. while normal subjects demonstrated the usual right ear effect, both the Broca's and Wernicke's aphasia groups demonstrated left ear effects. One salient explanation for these results was that any severe defect in the language systems of the left hemisphere affects the way that the left hemisphere processes linguistic information. It was postulated that left ear stimuli, which arrive at the left hemisphere later, disrupt the processing of right ear stimuli in subjects with aphasia. However, a more definitive explanation requires further research.
The relationship between phonological and morphological deficits in Broca's aphasia: further evidence from errors in verb inflection.
A previous study of 10 patients with Broca's aphasia demonstrated that the advantage for producing the past tense of irregular over regular verbs exhibited by these patients was eliminated when the two sets of past-tense forms were matched for phonological complexity (Bird, Lambon Ralph, Seidenberg, McClelland, & Patterson, 2003). The interpretation given was that a generalised phonological impairment was central to the patients' language deficits, including their poor performance on regular past tense verbs. The current paper provides further evidence in favour of this hypothesis, on the basis of a detailed analysis of the errors produced by these same 10 patients in reading, repetition, and sentence completion for a large number of regular, irregular, and nonce verbs. The patients' predominant error types in all tasks and for all verb types were close and distant phonologically related responses. The balance between close and distant errors varied along three continua: the severity of the patient (more distant errors produced by the more severely impaired patients); the difficulty of the task (more distant errors in sentence completion>reading>repetition); the difficulty of the item (more distant errors for novel word forms than real verbs). A position analysis for these phonologically related errors revealed that vowels were most likely to be preserved and that consonant onsets and offsets were equally likely to be incorrect. Critically, the patients' errors exhibited a strong tendency to simplify the phonological form of the target. These results are consistent with the notion that the patients' relatively greater difficulty with regular past tenses reflects a phonological impairment that is sensitive to the complexity of spoken forms.
Left precentral gyrus and Broca's aphasia: a clinicopathologic study.
We describe an autopsied case in which a circumscribed lesion involving the left precentral gyrus caused mild but lasting Broca's aphasia. The patient developed nonfluent speech and writing disturbances (consistent with mild Broca's aphasia) following malignant lymphoma of the brain. After subtotal resection of the tumor and whole brain irradiation, his language disturbances continued without remarkable change for 3 years until his death. A neuropathologic study indicated that the lesion responsible for the patient's aphasia was restricted to the lower one-third of the precentral gyrus in the left hemisphere. As for the relationship between the left precentral gyrus and Broca's aphasia and its allied syndrome (ie, aphemia), we concluded that in Broca's aphasia the lower part of the precentral gyrus plays a more important role than previously assumed.
A crosslinguistic study of grammaticality judgments in Broca's aphasia.
Crosslinguistic studies of sentence comprehension and production in Broca's aphasia have yielded two complementary findings: (1) grammatical morphology appears to be more impaired than word order principles in every language studied, but (2) the degree to which grammatical morphology is retained by aphasic patients depends upon the "strength" or importance of those morphemes in the patient's premorbid language. In an earlier study comparing violations of word order and agreement, we found that English-speaking Broca's aphasics showed greater sensitivity to errors of ordering than to errors of agreement, providing further evidence for the selective vulnerability of morphology. However, because English is a rigid word order language with a relatively weak inflectional system, it could be argued that word order is resilient to brain damage because it is the strongest source of information in this language. The present study compared the performance of English-speaking Broca's aphasics and normal controls with their Italian counterparts in the same grammaticality judgment experiment. Four predictions relating to our previous work were confirmed. (1) Italian aphasics, like their English-speaking counterparts, showed general preservation of grammatical knowledge and (2) they were able to use this knowledge in an "on-line" fashion. (3) Within each language, Broca's aphasics showed greater impairment in their ability to recognize errors of morphological selection (i.e., agreement) compared with errors made by moving the same words to an incorrect position downstream. Nevertheless (4), crosslinguistic differences observed in previous studies of comprehension and production were also observed in this grammaticality judgment task: a processing advantage for agreement errors in Italian normals and aphasics, and a processing advantage for ordering errors in English normals and aphasics.
Impaired syntactic comprehension and production in Broca's aphasia: CT lesion localization and recovery patterns.
Three of 50 patients with left hemisphere stroke manifested Broca's aphasia associated with deficits in syntactic processing. CT demonstrated anterior infarcts in two patients and a posterior infarct in the third. Two years later, all three patients showed improved syntactic production, but only the patient with the posterior lesion performed significantly above change on a sentence comprehension test requiring syntactic manipulations in the absence of semantic constraints. Prospective investigations combining psycholinguistic analyses and brain imaging techniques may provide empiric data relevant to neurologic models of language and ultimately may contribute to patient prognostication and rehabilitation.
[Broca's aphasia and apraxia of speech (author's transl)].
The paper shows that the aphasic syndrome originally described by Paul Broca corresponds to what is now called anarthria or apraxia of speech rather than to the nosological entity which nowadays goes by the name of Broca's aphasia. The paper further endeavours to demonstrate that the output difficulties of anarthric patients are different from those of patients with Broca's aphasia, and it suggests a number of criteria to discriminate between anarthria and Broca's aphasia (Acta neurol belg., 1982, 82, 80-90).