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Schevenels K, Michiels L, Lemmens R, De Smedt B, Zink I, Vandermosten M. The role of the hippocampus in statistical learning and language recovery in persons with post stroke aphasia. Neuroimage Clin 2022; 36:103243. [PMID: 36306718 PMCID: PMC9668653 DOI: 10.1016/j.nicl.2022.103243] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/11/2022]
Abstract
Although several studies have aimed for accurate predictions of language recovery in post stroke aphasia, individual language outcomes remain hard to predict. Large-scale prediction models are built using data from patients mainly in the chronic phase after stroke, although it is clinically more relevant to consider data from the acute phase. Previous research has mainly focused on deficits, i.e., behavioral deficits or specific brain damage, rather than compensatory mechanisms, i.e., intact cognitive skills or undamaged brain regions. One such unexplored brain region that might support language (re)learning in aphasia is the hippocampus, a region that has commonly been associated with an individual's learning potential, including statistical learning. This refers to a set of mechanisms upon which we rely heavily in daily life to learn a range of regularities across cognitive domains. Against this background, thirty-three patients with aphasia (22 males and 11 females, M = 69.76 years, SD = 10.57 years) were followed for 1 year in the acute (1-2 weeks), subacute (3-6 months) and chronic phase (9-12 months) post stroke. We evaluated the unique predictive value of early structural hippocampal measures for short-term and long-term language outcomes (measured by the ANELT). In addition, we investigated whether statistical learning abilities were intact in patients with aphasia using three different tasks: an auditory-linguistic and visual task based on the computation of transitional probabilities and a visuomotor serial reaction time task. Finally, we examined the association of individuals' statistical learning potential with acute measures of hippocampal gray and white matter. Using Bayesian statistics, we found moderate evidence for the contribution of left hippocampal gray matter in the acute phase to the prediction of long-term language outcomes, over and above information on the lesion and the initial language deficit (measured by the ScreeLing). Non-linguistic statistical learning in patients with aphasia, measured in the subacute phase, was intact at the group level compared to 23 healthy older controls (8 males and 15 females, M = 74.09 years, SD = 6.76 years). Visuomotor statistical learning correlated with acute hippocampal gray and white matter. These findings reveal that particularly left hippocampal gray matter in the acute phase is a potential marker of language recovery after stroke, possibly through its statistical learning ability.
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Affiliation(s)
- Klara Schevenels
- Research Group Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Onderwijs en Navorsing 2 (O&N2), Herestraat 49 box 721, Leuven 3000, Belgium; Leuven Brain Institute, KU Leuven, Onderwijs en Navorsing 5 (O&N 5), Herestraat 49 box 1020, Leuven 3000, Belgium.
| | - Laura Michiels
- Department of Neurology, University Hospitals Leuven, Herestraat 49, Leuven 3000, Belgium; Research Group Experimental Neurology, Department of Neurosciences, KU Leuven, Herestraat 49 box 7003, Leuven 3000, Belgium; Laboratory of Neurobiology, VIB Center for Brain & Disease Research, Onderwijs en Navorsing 5 (O&N 5), Herestraat 49 box 602, Leuven 3000, Belgium; Leuven Brain Institute, KU Leuven, Onderwijs en Navorsing 5 (O&N 5), Herestraat 49 box 1020, Leuven 3000, Belgium.
| | - Robin Lemmens
- Department of Neurology, University Hospitals Leuven, Herestraat 49, Leuven 3000, Belgium; Research Group Experimental Neurology, Department of Neurosciences, KU Leuven, Herestraat 49 box 7003, Leuven 3000, Belgium; Laboratory of Neurobiology, VIB Center for Brain & Disease Research, Onderwijs en Navorsing 5 (O&N 5), Herestraat 49 box 602, Leuven 3000, Belgium; Leuven Brain Institute, KU Leuven, Onderwijs en Navorsing 5 (O&N 5), Herestraat 49 box 1020, Leuven 3000, Belgium.
| | - Bert De Smedt
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU leuven, Leopold Vanderkelenstraat 32 box 3765, Leuven 3000, Belgium; Leuven Brain Institute, KU Leuven, Onderwijs en Navorsing 5 (O&N 5), Herestraat 49 box 1020, Leuven 3000, Belgium.
| | - Inge Zink
- Research Group Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Onderwijs en Navorsing 2 (O&N2), Herestraat 49 box 721, Leuven 3000, Belgium; Leuven Brain Institute, KU Leuven, Onderwijs en Navorsing 5 (O&N 5), Herestraat 49 box 1020, Leuven 3000, Belgium.
| | - Maaike Vandermosten
- Research Group Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Onderwijs en Navorsing 2 (O&N2), Herestraat 49 box 721, Leuven 3000, Belgium; Leuven Brain Institute, KU Leuven, Onderwijs en Navorsing 5 (O&N 5), Herestraat 49 box 1020, Leuven 3000, Belgium.
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Structural Integrity and Functional Neural Activity Associated with Oral Language Function after Stroke. J Clin Med 2022; 11:jcm11113028. [PMID: 35683416 PMCID: PMC9180994 DOI: 10.3390/jcm11113028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/25/2022] [Accepted: 05/26/2022] [Indexed: 02/04/2023] Open
Abstract
(1) Background: The impairment of language function after a stroke is common. It is unclear how the brain reorganizes for language function after cerebral infarction. The aim of this observational study is to investigate the association of structural integrity and functional neural activity with language function in aphasic patients with middle cerebral artery infarction. (2) Methods: Magnetic resonance images and scores from the Western Aphasia Battery on 20 patients were retrieved from medical records. A Voxel-wise linear regression analysis was performed using fractional anisotropy maps or the fractional amplitude of low-frequency fluctuation maps as dependent variables and scores of oral language function as independent variables while controlling for age and time elapsed after stroke. (3) Results: Spontaneous speech was positively associated with fractional anisotropy in the left dorsal stream and the right posterior corpus callosum and with the fractional amplitude of the low-frequency fluctuation of cranial nuclei in the pontomedullary junction. Comprehension was positively associated with the left ventral stream. Naming was positively associated with the left ventral stream and the bilateral occipitofrontal fasciculus, as well as with the fractional amplitude of low-frequency fluctuation of the supramarginal gyrus in the left hemisphere. (4) Conclusions: The dorsal and ventral streams are important for articulation and meaning after the reorganization of neural circuits following stroke. Subdomains of oral language function with a visual component are dependent on the visual association areas located in the right hemisphere.
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