Lesion correlates of patholinguistic profiles in chronic aphasia: comparisons of syndrome-, modality- and symptom-level assessment
| Autor: | Frank Regenbrecht, Hellmuth Obrig, Ilona Henseler |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
medicine.medical_specialty
Aphasiology Neuropsychological Tests Audiology computer.software_genre behavioral disciplines and activities Cohort Studies Lesion Voxel Neurolinguistics Agrammatism Aphasia medicine Humans Aged Brain Mapping Language Tests Modalities Brain Syndrome Middle Aged Magnetic Resonance Imaging Linguistic competence Stroke Neurology (clinical) medicine.symptom Psychology computer Cognitive psychology |
| Zdroj: | Brain |
| ISSN: | 1460-2156 0006-8950 |
| Popis: | One way to investigate the neuronal underpinnings of language competence is to correlate patholinguistic profiles of aphasicpatients to corresponding lesion sites. Constituting the beginnings of aphasiology and neurolinguistics over a century ago, thisapproach has been revived and refined in the past decade by statistical approaches mapping continuous variables (providingmetrics that are not simply categorical) on voxel-wise lesion information (voxel-based lesion–symptom mapping). Here weinvestigate whether and how voxel-based lesion–symptom mapping allows us to delineate specific lesion patterns for differ-entially fine-grained clinical classifications. The latter encompass ‘classical’ syndrome-based approaches (e.g. Broca’s aphasia),more symptom-oriented descriptions (e.g. agrammatism) and further refinement to linguistic sub-functions (e.g. lexico-semanticdeficits for inanimate versus animate items). From a large database of patients treated for aphasia of different aetiologies(n=1167) a carefully selected group of 102 first ever ischaemic stroke patients with chronic aphasia (;12 months) wereincluded in a VLSM analysis. Specifically, we investigated how performance in the Aachen Aphasia Test—the standard clinicaltest battery for chronic aphasia in German—relates to distinct brain lesions. The Aachen Aphasia Test evaluates aphasia ondifferent levels: a non-parametric discriminant procedure yields probabilities for the allocation to one of the four ‘standard’syndromes (Broca, Wernicke, global and amnestic aphasia), whereas standardized subtests target linguistic modalities (e.g. repe-tition), or even more specific symptoms (e.g. phoneme repetition). Because some subtests of the Aachen Aphasia Test (e.g. forthe linguistic level of lexico-semantics) rely on rather coarse and heterogeneous test items we complemented the analysis with anumber of more detailed clinically used tests in selected mostly mildly affected subgroups of patients. Our results indicate that:(i) Aachen Aphasia Test-based syndrome allocation allows for an unexpectedly concise differentiation between ‘Broca’s’ and‘Wernicke’s’ aphasia corresponding to non-overlapping anterior and posterior lesion sites; whereas (ii) analyses for modalitiesand specific symptoms yielded more circumscribed but partially overlapping lesion foci, often cutting across the above syndrometerritories; and (iii) especially for lexico-semantic capacities more specialized clinical test-batteries are required to delineateprecise lesion patterns at this linguistic level. In sum this is the first report on a successful lesion-delineation of syndrome-basedaphasia classification highlighting the relevance of vascular distribution for the syndrome level while confirming and extending anumber of more linguistically motivated differentiations, based on clinically used tests. We consider such a comprehensive viewreaching from the syndrome to a fine-grained symptom-oriented assessment mandatory to converge neurolinguistic, patholin-guistic and clinical-therapeutic knowledge on language-competence and impairment. |
| Databáze: | OpenAIRE |
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