Hemisphere Brain Damage Research Articles

Computed tomography findings as early predictors of long-term language impairment in patients with traumatic brain injury

This study aims to assess the relationship between computed tomography (CT) findings, during the acute phase of hospitalization, and long-term language impairment in people with traumatic brain injury (TBI). Another aim was to assess the receptive and expressive abilities of subjects with TBI based on the location of the injury. This is a retrospective observational study including 49 participants with TBI due to war injuries. The Arabic Diagnostic Aphasia Battery (A-DAB-1) was administered to the participants and the Helsinki CT score was computed to quantify brain damage. The results showed that the Helsinki CT score was negatively correlated with the total score of the A-DAB-1 (r = −0.544, p-value < 0.0001). Simple linear regression supported such findings and reflected an inversely proportional relationship between both variables (p-value < 0.0001). When compared with subjects having right hemisphere damage, subjects with left hemisphere and bilateral brain damage performed more poorly on language tasks respectively as follows: A-DAB-1 overall score (92.08-66.08-70.28, p-value = 0.021), Content of descriptive speech (9.57-6.69-7.22, p-value = 0.034), Verbal fluency (6.57-3.54-3.89, p-value = 0.002), Auditory comprehension (9.71-7.54-7.78, p-value = 0.039), Complex auditory commands (9.71-7.65-7.56, p-value = 0.043), Repetition (9.75-7.08-7.61, p-value = 0.036), Naming (9.93-7.15-8.11, p-value = 0.046). Following TBI, CT findings on admission can significantly predict long-term language abilities, with left side lesions inducing poorer outcomes.

Hemisphere stroke: impact on the semantic lexical aspects of language

ObjectiveTo investigate if right hemisphere stroke is associated with decreased lexical-semantic ability. MethodsWe compared subjects with right hemisphere brain damage after stroke with healthy controls using the validated version of the Montreal Evaluation of Communication to assess lexical-semantic domains of language. ResultsSixteen patients and thirty-two controls were included. The post-stroke group with right hemispheric brain lesions showed considerable limitations in metaphor interpretation, fluency, and semantic judgment. ConclusionIndividuals with right hemisphere damage after stroke may present with language changes in the lexical-semantic aspects.

Nonverbal Semantics Test (NVST)-A Novel Diagnostic Tool to Assess Semantic Processing Deficits: Application to Persons with Aphasia after Cerebrovascular Accident.

Assessment of semantic processing capacities often relies on verbal tasks which are, however, sensitive to impairments at several language processing levels. Especially for persons with aphasia there is a strong need for a tool that measures semantic processing skills independent of verbal abilities. Furthermore, in order to assess a patient’s potential for using alternative means of communication in cases of severe aphasia, semantic processing should be assessed in different nonverbal conditions. The Nonverbal Semantics Test (NVST) is a tool that captures semantic processing capacities through three tasks—Semantic Sorting, Drawing, and Pantomime. The main aim of the current study was to investigate the relationship between the NVST and measures of standard neurolinguistic assessment. Fifty-one persons with aphasia caused by left hemisphere brain damage were administered the NVST as well as the Aachen Aphasia Test (AAT). A principal component analysis (PCA) was conducted across all AAT and NVST subtests. The analysis resulted in a two-factor model that captured 69% of the variance of the original data, with all linguistic tasks loading high on one factor and the NVST subtests loading high on the other. These findings suggest that nonverbal tasks assessing semantic processing capacities should be administered alongside standard neurolinguistic aphasia tests.

Making Sense of Right Hemisphere Discourse Using RHDBank.

Right hemisphere brain damage (RHD) commonly causes pragmatic language disorders that are apparent in discourse production. Specific characteristics and approaches to assessment, diagnosis, and treatment of these disorders are not well-defined. RHDBank, a shared database of multimedia interactions for the study of communication using discourse, was created to address these gaps. The database, materials, and related analysis programs are free resources to clinicians, researchers, educators, and students. A standard discourse protocol was developed to elicit multiple types of discourse: free speech, conversation, picture description, storytelling, procedural discourse, and question-asking. Testing included measures of cognition, unilateral neglect, and communicative participation. Language samples were video-recorded and transcribed in CHAT format. Currently, the database includes 24 adults with RHD and 24 controls. Illustrative analyses show how RHDBank can facilitate research using micro- and macrolinguistic discourse analysis techniques both within this population and across populations. Educational resources, such as the Grand Rounds tutorial, were developed using case studies from the database. RHDBank is a shared database of resources that can facilitate educational and research efforts to address the gaps in knowledge about RHD communication and improve the clinical management of individuals with RHD.

Relationship between Visual Perception and Microstructural Change of the Superior Longitudinal Fasciculus in Patients with Brain Injury in the Right Hemisphere: A Preliminary Diffusion Tensor Tractography Study.

Right hemisphere brain damage often results in visual-spatial deficits. Because various microstructural changes of the superior longitudinal fasciculus (SLF) after a stroke in the right hemisphere affect visual perception, including neglect, the present study investigates the relationship between both microstructural change and lateralization of SLF and visual perception, using diffusion tensor imaging (DTI) in patients with lesions in the right hemisphere. Eight patients with strokes (five patients with intracranial hemorrhage, and three patients with infarction; mean age of 52.5 years) and 16 mean-age-matched healthy control subjects were involved in this study. The visual perception of all eight patients was assessed with the motor-free visual perception test (MVPT), and their SLFs were reconstructed using DTI. The results showed that there was a significant difference between the DTI parameters of the patients and the control subjects. Moreover, patients with microstructural damage to the right SLF showed impairment of visual perception. In patients with damage to both the dorsal and ventral pathways of the right SLF, spatial neglect was present. However, although a leftward SLF asymmetry was revealed in our patients, this lateralization did not show a relationship with visual perception. In conclusion, the microstructural changes of the right SLF play an important role in visual perception, and both pathways contribute to spatial neglect, but leftward lateralization of the right SFL activity after a stroke does not contribute to general visual perception.

Investigation of Speech and Language in a Persian Patient with Crossed Aphasia in Dextrals: A Case Report

Introduction: In the current study, we report a patient of crossed aphasia in dextrals (CAD) that presented with aphasia and typical neuropsychological deficits following right hemisphere brain damage. To the best of the authors’ knowledge, it is the first Persian language patient of CAD reported internationally. Case Presentation: The patient was a 59-year-old right-handed female with no history of left-handedness or ambidexterity in her family. Right handedness was measured in the current patient by the Edinburgh right-handedness inventory. Speech and language functions were measured by the Persian Western-Aphasia Battery (P-WAB) and the Bilingual Aphasia test (BAT). Also, the bedside version of Persian WAB (P-WAB-1) was used. Hemianopia/neglect was investigated by line bisection, painting, and cancellation tasks that confirmed left visuospatial neglect. Telegraphic speech was her dominant output feature. She had a problem with sentence construction; also, her morphological derivation skills were impaired. The syntactic structures of utterances were very simple. In writing tasks, her sample was unintelligible semantically. The auditory comprehension of the patient was impaired at the level of semi-complex and complex commands. It should be mentioned that difficulty in topic maintenance was observed in storytelling. Left visuospatial neglect was confirmed in the patient by assessments. The results confirmed the presence of neglect and language disorder, typologically consistent with Broca’s aphasia. Conclusions: The current study patient represented the typical symptoms of language dominant left hemisphere damage and a range of deficits indicating right hemisphere pathology. Analysis of patient symptoms confirmed the right hemisphere language dominance.

Zaburzenia sprawności językowych i komunikacyjnych u chorych po udarze prawej półkuli mózgu. Opisy przypadków.

Right hemisphere brain damage manifests itself in the language at the level of not only expression but also reception. Utterances of people with right hemisphere dysfunctions are often disorderly and illogical. As recipients, patients with right hemisphere brain damage, for instance, interrupt their interlocutor’s utterance, cannot understand jokes, mockeries, or ambiguous messages. The paper describes language and communication defi cits arising from right hemisphere brain damage and cases of patients suffering from right hemisphere disorder. The data obtained in the course of examining people with right hemisphere damage show that the most disturbed aspects of language include: lexical and semantic processing, processing complex language information, discourse, and prosody.

Neurite orientation dispersion and density imaging for evaluating the severity of neonatal hypoxic-ischemic encephalopathy in rats

PurposeTo evaluate the utility of neurite orientation dispersion and density imaging (NODDI) for longitudinally assessing neonatal hypoxic-ischemic (HI) encephalopathy severity with 7.0 T magnetic resonance imaging. MethodsThirteen 8-day-old Wistar rats underwent unilateral ligation of the left common carotid artery followed by mild (1 h; n = 6) or severe (2 h; n = 7) hypoxic exposure (8% O2, 34 °C). Diffusion-weighted, T2-weighted (T2W), and flow-sensitive alternating inversion recovery images were obtained with a horizontal 7.0 T scanner at 1, 24, 72, and 168 h after HI insult. The fractional anisotropy (FA), apparent diffusion coefficient (ADC), intracellular volume fraction (ICVF), isotropic volume fraction (ISO), orientation dispersion index (ODI), and cerebral blood flow (CBF) values were calculated for each group (mild and severe) at each time point (1, 24, 72, and 168 h). ICVF, ISO, and ODI were the NODDI parameters. ResultsLeft hemisphere brain damage was identified as slight hyperintensity on T2W images after 1 h in both groups. In the severe group only, the signal hyperintensity increased time-dependently over 168 h. The ADC and CBF were not significantly different between the groups within any region. The ICVF and ODI were significantly higher in the severe vs. mild group at various points between 1 and 168 h (cortex, striatum, or white matter), whereas the FA was significantly higher in the mild vs. severe group at 168 h (cortex and white matter). The ISO was higher in the severe vs. mild group at 72 h (striatum) and 168 h (all regions), while the ISO was significantly higher in the mild vs. severe group at 24 h (all regions). ConclusionHere, ODI, a NODDI metric, identified early differences between mild and severe HI injuries. Our findings support the potential utility of NODDI for determining neonatal HI encephalopathy severity in rats.

Neural networks for sentence comprehension and production: An ALE-based meta-analysis of neuroimaging studies.

Comprehending and producing sentences is a complex endeavor requiring the coordinated activity of multiple brain regions. We examined three issues related to the brain networks underlying sentence comprehension and production in healthy individuals: First, which regions are recruited for sentence comprehension and sentence production? Second, are there differences for auditory sentence comprehension vs. visual sentence comprehension? Third, which regions are specifically recruited for the comprehension of syntactically complex sentences? Results from activation likelihood estimation (ALE) analyses (from 45 studies) implicated a sentence comprehension network occupying bilateral frontal and temporal lobe regions. Regions implicated in production (from 15 studies) overlapped with the set of regions associated with sentence comprehension in the left hemisphere, but did not include inferior frontal cortex, and did not extend to the right hemisphere. Modality differences between auditory and visual sentence comprehension were found principally in the temporal lobes. Results from the analysis of complex syntax (from 37 studies) showed engagement of left inferior frontal and posterior temporal regions, as well as the right insula. The involvement of the right hemisphere in the comprehension of these structures has potentially important implications for language treatment and recovery in individuals with agrammatic aphasia following left hemisphere brain damage.

Design fluency subsequent to onset of aphasia: a distinct pattern of executive function difficulties?

ABSTRACTBackground: Executive function problems commonly co-occur with aphasia and influence language and communication performance as well as aphasia treatment outcomes and prognosis. Prior research, however, has focused on a restricted set of executive skills.Aims: This study examined further the integrity of executive functioning and its relationship to language performance in individuals with aphasia by utilising a design fluency measure, which assesses executive skills like initiation, planning, and cognitive flexibility. To examine domain-general versus domain-specific executive problems and determine the distinctiveness of the aphasic group’s performance pattern, adults with right hemisphere brain damage (RHD) were included. The hypotheses examined were: (a) compared to adults with no brain damage, the aphasic and RHD groups would display design fluency impairments; (b) the design fluency performances of aphasic and RHD groups would be quantitatively but not qualitatively similar; and (c) the design fluency performances of the aphasic and RHD groups would be related to their language abilities, as well as their performance of other executive and cognitive measures.Methods and Procedures: Participants with aphasia, RHD, or no brain damage completed the Ruff Figural Fluency Test (RFFT; Ruff, 1996), the results of which were quantitatively (i.e., number of unique designs, a perseverative error ratio) and qualitatively analysed (i.e., number and maximum length of orderly patterns, design complexity, number, and types of non-repetition errors), along with a formal cognitive-linguistic test battery and a verbal fluency task.Outcomes and Results: The traditional, quantitative RFFT scores of the aphasia, and RHD groups were significantly lower than those of the control group. Only the RHD group significantly differed from the control group when qualitative RFFT variables were analysed. RFFT performances correlated with language and other cognitive test scores, with some differences in the number and nature of these associations across the aphasic and RHD groups.Conclusions: The current design fluency findings indicated that executive function deficits involving initiation, planning, self-monitoring, and cognitive flexibility commonly co-occur with aphasia. These results supported previous research by identifying executive function impairments in many, however, not all individuals with aphasia, and by confirming influential associations between executive function and language, and communication measures. Inclusion of individuals with RHD indicated that such executive function difficulties and a potent relationship between executive functioning and language skills are not only unique to those with aphasia but also prevalent in other patient populations and consistent with the contribution of domain-general factors in acquired cognitive impairments.

Co-speech hand movements during narrations: What is the impact of right vs. left hemisphere brain damage?

Persons with brain damage show deviant patterns of co-speech hand movement behaviour in comparison to healthy speakers. It has been claimed by several authors that gesture and speech rely on a single production mechanism that depends on the same neurological substrate while others claim that both modalities are closely related but separate production channels. Thus, findings so far are contradictory and there is a lack of studies that systematically analyse the full range of hand movements that accompany speech in the condition of brain damage. In the present study, we aimed to fill this gap by comparing hand movement behaviour in persons with unilateral brain damage to the left and the right hemisphere and a matched control group of healthy persons. For hand movement coding, we applied Module I of NEUROGES, an objective and reliable analysis system that enables to analyse the full repertoire of hand movements independent of speech, which makes it specifically suited for the examination of persons with aphasia.The main results of our study show a decreased use of communicative conceptual gestures in persons with damage to the right hemisphere and an increased use of these gestures in persons with left brain damage and aphasia. These results not only suggest that the production of gesture and speech do not rely on the same neurological substrate but also underline the important role of right hemisphere functioning for gesture production.

顔を構成するパーツを配置する課題で著明な異常を認めた 左半球損傷患者 2 例

顔を構成するパーツを配置する課題で著明な異常を認めた 左半球損傷患者 2 例

Negative Word Production in Adults With Right Hemisphere Brain Damage: Effects of Implicit Assessment and Contextual Bias.

Both theory and evidence suggest that unilateral right hemisphere brain damage (RHD) should impair the processing of negative emotions. Typical metalinguistic assessments, however, may obscure processing strengths. This study investigated whether adults with RHD would produce proportionately fewer negative emotion words than control participants in an implicit assessment task and whether a negatively toned contextual bias would enhance performance. Eleven participants with RHD and 10 control participants without brain damage watched a video in 2 parts and described each segment. Between segments, participants evaluated the emotion conveyed by sentences designed to induce the negative bias. The primary outcome measure, percentage of negative emotion words in video descriptions, did not differ between groups. After the contextual bias, this measure significantly increased for both groups, whereas production of motion words, a control variable, remained constant. Findings are consistent with a view that attributes some deficient RHD performances to the nature and/or demands of explicit metalinguistic assessment tasks. These results call for modulation of prevailing hypotheses that attribute negative emotion processing as an undifferentiated whole solely to the right cerebral hemisphere. The results also further substantiate the rationale of an experimental treatment that exploits contextual bias and priming for individuals with RHD.

Early sensory processing in right hemispheric stroke patients with and without extinction

While extinction is most commonly viewed as an attentional disorder and not as a consequence of a failure to process contralesional sensory information, it has been speculated that early sensory processing of contralesional targets in extinction patients might not be fully normal. We used a masked visuo-motor response priming paradigm to study the influence of both contralesional and ipsilesional peripheral subliminal prime stimuli on central target performance, allowing us to compare the strength of the early sensory processing associated with these prime stimuli between right brain damaged patients with and without extinction as well as healthy elderly subjects. We found that the effect of an informative subliminal prime in the left contralesional visual field on central target performance was significantly reduced in both right brain damaged patients with and without extinction. The results suggest that a low-level early sensory deterioration of the neural representation for contralesional prime stimuli is a general consequence of right hemispheric brain damage unrelated to the presence or absence of extinction. This suggests that the presence of a spatial bias against contralesional information is not sufficient to elicit extinction. For extinction to occur, this spatial bias might need to be accompanied by a pathological (non-directional) reduction of attentional capacity.

Speech repetition as a window on the neurobiology of auditory–motor integration for speech: A voxel-based lesion symptom mapping study

For more than a century, speech repetition has been used as an assay for gauging the integrity of the auditory–motor pathway in aphasia, thought classically to involve a linkage between Wernicke's area and Broca's area via the arcuate fasciculus. During the last decade, evidence primarily from functional imaging in healthy individuals has refined this picture both computationally and anatomically, suggesting the existence of a cortical hub located at the parietal–temporal boundary (area Spt) that functions to integrate auditory and motor speech networks for both repetition and spontaneous speech production. While functional imaging research can pinpoint the regions activated in repetition/auditory–motor integration, lesion-based studies are needed to infer causal involvement. Previous lesion studies of repetition have yielded mixed results with respect to Spt's critical involvement in speech repetition. The present study used voxel-based lesion symptom mapping (VLSM) to investigate the neuroanatomy of repetition of both real words and non-words in a sample of 47 patients with focal left hemisphere brain damage. VLSMs identified a large voxel cluster spanning gray and white matter in the left temporal–parietal junction, including area Spt, where damage was significantly related to poor non-word repetition. Repetition of real words implicated a very similar dorsal network including area Spt. Cortical regions including Spt were implicated in repetition performance even when white matter damage was factored out. In addition, removing variance associated with speech perception abilities did not alter the overall lesion pattern for either task. Together with past functional imaging work, our results suggest that area Spt is integral in both word and non-word repetition, that its contribution is above and beyond that made by white matter pathways, and is not driven by perceptual processes alone. These findings are highly consistent with the claim that Spt is an area of sensory-motor translation in speech processing.

A combination of mild hypothermia and sevoflurane affords long-term protection in a modified neonatal mouse model of cerebral hypoxia-ischemia.

Infant brain injury from hypoxia-ischemia (HI) can lead to life-long impairment, but protective strategies are lacking. Short-term but not long-term protection has been demonstrated in the Rice-Vannucci neonatal brain ischemia model (RVM) by volatile anesthetic administration before HI, while exposure during HI has not been tested. In the current study, we evaluated a combination of sevoflurane and mild hypothermia as a protective approach during HI, both short- and long-term, by introducing intubation and mechanical ventilation to the RVM. The right common carotid artery was ligated in 10-day-old mice during brief sevoflurane anesthesia, followed by a 2-hour recovery with the dam. Littermates were then randomized to either: HI spontaneously breathing 10% oxygen for 60 minutes (the classical RVM); HI-Protect mild hypothermia and orotracheal intubation and mechanical ventilation with 3.5% sevoflurane in 10% oxygen for 60 minutes; or Room Air spontaneously breathing room air for 60 minutes. In a nonsurviving cohort, cerebral oxygenation was monitored in the area at risk and the contralateral hemisphere during HI or HI-Protect using visible-light spectroscopy (Spectros Corp). Mean arterial blood pressure and heart rate were measured. Arterial blood gases were obtained. Right/left brain hemispheric weight ratios and brain damage scores were determined 1 week after HI. In another group, learning and behavior were assessed in young adulthood (9 weeks) using spontaneous locomotion, Morris water maze, and apomorphine injection. During HI, ipsilateral and contralateral brain oxygenation, arterial blood pressures, blood gases, and glucose levels were similar in both ischemic groups, while heart rate was slower in the HI-Protect group. One week after ischemia, brain hemispheric weight ratios and injury scores in several brain regions were significantly worse after HI, compared with HI-Protect. Nine weeks after HI, Morris water maze hidden platform and reversal platform escape latencies, measures of spatial memory function, were superior after HI-Protect, compared with HI (P < 0.0001). HI-Protect animals demonstrated significantly less circling behavior after an apomorphine challenge (P < 0.0001), a measure of striatal integrity. To test the neuroprotective effects of volatile anesthetics during neonatal brain ischemia, we developed a modification of the RVM. By using mechanical ventilation and endotracheal intubation, sevoflurane administration during HI was survivable. The combination of sevoflurane administration and mild hypothermia during HI conferred not only short-term structural, but also long-term functional protection, compared with littermates treated according to the RVM. These findings warrant further studies to improve neurological outcome in critically ill infants.

Contextual Constraint Treatment for coarse coding deficit in adults with right hemisphere brain damage: Generalisation to narrative discourse comprehension

Coarse coding is the activation of broad semantic fields that can include multiple word meanings and a variety of features, including those peripheral to a word's core meaning. It is a partially domain-general process related to general discourse comprehension and contributes to both literal and non-literal language processing. Adults with damage to the right cerebral hemisphere (RHD) and a coarse coding deficit are particularly slow to activate features of words that are relatively distant or peripheral. This manuscript reports a pre-efficacy study of Contextual Constraint Treatment (CCT), a novel, implicit treatment designed to increase the efficiency of coarse coding with the goal of improving narrative comprehension and other language performance that relies on coarse coding. Participants were four adults with RHD. The study used a single-subject controlled experimental design across subjects and behaviours. The treatment involved pre-stimulation, using a hierarchy of strong and moderately biased contexts, to prime the intended distantly related features of critical stimulus words. Three of the four participants exhibited gains in auditory narrative discourse comprehension, the primary outcome measure. All participants exhibited generalisation to untreated items. No strong generalisation to processing non-literal language was evident. The results indicate that CCT yields both improved efficiency of the coarse coding process and generalisation to narrative comprehension.

Montreal-Toulouse Language Assessment Battery for aphasia: Validity and reliability evidence

In Brazil, no standardized instruments are available to assess language in patients with aphasia. The aim of the current study was to search for reliability and validity evidence for the Montreal-Toulouse Language Assessment Battery (MTL-BR). The sample was composed of 537 adults, of whom 463 were healthy individuals and 74 had neurological lesions (25 participants had right hemisphere brain damage, 21 had left hemisphere damage (LHD) with aphasia and 28 had LHD without aphasia). Reliability was assessed by internal consistency (Cronbach's alpha) and test-retest analyses. Test-retest reliability was calculated using the Pearson correlation coefficient, and a repeated measures analysis of variance, with years of education as a covariate. Construct validity was verified by correlations between scores in MTL-BR subtest and similar tasks from other language assessment instruments. Internal consistency was satisfactory (Cronbach's alpha between 0.79 and 0.90), as were correlations between test and retest scores (mean 0.52), and between the MTL-BR and scores in similar instruments. The present results suggested that the MTL-BR battery had adequate reliability and validity as a method for diagnosing and monitoring aphasia.

The influence of left and right hemisphere brain damage on configural and featural processing of affective faces

The literature about the lateralization of facial emotion perception according to valence (positive, negative) is conflicting; investigating the underlying processes may shed light on why some studies show right-hemisphere dominance across valence and other studies demonstrate hemispheric differences according to valence. This is the first clinical study to examine whether the use of configural and featural cues underlies hemispheric differences in affective face perception. Right brain-damaged (RBD; n = 17), left brain-damaged (LBD; n = 17) and healthy control (HC; n = 34) participants completed an affective face discrimination task that tested configural processing using whole faces and featural processing using partial faces. No group differences in expression perception according to valence or processing strategy were found. Across emotions, the RBD group was less accurate than the HC group in discriminating whole faces, whilst the RBD and LBD groups were less accurate than HCs in discriminating partial faces. This suggests that the right hemisphere processes facial expressions from configural and featural information, whereas the left hemisphere relies more heavily on featural facial information.

An Evidence-Based Systematic Review on Communication Treatments for Individuals With Right Hemisphere Brain Damage

The purpose of this review is to evaluate and summarize the research evidence related to the treatment of individuals with right hemisphere communication disorders. A comprehensive search of the literature using key words related to right hemisphere brain damage and communication treatment was conducted in 27 databases (e.g., PubMed, CINAHL). On the basis of a set of pre-established clinical questions, inclusion/exclusion criteria, and search parameters, studies investigating sentence- or discourse-level treatments were identified and evaluated for methodological quality. Data regarding participant, intervention, and outcome variables were reported. Only 5 studies were identified, each representing a different sentence- or discourse-level treatment approach and reporting a wide range of prosodic, expressive, receptive, and pragmatic outcomes. Although the state of the evidence pertaining to right hemisphere communication treatments is at a very preliminary stage, some positive findings were identified to assist speech-language pathologists who are working with individuals with right hemisphere brain damage. Clinical implications and recommendations for future research are explored.