Effects of sentential stress and word class upon comprehension in Broca's aphasics

The roles which word class (open/closed) and sentential stress play in the sentence comprehension processes of both agrammatic (Broca's) aphasics and normal listeners were examined with a word monitoring task. Overall, normal listeners responded more quickly to stressed than to unstressed items, but showed no effect of word class. Aphasics also responded more quickly to stressed than to unstressed materials, but, unlike the normals, responded faster to open than to closed class words regardless of their stress. The results are interpreted as support for the theory that Broca's aphasics lack the functional underlying open/closed class word distinction used in word recognition by normal listeners.     

Defects of immediate memory in Broca's and conduction aphasia

It has been suggested that the repetition defect seen in conduction aphasia is caused by an auditory immediate memory defect. The purposes of this study were the following: to ascertain whether the finding of an auditory immediate memory defect in conduction aphasia could be replicated, to ascertain whether Broca's aphasics have a similar type of immediate memory defect, and to ascertain whether a relationship exists between immediate memory and comprehension of spoken language. Digits were either spoken or presented visually to Broca's and conduction aphasics. An analysis of span scores reveals that within each group there were no significant differences between the modes of presentation or the response modes. There were no significant differences between the aphasic groups. Comprehension of spoken language significantly correlated with digit span scores.     

Processing of locatives “in,” “on,” and “under” by aphasic patients: An analysis of the regression hypothesis

The present study investigated the comprehension of aphasic subjects as to locative prepositions “in,” “on,” and “under.” Patients had to locate a movable object with reference to a stationary referential object in order to achieve the spatial relations requested under oral instructions. The influence of two types of contextual relations between the objects in each stimulus pair on the subjects' performances was examined. Spatial relations were biased by the conventional knowledge of the most normal relationship between the two elements in everyday life in Experiment 1; in Experiment 2, perceptivomotor constraints constituted the contextual bias. Analyzing the patients' responses in the light of developmental strategies did not lend support to the regression hypothesis. Broca's aphasics were sensitive to the two contextual factors investigated; Wernickes' performances were affected only by the perceptivomotor contextual bias. The results are discussed with reference to earlier studies on the differential syntactical comprehension skills of Broca's and Wernicke's aphasics in sentence-picture matching tasks and production tasks.     

Aphasics' selective deficits in appreciating grammatical agreements

This study attempted to dissociate in aphasic patients different aspects of grammatical capacity. Subjects were asked to evaluate sentences containing violations of agreements between pronouns and verbs. Agreements which are considered primarily structural in nature were violated (e.g., a surface object case like “them” placed in a surface subject sentential slot) while other violated agreements seemed to involve both structural and semantic information (e.g., lack of agreement between a pronoun and a verb in terms of the number of people performing the act). These violations were couched in one of three types of sentential frames which varied in terms of syntactic complexity (e.g., active declarative vs. passive syntactic voices). The results revealed that Broca's aphasics found agreement violations difficult to detect in complex syntactic frames. They were quite successful at detecting even violations of the largely structural “case” type of agreement, however, when couched in simpler syntactic frames. Fluent aphasics encountered more difficulty detecting violations of agreements involving both semantic and structural information than agreements which were primarily structural in nature, that is, regardless of the syntactic frame. These unique performance profiles suggest that Broca's aphasics may be agrammatic only with respect to certain aspects of a sentence's structure, and that fluent aphasics may also experience some selective—but different—grammatical deficits.     

Phonetic disintegration in aphasia: Acoustic analysis of spectral characteristics for place of articulation

In this study, we attempted to determine whether phonetic disintegration of speech in Broca's aphasia affects the spectral characteristics of speech sounds as has been shown for the temporal characteristics of speech. To this end, we investigated the production of place of articulation in Broca's aphasics. Acoustic analysis of the spectral characteristics for stop consonants were conducted. Results indicated that the static aspects of speech production were preserved, as Broca's aphasics seemed to be able to reach the articulatory configuration for the appropriate place of articulation. However, the dynamic aspects of speech production seemed to be impaired, as their productions reflected problems with the source characteristics of speech sounds and with the integration of articulatory movements in the vocal tract. Listener perceptions of the aphasics' productions were compared with acoustic analyses for these same productions. The two measures were related; that is, the spectral characteristics of the utterances provided salient cues for place of articulation perception. An analysis of the occurrences of errors along the dimensions of voicing and place showed that aphasics rarely produce utterances containing both voice and place substitutions.     

Speech production mechanisms in aphasia: A delayed auditory feedback study

Data collected from a delayed auditory feedback (DAF) study conducted by F. Boller, P. B. Vrtunski, Y. Kim, and J. L. Mack (1978, Cortex, 14, 212–226) were reanalyzed to determine if speech quality measures which were significantly affected during DAF could be operationalized and to ascertain which type of errors are responsible for the judgement. A second goal of this study was to determine if Conduction aphasics were relatively spared under conditions of DAF, as has been shown in previous studies. Twenty aphasic patients and ten controls were presented with several speech production tasks under two delay conditions and two simultaneous feedback conditions. Results indicated that only the category of vowel length produced a significant number of errors, suggesting that DAF affects articulatory implementation. Conduction aphasics showed the least effect of all the groups. These results support Wernicke's and Geschwind's model, in which Conduction aphasics have a disconnection between the sensory and motor images of words. In contrast, Broca's aphasics were the most affected group under DAF, suggesting that a major component of their disorder is phonetic in nature.     

A study of repetition in aphasic patients

The ability of the aphasic patient to repeat a message is a capacity of considerable diagnostic value. While it is well known that certain aphasic groups (e.g., transcortical aphasics) repeat better than other groups (e.g., conduction aphasics), possible qualitative differences among the groups have not been subjected to analysis. To secure information on repetition profiles in various aphasic subgroups, a test consisting of 11 types of items, presented under conditions of both immediate and delayed recall, was administered to eight groups of aphasic patients. The results documented a significant difference across aphasic groups, one related to site of lesion but not to severity of comprehension defect. Performance proved to be a joint product of the length and the meaningfulness of the stimulus items. The delayed condition aided Broca's aphasics and impeded anomic aphasics; in addition, nonsense syllables proved to be easier on immediate recall, while meaningful stimuli, particularly those which were number related, were relatively easier on delayed recall. Finally, sound errors were more likely to be made by Broca's and “mixed anterior” aphasics, while meaning errors were particularly prominent among conduction aphasics. These results are discussed in terms of the mechanisms which may mediate repetition in aphasic patients.     

Naming in aphasia: Interacting effects of form and function

The naming difficulties of Broca's and anomic aphasics were explored in relation to a recently developed model of the normal mental lexicon which stresses the importance of integrating perceptual and functional information in the act of naming, and equally stresses the inherent vagueness of conceptual categories based on such information. Subjects were shown line drawings of various food containers varying in physical features such as height and width; they were required to select a name for the object from a multiple choice list (cup, bowl, or glass). Prototypical as well as nonprototypical objects were shown. The Broca's aphasics showed relatively normal naming profiles. In contrast, the posterior patients were unable to integrate perceptual and functional information and were insensitive to the fuzzy boundaries between conceptual categories. The results obtained for the posterior patients are interpreted as reflecting an impairment in the underlying conceptual organization of the lexicon rather than retrieval difficulties.     

Disfluent speech associated with brain damage

The frequency and type of disfluencies in the spontaneous speech of 15 people with Broca's aphasia and right hemiplegia was studied. Two aged-matched control groups (15 nonaphasic stroke patients with left hemiplegia and 15 normals) were also studied. The frequency of disfluencies in the speech of aphasics was three times greater than that in the speech of either control group. However, most of the disfluencies uttered by aphasics were of the types commonly found in speech of normals.     

Semantic aphasia: A neglected entity

Three cases of semantic aphasia are reported. Computerized brain tomography showed bilateral temporo-parieto-occipital junction hemorrhages in one patient, and left parieto-occipital junction infarctions in the other two patients. The auditory comprehension defect of the three patients was characterized by preserved understanding of single words and impaired understanding of grammatically complex constructions. It is suggested that this comprehension defect reflects an inability to fully grasp the meaning of words and grammatical constructions imbued with spatial or quasi-spatial significance. Each of the three patients showed a complex spatial disorder that included constructional apraxia, spatial agnosia, and elements of Gerstmann's syndrome. The aphasic as well as the spatial disorder of semantic aphasics may be manifestations of a common defect in the perception of spatial relationships produced by left temporo-parieto-occipital region damage.     

Sentence understanding and knowledge of the world: Evidences from a sentence-picture matching task performed by aphasic patients

The abilities of aphasic patients to perform a sentence-picture matching task were investigated on simple declarative reversible sentences. Two factors were found to differentially affect Broca's versus Wernicke's aphasics' performance: sentence plausibility and spatial arrangement. Sentence plausibility, that is to say, the liability of two given nouns in a sentence to act as agent and recipient according to normal subjects' expectancies, had a significant effect on the frequency of correct responses of Broca's aphasics but not on those of Wernicke's. Conversely, the latter were found to be more sensitive to a match or mismatch in the left-to-right spatial arrangement of the grammatical subject and object in a sentence on the one hand, and the order of the corresponding personages in the picture on the other. The results are discussed in terms of “frame selection” and the handling of ordered structure strategies contributing to normal system, but selectively disturbed in the case of brain damage.     

The recovery processes of two English-Japanese bilingual aphasics

The recovery processes of two English-Japanese bilingual aphasics, one with Broca's aphasia and the other with Wernicke's aphasia, were investigated with special emphasis on the effect of language therapy. The degree of impairment initially manifested in English and Japanese was almost equivalent in each case, the pattern of impairment corresponding to the respective types of aphasia. In both cases, systematic, controlled language therapy was conducted. Analysis of the recovery courses revealed that language therapy was one decisive variable in the relative degree of recovery of a bilingual aphasic's two languages. The type of aphasia appeared to exert a crucial influence on the relative recovery rate of different modalities.     

On-line Sensitivity to Subject-Verb Agreement Violations in Broca′s Aphasics: The Role of Syntactic Complexity and Time

This study examined on-line sensitivity to subject-verb agreement violations in patients with Broca′s aphasia and age-matched controls using a word monitoring paradigm. The agreement violations were couched in either simple or complex syntactic frames. In a first experiment, these syntactic frames were immediately followed by the noun phrase containing the target, whereas in the second experiment a 750-msec separation was introduced. The main finding of the first experiment was that patients with Broca′s aphasia showed an agreement effect only for simple (i.e., conjoined) sentences but not for complex (i.e., embedded) ones, while controls showed the expected agreement effect for both. The results of the second experiment demonstrated further that the 750-msec delay in target presentation abolished the agreement effect in Broca′s aphasics but not in normal controls. The findings are interpreted to suggest that Broca′s suffer from a pathological limitation in parsing capacity, giving rise to a faster than normal decay of syntactic information.     

Aphasic adults' understanding of complex adverbial sentences

Twelve aphasics with relatively preserved auditory comprehension were tested for their understanding of four adverbial sentence types expressing the temporal order of events. The relative effects of order of mention, adverbial choice, and adverbial clause placement on subjects' comprehension were investigated. Only adverbial choice was significant with aphasics producing more errors of temporal order on after than before sentences. Subjects' error patterns were not similar to those of children acquiring language. The results are discussed with respect to the theory of lexical marking and the regression hypothesis.     

Semantic processing in aphasia: Evidence from an auditory lexical decision task

W. Milberg and S. E. Blumstein (1981, Brain and Language 14, 371–385) demonstrated semantic facilitation effects in a visual lexical decision task administered to Wernicke and other aphasics with severe comprehension deficits. In an attempt to explore the generalizability of these findings in a task where the acoustic-phonetic system could not be bypassed to access meaning, Wernicke's, Global, Broca's, and Conduction aphasics were administered a lexical decision task in the auditory modality. The patients were also given a simple semantic judgment task using the word pairs from the lexical decision task. The aphasic patients showed evidence of semantic facilitation whether they were categorized by diagnostic group or comprehension level. Performance of the semantic judgment task correlated with the severity of auditory comprehension deficits, whereas the consistency of the semantic facilitation effect did not. Even patients with severe comprehension deficits showed semantic facilitation. These results decrease the likelihood that auditory comprehension deficits are due to semantic organization per se and increase the likelihood that the deficits lie in one of the many processes involved in access to that information.     

Semantic field,naming, and auditory comprehension in aphasia

The status of semantic fields for 16 target nouns was compared in high and low comprehension aphasics, brain damaged, and normal controls, by measuring latency and miss rate for recognition of six classes of associates, which were presented orally on tape. The ability to name each target was also examined as a function of the integrity of the subject's semantic field for that word. Low comprehension aphasics showed both quantitative and qualitative changes in semantic fields, while milder aphasics showed only mild quantitative impairment, as compared to controls. Both latency and miss rate measures indicated that failure to name a word is associated with reduced semantic field for that word. This result is interpreted as supporting the view that nameing is, in part, determined by the convergence of associations.     

The linguistic interpretation of aphasic syndromes: Agrammatism in Broca's aphasia,an example

One of the most striking characteristics typical of the speech of Broca's aphasics is its agrammatism — the omission of ‘function’ words and inflectional morphemes. Agrammatism is generally viewed as being symptomatic of a syntactic deficit. We argue here that such an account lacks grammatical systematicity, and that the only uniform and systematic interpretation of this deficit is in terms of phonological structure. A natural class consisting of ‘function’ words and some bound morphemes can be defined with reference to the junctural properties of sentences which characterize phonological words. It is this class of elements which tend to be omitted in agrammatic speech. The goal of this paper is not only to provide an hypothesis for the interpretation of one aphasic syndrome, but also to test and illustrate the efficacy of paying close attention to substantive universals of grammatical structure in proposing accounts of linguistic deficits.     

Aphasic adults' use of heuristic and structural linguistic cues for sentence analysis

Eight aphasic adults with relatively preserved auditory comprehension and 12 normal adults were tested for their ability to analyze sentences in which the functional relations between the verb and nouns was either directly reflected by word order expectancies, or marked by a functor or non-NVN word order. The subjects' task was to designate the agent of each sentence. Results indicated that aphasics utilize word order expectancies but are impaired in their ability to exploit functors and particularly, word order markers for sentence analysis. Results are discussed in terms of aphasics' use of heuristic versus structural linguistic cues for interpreting sentences.     

Computer tomographic localization, lesion size, and prognosis in aphasia and nonverbal impairment.

Computerized tomography scans (80) were used to localize infarcts in 70 patients. Twenty-three aphasics were scanned within 35 days from onset, 39 beyond a year, and 18 were nondominant cases. Aphasics were also grouped according to test scores obtained within 35 days of scan. Chronic global aphasics have larger lesions than persisting Broca's aphasics. The area of persisting Broca's aphasia is similarly anterior but larger than that of recovered motor aphasia. Anomic aphasics evolve from Broca's and Wernicke's types with differing localization. Lesion size correlated with severity and recovery, and comprehension among the subtests.