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Hugues Duffau - One of the best experts on this subject based on the ideXlab platform.

  • probabilistic map of critical functional regions of the human cerebral cortex broca s area revisited
    Brain, 2014
    Co-Authors: Hugues Duffau, Matthew C Tate, Guillaume Herbet, Sylvie Moritzgasser, Joseph Euzebe Tate
    Abstract:

    The organization of basic functions of the human brain, particularly in the right hemisphere, remains poorly understood. Recent advances in functional neuroimaging have improved our understanding of cortical organization but do not allow for direct interrogation or determination of essential (versus participatory) cortical regions. Direct cortical stimulation represents a unique opportunity to provide novel insights into the functional distribution of critical epicentres. Direct cortical stimulation (bipolar, 60 Hz, 1-ms pulse) was performed in 165 consecutive patients undergoing awake mapping for resection of low-grade gliomas. Tasks included motor, sensory, counting, and picture naming. Stimulation sites eliciting positive (sensory/motor) or negative (speech arrest, dysarthria, anomia, phonological and semantic Paraphasias) findings were recorded and mapped onto a standard Montreal Neurological Institute brain atlas. Montreal Neurological Institute-space functional data were subjected to cluster analysis algorithms (K-means, partition around medioids, hierarchical Ward) to elucidate crucial network epicentres. Sensorimotor function was observed in the pre/post-central gyri as expected. Articulation epicentres were also found within the pre/post-central gyri. However, speech arrest localized to ventral premotor cortex, not the classical Broca's area. Anomia/Paraphasia data demonstrated foci not only within classical Wernicke's area but also within the middle and inferior frontal gyri. We report the first bilateral probabilistic map for crucial cortical epicentres of human brain functions in the right and left hemispheres, including sensory, motor, and language (speech, articulation, phonology and semantics). These data challenge classical theories of brain organization (e.g. Broca's area as speech output region) and provide a distributed framework for future studies of neural networks.

  • Evidence for an occipito-temporal tract underlying visual recognition in picture naming.
    Clinical neurology and neurosurgery, 2009
    Co-Authors: Emmanuel Mandonnet, Peggy Gatignol, Hugues Duffau
    Abstract:

    A 24-year-old male underwent awake surgery for a lesion in the left dominant basal temporo-occipital junction. During the intraoperative functional mapping using picture naming, cortical stimulation near the visual word form area led to visual Paraphasia. These visual Paraphasias were also elicited axonally by subcortical stimulation at the anterior wall of the cavity. We propose to discuss the existence of this "visual object form area", devoted to the visual recognition of object, and its links with the closely related "visual word form area". We suggest that its afference, whose stimulation also induced visual Paraphasias, may be one part of the U-shaped fibers distributed along the posterior part of the occipito-temporal connection system (inferior longitudinal fasciculus). Preservation of this white matter tract is essential for visual recognition. Thus, it should be mapped intraoperatively more systematically.

  • cortico subcortical organization of language networks in the right hemisphere an electrostimulation study in left handers
    Neuropsychologia, 2008
    Co-Authors: Hugues Duffau, Marianne Leroy, Peggy Gatignol
    Abstract:

    We have studied the configuration of the cortico-subcortical language networks within the right hemisphere (RH) in nine left-handers, being operated on while awake for a cerebral glioma. Intraoperatively, language was mapped using cortico-subcortical electrostimulation, to avoid permanent deficit. In frontal regions, cortical stimulation elicited articulatory disorders (ventral premotor cortex), anomia (dorsal premotor cortex), speech arrest (pars opercularis), and semantic Paraphasia (dorsolateral prefrontal cortex). Insular stimulation generated dysarthria, parietal stimulation phonemic Paraphasias, and temporal stimulation semantic Paraphasias. Subcortically, the superior longitudinal fasciculus (inducing phonological disturbances when stimulated), inferior occipito-frontal fasciculus (eliciting semantic disturbances during stimulation), subcallosal fasciculus (generating control disturbances when stimulated), and common final pathway (inducing articulatory disorders during stimulation) were identified. These cortical and subcortical structures were preserved, avoiding permanent aphasia, despite a transient immediate postoperative language worsening. Both intraoperative results and postsurgical transitory dysphasia support the major role of the RH in language in left-handers, and provide new insights into the anatomo-functional cortico-subcortical organization of the language networks in the RH-suggesting a “mirror” configuration in comparison to the left hemisphere.

  • intraoperative subcortical stimulation mapping of language pathways in a consecutive series of 115 patients with grade ii glioma in the left dominant hemisphere
    Journal of Neurosurgery, 2008
    Co-Authors: Hugues Duffau, Emmanuel Mandonnet, S Peggy T Gatignol, Laurent Capelle, Luc Taillandier
    Abstract:

    Object Despite better knowledge of cortical language organization, its subcortical anatomofunctional connectivity remains poorly understood. The authors used intraoperative subcortical stimulation in awake patients undergoing operation for a glioma in the left dominant hemisphere to map the language pathways and to determine the contribution of such a method to surgical results. Methods One hundred fifteen patients harboring a World Health Organization Grade II glioma within language areas underwent operation after induction of local anesthesia, using direct electrical stimulation to perform online cortical and subcortical language mapping throughout the resection. Results After detection of cortical language sites, the authors identified 1 or several of the following subcortical language pathways in all patients: 1) arcuate fasciculus, eliciting phonemic Paraphasia when stimulated; 2) inferior frontooccipital fasciculus, generating semantic Paraphasia when stimulated; 3) subcallosal fasciculus, inducing ...

  • COMPLETE RECOVERY AFTER SURGICAL RESECTION OF LEFT WERNICKE’S AREA IN AWAKE PATIENT: A BRAIN STIMULATION AND FUNCTIONAL MRI STUDY
    1
    Co-Authors: S Sarubbo, Le E Bars, S Moritz-gasser, Hugues Duffau
    Abstract:

    Abstract We report the first observation of a complete functional recovery following surgical resection of the left Wernicke’s area involved by a WHO grade II glioma in a 38-year-old right-handed woman. Intraoperative electrostimulation language mapping performed during awake procedure revealed a compensatory cortico- subcortical circuit around Wernicke’s area, including the left insula (eliciting articulatory disturbances when stimulated), the left superior longitudinal fascicle (inducing phonemic Paraphasia during stimulation) and the left inferior occipito-frontal fascicle (eliciting semantic Paraphasia when stimulated). Following a specific functional rehabilitation, especially concerning verbal working memory, the patient returned to a normal social and professional life two months after surgery, with a normal language examination despite resection of the left Wernicke’s area. Interestingly, postoperative language functional MR demonstrated a wide bilateral network partly common between phonological and semantic processing, underlying the functional recovery. Therefore, combination of intraoperative mapping with functional neuroimaging may provide original insights into the neural basis of compensation of Wernicke’s area, opening the door to surgery in this structure classically considered inoperable

Jessica D. Richardson - One of the best experts on this subject based on the ideXlab platform.

  • Repeated word production is inconsistent in both aphasia and apraxia of speech
    Aphasiology, 2020
    Co-Authors: Katarina L Haley, Jessica D. Richardson, Adam Jacks, Kevin T Cunningham, Tyson G. Harmon, Peter E. Turkeltaub
    Abstract:

    Purpose: There is persistent uncertainty about whether sound error consistency is a valid criterion for differentiating between apraxia of speech (AOS) and aphasia with phonemic Paraphasia. The pur...

  • Describing Phonological Paraphasias in Three Variants of Primary Progressive Aphasia.
    American journal of speech-language pathology, 2018
    Co-Authors: Sarah Grace Dalton, Christine Shultz, Maya L. Henry, Argye E. Hillis, Jessica D. Richardson
    Abstract:

    Purpose The purpose of this study was to describe the linguistic environment of phonological Paraphasias in 3 variants of primary progressive aphasia (semantic, logopenic, and nonfluent) and to des...

  • Phonological Paraphasias in 3 variants of primary progressive aphasia (Dalton et al., 2018)
    2018
    Co-Authors: Sarah Grace Hudspeth Dalton, Christine Shultz, Maya L. Henry, Argye E. Hillis, Jessica D. Richardson
    Abstract:

    Purpose: The purpose of this study was to describe the linguistic environment of phonological Paraphasias in 3 variants of primary progressive aphasia (semantic, logopenic, and nonfluent) and to describe the profiles of Paraphasia production for each of these variants.Method: Discourse samples of 26 individuals diagnosed with primary progressive aphasia were investigated for phonological Paraphasias using the criteria established for the Philadelphia Naming Test (Moss Rehabilitation Research Institute, 2013). Phonological Paraphasias were coded for Paraphasia type, part of speech of the target word, target word frequency, type of segment in error, word position of consonant errors, type of error, and degree of change in consonant errors.Results: Eighteen individuals across the 3 variants produced phonological Paraphasias. Most Paraphasias were nonword, followed by formal, and then mixed, with errors primarily occurring on nouns and verbs, with relatively few on function words. Most errors were substitutions, followed by addition and deletion errors, and few sequencing errors. Errors were evenly distributed across vowels, consonant singletons, and clusters, with more errors occurring in initial and medial positions of words than in the final position of words. Most consonant errors consisted of only a single-feature change, with few 2- or 3-feature changes. Importantly, Paraphasia productions by variant differed from these aggregate results, with unique production patterns for each variant.Conclusions: These results suggest that a system where Paraphasias are coded as present versus absent may be insufficient to adequately distinguish between the 3 subtypes of PPA. The 3 variants demonstrate patterns that may be used to improve phenotyping and diagnostic sensitivity. These results should be integrated with recent findings on phonological processing and speech rate. Future research should attempt to replicate these results in a larger sample of participants with longer speech samples and varied elicitation tasks.Supplemental Material S1. Results for participants who produced Paraphasias.Supplemental Material S2. Average target frequency. Supplemental Material S3. Median target frequency. Supplemental Material S4. Average target frequency, including outlier. Supplemental Material S5. Motor speech and speech sample characteristics of participants who produced Paraphasias.Dalton, S. G. H., Shultz, C., Henry, M. L., Hillis, A. E., & Richardson, J. D. (2018). Describing phonological Paraphasias in three variants of primary progressive aphasia. American Journal of Speech-Language Pathology, 27(1S), 336–349.

  • Perceptually Salient Sound Distortions and Apraxia of Speech: A Performance Continuum.
    American journal of speech-language pathology, 2017
    Co-Authors: Katarina L Haley, Jessica D. Richardson, Adam Jacks, Julie L. Wambaugh
    Abstract:

    Purpose We sought to characterize articulatory distortions in apraxia of speech and aphasia with phonemic Paraphasia and to evaluate the diagnostic validity of error frequency of distortion and dis...

Adam Jacks - One of the best experts on this subject based on the ideXlab platform.

Mario F Mendez - One of the best experts on this subject based on the ideXlab platform.

  • fluent versus nonfluent primary progressive aphasia a comparison of clinical and functional neuroimaging features
    Brain and Language, 2005
    Co-Authors: David G Clark, Anthony Charuvastra, Bruce L Miller, Jill Shapira, Mario F Mendez
    Abstract:

    To better characterize fluent and nonfluent variants of primary progressive aphasia (PPA). Although investigators have recognized both fluent and nonfluent patients with PPA (Mesulam, 2001), the clinical and neuroimaging features of these variants have not been fully defined. We present clinical and neuropsychological data on 47 PPA patients comparing the fluent (n = 21) and nonfluent (n = 26) subjects. We further compared language features with PET/SPECT data available on 39 of these patients. Compared to the nonfluent PPA patients, those with fluent PPA had greater impairment of confrontational naming and loss of single word comprehension. They also exhibited semantic paraphasic errors and loss of single word comprehension. Patients with nonfluent PPA were more likely to be female, were more often dysarthric, and exhibited phonological speech errors in the absence of semantic errors. No significant differences were seen with regard to left hemisphere abnormalities, suggesting that both variants result from mechanisms that overlap frontal, temporal, and parietal regions. Of the language measures, only semantic Paraphasias were strongly localized, in this case to the left temporal lobe. Fluent and nonfluent forms of PPA are clinically distinguishable by letter fluency, single word comprehension, object naming, and types of paraphasic errors. Nevertheless, there is a large amount of overlap between dysfunctional anatomic regions associated with these syndromes.

Antonio Culebras - One of the best experts on this subject based on the ideXlab platform.

  • SUBCORTICAL APHASIAS-QUESTIONING VALIDITY OF APHASIA AS A CORTICAL INFARCT SIGN (P1.287)
    Neurology, 2017
    Co-Authors: Gurmeen Kaur, Antonio Culebras
    Abstract:

    Objective: We present 2 distinct cases of subcortical aphasias. Background: While aphasia is popularly considered a cortical sign, dating back to 1906 Pierre Marie described subcortical aphasia with the involvement of Marie’s quadrilateral space (bordering the external capsule, claustrum, parts of insula and putamen) presenting as predominantly anarthria. Other subcortical aphasias include thalamic aphasia and striato-capsular aphasia. Design/Methods: Patient 1: 64 year old female with risk factors including prior radiation and diabetes type 2 presented with anarthria/mutism. MR imaging revealed a subcortical lesion suggestive of ischemic stroke involving the quadrangular space of Pierre Marie. Anarthria improved in the course of one week but the patient remained with residual expressive aphasia, akin to Broca’s cortical aphasia with 2–3 word sentences. Comprehension was preserved but repetition was impaired. Patient 2: 78-year-old male presented with fluent aphasia with paraphasic errors; imaging showed an isolated infarct in the left thalamus. During the inpatient stay, paraphasic errors gradually improved but he had severe difficulty with comprehension, naming and repetition. Results: The subcortical stroke involving white matter tracts in the quadrangular space of Pierre Marie affects the superior tip of the prefrontal gyrus of the insula which is involved in verbal output. The resulting anarthria has also been described as ‘apraxia of speech.’ Striato-capsular aphasia presents similarly with lack of speech fluency, occurrence of literary Paraphasias, preserved comprehension and naming. Thalamic aphasia, however, is characterized by fluent output, impaired comprehension and naming with predominant verbal Paraphasias. While lesions in the paramedian thalamus can mimic aphasias because of deficits in attention, true thalamic aphasias are related to lesions in the antero-lateral nuclei. Subcortical aphasias tend to be transient. Conclusions: Given that a small subcortical infarction can present as pure aphasia, the belief that aphasia is always a sign of a cortical infarct is unfounded and should be revisited. Disclosure: Dr. Kaur has nothing to disclose. Dr. Culebras received personal compensation in an editorial capacity for Medlink and UpToDate.