Damage to Broca’s area does not contribute to long-term speech production outcome after stroke
| Autor: | Ploras Team, Sharon Geva, Alexander P. Leff, Thomas M.H. Hope, Holly Warner, Mohamed L. Seghier, Howard Bowman, Jennifer T. Crinion, David W. Green, Cathy J. Price, Andrea Gajardo-Vidal, Diego L Lorca-Puls, Bawan Pshdary |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Adult
Male medicine.medical_specialty Speech production speech production Uncinate fasciculus Audiology behavioral disciplines and activities Premotor cortex 03 medical and health sciences 0302 clinical medicine Broca’s area medicine Arcuate fasciculus Humans Broca's area Letters to the Editor 030304 developmental biology Aged Aged 80 and over 0303 health sciences Aphasia Broca business.industry AcademicSubjects/SCI01870 Superior longitudinal fasciculus Original Articles Middle Aged stroke Broca Area humanities aphasia Frontal Lobe medicine.anatomical_structure Frontal lobe nervous system RC0321 arcuate fasciculus Female AcademicSubjects/MED00310 Neurology (clinical) Primary motor cortex business 030217 neurology & neurosurgery |
| Zdroj: | Brain |
| ISSN: | 1460-2156 0006-8950 |
| Popis: | 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. Contrary to the dominant view that speech production impairments after a left frontal lobe stroke involving Broca’s area are caused by the combination of damage to Broca’s area and neighbouring regions, Gajardo-Vidal et al. show that Broca’s area damage does not in fact contribute to long-term speech production outcomes. |
| Databáze: | OpenAIRE |
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