Search

Most naming error lesion-symptom mapping (LSM) studies have focused on semantic and/or phonological errors. Anomic individuals also produce unrelated word errors, which may be linked to semantic or modality-independent lexical deficits. To investigate the neural underpinnings of rarely-studied unrelated errors, we conducted LSM analyses in 100 individuals hospitalized with a left hemisphere stroke who completed imaging protocols and language assessments. We used least absolute shrinkage and selection operator regression to capture relationships between naming errors and dysfunctional brain tissue metrics (regional damage or hypoperfusion in vascular territories) in two groups: participants with and without impaired single-word auditory comprehension. Hypoperfusion—particularly within the parietal lobe—was an important error predictor, especially for the unimpaired group. In both groups, higher unrelated error proportions were associated with primarily ventral stream damage, the language route critical for processing meaning. Nonetheless, brain metrics implicated in unrelated errors were distinct from semantic error correlates.

INTRODUCTION: Aphasia is a debilitating language disorder and even mild forms of aphasia can negatively affect functional outcomes, mood, quality of life, social participation, and the ability to return to work. Language deficits after post-stroke aphasia are heterogeneous. AREAS COVERED: The first part of this manuscript reviews the traditional syndrome-based classification approach as well as recent advances in aphasia classification that incorporate automatic speech recognition for aphasia classification. The second part of this manuscript reviews the behavioral approaches to aphasia treatment and recent advances such as non-invasive brain stimulation techniques and pharmacotherapy options to augment the effectiveness of behavioral therapy. EXPERT OPINION: Aphasia diagnosis has largely evolved beyond the traditional approach of classifying patients into specific syndromes and instead focuses on individualized patient profiles. In the future there is a great need for more large scale randomized, double-blind, placebo-controlled clinical trials of behavioral treatments, non-invasive brain stimulation and medications to boost aphasia recovery.

ObjectiveTo determine whether right ventral stream and limbic structures (including posterior superior temporal gyrus [STG], STG, temporal pole, inferior frontal gyrus pars orbitalis, orbitofrontal cortex, amygdala, anterior cingulate, gyrus, and the sagittal stratum) are implicated in emotional prosody identification.MethodsPatients with MRI scans within 48 hours of unilateral right hemisphere ischemic stroke were enrolled. Participants were presented with 24 sentences with neutral semantic content spoken with happy, sad, angry, afraid, surprised, or bored prosody and chose which emotion the speaker was feeling based on tone of voice. Multivariable linear regression was used to identify individual predictors of emotional prosody identification accuracy from a model, including percent damage to proposed right hemisphere structures, age, education, and lesion volume across all emotions (overall emotion identification) and 6 individual emotions. Patterns of recovery were also examined at the chronic stage.ResultsThe overall emotion identification model was significant (adjusted r2 = 0.52; p = 0.043); greater damage to right posterior STG (p = 0.038) and older age (p = 0.009) were individual predictors of impairment. The model for recognition of fear was also significant (adjusted r2 = 0.77; p = 0.002), with greater damage to right amygdala (p = 0.047), older age (p < 0.001), and less education (p = 0.005) as individual predictors. Over half of patients with chronic stroke had residual impairments.ConclusionsRight posterior STG in the right hemisphere ventral stream is critical for emotion identification in speech. Patients with stroke with damage to this area should be assessed for emotion identification impairment.

BACKGROUND: Naming impairment is commonly noted in individuals with aphasia. However, object naming receives more attention than action naming. Furthermore, most studies include participants with aphasia due to only one aetiology, commonly stroke. We developed a new assessment, the Hopkins Action Naming Assessment (HANA), to evaluate action naming impairments. AIMS: Our aims were to show that the HANA is a useful tool that can (1) identify action naming impairments and (2) be used to investigate the neural substrates underlying naming. We paired the HANA with the Boston Naming Test (BNT) to compare action and object naming. We considered participants with aphasia due to primary progressive aphasia (PPA) or acute left hemisphere stroke to provide a more comprehensive picture of brain-behaviour relationships critical for naming. Behaviourally, we hypothesised that there would be a double dissociation between object and action naming performance. Neuroanatomically, we hypothesised that different neural substrates would be implicated in object vs. action naming and that different lesion-deficit associations would be identified in participants with PPA vs. acute stroke. METHODS & PROCEDURES: Participants (N=138 with PPA, N=37 with acute stroke) completed the BNT and HANA. Behavioural performance was compared. A subset of participants (N=31 with PPA, N=37 with acute stroke) provided neuroimaging data. The whole brain was automatically segmented into regions of interest (ROIs). For participants with PPA, the image variables were the ROI volumes, normalised by the brain volume. For participants with acute stroke, the image variables were the percentage of each ROI affected by the lesion. The relationship between ROIs likely to be involved in naming performance was modelled with LASSO regression. OUTCOMES & RESULTS: Behavioural results showed a double dissociation in performance: in each group, some participants displayed intact performance relative to healthy controls on actions but not objects and/or significantly better performance on actions than objects, while others showed the opposite pattern. These results support the need to assess both objects and actions when evaluating naming deficits. Neuroimaging results identified different regions associated with object vs. action naming, implicating overlapping but distinct networks of regions. Furthermore, results differed for participants with PPA vs. acute stroke, indicating that critical information may be missed when only one aetiology is considered. CONCLUSIONS: Overall, the study provides a more comprehensive picture of the neural bases of naming, underscoring the importance of assessing both objects and actions and considering different aetiologies of damage. It demonstrates the utility of the HANA.

Difficulty recognizing affective prosody (receptive aprosodia) can occur following right hemisphere damage (RHD). Not all individuals spontaneously recover their ability to recognize affective prosody, warranting behavioral intervention. However, there is a dearth of evidence-based receptive aprosodia treatment research in this clinical population. The purpose of the current study was to investigate an explicit training protocol targeting affective prosody recognition in adults with RHD and receptive aprosodia. Eighteen adults with receptive aprosodia due to acute RHD completed affective prosody recognition before and after a short training session that targeted proposed underlying perceptual and conceptual processes. Behavioral impairment and lesion characteristics were investigated as possible influences on training effectiveness. Affective prosody recognition improved following training, and recognition accuracy was higher for pseudo- vs. real-word sentences. Perceptual deficits were associated with the most posterior infarcts, conceptual deficits were associated with frontal infarcts, and a combination of perceptual-conceptual deficits were related to temporoparietal and subcortical infarcts. Several right hemisphere ventral stream regions and pathways along with frontal and parietal hypoperfusion predicted training effectiveness. Explicit acoustic-prosodic-emotion training improves affective prosody recognition, but it may not be appropriate for everyone. Factors such as linguistic context and lesion location should be considered when planning prosody training.

BACKGROUND: Individuals with primary progressive aphasia (PPA) develop visuospatial deficits over time, and those with logopenic variant (lvPPA) are at greatest risk of developing such deficits. However, not all previous studies of visuospatial deficits in PPA have ensured equivalent duration of disease across variants and few have measured deficits longitudinally. AIMS: The aims of our study were to: 1) investigate differences in baseline visuomotor figure construction, visual figure delayed recall, and figure recognition in PPA variants with similar symptom duration at baseline, and 2) explore patterns of decline in these areas. METHODS & PROCEDURES: Ninety-three individuals with PPA [39 lvPPA, 24 nonfluent agrammatic PPA (nfaPPA), and 30 semantic variant PPA (svPPA)] were administered the Benson Complex Figure Copy, Benson Complex Figure Delay (Recall), and Benson Figure Recognition. Thirty individuals completed this testing 3 to 47 months post baseline. OUTCOME & RESULTS: Participants with lvPPA and svPPA showed lower mean scores than those with nfaPPA on visual figure delayed recall at baseline, even though there were no differences in estimated time from disease onset or correlation with disease severity as reflected by naming performance, F(2, 90) = 5.78, p < .004. Those with nfaPPA performed significantly better than those with lvPPA, Tukey HSD p < .05, and those with svPPA, Tukey HSD p < .01. There were no differences between variants in rate of decline in visuomotor figure construction, visual figure delayed recall, and figure recognition. CONCLUSIONS: These findings revealed relatively spared visuospatial memory in nfaPPA, which may aid in the differential diagnosis of PPA and contribute to designing therapy or compensatory strategies

BACKGROUND: Language characteristics of logopenic variant primary progressive aphasia (lvPPA) are well-defined; however, there is a paucity of research investigating behavioral characteristics specific to this subtype. OBJECTIVE: To determine the relationship between language abilities and behavior across the three variants of primary progressive aphasia (PPA). We hypothesized that, associations between language and behavior (measured by the Frontal Behavioral Inventory; FBI) would vary across subtypes due to distinct neuropathologies. More specifically, we hypothesized that the severity of language and behavioral problems would be independent in semantic (svPPA) and nonfluent (nfaPPA) PPA subtypes and related in lvPPA. METHODS: We used Spearman’s rank correlation coefficients to investigate correlations between language and behavioral scores. Total scores on the FBI-mod significantly correlated with scores on the Pyramids and Palm Trees Test (r = −0.589, p = 0.001), a Sentence Repetition test (r = −0.559, p = 0.003), and the Hopkins Assessment of Naming Actions (r = −0.550, p = 0.003) in lvPPA. CONCLUSIONS: Results were interpreted as evidence that individuals with lvPPA show a correlation between language scores and negative behavior scores because they do not develop negative behaviors until language deficits are severe, consistent with the common underlying cause of lvPPA—Alzheimer’s disease. In contrast, behavioral symptoms are early symptoms in semantic variant PPA and nonfluent agrammatic PPA. Such findings are crucial to clinical care because, after receiving a PPA diagnosis, patients, families and caregivers often seek prognoses specific to language and behavior, especially when considering the progressive nature of this disease.

Broca’s area is frequently implicated in sentence comprehension but its specific role is debated. Most lesion studies have investigated deficits at the chronic stage. We aimed (1) to use acute imaging to predict which left hemisphere stroke patients will recover sentence comprehension; and (2) to better understand the role of Broca’s area in sentence comprehension by investigating acute deficits prior to functional reorganization. We assessed comprehension of canonical and noncanonical sentences in 15 patients with left hemisphere stroke at acute and chronic stages. LASSO regression was used to conduct lesion symptom mapping analyses. Patients with more severe word-level comprehension deficits and a greater proportion of damage to supramarginal gyrus and superior longitudinal fasciculus were likely to experience acute deficits prior to functional reorganization. Broca’s area was only implicated in chronic deficits. We propose that when temporoparietal regions are damaged, intact Broca’s area can support syntactic processing after functional reorganization occurs.

Introduction Speakers naturally produce prosodic variations depending on their emotional state. Receptive prosody has several processing stages. We aimed to conduct lesion-symptom mapping to determine whether damage (core infarct or hypoperfusion) to specific brain areas was associated with receptive aprosodia or with impairment at different processing stages in individuals with acute right hemisphere stroke. We also aimed to determine whether different subtypes of receptive aprosodia exist that are characterized by distinctive behavioral performance patterns. Methods Twenty patients with receptive aprosodia following right hemisphere ischemic stroke were enrolled within five days of stroke; clinical imaging was acquired. Participants completed tests of receptive emotional prosody, and tests of each stage of prosodic processing (Stage 1: acoustic analysis; Stage 2: analyzing abstract representations of acoustic characteristics that convey emotion; Stage 3: semantic processing). Emotional facial recognition was also assessed. LASSO regression was used to identify predictors of performance on each behavioral task. Predictors entered into each model included 14 right hemisphere regions, hypoperfusion in four vascular territories as measured using FLAIR hyperintense vessel ratings, lesion volume, age, and education. A k-medoid cluster analysis was used to identify different subtypes of receptive aprosodia based on performance on the behavioral tasks. Results Impaired receptive emotional prosody and impaired emotional facial expression recognition were both predicted by greater percent damage to the caudate. The k-medoid cluster analysis identified three different subtypes of aprosodia. One group was primarily impaired on Stage 1 processing and primarily had frontotemporal lesions. The second group had a domain-general emotion recognition impairment and maximal lesion overlap in subcortical areas. Finally, the third group was characterized by a Stage 2 processing deficit and had lesion overlap in posterior regions. Conclusions Subcortical structures, particularly the caudate, play an important role in emotional prosody comprehension. Receptive aprosodia can result from impairments at different processing stages.

Background It is estimated that ∼30% of stroke survivors have aphasia, a language disorder resulting from damage to left-hemisphere language networks. In acute care settings, efficient identification of aphasia is critical, but there is a paucity of efficient bedside assessments. Objective To determine whether objective measures on a picture description task administered within 48 hours post stroke (a) predict language recovery, (b) estimate left-hemisphere lesion volume and location, and (c) correlate with other bedside language assessments. Method Behavioral data were scored at acute and chronic time points. Neuroimaging data were used to determine associations between the picture description task, other language assessments, and lesion volume and location. Results Acute content units, age, and total lesion volume predicted communication recovery; F3,18 = 3.98, P = 0.024; r = 0.40. Significant correlations were found between the picture description task and lesion volume and location. Picture description outcomes were also associated with other clinical language assessments. Discussion This picture description task quickly predicted the language performance (communication recovery and outcome) for patients who suffered a left-hemisphere stroke. Picture description task measures correlated with damage in the left hemisphere and with other, more time-consuming and cumbersome language assessments that are typically administered acutely at bedside. Conclusion The predictive value of this picture description task and correlations with existing language assessments substantiate the clinical importance of a reliable yet rapid bedside measure for acute stroke patients that can be administered by a variety of health care professionals.

Objective To determine the contribution of white matter hyperintensities (WMH) to language deficits while accounting for cortical atrophy in individuals with primary progressive aphasia (PPA). Method Forty-three individuals with PPA completed neuropsychological assessments of nonverbal semantics, naming, and sentence repetition plus T2-weighted and fluid-attenuated inversion recovery scans. Using three visual scales, we rated WMH and cerebral ventricle size for both scan types. We used Spearman correlations to evaluate associations between the scales and scans. To test whether visual ratings-particularly of WMH-are associated with language, we compared a base model (including gray matter component scores obtained via principal component analysis, age, and days between assessment and MRI as independent variables) with full models (ie, the base model plus visual ratings) for each language variable. Results Visual ratings were significantly associated within and between scans and were significantly correlated with age but not with other vascular risk factors. Only the T2 scan ratings were associated with language abilities. Specifically, controlling for other variables, poorer naming was significantly related to larger ventricles (P = 0.033) and greater global (P = 0.033) and periventricular (P = 0.049) WMH. High global WMH (P = 0.034) were also correlated with worse sentence repetition skills. Conclusion Visual ratings of global brain health were associated with language deficits in PPA independent of cortical atrophy and age. While WMH are not unique to PPA, measuring WMH in conjunction with cortical atrophy may elucidate more accurate brain structure-behavior relationships in PPA than cortical atrophy measures alone.

This study investigated the interaction of prosody and thematic fit/plausibility information during the processing of sentences containing temporary early closure (correct) or late closure (incorrect) syntactic ambiguities using event-related potentials (ERPs). Early closure sentences with congruent and incongruent prosody were presented where the temporarily ambiguous NP was either a plausible or an implausible continuation for the subordinate verb (e.g. “While the band played the song/beer pleased all the customers.”). N400 and P600 components were examined at critical points in each condition. The CPS was examined in sentences with congruent prosody. Prosodic and thematic fit cues interacted immediately (N400–P600) at the implausible NP (beer), when it was paired with incongruent prosody. Incongruent prosody paired with a plausible NP (song) resulted in garden-path effects (N400–P600) at the critical verb (pleased). These findings provide strong evidence that prosodic and thematic fit/plausibility cues interact to aid the parser in syntactic structure building.

Language recovery following acute left hemisphere (LH) stroke is notoriously difficult to predict. Global language measures (e.g., overall aphasia severity) and gross lesion metrics (e.g., size) provide incomplete recovery predictions. In this study, we test the hypothesis that the types of naming errors patients produce, combined with dysfunctional brain tissue metrics, can provide additional insight into recovery following acute LH stroke. One hundred forty-eight individuals who were hospitalized with a new LH stroke completed clinical neuroimaging and assessments of naming and global language skills. A subset of participants again completed language testing at subacute, early (5–7 months post-stroke), and late (≥11 months post-stroke) chronic phases. At each time point, we coded naming errors into four types (semantic, phonological, mixed and unrelated) and determined error type totals and proportions. Dysfunctional tissue measures included the percentage of damage to language network regions and hypoperfusion in vascular territories. A higher proportion of semantic errors was associated with better acute naming, but higher proportions of other error types was related to poorer accuracy. Naming and global language skills significantly improved over time , but naming error profiles did not change. Fewer acute unrelated errors and less damage to left angular gyrus resulted in optimal naming and language recovery by the final testing time point, yet patients with more acute errors and damage to left middle temporal gyrus demonstrated the greatest increases in language over time. These results illustrate that naming error profiles, particularly unrelated errors, add power to predictions of language recovery after stroke., Highlights • In acute stroke, a high proportion of semantic errors was related to better naming. • Higher proportions of other errors were related to lower acute naming skills. • Over time, naming and global language improved, but error patterns did not change. • The strongest recovery predictors were unrelated errors and temporoparietal integrity.

The intent and feelings of the speaker are often conveyed less by what they say than by how they say it, in terms of the affective prosody - modulations in pitch, loudness, rate, and rhythm of the speech to convey emotion. Here we propose a cognitive architecture of the perceptual, cognitive, and motor processes underlying recognition and generation of affective prosody. We developed the architecture on the basis of the computational demands of the task, and obtained evidence for various components by identifying neurologically impaired patients with relatively specific deficits in one component. We report analysis of performance across tasks of recognizing and producing affective prosody by four patients (three with right hemisphere stroke and one with frontotemporal dementia). Their distinct patterns of performance across tasks and quality of their abnormal performance provides preliminary evidence that some of the components of the proposed architecture can be selectively impaired by focal brain damage.

Event-related potentials (ERPs) were used to examine how individuals with aphasia and a group of age-matched controls use prosody and thematic fit information in sentences containing temporary syntactic ambiguities. Two groups of individuals with aphasia were investigated; those demonstrating relatively good sentence comprehension whose primary language difficulty is anomia (Individuals with Anomic Aphasia (IWAA)), and those who demonstrate impaired sentence comprehension whose primary diagnosis is Broca’s aphasia (Individuals with Broca’s Aphasia (IWBA). The stimuli had early closure syntactic structure and contained a temporary early closure (correct) / late closure (incorrect) syntactic ambiguity. The prosody was manipulated to either be congruent or incongruent, and the temporarily ambiguous NP was also manipulated to either be a plausible or an implausible continuation for the subordinate verb (e.g., “While the band played the song/the beer pleased all the customers.”). It was hypothesized that an implausible NP in sentences with incongruent prosody may provide the parser with a plausibility cue that could be used to predict syntactic structure. The individuals with aphasia were broken into a group of High Comprehenders and a group of Low Comprehenders depending on the severity of their sentence comprehension deficit. The results revealed that incongruent prosody paired with a plausibility cue resulted in an N400-P600 complex at the implausible NP (the beer) in both the controls and the IWAAs, yet incongruent prosody without a plausibility cue resulted in an N400-P600 at the critical verb (pleased) only in healthy controls. IWBAs did not show evidence of N400 or P600 effects at the ambiguous NP or critical verb, although they did show evidence of a delayed N400 effect at the sentence-final word in sentences with incongruent prosody. These results suggest that IWAAs have difficulty integrating prosodic cues with underlying syntactic structure when lexical-semantic information is not available to aid their parse. IWBAs have difficulty integrating both prosodic and lexical-semantic cues with syntactic structure, likely due to a processing delay.

We aimed to identify neural regions where ischemia acutely after stroke is associated with impairment in phoneme discrimination, and to determine whether such deficits are associated with impairment of spoken word comprehension. We evaluated 33 patients within 48 h of left hemisphere ischemic stroke onset with tests of phoneme discrimination and word-picture matching. We identified Pearson correlations between accuracy in phoneme discrimination and accuracy of word comprehension and identified areas where the percentage of infarcted tissue was associated with severity of phoneme discrimination deficit. We found that 54% had deficits in phoneme discrimination relative to healthy controls. Accuracy in phoneme discrimination correlated with accuracy on word comprehension tests. Damage to left intraparietal sulcus and hypoperfusion and/or infarct of left superior temporal gyrus were associated with phoneme discrimination deficits acutely, although patients with these lesions showed improvement or resolution of the deficit by six months.