The impact of lesion location on dysphagia incidence, pattern and complications in acute stroke. Part 1: dysphagia incidence, severity and aspiration.

BACKGROUND AND PURPOSE: Although early identification of patients at risk for dysphagia is crucial in acute stroke care, predicting whether a particular patient is likely to have swallowing problems based on the brain scan is difficult because a comprehensive model of swallowing control is missing. In this study whether stroke location is associated with dysphagia incidence, severity and the occurrence of penetration or aspiration was systematically evaluated relying on a voxel-based imaging analysis approach. METHODS: Two hundred acute stroke patients were investigated applying fiberoptic endoscopic evaluation of swallowing within 96 h from admission. Lesion masks were obtained from each patient's brain scan and registered to standard space. The percentage of lesioned volume of 137 atlas-based brain regions was determined in each case. Region-specific odds ratios were afterwards calculated with respect to presence of dysphagia, its severity and occurrence of penetration or aspiration. RESULTS: In all, 165 patients were diagnosed with dysphagia, 80 of whom had severe swallow impairment. For each investigated item there were significant differences of regional percentage infarction in distinct brain areas between affected patients and those who did not present with that specific dysfunction. In particular, right hemispheric lesions of the pre- and post-central gyri, opercular region, supramarginal gyrus and respective subcortical white matter tracts were related to dysphagia, with post-central lesions being especially associated with severe swallowing impairment. CONCLUSIONS: Distinct brain lesion locations are related to the incidence, severity and pattern of swallowing dysfunction.

[Dysphagia diagnostics and therapy of acute stroke: federal survey of certified stroke units]. / Dysphagiediagnostik und -therapie des akuten Schlaganfalls : Eine bundesweite Erhebung auf zertifizierten Stroke-Units.

BACKGROUND: Due to malnutrition and aspiration pneumonia dysphagia is associated with increased morbidity and mortality in acute stroke patients. Early detection of patients at risk of dysphagia leading to timely treatment improves the outcome. METHODS: A survey concerning the current state of dysphagia diagnostics and therapy was carried out among certified stoke units in Germany. RESULTS: Of the 163 invited hospitals 51% participated in the study. A standardized dysphagia program lying mainly within the responsibility of speech language therapists (64%) is established in 94%. Main elements are swallowing assessments carried out by nurses (72%) and the clinical swallowing examination (93%). Instrumental diagnostics are available in 55% with videoendoscopy (52%) being more widely used than videofluoroscopy (17%). In the acute stage nutrition with texture modified diets is the primary therapeutic strategy. CONCLUSIONS: Structured programs for the diagnosis and treatment of dysphagia have generally been established but individual strategies differ and differences in the quality of care are obvious.

Local sphere-based co-registration for SAM group analysis in subjects without individual MRI.

Synthetic aperture magnetometry (SAM) is a powerful MEG source localization method to analyze evoked as well as induced brain activity. To gain structural information of the underlying sources, especially in group studies, individual magnetic resonance images (MRI) are required for co-registration. During the last few years, the relevance of MEG measurements on understanding the pathophysiology of different diseases has noticeable increased. Unfortunately, especially in patients and small children, structural MRI scans cannot always be performed. Therefore, we developed a new method for group analysis of SAM results without requiring structural MRI data that derives its geometrical information from the individual volume conductor model constructed for the SAM analysis. The normalization procedure is fast, easy to implement and integrates seamlessly into an existing landmark based MEG-MRI co-registration procedure. This new method was evaluated on different simulated points as well as on a pneumatic index finger stimulation paradigm analyzed with SAM. Compared with an established MRI-based normalization procedure (SPM2) the new method shows only minor errors in single subject results as well as in group analysis. The mean difference between the two methods was about 4 mm for the simulated as well as for finger stimulation data. The variation between individual subjects was generally higher than the error induced by the missing MRIs. The method presented here is therefore sufficient for most MEG group studies. It allows accomplishing MEG studies with subject groups where MRI measurements cannot be performed.