Predicting speech fluency and naming abilities in chronic aphasic patients
There is a need for identifying biomarkers that predict chronic speech fluency/language impairment and improvement after stroke. We previously showed that the Arcuate Fasciculus lesion load (AF-LL), a combined variable of lesion site and size, predicted speech fluency in chronic aphasic patients. In...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2013-12-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fnhum.2013.00831/full |
| _version_ | 1819047520999833600 |
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| author | Jasmine eWang Sarah eMarchina Andrea C. Norton Catherine Y Wan Gottfried eSchlaug |
| author_facet | Jasmine eWang Sarah eMarchina Andrea C. Norton Catherine Y Wan Gottfried eSchlaug |
| author_sort | Jasmine eWang |
| collection | DOAJ |
| description | There is a need for identifying biomarkers that predict chronic speech fluency/language impairment and improvement after stroke. We previously showed that the Arcuate Fasciculus lesion load (AF-LL), a combined variable of lesion site and size, predicted speech fluency in chronic aphasic patients. In the current study, we compared lesion loads of such a structural map (i.e., AF-LL) with those of a functional map (i.e., the functional grey matter lesion load (fGM-LL)) in their ability to predict speech fluency and naming performance in a large group of patients. The fGM map was constructed from functional brain images acquired during an overt speaking task in a group of healthy elderly controls. The AF map was reconstructed from high-resolution diffusion tensor images also from a group of healthy elderly controls. In addition to these two canonical maps, a combined AF-fGM was derived from summing fGM and AF maps. Each canonical map was overlaid with individual lesion masks of 50 chronic aphasic patients with varying degrees of impairment in speech production and fluency to calculate a functional and structural lesion load value for each patient, and to regress these values with measures of speech fluency and naming. We found that both AF-LL and fGM-LL independently predicted speech fluency and naming ability; however, AF lesion load explained most of the variance for both measures. The combined AF-fGM lesion load did not have a higher predictability than either AF-LL or fGM-LL alone. Clustering and classification methods confirmed that AF lesion load was best at stratifying patients into severe and non-severe outcome groups with 96% accuracy for speech fluency and 90% accuracy for naming. An AF-LL of greater than 4cc was the critical threshold that determined poor fluency and naming outcomes, and constitutes the severe outcome group. Thus, surrogate markers of impairments have the potential to predict outcomes and can be used as a stratifier in experimental studies. |
| first_indexed | 2024-12-21T11:01:41Z |
| format | Article |
| id | doaj.art-f9daf5b628034ae796e67e8ab078aeb7 |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-12-21T11:01:41Z |
| publishDate | 2013-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-f9daf5b628034ae796e67e8ab078aeb72022-12-21T19:06:20ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612013-12-01710.3389/fnhum.2013.0083161548Predicting speech fluency and naming abilities in chronic aphasic patientsJasmine eWang0Sarah eMarchina1Andrea C. Norton2Catherine Y Wan3Gottfried eSchlaug4Beth Israel Deaconess Medical Center and Harvard Medical SchoolBeth Israel Deaconess Medical Center and Harvard Medical SchoolBeth Israel Deaconess Medical Center and Harvard Medical SchoolBeth Israel Deaconess Medical Center and Harvard Medical SchoolBeth Israel Deaconess Medical Center and Harvard Medical SchoolThere is a need for identifying biomarkers that predict chronic speech fluency/language impairment and improvement after stroke. We previously showed that the Arcuate Fasciculus lesion load (AF-LL), a combined variable of lesion site and size, predicted speech fluency in chronic aphasic patients. In the current study, we compared lesion loads of such a structural map (i.e., AF-LL) with those of a functional map (i.e., the functional grey matter lesion load (fGM-LL)) in their ability to predict speech fluency and naming performance in a large group of patients. The fGM map was constructed from functional brain images acquired during an overt speaking task in a group of healthy elderly controls. The AF map was reconstructed from high-resolution diffusion tensor images also from a group of healthy elderly controls. In addition to these two canonical maps, a combined AF-fGM was derived from summing fGM and AF maps. Each canonical map was overlaid with individual lesion masks of 50 chronic aphasic patients with varying degrees of impairment in speech production and fluency to calculate a functional and structural lesion load value for each patient, and to regress these values with measures of speech fluency and naming. We found that both AF-LL and fGM-LL independently predicted speech fluency and naming ability; however, AF lesion load explained most of the variance for both measures. The combined AF-fGM lesion load did not have a higher predictability than either AF-LL or fGM-LL alone. Clustering and classification methods confirmed that AF lesion load was best at stratifying patients into severe and non-severe outcome groups with 96% accuracy for speech fluency and 90% accuracy for naming. An AF-LL of greater than 4cc was the critical threshold that determined poor fluency and naming outcomes, and constitutes the severe outcome group. Thus, surrogate markers of impairments have the potential to predict outcomes and can be used as a stratifier in experimental studies.http://journal.frontiersin.org/Journal/10.3389/fnhum.2013.00831/fullAphasiaDiffusion Tensor Imagingfunctional MRIfluencyOutcomeLesion Load |
| spellingShingle | Jasmine eWang Sarah eMarchina Andrea C. Norton Catherine Y Wan Gottfried eSchlaug Predicting speech fluency and naming abilities in chronic aphasic patients Frontiers in Human Neuroscience Aphasia Diffusion Tensor Imaging functional MRI fluency Outcome Lesion Load |
| title | Predicting speech fluency and naming abilities in chronic aphasic patients |
| title_full | Predicting speech fluency and naming abilities in chronic aphasic patients |
| title_fullStr | Predicting speech fluency and naming abilities in chronic aphasic patients |
| title_full_unstemmed | Predicting speech fluency and naming abilities in chronic aphasic patients |
| title_short | Predicting speech fluency and naming abilities in chronic aphasic patients |
| title_sort | predicting speech fluency and naming abilities in chronic aphasic patients |
| topic | Aphasia Diffusion Tensor Imaging functional MRI fluency Outcome Lesion Load |
| url | http://journal.frontiersin.org/Journal/10.3389/fnhum.2013.00831/full |
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