A data-driven approach to post-stroke aphasia classification and lesion-based prediction

Aphasia is an acquired impairment in the production or comprehension of language, typically caused by left hemisphere stroke. The subtyping framework used in clinical aphasiology today is based on the Wernicke-Lichtheim model of aphasia formulated in the late 19th century, which emphasizes the distinction between language production and comprehension. The current study used a data-driven approach that combined modern statistical, machine learning, and neuroimaging tools to examine behavioural deficit profiles and their lesion correlates and predictors in a large cohort of individuals with post-stroke aphasia. First, individuals with aphasia were clustered based on their behavioural deficit profiles using community detection analysis (CDA) and these clusters were compared with the traditional aphasia subtypes. Random forest classifiers were built to evaluate how well individual lesion profiles predict cluster membership. The results of the CDA analyses did not align with the traditional model of aphasia in either behavioural or neuroanatomical patterns. Instead, the results suggested that the primary distinction in aphasia (after severity) is between phonological and semantic processing rather than between production and comprehension. Further, lesion-based classification reached 75% accuracy for the CDA-based categories and only 60% for categories based on the traditional fluent/non-fluent aphasia distinction. The results of this study provide a data-driven basis for a new approach to classification of post-stroke aphasia subtypes in both research and clinical settings.

A Retrospective Study of Long-Term Improvement on the Boston Naming Test

Purpose Lexical retrieval impairment is a universal characteristic of aphasia and a common treatment focus. Although naming improvement is well documented, there is limited information to shape expectations regarding long-term recovery. This was the motivation for a retrospective study of longitudinal data on the Boston Naming Test (BNT; Kaplan, Goodglass, & Weintraub, 1983, 2000). Method BNT scores were analyzed from a heterogeneous cohort of 42 individuals with anomia associated with a range of aphasia types. The data were collected over the course of 20 years from individuals who had participated in treatment and received at least 2 BNT administrations. A linear mixed model was implemented to evaluate effects of initial BNT score, time postonset, and demographic variables. For those over 55 years of age, BNT change was evaluated relative to data from the Mayo Clinic's Older Americans Normative Studies. Results There was a significant average improvement of +7.67 points on the BNT in individuals followed for an average of 2 years. Overall, the average rate of improvement was +5.84 points per year, in contrast to a decline of 0.23 points per year in a healthy adult cohort from the Mayo Clinic's Older Americans Normative Studies. Naming recovery was approximately linear, with significant main effects of initial BNT score (i.e., initial severity) and time postonset; the greatest changes were noted in those whose initial severity was moderate. Conclusions These findings indicate a positive prognosis for naming improvement over time regardless of demographic factors and provide estimates for clinical predictions for those who seek rehabilitation during the chronic phase.

Facilitator Behaviors Leading to Engagement and Disengagement in Aphasia Conversation Groups

Purpose Researchers have identified features of successful aphasia conversation groups and clinician behaviors leading to engagement and group cohesion. There has been less focus in the literature on facilitator behaviors that hinder participation or result in disengagement. This study aims to explore the behaviors of graduate student facilitators that contribute to and detract from engagement in aphasia conversation groups. Method Data were drawn from 4 conversation group sessions from 2 different university settings. Groups included 1 graduate student facilitator and 3 or more persons with aphasia. Sociolinguistic discourse analysis was applied to transcripts of group sessions. Results Three broad patterns detailing facilitator behaviors were identified. Several facilitator actions contributing to engagement were noted, including strategic use of topic elicitors, multimodal communication supports, and techniques to avoid interactional asymmetry. Behaviors associated with participant disengagement were also noted across sessions, including restricted discourse behaviors and difficulty managing the competing needs of participants. Engagement and disengagement were the product of several coordinating actions of the facilitator and group members that together influenced participation in conversation. Conclusion Results suggest that novice facilitators exhibit behaviors that contribute to and detract from participant engagement in aphasia conversation groups. Findings, discussed within the context of the literature on well-managed groups, highlight the skill required in managing the needs of participants with aphasia and knowing how and when to employ clinician-led strategies.

Effect of Text-to-Speech Rate on Reading Comprehension by Adults With Aphasia

Purpose Accessing auditory and written material simultaneously benefits people with aphasia; however, the extent of benefit as well as people's preferences and experiences may vary given different auditory presentation rates. This study's purpose was to determine how 3 text-to-speech rates affect comprehension when adults with aphasia access newspaper articles through combined modalities. Secondary aims included exploring time spent reviewing written texts after speech output cessation, rate preference, preference consistency, and participant rationales for preferences. Method Twenty-five adults with aphasia read and listened to passages presented at slow (113 words per minute [wpm]), medium (154 wpm), and fast (200 wpm) rates. Participants answered comprehension questions, selected most and least preferred rates following the 1st and 3rd experimental sessions and after receiving performance feedback, and explained rate preferences and reading and listening strategies. Results Comprehension accuracy did not vary significantly across presentation rates, but reviewing time after cessation of auditory content did. Visual data inspection revealed that, in particular, participants with substantial extra reviewing time took longer given fast than medium or slow presentation. Regardless of exposure amount or receipt of performance feedback, participants most preferred the medium rate and least preferred the fast rate; rationales centered on reading and listening synchronization, benefits to comprehension, and perceived normality of speaking rate. Conclusion As a group, people with aphasia most preferred and were most efficient given a text-to-speech rate around 150 wpm when processing dual modality content; individual differences existed, however, and mandate attention to personal preferences and processing strengths.

Evaluating informative content and global coherence in fluent and non-fluent aphasia

BACKGROUND

Discourse analysis is an important component of aphasia assessment because it can provide an insight into functional communication abilities. However, there are many unknowns regarding the levels of discourse breakdowns that occur across aphasia types. The purpose of the current study is to explore the possible differences in discourse-level communication in persons with fluent and non-fluent aphasia during picture description.

AIMS

To examine if persons with fluent and non-fluent aphasia differ on utterance-level discourse measures when evaluating informative content and global coherence. Additionally, to evaluate and compare the types of global coherence violations made by each group.

METHODS & PROCEDURES

Data from 31 people with aphasia was collected from AphasiaBank, which included 13 people with fluent aphasia and 18 people with non-fluent aphasia. Discourse samples from three picture descriptions were analysed. Discourse outcomes included utterances with new information (UNIs-relevant utterances containing new information) and global coherence (the extent to which each utterance maintained the overall discourse theme). Additionally, seven types of errors were identified to explore the nature of breakdowns in global coherence.

OUTCOMES & RESULTS

People with fluent aphasia produced significantly higher proportions of UNIs and had significantly higher average global coherence ratings than those with non-fluent aphasia. Differences in global coherence violations were identified with people with fluent aphasia producing more non-specific, incorrect and off-topic utterances and people with non-fluent aphasia producing more incomplete utterances. One of the most common global coherence error types in both groups was commentary.

CONCLUSIONS & IMPLICATIONS

Although people with fluent aphasia produced more types of global coherence errors, including incorrect, non-specific and off-topic utterances, the group was still rated significantly higher on utterance relevance and topic maintenance, indicating that the ability to produce a complete utterance plays an important role in some aspects of discourse production. Additionally, these findings provide an insight into potential targets for intervention.

Speech Fluency in Acquired Apraxia of Speech During Narrative Discourse: Group Comparisons and Dual-Task Effects

Purpose Slowed speech and interruptions to the flow of connected speech are common in aphasia. These features are also observed during dual-task performance for neurotypical adults. The purposes of this study were to determine (a) whether indices of fluency related to cognitive-linguistic versus motor processing would differ between speakers with aphasia plus apraxia of speech (AOS) and speakers with aphasia only and (b) whether cognitive load reduces fluency in speakers with aphasia with and without AOS. Method Fourteen speakers with aphasia (7 with AOS) and 7 neurotypical controls retold short stories alone (single task) and while simultaneously distinguishing between a high and a low tone (dual task). Their narrative samples were analyzed for speech fluency according to sample duration, speech rate, pause/fill time, and repetitions per syllable. Results As expected, both speaker groups with aphasia spoke slower and with more pauses than the neurotypical controls. The speakers with AOS produced more repetitions and longer samples than controls, but they did not differ on these measures from the speakers with aphasia without AOS. Relative to the single-task condition, the dual-task condition increased the duration of pauses and fillers for all groups but reduced speaking rate only for the control group. Sample duration and frequency of repetitions did not change in response to cognitive load. Conclusions Speech output in aphasia becomes less fluent when speakers have to engage in simultaneous tasks, as is typical in everyday conversation. Although AOS may lead to more sound and syllable repetitions than normal, speaking tasks other than narrative discourse might better capture this specific type of disfluency. Future research is needed to confirm and expand these preliminary findings. Supplemental Material https://doi.org/10.23641/asha.8847845.

Interrater Reliability and Concurrent Validity for the Apraxia of Speech Rating Scale 3.0: Application With Persons With Acquired Apraxia of Speech and Aphasia

Purpose This investigation was designed to provide interrater reliability data for the Apraxia of Speech Rating Scale 3.0 (ASRS 3.0; Strand, Duffy, Clark, & Josephs, 2014 ). Importantly, ratings were completed by investigators who were not involved with the ASRS development. Another aim was to evaluate the relationship of the ASRS 3.0 total score to word intelligibility. Method Two investigators independently completed ASRS 3.0 ratings for 28 participants with chronic apraxia of speech and aphasia. Intelligibility scores were obtained for all participants. Results Consistency of ratings for each feature and total score of the ASRS 3.0 was measured using intraclass correlation coefficients. Twelve of 13 intraclass correlation coefficients for feature ratings reached significance; clinical meaningfulness ranged from poor to excellent. Interrater reliability for the total scores was excellent. Similarly, absolute difference of ratings was minimal for the total scores, but varied across the 13 feature ratings. Correlations between the intelligibility scores and ASRS 3.0 total score were moderate to strong. Conclusion The total ASRS 3.0 score may be viewed as a reliable indicator of prevalence of apraxia of speech features. Although there was good to acceptable correspondence in ratings of the majority of the individual features, additional operationalization of rating procedures may be needed to improve interrater reliability for a few features.

[Networks involved in motor cognition : Physiology and pathophysiology of apraxia]

Apraxia is an umbrella term for different disorders of higher motor abilities that are not explained by elementary sensorimotor deficits (e. g. paresis or ataxia). Characteristic features of apraxia that are easy to recognize in clinical practice are difficulties in pantomimed or actual use of tools as well as in imitation of meaningless gestures. Apraxia is bilateral, explaining the cognitive motor disorders and occurs frequently (but not exclusively) after left hemispheric lesions, as well as in neurodegenerative diseases, such as corticobasal syndrome and Alzheimer's disease. Apraxic deficits can seriously impair activities of daily living, which is why the appropriate diagnosis is of great relevance. At the functional anatomical level, different cognitive motor skills rely on at least partly different brain networks, namely, a ventral processing pathway for semantic components, such as tool-action associations, a ventro-dorsal pathway for sensorimotor representations of learnt motor acts, as well as a dorso-dorsal pathway for on-line motor control and, probably, imitation of meaningless gestures. While these networks partially overlap with language-relevant regions, more clear cut dissociations are found between apraxia deficits and disorders of spatial attention. In addition to behavioral interventions, noninvasive neuromodulation approaches, as well as human-computer interface assistance systems are a growing focus of interest for the treatment of apraxia.

Different Cognitive Profiles of Patients with Severe Aphasia

Cognitive dysfunction frequently occurs in aphasic patients and primarily compromises linguistic skills. However, patients suffering from severe aphasia show heterogeneous performance in basic cognition. Our aim was to characterize the cognitive profiles of patients with severe aphasia and to determine whether they also differ as to residual linguistic abilities. We examined 189 patients with severe aphasia with standard language tests and with the CoBaGA (Cognitive Test Battery for Global Aphasia), a battery of nonverbal tests that assesses a wide range of cognitive domains such as attention, executive functions, intelligence, memory, visual-auditory recognition, and visual-spatial abilities. Twenty patients were also followed longitudinally in order to assess their improvement in cognitive skills after speech therapy. Three different subgroups of patients with different types and severity of cognitive impairment were evidenced. Subgroups differed as to residual linguistic skills, in particular comprehension and reading-writing abilities. Attention, reasoning, and executive functions improved after language rehabilitation. This study highlights the importance of an extensive evaluation of cognitive functions in patients with severe aphasia.

Bilingualism delays the onset of behavioral but not aphasic forms of frontotemporal dementia

Bilingualism has been found to delay onset of dementia and this has been attributed to an advantage in executive control in bilinguals. However, the relationship between bilingualism and cognition is complex, with costs as well as benefits to language functions. To further explore the cognitive consequences of bilingualism, the study used Frontotemporal dementia (FTD) syndromes, to examine whether bilingualism modifies the age at onset of behavioral and language variants of Frontotemporal dementia (FTD) differently. Case records of 193 patients presenting with FTD (121 of them bilingual) were examined and the age at onset of the first symptoms were compared between monolinguals and bilinguals. A significant effect of bilingualism delaying the age at onset of dementia was found in behavioral variant FTD (5.7 years) but not in progressive nonfluent aphasia (0.7 years), semantic dementia (0.5 years), corticobasal syndrome (0.4 years), progressive supranuclear palsy (4.3 years) and FTD-motor neuron disease (3 years). On dividing all patients predominantly behavioral and predominantly aphasic groups, age at onset in the bilingual behavioral group (62.6) was over 6 years higher than in the monolingual patients (56.5, p=0.006), while there was no difference in the aphasic FTD group (60.9 vs. 60.6 years, p=0.851). The bilingual effect on age of bvFTD onset was shown independently of other potential confounding factors such as education, gender, occupation, and urban vs rural dwelling of subjects. To conclude, bilingualism delays the age at onset in the behavioral but not in the aphasic variants of FTD. The results are in line with similar findings based on research in stroke and with the current views of the interaction between bilingualism and cognition, pointing to advantages in executive functions and disadvantages in lexical tasks.

Delivering communication strategy training for people with aphasia: what is current clinical practice?

BACKGROUND

Communication strategy training (CST) is a recognized part of UK speech and language therapists' (SLTs) role when working with a person with aphasia. Multiple CST interventions have been published but, to date, there are no published studies exploring clinical practice in this area.

AIMS

To investigate UK SLTs' current CST practices.

METHODS & PROCEDURES

Thirty-seven UK SLTs completed an online questionnaire, eight of whom attended a follow-up focus group. A clinical consistency scale was applied to the questionnaire data and tasks that were most consistently used were explored in the focus group and analyzed using a primarily deductive thematic data analysis approach.

OUTCOMES & RESULTS

Three key CST findings arose: (1) the rarity with which SLTs focus equally and explicitly on both communication partners' strategies; (2) SLTs' differing understandings of CST terminologies and concepts and underuse of formal assessment; and (3) the absence of video feedback.

CONCLUSION & IMPLICATIONS

This study's survey findings suggest that conversation partners not only receive half the amount of CST given to people with aphasia but also play a more passive learning role when they are present. This is an interesting point to consider when the current evidence base contains stronger evidence for the effectiveness of conversation partner CST over other CST approaches, it being described as an effective method that may be maintained over time.

The unbridged gap between clinical diagnosis and contemporary research on aphasia: A short discussion on the validity and clinical utility of taxonomic categories

Even if the traditional aphasia classification is continuously questioned by many scholars, it remains widely accepted among clinicians and included in textbooks as the gold standard. The present study aims to investigate the validity and clinical utility of this taxonomy. For this purpose, 65 left-hemisphere stroke patients were assessed and classified with respect to aphasia type based on performance on a Greek adaptation of the Boston Diagnostic Aphasia Examination. MRI and/or CT scans were obtained for each patient and lesions were identified and coded according to location. Results indicate that 26.5% of the aphasic profiles remained unclassified. More importantly, we failed to confirm the traditional lesion-to-syndrome correspondence for 63.5% of patients. Overall, our findings elucidate crucial vulnerabilities of the neo-associationist classification, and further support a deficit-rather than a syndrome-based approach. The issue of unclassifiable patients is also discussed.

Can we separate verbs from their argument structure? A group study in aphasia

BACKGROUND

Given the integral role that verbs play in sentence production, understanding verb deficits is critical to clinical practice. Difficulties in sentence production are often directly related to an inability to retrieve argument structure information which, according to most theoretical accounts, is specified at a lexical level as part of the semantic representation of the verb. The presence of an argument complexity effect when retrieving verbs in isolation, i.e. increased difficulty with increasing number of arguments required by the verb, is considered evidence of the integral link between verbs and the ensuing structure. Recent reports, however, of relatively intact verb retrieval and impaired argument structure suggest that difficulties with verbs and argument structure may not always co-occur. One explanation for this is that lexical-syntactic information may be stored separately to lexical-semantic information at the lemma level and then differentially impaired.

AIMS

To determine whether the presence of difficulties creating argument structure in a group of people with aphasia with verb-retrieval deficits consistently aligned with the underlying nature of their impairment, where semantic involvement resulted in argument structure difficulties and post-semantic impairment resulted in intact argument structure. This would provide evidence either to support or to challenge the view that argument structure is lexically specified. The presence of an argument complexity effect within the participants' single verb naming was also investigated to examine the relationship between verb argument information and any subsequent difficulties creating argument structure for sentence production.

METHODS & PROCEDURES

Verb retrieval and argument structure production were investigated in 12 people with aphasia with verb-retrieval deficits on single-word and sentence-production measures.

OUTCOMES & RESULTS

Eight of the 12 participants presented with a semantic verb deficit (five semantic and three mixed semantic and phonological) and had difficulties in creating argument structure. Four participants presented with a phonological verb deficit. Of these, two had intact argument structure while two had impaired argument structure. An argument complexity effect in verb naming was seen in both groups.

CONCLUSIONS & IMPLICATIONS

Semantic verb-retrieval deficits consistently resulted in argument structure production difficulties, supporting the view that syntactic information is stored within the lemma. The presence of argument structure difficulties in two participants with phonological deficits; however, lends support for the separate coding of lexical-syntactic from lexical-semantic information at the lemma level, a factor that has both theoretical and clinical implications with respect to diagnosis and management.

Algorithmic Classification of Five Characteristic Types of Paraphasias

PURPOSE

This study was intended to evaluate a series of algorithms developed to perform automatic classification of paraphasic errors (formal, semantic, mixed, neologistic, and unrelated errors).

METHOD

We analyzed 7,111 paraphasias from the Moss Aphasia Psycholinguistics Project Database (Mirman et al., 2010) and evaluated the classification accuracy of 3 automated tools. First, we used frequency norms from the SUBTLEXus database (Brysbaert & New, 2009) to differentiate nonword errors and real-word productions. Then we implemented a phonological-similarity algorithm to identify phonologically related real-word errors. Last, we assessed the performance of a semantic-similarity criterion that was based on word2vec (Mikolov, Yih, & Zweig, 2013).

RESULTS

Overall, the algorithmic classification replicated human scoring for the major categories of paraphasias studied with high accuracy. The tool that was based on the SUBTLEXus frequency norms was more than 97% accurate in making lexicality judgments. The phonological-similarity criterion was approximately 91% accurate, and the overall classification accuracy of the semantic classifier ranged from 86% to 90%.

CONCLUSION

Overall, the results highlight the potential of tools from the field of natural language processing for the development of highly reliable, cost-effective diagnostic tools suitable for collecting high-quality measurement data for research and clinical purposes.

Cognitive grammar and aphasic discourse

In cognitive grammar (CG), there is no clear division between language and other cognitive processes; all linguistic form is conceptually meaningful. In this pilot study, a CG approach was applied to investigate whether people with aphasia (PWA) have cognitive linguistic difficulty not predicted from traditional, componential models of aphasia. Narrative samples from 22 PWA (6 fluent, 16 non-fluent) were compared with samples from 10 participants without aphasia. Between-group differences were tested statistically. PWA had significant difficulty with temporal sequencing, suggesting problems that are not uniquely linguistic. For some, these problems were doubly dissociated with naming, used as a general measure of severity, which indicates that cognitive linguistic difficulties are not linked with more widespread brain damage. Further investigation may lead to a richer account of aphasia in line with contemporary linguistics and cognitive science approaches.

The Aphasia Quotient: The Taxonomic Approach to Measurement of Aphasic Disability

150 aphasiacs and 59 controls were examined with a scorable, comprehensive battery, designed to be used by the clinician and the research worker. The subtests of Fluency, Information, Comprehension, Repetition and Naming were added and compared to a hypothetical normal of 100 obtaining the “aphasia Quotient.” This is a measurement of the severity of language impairment. On the basis of their performance on the subtests, the patients were classified according to taxonomic principles into Global, Motor (Broca’s), Isolation, Sensory (Wernicke’s), Transcortical Motor, Transcortical Sensory, Conduction and Anomic groups (in order of severity). This classification is considered a clinically valid baseline for research, diagnosis and prognosis.

A Taiwanese Mandarin Main Concept Analysis (TM-MCA) for quantification of aphasic oral discourse

BACKGROUND

Various quantitative systems have been proposed to examine aphasic oral narratives in English. A clinical tool for assessing discourse produced by Cantonese-speaking persons with aphasia (PWA), namely Main Concept Analysis (MCA), was developed recently for quantifying the presence, accuracy and completeness of a narrative. Similar tools for Mandarin speakers are currently absent.

AIMS

The first aim is to develop and establish the validity of the Taiwanese Mandarin Main Concept Analysis (TM-MCA) for the Mandarin-speaking population in Taiwan, given the paucity of related investigations. Another aim is to establish the influence of age and education level on Taiwanese Mandarin speakers' oral narrative abilities. The third purpose is to examine how well the TM-MCA could distinguish between native speakers with and without aphasia in Taiwan. The final aim is to examine the reliability and validity of the TM-MCA.

METHODS & PROCEDURES

Eight speech-language pathologists (SLPs) and eight neurologically intact participants were involved to establish the TM-MCA main concepts. Another 36 neurologically intact participants and 10 PWA participated to validate the TM-MCA by contrasting their performance.

OUTCOMES & RESULTS

Both age and educational level affected the oral discourse performance among the neurologically intact adults. Significant differences on the TM-MCA measures were noted between the control group and the group with aphasia. Moreover, the degree of aphasia significantly affected the oral discourse of PWA.

CONCLUSIONS & IMPLICATIONS

The TM-MCA is a culturally appropriate quantitative system for the Taiwanese Mandarin population. It can be used to supplement standardized aphasia tests to help SLPs make more informative decisions not only on clinical diagnosis but also on treatment planning.

Aphasia, Alexia, and Oral Reading

Alexia is an acquired disturbance in reading. Alexias that occur after left hemisphere damage typically result from linguistic deficits and may occur as isolated symptoms or as part of an aphasia syndrome. This article presents an overview of the classification of the alexias, including both the traditional neuroanatomical perspective and the more recent psycholinguistic approach. Then, assessment procedures are reviewed, followed by a summary of treatment approaches for alexia. Finally, two case studies illustrate how oral reading of connected language (sentences and paragraphs rather than single words) has been used as a technique for treating alexia in patients with aphasia.

Aphasia--the hidden disability

Aphasia is an acquired language disorder due to brain damage and which may include difficulty in producing or comprehending spoken or written language. Stroke is the commonest cause and each year 50,000 new patients develop aphasia. People with aphasia differ in their speech output and in their fluency. Some people communicate reasonably well, while others have very limited powers of expression. This review will describe the neurology of speech and aphasia, and will focus on the role of the speech and language therapist in dealing with people with aphasia.

CLINICAL RELEVANCE

Dentists and their staff should be aware that after a stroke some people are unable to talk or have limited powers of expression. Comprehension might be impaired and people with aphasia may be unable to grasp some common language, such as appointment letters and patient information.

Support for anterior temporal involvement in semantic error production in aphasia: new evidence from VLSM

Semantic errors in aphasia (e.g., naming a horse as "dog") frequently arise from faulty mapping of concepts onto lexical items. A recent study by our group used voxel-based lesion-symptom mapping (VLSM) methods with 64 patients with chronic aphasia to identify voxels that carry an association with semantic errors. The strongest associations were found in the left anterior temporal lobe (L-ATL), in the mid- to anterior MTG region. The absence of findings in Wernicke's area was surprising, as were indications that ATL voxels made an essential contribution to the post-semantic stage of lexical access. In this follow-up study, we sought to validate these results by re-defining semantic errors in a manner that was less theory dependent and more consistent with prior lesion studies. As this change also increased the robustness of the dependent variable, it made it possible to perform additional statistical analyses that further refined the interpretation. The results strengthen the evidence for a causal relationship between ATL damage and lexically-based semantic errors in naming and lend confidence to the conclusion that chronic lesions in Wernicke's area are not causally implicated in semantic error production.

Post-stroke language disorders

Post-stroke language disorders are frequent and include aphasia, alexia, agraphia and acalculia. There are different definitions of aphasias, but the most widely accepted neurologic and/or neuropsychological definition is that aphasia is a loss or impairment of verbal communication, which occurs as a consequence of brain dysfunction. It manifests as impairment of almost all verbal abilities, e.g., abnormal verbal expression, difficulties in understanding spoken or written language, repetition, naming, reading and writing. During the history, many classifications of aphasia syndromes were established. For practical use, classification of aphasias according to fluency, comprehension and abilities of naming it seems to be most suitable (nonfluent aphasias: Broca's, transcortical motor, global and mixed transcortical aphasia; fluent aphasias: anomic, conduction, Wernicke's, transcortical sensory, subcortical aphasia). Aphasia is a common consequence of left hemispheric lesion and most common neuropsychological consequence of stroke, with a prevalence of one-third of all stroke patients in acute phase, although there are reports on even higher figures. Many speech impairments have a tendency of spontaneous recovery. Spontaneous recovery is most remarkable in the first three months after stroke onset. Recovery of aphasias caused by ischemic stroke occurs earlier and it is most intensive in the first two weeks. In aphasias caused by hemorrhagic stroke, spontaneous recovery is slower and occurs from the fourth to the eighth week after stroke. The course and outcome of aphasia depend greatly on the type of aphasia. Regardless of the fact that a significant number of aphasias spontaneously improve, it is necessary to start treatment as soon as possible. The writing and reading disorders in stroke patients (alexias and agraphias) are more frequent than verified on routine examination, not only in less developed but also in large neurologic departments. Alexia is an acquired type of sensory aphasia where damage to the brain causes the patient to lose the ability to read. It is also called word blindness, text blindness or visual aphasia. Alexia refers to an acquired inability to read due to brain damage and must be distinguished from dyslexia, a developmental abnormality in which the individual is unable to learn to read, and from illiteracy, which reflects a poor educational background. Most aphasics are also alexic, but alexia may occur in the absence of aphasia and may occasionally be the sole disability resulting from specific brain lesions. There are different classifications of alexias. Traditionally, alexias are divided into three categories: pure alexia with agraphia, pure alexia without agraphia, and alexia associated with aphasia ('aphasic alexia'). Agraphia is defined as disruption of previously intact writing skills by brain damage. Writing involves several elements: language processing, spelling, visual perception, visuospatial orientation for graphic symbols, motor planning, and motor control of writing. A disturbance of any of these processes can impair writing. Agraphia may occur by itself or in association with aphasias, alexia, agnosia and apraxia. Agraphia can also result from 'peripheral' involvement of the motor act of writing. Like alexia, agraphia must be distinguished from illiteracy, where writing skills were never developed. Acalculia is a clinical syndrome of acquired deficits in mathematical calculation, either mentally or with paper and pencil. These language disturbances can be classified differently, but there are three principal types of acalculia: acalculia associated with language disturbances, including number paraphasia, number agraphia, or number alexia; acalculia secondary to visuospatial dysfunction with malalignment of numbers and columns, and primary anarithmetria entailing disruption of the computation process.

[Topical features of speech disorders in children with focal cortical dysplasia and symptomatic epilepsy]

We studied speech function in 11 patients with focal cortical dysplasia (FCD) of different localization. The character of speech disorders was strongly correlated with the time of seizure onset and their frequency, while the localization of dysplasia did not play a significant role. The speech remained intact during seizures in the school age and during the relatively rare (weekly or monthly) seizures. The complete disappearance of speech after the period of normal development occurred in the daily multiple secondary-generalized seizures and resembled the previously described Landau-Kleffner syndrome ("aphasia-epilepsy"). Based on the literature and own data, the authors suggest that such global speech disorders can not be considered as aphasia, i.e., the disorder due to the focal lesions of speech brain areas. The authors did not reject the possibility of the development of aphasia in epileptic patients but only in those cases when the epileptic activity confined to mostly speech areas. Global speech disorders (up to the complete disappearance of impressive and expressive speech) at any localization of epileptic focus developed during the negative rearrangement of the speech functional system as a whole. These speech disorders are often accompanied by the acquired epileptic frontal syndrome. That is, in the first place are the most phylo- and ontogenetically young functional systems, namely, speech and regulatory functions, the damage of which emerges as a frontal syndrome. At the same time, the old consolidated pre-speech connections remain. Presumably, in this view, in cases of global speech disorders and speech disappearance, it is more correctly to substitute the terms "aphasia-epilepsy" and "total aphasia" for the familiar term "regression of speech development".

The influence of phonetic dimensions on aphasic speech perception

Individuals with aphasia have more problems detecting small differences between speech sounds than larger ones. This paper reports how phonemic processing is impaired and how this is influenced by speechreading. A non-word discrimination task was carried out with 'audiovisual', 'auditory only' and 'visual only' stimulus display. Subjects had to decide whether two presented stimuli were the same. Six aphasic subjects with speech sound processing difficulties and 14 non-brain-damaged control subjects participated in this study. It was found that the aphasic subjects have difficulties in discriminating pairs of non-words, which are more profound for small differences. Differences in 'voicing' were least often detected and therefore seem most difficult to perceive. This implies different processing of the phonetic dimensions in speech sound perception. Performance improved when speechreading was possible. As this improvement is not based on differences in place of articulation only, theories of audiovisual processing need to be revised.

Production latencies of morphologically simple and complex verbs in aphasia

There are several accounts of why some individuals with post-stroke aphasia experience difficulty in producing morphologically complex verbs. Although a majority of these individuals also produce syntactically flawed utterances, at least two accounts focus on word-level encoding operations. One account proposes a difficulty with rule-governed affixation, predicting that verbs without affixes (stems and irregular past) should be produced with ease. The second account emphasises the contribution of phonological encoding, noting that morphological complexity is often confounded by phonological complexity. The present study investigated the effect of morphological complexity (presence vs. absence of affixes) on verb production when phonological complexity and lexical frequency was controlled. A novel delayed repetition paradigm was used, accuracy and latency of production were the dependent measures. Data from nine agrammatic aphasic and nine unimpaired participants revealed no effects of morphological complexity, but a significant effect of frequency on production latency. The results indicate that morphological complexity plays little role, if any, in production difficulty, at least for this experimental task and this group of non-apraxic agrammatic aphasic individuals. A difficulty in usage of contextually appropriate verb inflections, rather than in morphophonological encoding, is suggested.

[Syndromes or symptoms in the assessment of aphasic patients?]

The procedure generally used to diagnose aphasic patients consists of classifying them in one of the classic syndromes on the basis of the analysis of their symptoms. However, this taxonomy has several important problems, the main one being that it does not take into account the variability of aphasic patients, as there are many more disorder profiles than those included in the syndromes. In order to test the homogeneity of a sample of patients diagnosed with the classic taxonomy, 15 aphasic patients (5 Broca, 5 Wernicke and 5 Conduction) and 5 healthy controls were tested with nine comprehension and production tasks. Participants were aged 38 to 81 years old. The results indicate the existence of great variability in patients labeled with the same diagnosis, as revealed by the differences in within-group scores in each task, and a limited adjustment to the expected profile, with some patients showing symptoms allegedly corresponding to other syndromes. Our results call attention to the need to study each patient individually and interpret their disorders regardless of the syndromes.

Severity of post-stroke aphasia according to aphasia type and lesion location in Koreans

To determine the relations between post-stroke aphasia severity and aphasia type and lesion location, a retrospective review was undertaken using the medical records of 97 Korean patients, treated within 90 days of onset, for aphasia caused by unilateral left hemispheric stroke. Types of aphasia were classified according to the validated Korean version of the Western Aphasia Battery (K-WAB), and severities of aphasia were quantified using WAB Aphasia Quotients (AQ). Lesion locations were classified as cortical or subcortical, and were determined by magnetic resonance imaging. Two-step cluster analysis was performed using AQ values to classify aphasia severity by aphasia type and lesion location. Cluster analysis resulted in four severity clusters: 1) mild; anomic type, 2) moderate; Wernicke's, transcortical motor, transcortical sensory, conduction, and mixed transcortical types, 3) moderately severe; Broca's aphasia, and 4) severe; global aphasia, and also in three lesion location clusters: 1) mild; subcortical 2) moderate; cortical lesions involving Broca's and/or Wernicke's areas, and 3) severe; insular and cortical lesions not in Broca's or Wernicke's areas. These results revealed that within 3 months of stroke, global aphasia was the more severely affected type and cortical lesions were more likely to affect language function than subcortical lesions.

Automated MRI-based classification of primary progressive aphasia variants

Degeneration of language regions in the dominant hemisphere can result in primary progressive aphasia (PPA), a clinical syndrome characterized by progressive deficits in speech and/or language function. Recent studies have identified three variants of PPA: progressive non-fluent aphasia (PNFA), semantic dementia (SD) and logopenic progressive aphasia (LPA). Each variant is associated with characteristic linguistic features, distinct patterns of brain atrophy, and different likelihoods of particular underlying pathogenic processes, which makes correct differential diagnosis highly clinically relevant. Evaluation of linguistic behavior can be challenging for non-specialists, and neuroimaging findings in single subjects are often difficult to evaluate by eye. We investigated the utility of automated structural MR image analysis to discriminate PPA variants (N=86) from each other and from normal controls (N=115). T1 images were preprocessed to obtain modulated grey matter (GM) images. Feature selection was performed with principal components analysis (PCA) on GM images as well as images of lateralized atrophy. PC coefficients were classified with linear support vector machines, and a cross-validation scheme was used to obtain accuracy rates for generalization to novel cases. The overall mean accuracy in discriminating between pairs of groups was 92.2%. For one pair of groups, PNFA and SD, we also investigated the utility of including several linguistic variables as features. Models with both imaging and linguistic features performed better than models with only imaging or only linguistic features. These results suggest that automated methods could assist in the differential diagnosis of PPA variants, enabling therapies to be targeted to likely underlying etiologies.

Factors associated with life satisfaction in Japanese stroke outpatients

PURPOSE

To measure life satisfaction in Japanese stroke outpatients and randomly-sampled community residents and to investigate variables influencing their life satisfaction.

METHOD

Data on the demographic and clinical profiles, Satisfaction in Daily Life (SDL), other measurements, were obtained from 869 stroke outpatients (552 males, 317 females) and 748 community-dwelling elderly (360 males, 388 females), aged 55 years and older. Differences in categorical variables and continuous variables were tested by chi-square test and ANCOVA with age as the covariate, respectively.

RESULTS

The 11 SDL items were subjected to a factor analysis, which extracted two factors. Factor 1 (F1), labeled as 'satisfaction with one's own abilities', included satisfaction with housework, self-care, gait, physical health, hobby and leisure, social intercourse and mental health. Factor 2 (F2), 'satisfaction with external factors', included satisfaction with partner/ family relationship, economic state and social security, and house facilities. Both F1 and F2 scores were significantly lower for stroke outpatients (M = 19.7 and 10.9, respectively) than for community-dwelling elderly (M = 28.2 and 12.0, respectively) (p < 0.001). Living conditions were significantly associated with F2, but not with F1. Males living alone scored lowest on F2 than the others for both groups. Among stroke outpatients, both F1 and F2 scores differed significantly by the type of hemiparesis and the severity of aphasia.

CONCLUSIONS

SDL of stroke outpatients, which was lower than community-dwelling elderly, differed by the type of hemiparesis, the severity of aphasia, and living conditions. The effects of living conditions might vary with gender.

Proxy and self-report agreement on the Stroke and Aphasia Quality of Life Scale-39

BACKGROUND AND PURPOSE

Health related quality of life outcomes are increasingly used to measure the effectiveness of stroke interventions. People with severe aphasia after stroke may be unable to self-report on such measures, necessitating the use of proxy respondents. We explored the level of agreement between people with aphasia (PWA) and their proxies on the Stroke and Aphasia Quality of Life Scale (SAQOL-39) and whether this agreement is influenced by demographic variables and proxy levels of depression and carer strain.

METHODS

People with chronic aphasia (> or = 6 months post stroke) were recruited through the UK national charity for PWA. They were interviewed on the SAQOL-39 and their nominated proxies were interviewed on the SAQOL-39, the General Health Questionnaire and the Caregiver Strain Index. Proxy respondents had to be > or = 18 years of age, see the person with aphasia at least twice a week and have no known severe mental health problems or cognitive decline.

RESULTS

50 of 55 eligible pairs (91%) took part in the study. Proxies rated PWA as more severely affected than PWA rated themselves. The SDs of the difference scores were large and the difference was significant for three of the four SAQOL-39 domains and the overall mean (p < or = 0.01). However, the bias as indicated by effect sizes was small to moderate (0.2-0.5). The strength of the agreement was excellent for the overall SAQOL-39 and the physical domain (intra-class correlation coefficient ICC 0.8), good for the psychosocial and communication domains (0.7) and fair for the energy domain (0.5). Demographic variables and proxy's mood and carer strain did not affect the level of agreement.

CONCLUSIONS

For group comparisons, proxy respondents who are in frequent contact with people with chronic aphasia can reliably report on their health related quality of life, using the SAQOL-39. Although there are significant differences between PWA and proxy responses, the magnitude of this difference is small to moderate.

Dysphagia in stroke: Development of a standard method to examine swallowing recovery

This study began development of a standard method that uses the videofluoroscopic swallow study for evaluation of swallowing recovery after stroke based on a definition of dysphagia derived from three domains: bolus timing, bolus direction, and bolus clearance. Two experiments were conducted: one that defined normal versus disordered swallowing based on the range of scores in a sample of healthy adults (n = 13), and one that applied these thresholds to nine stroke patients to identify the presence of dysphagia. Results indicate that acute and protracted dysphagia may be more accurately detected by identifying abnormalities on multiple objective measures of swallowing rather than on laryngeal penetration or aspiration alone. Results indicate that our selected measures and use of healthy control subjects to establish normal thresholds may eventually contribute to the definition and differentiation of dysphagic and nondysphagic patients. Further research with a broader sample of healthy controls and stroke patients is mandatory.

[Neurolinguistic approaches to aphasia]

Aphasias are language pathologies, therefore the acquaintance of its structure is required for proper understanding. Language is a cultural interaction system, logical, set much above common natural. It separates the symbolic function, which establishes the distinction between significant and signification. We establish a neurolinguistic classification of aphasias, refuting improper expressions. We broach the wrongly called "conduction aphasia". We detach the unit of speech act and we distinguish the existence of a joint project that sheds light on all sentences brought forth. The complex texture of the "transcorticalism" qualify is analyzed. Aphasia field and some forms of its unfolding are questions aborded under the light of basic neurolinguistic concepts. We detach the unit of speech act and we distinguish the existence of a common project that sheds light on all sentences brought forth.

Lesion correlates of conversational speech production deficits

We assess brain areas involved in speech production using a recently developed lesion-symptom mapping method (voxel-based lesion-symptom mapping, VLSM) with 50 aphasic patients with left-hemisphere lesions. Conversational speech was collected through a standardized biographical interview, and used to determine mean length of utterance in morphemes (MLU), type token ratio (TTR) and overall tokens spoken for each patient. These metrics are used as indicators of grammatical complexity, semantic variation, and amount of speech, respectively. VLSM analysis revealed that damage to the anterior insula was predictive of low scores on MLU and tokens, consistent with prior findings of the role of this region in speech production [Dronkers, N. F. (1996). A new brain region for coordinating speech articulation. Nature, 384(6605), 159-161]. Additionally, the inferior frontal gyrus, sensorimotor and anterior temporal areas were also associated with lower scores on both of these measures. Overall, token and MLU maps were highly similar, suggesting an overlap between grammatical language networks and overall fluency. TTR maps also shared some portions of this network, but damage to posterior temporal regions also reduced scores on this measure. These results represent the first voxel-based lesion analysis of speech production performance in aphasic patients.

Clinicopathological and imaging correlates of progressive aphasia and apraxia of speech

Apraxia of speech (AOS) is a motor speech disorder characterized by slow speaking rate, abnormal prosody and distorted sound substitutions, additions, repetitions and prolongations, sometimes accompanied by groping, and trial and error articulatory movements. Although AOS is frequently subsumed under the heading of aphasia, and indeed most often co-occurs with aphasia, it can be the predominant or even the sole manifestation of a degenerative neurological disease. In this study we determine whether the clinical classifications of aphasia and AOS correlated with pathological diagnoses and specific biochemical and anatomical structural abnormalities. Seventeen cases with initial diagnoses of a degenerative aphasia or AOS were re-classified independently by two speech-language pathologists--blinded to pathological and biochemical findings--into one of five operationally defined categories of aphasia and AOS. Pathological diagnoses in the 17 cases were progressive supranuclear palsy in 6, corticobasal degeneration in 5, frontotemporal lobar degeneration with ubiquitin-only-immunoreactive changes in 5 and Pick's disease in 1. Magnetic resonance imaging analysis using voxel-based morphometry (VBM), and single photon emission tomography were completed, blinded to the clinical diagnoses, and clinicoimaging and clinicopathological associations were then sought. Interjudge clinical classification reliability was 87% (kappa = 0.8) for all evaluations. Eleven cases had evidence of AOS, of which all (100%) had a pathological diagnosis characterized by underlying tau biochemistry, while five of the other six cases without AOS did not have tau biochemistry (P = 0.001). A majority of the 17 cases had more than one yearly evaluation, demonstrating the evolution of the speech and language syndromes, as well as motor signs. VBM revealed the premotor and supplemental motor cortices to be the main cortical regions associated with AOS, while the anterior peri-sylvian region was associated with non-fluent aphasia. Refining the classification of the degenerative aphasias and AOS may be necessary to improve our understanding of the relationships among behavioural, pathological and imaging correlations.

Adult crossed aphasia in dextrals revisited

The clinical study of crossed aphasia in dextrals (CAD) may shed light on the discreteness and modularity of several cognitive functions, such as language, gestures and visual spatial abilities, with respect to hemispheric lateralisation. Since 1975 over 180 cases have been described, employing, however, different criteria of assessment and classification. The purpose of this paper is to review them and to propose a set of diagnostic criteria that may be useful to single out a series of reliable CAD cases on which research can be safely carried out. A detailed analysis of such series is dealt with in terms of a number of characteristics concerning both the language disorder and the associated nonverbal cognitive impairments.

Variability in subcortical aphasia is due to variable sites of cortical hypoperfusion

A variety of fluent and nonfluent aphasias have been reported after left basal ganglia stroke. It has been speculated that this heterogeneity may reflect variations in cortical hypoperfusion resulting from large vessel stenosis. To test this hypothesis, a consecutive series of 24 patients with left caudate infarct identified with diffusion-weighted imaging underwent language testing and perfusion-weighted imaging < 24h from onset of symptoms. Specific regions in perisylvian cortex were rated for the percentage of the region that was hypoperfused. Aphasia type was determined on the basis of speech fluency, comprehension, and repetition performance on the language tests. Association between aphasia type/language impairment and regions of hypoperfusion were identified with Fisher's exact tests. Results demonstrated that in patients with acute left caudate infarct, the presence and type of aphasia reflected regions of hypoperfusion, and generally followed predictions based on chronic lesion studies, regarding anatomical lesions associated with classic aphasia types.

Communicative Responsibility and Semantic Task in the Language of Adults with Dementia

A probe technique requiring convergent and divergent semantic behavior and representing five levels of communicative responsibility served as the research tool. Stimuli were presented to adults identified as having Alzheimer disease or multi-infarct dementia. Within each group differences were observed on the semantic task (convergent and divergent) and on communicative responsibility. Group characteristics are compared with data previously published in 1994 on aphasic and schizophrenic adults responding to the same stimuli.

Grammaticality Judgment in Aphasia: Deficits Are Not Specific to Syntactic Structures, Aphasic Syndromes, or Lesion Sites

We examined the abilities of aphasic patients to make grammaticality judgments on English sentences instantiating a variety of syntactic structures. Previous studies employing this metalinguistic task have suggested that aphasic patients typically perform better on grammaticality judgment tasks than they do on sentence comprehension tasks, a finding that has informed the current view that grammatical knowledge is relatively preserved in agrammatic aphasia. However, not all syntactic structures are judged equally accurately, and several researchers have attempted to provide explanatory principles to predict which structures will pose problems to agrammatic patients. One such proposal is Grodzinsky and Finkel's (1998) claim that agrammatic aphasics are selectively impaired in their ability to process structures involving traces of maximal projections. In this study, we tested this claim by presenting patients with sentences with or without such traces, but also varying the level of difficulty of both kinds of structures, assessed with reference to the performance of age-matched and young controls. We found no evidence that agrammatic aphasics, or any other subgroup, are selectively impaired on structures involving traces: Some judgments involving traces were made quite accurately, whereas other judgments not involving traces were made very poorly. Subgroup analyses revealed that patient groups and agematched controls had remarkably similar profiles of performance across sentence types, regardless of whether the patients were grouped based on Western Aphasia Battery classification, an independent screening test for agrammatic comprehension, or lesion site. This implies that the pattern of performance across sentence types does not result from any particular component of the grammar, or any particular brain region, being selectively compromised. Lesion analysis revealed that posterior temporal areas were more reliably implicated in poor grammaticality judgment performance than anterior areas, but poor performance was also observed with some anterior lesions, suggesting that areas important for syntactic processing are distributed throughout the left peri-sylvian region.

Language processing: functional organization and neuroanatomical basis

Earlier formulations of the relation of language and the brain provided oversimplified accounts of the nature of language disorders, classifying patients into syndromes characterized by the disruption of sensory or motor word representations or by the disruption of syntax or semantics. More recent neuropsychological findings, drawn mainly from case studies, provide evidence regarding the various levels of representations and processes involved in single-word and sentence processing. Lesion data and neuroimaging findings are converging to some extent in providing localization of these components of language processing, particularly at the single-word level. Much work remains to be done in developing precise theoretical accounts of sentence processing that can accommodate the observed patterns of breakdown. Such theoretical developments may provide a means of accommodating the seemingly contradictory findings regarding the neural organization of sentence processing.

Action comprehension in aphasia: linguistic and non-linguistic deficits and their lesion correlates

We tested aphasic patients' comprehension of actions to examine processing deficits in the linguistic and non-linguistic domains and their lesion correlates. Twenty-nine left-hemisphere injured patients and 18 age-matched control subjects matched pictured actions (with the objects missing) or their linguistic equivalents (printed sentences with the object missing) to one of two visually-presented pictures of objects. Aphasic patients performed poorly not only in the linguistic domain but also in the non-linguistic domain. A subset of the patients, largely consisting of severe and non-fluent aphasics, showed a greater deficit in the linguistic domain compared with the non-linguistic domain and across the patient group, deficits in the linguistic and non-linguistic domains were not tightly correlated. Poor performance in pantomime interpretation was associated with lesions in the inferior frontal, premotor and motor cortex, a portion of somatosensory cortex, and the caudate, while poor reading comprehension of actions was associated with lesions around the anterior superior temporal lobe, the anterior insula and the anterior portion of the inferior parietal lobe. Lesion size did not correlate with deficits. The lesion results for pantomime interpretation deficits demonstrate that lesions in the frontal component of the human analog of the "mirror neuron system" are associated with deficits in non-linguistic action understanding. For reading comprehension deficits, the lesion correlates are brain areas known to be involved in linguistic tasks including sentence processing and speech articulation; the parietal lesion site may also correspond to a subpart of the human mirror neuron system. These results indicate that brain areas important for the production of language and action are also recruited in their comprehension. Similar findings have been reported in electrophysiological and neuroimaging studies. Our findings now also lend neuropsychological support to an embodied view of brain organization for action processing.

Aphasia after stroke: type, severity and prognosis. The Copenhagen aphasia study

AIM

To determine the types, severity and evolution of aphasia in unselected, acute stroke patients and evaluate potential predictors for language outcome 1 year after stroke.

METHODS

270 acute stroke patients with aphasia (203 with first-ever strokes) were included consecutively and prospectively from three hospitals in Copenhagen, Denmark, and assessed with the Western Aphasia Battery. The assessment was repeated 1 year after stroke.

RESULTS

The frequencies of the different types of aphasia in acute first-ever stroke were: global 32%, Broca's 12%, isolation 2%, transcortical motor 2%, Wernicke's 16%, transcortical sensory 7%, conduction 5% and anomic 25%. These figures are not substantially different from what has been found in previous studies of more or less selected populations. The type of aphasia always changed to a less severe form during the first year. Nonfluent aphasia could evolve into fluent aphasia (e.g., global to Wernicke's and Broca's to anomic), whereas a fluent aphasia never evolved into a nonfluent aphasia. One year after stroke, the following frequencies were found: global 7%, Broca's 13%, isolation 0%, transcortical motor 1%, Wernicke's 5%, transcortical sensory 0%, conduction 6% and anomic 29%. The distribution of aphasia types in acute and chronic aphasia is, thus, quite different. The outcome for language function was predicted by initial severity of the aphasia and by the initial stroke severity (assessed by the Scandinavian Stroke Scale), but not by age, sex or type of aphasia. Thus, a scoring of general stroke severity helps to improve the accuracy of the prognosis for the language function. One year after stroke, fluent aphasics were older than nonfluent aphasics, whereas such a difference was not found in the acute phase.

Subcortical aphasia: three different language disorder syndromes?

The study analyses clinical presentation of language functions of 32 patients with subcortical aphasia induced by stroke. The patients have been divided into three groups according to neuroanatomic localization of the lesion, defined by CT and MRI examination (striato-capsular aphasia, aphasia associated with white matter paraventricular lesions and thalamic aphasia). The following batteries and tests were used: the neurologic examination, CT scan, MRI, Doppler ultrasound, Mini Mental State Examination, Boston Diagnostic Aphasia Examination (BDAE), Boston Naming Test (BNT), Token Test and Verbal Fluency Test. Clinical presentation of subcortical aphasias is characterized with preserved repetition, however, some groups differ by certain specific features of language impairment. Striato-capsular aphasia and aphasia associated with white matter paraventricular lesions are characterized with lack of speech fluency, occurrence of literary paraphasias, mainly preserved comprehension and naming. Thalamic aphasia, however, is characterized with fluent output, impaired comprehension and naming with predominant verbal paraphasias. The specific features of language impairment suggest that subcortical structures contribute to language organization. Considering the results of language tests we presume that the most prominent feature in striato-capsular aphasia is phonetic impairment of language, opposite to thalamic aphasia where lexical-sematic processing seems to be affected.