GAJARDO VIDAL, ANDREA ELIZABETH
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GAJARDO VIDAL, ANDREA ELIZABETH
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agajardo@udd.cl
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57194767907

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How right hemisphere damage after stroke can impair speech comprehension

2018 , GAJARDO VIDAL, ANDREA ELIZABETH , Diego L Lorca-Puls , Thomas M H Hope , Oiwi Parker Jones , Mohamed L Seghier , Susan Prejawa , Jennifer T Crinion , Alex P Leff , David W Green , Cathy J Price

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A functional dissociation of the left frontal regions that contribute to single word production tasks

2021 , Justyna O. Ekert , Diego L. Lorca-Puls , GAJARDO VIDAL, ANDREA ELIZABETH , Jennifer T. Crinion , Thomas M.H. Hope , David W. Green , Cathy J. Price

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Right cerebral motor areas that support accurate speech production following damage to cerebellar speech areas

2021 , Sharon Geva , Letitia M. Schneider , Sophie Roberts , Shamima Khan , GAJARDO VIDAL, ANDREA ELIZABETH , Diego L. Lorca-Puls , PLORAS team , Thomas M.H. Hope , David W. Green , Cathy J. Price

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Using transcranial magnetic stimulation of the undamaged brain to identify lesion sites that predict language outcome after stroke

2017 , Diego L. Lorca-Puls , GAJARDO VIDAL, ANDREA ELIZABETH , Mohamed L. Seghier , Alexander P. Leff , Varun Sethi , Susan Prejawa , Thomas M. H. Hope , Joseph T. Devlin , Cathy J. Price

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Enhanced left superior parietal activation during successful speech production in patients with left dorsal striatal damage and error-prone neurotypical participants

2022 , Sharon Geva , Letitia M Schneider , Shamima Khan , Diego L Lorca-Puls , GAJARDO VIDAL, ANDREA ELIZABETH , Storm Anderson , Rachel Bruce , Megan Docksey , Kate Ledingham , Louise Lim , Sophie Roberts , Thomas M H Hope , David W Green , Cathy J Price

AbstractFunctional imaging studies of neurotypical adults report activation in the left putamen during speech production. The current study asked how stroke survivors with left putamen damage are able to produce correct spoken responses during a range of speech production tasks. Using functional magnetic resonance imaging, activation during correct speech production responses was assessed in 5 stroke patients with circumscribed left dorsal striatal lesions, 66 stroke patient controls who did not have focal left dorsal striatal lesions, and 54 neurotypical adults. As a group, patients with left dorsal striatal damage (our patients of interest) showed higher activation than neurotypical controls in the left superior parietal cortex during successful speech production. This effect was not specific to patients with left dorsal striatal lesions as we observed enhanced activation in the same region in some patient controls and also in more error-prone neurotypical participants. Our results strongly suggest that enhanced left superior parietal activation supports speech production in diverse challenging circumstances, including those caused by stroke damage. They add to a growing body of literature indicating how upregulation within undamaged parts of the neural systems already recruited by neurotypical adults contributes to recovery after stroke.

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Neural basis of speech and grammar symptoms in non-fluent variant primary progressive aphasia spectrum

2023 , Diego L Lorca-Puls , GAJARDO VIDAL, ANDREA ELIZABETH , Maria Luisa Mandelli , Ignacio Illán-Gala , Zoe Ezzes , Lisa D Wauters , Giovanni Battistella , Rian Bogley , Buddhika Ratnasiri , Abigail E Licata , Petronilla Battista , Adolfo M García , Boon Lead Tee , Sladjana Lukic , Adam L Boxer , Howard J Rosen , William W Seeley , Lea T Grinberg , Salvatore Spina , Bruce L Miller , Zachary A Miller , Maya L Henry , Nina F Dronkers , Maria Luisa Gorno-Tempini

The non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA) is a neurodegenerative syndrome primarily defined by the presence of apraxia of speech (AoS) and/or expressive agrammatism. In addition, many patients exhibit dysarthria and/or receptive agrammatism. This leads to substantial phenotypic variation within the speech-language domain across individuals and time, in terms of both the specific combination of symptoms as well as their severity. How to resolve such phenotypic heterogeneity in nfvPPA is a matter of debate. ‘Splitting’ views propose separate clinical entities: ‘primary progressive apraxia of speech’ when AoS occurs in the absence of expressive agrammatism, ‘progressive agrammatic aphasia’ (PAA) in the opposite case, and ‘AOS + PAA’ when mixed motor speech and language symptoms are clearly present. While therapeutic interventions typically vary depending on the predominant symptom (e.g. AoS versus expressive agrammatism), the existence of behavioural, anatomical and pathological overlap across these phenotypes argues against drawing such clear-cut boundaries. In the current study, we contribute to this debate by mapping behaviour to brain in a large, prospective cohort of well characterized patients with nfvPPA (n = 104). We sought to advance scientific understanding of nfvPPA and the neural basis of speech-language by uncovering where in the brain the degree of MRI-based atrophy is associated with inter-patient variability in the presence and severity of AoS, dysarthria, expressive agrammatism or receptive agrammatism. Our cross-sectional examination of brain-behaviour relationships revealed three main observations. First, we found that the neural correlates of AoS and expressive agrammatism in nfvPPA lie side by side in the left posterior inferior frontal lobe, explaining their behavioural dissociation/association in previous reports. Second, we identified a ‘left-right’ and ‘ventral-dorsal’ neuroanatomical distinction between AoS versus dysarthria, highlighting (i) that dysarthria, but not AoS, is significantly influenced by tissue loss in right-hemisphere motor-speech regions; and (ii) that, within the left hemisphere, dysarthria and AoS map onto dorsally versus ventrally located motor-speech regions, respectively. Third, we confirmed that, within the large-scale grammar network, left frontal tissue loss is preferentially involved in expressive agrammatism and left temporal tissue loss in receptive agrammatism. Our findings thus contribute to define the function and location of the epicentres within the large-scale neural networks vulnerable to neurodegenerative changes in nfvPPA. We propose that nfvPPA be redefined as an umbrella term subsuming a spectrum of speech and/or language phenotypes that are closely linked by the underlying neuroanatomy and neuropathology.

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Lesions that do or do not impair digit span: a study of 816 stroke survivors

2021 , Sharon Geva , Teodros Truneh , Mohamed L Seghier , Thomas M H Hope , Alex P Leff , Jennifer T Crinion , GAJARDO VIDAL, ANDREA ELIZABETH , Diego L Lorca-Puls , David W Green , Cathy J Price

Abstract Prior studies have reported inconsistency in the lesion sites associated with verbal short-term memory impairments. Here we asked: How many different lesion sites can account for selective impairments in verbal short-term memory that persist over time, and how consistently do these lesion sites impair verbal short-term memory? We assessed verbal short-term memory impairments using a forward digit span task from the Comprehensive Aphasia Test. First, we identified the incidence of digit span impairments in a sample of 816 stroke survivors (541 males/275 females; age at stroke onset 56 ± 13 years; time post-stroke 4.4 ± 5.2 years). Second, we studied the lesion sites in a subgroup of these patients (n = 39) with left hemisphere damage and selective digit span impairment—defined as impaired digit span with unimpaired spoken picture naming and spoken word comprehension (tests of speech production and speech perception, respectively). Third, we examined how often these lesion sites were observed in patients who either had no digit span impairments or digit span impairments that co-occurred with difficulties in speech perception and/or production tasks. Digit span impairments were observed in 222/816 patients. Almost all (199/222 = 90%) had left hemisphere damage to five small regions in basal ganglia and/or temporo-parietal areas. Even complete damage to one or more of these five regions was not consistently associated with persistent digit span impairment. However, when the same regions were spared, only 5% (23/455) presented with digit span impairments. These data suggest that verbal short-term memory impairments are most consistently associated with damage to left temporo-parietal and basal ganglia structures. Sparing of these regions very rarely results in persistently poor verbal short-term memory. These findings have clinical implications for predicting recovery of verbal short-term memory after stroke.

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Erratum to: Reply: Broca’s area: why was neurosurgery neglected for so long when seeking to re-establish the scientific truth? and Where is the speech production area? Evidence from direct cortical electrical stimulation mapping

2021 , Diego L Lorca-Puls , GAJARDO VIDAL, ANDREA ELIZABETH , David W Green , Cathy J Price

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Damage to Broca’s area does not contribute to long-term speech production outcome after stroke

2021 , GAJARDO VIDAL, ANDREA ELIZABETH , Diego L Lorca-Puls , PLORAS team , Holly Warner , Bawan Pshdary , Jennifer T Crinion , Alexander P Leff , Thomas M H Hope , Sharon Geva , Mohamed L Seghier , David W Green , Howard Bowman , Cathy J Price

Abstract Broca’s area in the posterior half of the left inferior frontal gyrus has long been thought to be critical for speech production. The current view is that long-term speech production outcome in patients with Broca’s area damage is best explained by the combination of damage to Broca’s area and neighbouring regions including the underlying white matter, which was also damaged in Paul Broca’s two historic cases. Here, we dissociate the effect of damage to Broca’s area from the effect of damage to surrounding areas by studying long-term speech production outcome in 134 stroke survivors with relatively circumscribed left frontal lobe lesions that spared posterior speech production areas in lateral inferior parietal and superior temporal association cortices. Collectively, these patients had varying degrees of damage to one or more of nine atlas-based grey or white matter regions: Brodmann areas 44 and 45 (together known as Broca’s area), ventral premotor cortex, primary motor cortex, insula, putamen, the anterior segment of the arcuate fasciculus, uncinate fasciculus and frontal aslant tract. Spoken picture description scores from the Comprehensive Aphasia Test were used as the outcome measure. Multiple regression analyses allowed us to tease apart the contribution of other variables influencing speech production abilities such as total lesion volume and time post-stroke. We found that, in our sample of patients with left frontal damage, long-term speech production impairments (lasting beyond 3 months post-stroke) were solely predicted by the degree of damage to white matter, directly above the insula, in the vicinity of the anterior part of the arcuate fasciculus, with no contribution from the degree of damage to Broca’s area (as confirmed with Bayesian statistics). The effect of white matter damage cannot be explained by a disconnection of Broca’s area, because speech production scores were worse after damage to the anterior arcuate fasciculus with relative sparing of Broca’s area than after damage to Broca’s area with relative sparing of the anterior arcuate fasciculus. Our findings provide evidence for three novel conclusions: (i) Broca’s area damage does not contribute to long-term speech production outcome after left frontal lobe strokes; (ii) persistent speech production impairments after damage to the anterior arcuate fasciculus cannot be explained by a disconnection of Broca’s area; and (iii) the prior association between persistent speech production impairments and Broca’s area damage can be explained by co-occurring white matter damage, above the insula, in the vicinity of the anterior part of the arcuate fasciculus.

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Dissociating the functions of three left posterior superior temporal regions that contribute to speech perception and production

2021 , Justyna O. Ekert , GAJARDO VIDAL, ANDREA ELIZABETH , Diego L. Lorca-Puls , Thomas M.H. Hope , Fred Dick , Jennifer T. Crinion , David W. Green , Cathy J. Price

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