Aphasic Subgroups Research Articles

Direct speech constructions in aphasic Dutch narratives

Background: Previous studies have shown that individuals with aphasia are usually able to produce direct reported speech constructions. So far these studies have mainly been conducted in English. The results show that direct speech is beneficial for aphasic speakers for various reasons. In Dutch the construction goes along with a grammatical characteristic that makes it attractive for aphasic speakers. This study examines the diffuse phenomenon of direct speech in narratives of Dutch individuals with and without aphasia. Aims: The purpose of this study is to assess the use of direct speech in the semi-spontaneous speech of Dutch individuals with aphasia. The question is whether this construction, which is highly communicative, is used by aphasic speakers and in which forms it becomes manifest. In addition the effect of the nature of the underlying disorder, (i.e., grammatical versus lexical), is assessed. Methods & Procedures: A total of 61 transcripts of individuals with aphasia (n = 31) and 146 transcripts of non-brain-damaged speakers (n = 88) were analysed. The question of how the forms and relative frequencies of direct speech constructions differ across tasks and subgroups is addressed. For this purpose the relative frequencies of direct speech are determined and compared within and between tasks and subgroups. In addition different forms of the phenomenon are distinguished and categorised based on the patterns found in the data. Outcomes & Results: Individuals with aphasia use direct speech significantly more often than non-brain-damaged speakers. Individuals with Broca's aphasia exhibit a preference for direct speech constructions without a reporting verb, whereas individuals with anomic aphasia predominantly produce instances of direct speech that do include a reporting verb. Even though all subgroups produce direct speech constructions, the frequencies and forms vary across tasks and subgroups. Conclusions: Both groups make use of various forms of direct speech but the frequencies and distributions over categories are different. A possible explanation for the greater production of direct speech by aphasic speakers is its strategic utilisation to get around grammatical problems and word-finding difficulties. There is a quantitative difference between the individuals with anomic aphasia and the control speakers, whereas the difference between the individuals with Broca's aphasia and the control group is qualitative in nature. An explanation for the dissimilarities between the aphasic subgroups is the difference in grammatical complexity between subtypes of direct speech constructions.

Successful syllable detection in aphasia despite processing impairments as revealed by event-related potentials

BackgroundThe role of impaired sound and speech sound processing for auditory language comprehension deficits in aphasia is unclear. No electrophysiological studies of attended speech sound processing in aphasia have been performed for stimuli that are discriminable even for patients with severe auditory comprehension deficits.MethodsEvent-related brain potentials (ERPs) were used to study speech sound processing in a syllable detection task in aphasia. In an oddball paradigm, the participants had to detect the infrequent target syllable /ta:/ amongst the frequent standard syllable /ba:/. 10 subjects with moderate and 10 subjects with severe auditory comprehension impairment were compared to 11 healthy controls.ResultsN1 amplitude was reduced indicating impaired primary stimulus analysis; N1 reduction was a predictor for auditory comprehension impairment. N2 attenuation suggests reduced attended stimulus classification and discrimination. However, all aphasic patients were able to discriminate the stimuli almost without errors, and processes related to the target identification (P3) were not significantly reduced. The aphasic subjects might have discriminated the stimuli by purely auditory differences, while the ERP results reveal a reduction of language-related processing which however did not prevent performing the task. Topographic differences between aphasic subgroups and controls indicate compensatory changes in activation.ConclusionStimulus processing in early time windows (N1, N2) is altered in aphasics with adverse consequences for auditory comprehension of complex language material, while allowing performance of simpler tasks (syllable detection). Compensational patterns of speech sound processing may be activated in syllable detection, but may not be functional in more complex tasks. The degree to which compensational processes can be activated probably varies depending on factors as lesion site, time after injury, and language task.

Primary Progressive Aphasia: A Review

This review summarizes clinical and imaging features associated with primary progressive aphasia (PPA). We investigate the hypothesis that these patients can be divided into subgroups of progressive non-fluent aphasia (PNFA) and semantic dementia (SD), based on their linguistic profiles and related imaging studies, and examine whether each of these major subgroups can be further subdivided. We focus on several critical features within each progressive aphasic subgroup. In PNFA, we examine agrammatism, phonologic disorder, and impaired verb processing to determine whether this syndrome is related to a modality-specific impairment in word formation and articulation, or a conceptual deficit that interferes with grammatical processing. In SD, we examine impaired semantic memory, limited remote memory, and anomia to assess whether this syndrome is due to a modality-neutral interruption of semantic memory, or the degradation of various material-specific representations of object features and words. We conclude that there is sufficiently consistent and converging evidence from clinical and imaging studies to support the claim that PNFA and SD are distinct subgroups of PPA. However, there does not appear to be sufficient evidence at this point to support further discrimination within these progressive aphasic subgroups. Testing hypotheses about finer-grained syndromes such as progressive dysarthria or progressive anomia has important consequences for improving our understanding of language organization and the neural basis for language.

Verb–Noun Double Dissociation in Aphasic Lexical Impairments: The Role of Word Frequency and Imageability

Neurolinguistic studies have provided important evidence regarding the organization of lexical representations and the structure of underlying conceptual knowledge; in particular, it has been shown that the retrieval of verbs and nouns can be damaged selectively. Dissociated lexical damage is proof of an independent mental organization of lexical representations and/or of the underlying processes. The aim of the present study is to estimate the rate of dissociated impairments for nouns and verbs on a large sample of mild to moderate aphasic patients and to investigate the mechanisms underlying such phenomena. In addition, the authors wished to verify to what degree the impairment for nouns and verbs is related to a specific type of language disorder. A confrontation naming task for verbs and nouns was administered to 58 aphasic patients. The major lexical (word frequency and age of acquisition) and semantic variables (familiarity and imageability of the underlying concept) were considered for each noun and verb used in the task. Verbs were distinguished by major functional classes (transitive, intransitive, and ergative verbs). The data collected from this task were analyzed twice: (i) as a group study comparison of major aphasic subgroups and (ii) as a multiple single case study to evaluate the differences on the naming of verbs and nouns and the effect of the lexical semantic variables on each individual patient. The results confirm the existence of dissociated naming impairments of verbs and nouns. Selective impairment of verbs is more frequent (34%) than that of nouns (10%). In many cases, the dissociated pattern of naming impairment disappeared when the effect of the concomitant variables (word frequency and imageability) was removed, but in approximately one-fifth of the cases the noun or verb superiority was preserved. Noun superiority emerged in five of six agrammatic patients. Both the naming of verbs (n = 9) or of nouns (n = 6) could be impaired selectively in fluent aphasic patients. The results lend support to the hypothesis of an independent mental organization of nouns and verbs, but a substantial effect of imageability and word frequency suggests an interaction of the naming impairment with underlying lexical and semantic aspects.

Verb retrieval in action naming and spontaneous speech in agrammatic and anomic aphasia

The production of verbs in an action naming test and in spontaneous speech was evaluated in 16 aphasic patients: eight agrammatics and eight anomics. Action naming was also compared to object naming. The action naming test was controlled for factors known to be relevant for verb retrieval (i.e. word frequency, instrumentality, name-relation to a noun, transitivity and argument structure) and the objects were related to the verbs and chosen to match the verbs as precisely as possible on word frequency. For both aphasic subgroups object naming was better than action naming and there was no difference between agrammatics and anomics, neither in object naming, nor in action naming. In spontaneous speech, both agrammatics and anomics differed from normal controls on ‘verb diversity’ furthermore the agrammatics were significantly worse than normal speakers (and the anomics) in verb inflection and the proportion of verbs produced without internal argument was higher than in normal speakers (and in anomics). There was no significant correlation between the scores on the action naming tests and the diversity of verbs produced in spontaneous speech. It is suggested that for the anomics, this is due to the fact that for some patients it is more difficult to retrieve verbs in spontaneous speech than in isolation. For the agrammatics, the interference between verb retrieval and verb inflection seems responsible for the lack of a significant correlation.

Selective preservation of a lexical category in aphasia: Dissociations in comprehension of body parts and geographical place names following focal brain lesion

The selective dissociation of memory for proper names is discussed in the context of a review of dissociations involving broadly defined vs narrowly defined semantic categories in brain damaged adults. Two narrowly defined categories for which dissociations have been reported are body parts (selectively impaired in comprehension) and geographical place names (selectively preserved in comprehension). In this study, 167 aphasic patients were tested for their ability to correctly identify body parts and map locations from spoken names, relative to a baseline for correct responses on general word discrimination (object identification). Wernicke's aphasics and Global aphasics both had significantly more success in pointing to named map locations and significantly worse performance in pointing to named body parts than they had in selecting other objects from multiple choice. Anomic aphasics showed precisely the opposite pattern of results. Other aphasic subgroups (Broca's aphasics, Mixed Nonfluent aphasics, Conduction aphasics, Transcortical Motor and Transcortical Sensory aphasics, and Mixed Fluent aphasics) did not show significant deviations in either direction. We suggest that the selective preservation for place names may be related to their status as proper names.

Repetition deficits in three aphasic syndromes

This study examined the repetition errors of three aphasic subgroups during a repetition task. A total of 95 subjects, including 32 conduction, 38 Broca's, and 25 Wernicke's aphasics, repeated phrases and sentences from the Repeating Phrases Subtest of the Boston Diagnostic Aphasia Examination. Conduction aphasics exhibited a greater number of phonemic attempts, word revisions, and word and phrase repetitions. Broca's aphasics demonstrated more phonemic errors and omissions. Finally, Wernicke's aphasics showed more unrelated words and jargon.

The efficacy of two types of cues in aphasic patients

Abstract This study investigated the efficacy of two types of cues (phonemic and semantic) in aphasic patients with naming deficits. Subjects consisted of ten Broca's, ten Wernicke's, eight conduction, and eight anomic aphasic subjects. Cues were administered following failure to name on confrontation. Responsiveness to cueing was dependent on type of cue and type of aphasia. Subjects performed better on phonemic as compared to semantic cues. In addition, aphasic subgroups responded differentially, with conduction subjects responding significantly better to cueing than Wernicke's subjects. These findings are discussed with respect to the neuropsychological mechanisms involved in cueing.

An investigation of Luria's hypothesis on prompting in aphasic naming disturbances

This study investigated Luria's hypothesis that aphasic subgroups would respond differentially to phonemic prompts. Responsiveness to initial-sound cues was examined in 40 aphasics—10 Broca's, conduction, Wernicke's, and anomic aphasics who had naming difficulties. Results, with the exception of the anomic aphasic group, supported Luria's predictions. Broca's aphasics were responsive to phonemic cueing, while Wernicke's aphasics were not. Conduction aphasics tended to respond in a fashion similar to the Wernicke's group. The relationship of cueing responsiveness to underlying naming mechanisms is discussed.

Naming to Picture Versus Description in Three Aphasic Subgroups

Twenty-three male aphasics, classified as Broca's, Wernicke's and anomic, were tested on their ability to name objects to either visual confrontation or oral associative description. For the Broca's and Wernicke's aphasics, naming to visual confrontation was significantly better than to oral description. Broca's aphasics tended to produce more correct names than both other groups in both conditions, although significance was reached only in oral description. Differences were not significantly affected by the comprehension deficit or severity of aphasia. With picture naming, all groups tended to name immediately or not al all. For oral description, there was a greater proportion of long latency responses for the posterior patients. When given phonemic or visual cues to assist naming, Broca's aphasics benefited the most, the anomics performing most poorly. All these results suggest qualitative differences in naming ability in aphasic subgroups.

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.

Self-Correctional Strategies In The Conversational Speech Of Aphasic And Nonaphasic Brain Damaged Adults

Self-correctional strategies in the conversational speech of aphasic and non-aphasic brain-damaged adults were analyzed for frequency of occurrence and percentage of success. Similar strategies were used by groups resulting in the same rank order of most to least successful for delay, association, description and generalization. Further analysis of self-correctional strategies among aphasic subgroups indicated that frequency and success of strategies were not significantly related to type of aphasia. Severity level and success of a particular strategy appeared to depend on the amount of information about the target word which was available to the subject at the time of error.

Stuttering Repetitions in Aphasic and Nonaphasic Brain Damaged Adults

Stuttering repetitions were analyzed by frequency of occurrence in aphasic and nonaphasic brain damaged adults. Aphasics used significantly more stuttering repetitions than did nonaphasics. The frequency distribution of stuttering repetitions among aphasic subgroups indicated a relationship with sound problems in anterior and posterior groups.

Effects of Vocabulary, Syntax, and Sentence Length on Auditory Comprehension in Aphasic Patients

Three groups of adult aphasics (Broca’s, Wernicke’s and amnesic) and a group of normal control subjects were compared on a test of auditory comprehension for sentences. The test sentences constructed varied systematically in the parameters of length, vocabullary difficulty, and syntactic complexity. The pattern of aphasics’ responses indicated that they differed from the normal controls in quantitative performance, but not in qualitative aspects. The aphasic subgroups varied in comprehension ability, with the Wernicke's patients performing the poorest. Syntactic complexity proved to be the most difficult parameter for all subjects. Comprehension of sentences of increased difficulty was significantly poorer than comprehension of easy sentences. Clinical applications of the test were discussed.

Selective Impairment of Phonetic and Non-Phonetic Transcription of Words in Japanese Aphasic Patients: Kana vs. Kanji in Visual Recognition and Writing

Two aphasic subgroups of 10 each, with and without apraxia of speech, and two nonaphasic right- and left-hemiplegic groups of six each were administered two sets of tasks: 1) three visual recognition tasks in which kanji (ideogram) and hiragana (phonogram) representations of 10 highfrequency nouns and katakana representations of 10 comparative imported nouns were used as stimuli, and 2) two writing tasks with the same nouns using kanji, hiragana and katakana transcriptions. In the visual recognition tasks, each subject was presented tachistoscopically with three sets of transcriptional stimuli, i.e., kanji, katakana, and hiragana stimuli, arranged in random order. Three subsessions were conducted with different exposure durations, 1/10 second (Task 1), 1/2 second (Task 2), and 1 second (Task 3), respectively. In the writing tasks, each patient was required to write the word for each of 20 different pictures presented (Task 4) and also to write the words to dictation (Task 5), using both kanji and hiragana (for the 10 non-imported words) or katakana only (for the 10 imported words). The results showed that 1) the performance levels of aphasics subjects in all tasks were significantly lower than those of non-aphasic subjects, 2) Group B aphasics (with apraxia of speech) made a significantly greater number of errors in kana processings than in kanji processings in the tachistoscopic tasks (Tasks 1, 2, and 3) as well as in the writing tasks (Tasks 4 and 5), while Group A aphasics (without apraxia of speech) exhibited no such clear difference. On the basis of the findings it was concluded that the selective impairment of kana processing exhibited by the Group B patients is associated not only with the overall severity but with the specific type of the aphasic syndrome of this group, i.e., “apraxia of speech” superimposed on aphasia. Hypotheses concerning the possible underlying mechanisms for this phenomenon are discussed.

Some dimensions of auditory language comprehension in aphasia.

Four aspects of auditory comprehension were compared in 44 normal children ages 4 to 9, in 12 normal adults, and in 52 aphasics of 5 diagnostic classes: Broca’s, Wernicke’s, conduction, anomic, and global aphasics. The 4 aspects studied were breadth of vocabulary, auditory sequential pointing-span, comprehension of directional prepositions, and recognition of correct grammatical usage of prepositions. The aphasics' patterns of success were all different from those of the children, and the diagnostic subgroups could be distinguished from each other by a discriminant analysis. The mean pointing-span of the best aphasic group (anomics) was below the level of 6-year-olds. Broca’s aphasics had by far the poorest score. It is concluded that auditory comprehension is multidimensional, and that its pattern of disturbance is characteristic for different aphasic subgroups.