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The use of resting-state functional connectivity MRI (fcMRI) in the evaluation of the swallowing network areas in healthy adults and chronic stroke patients

Grant number: 13/26715-6
Support type:Scholarships abroad - Research
Effective date (Start): September 01, 2014
Effective date (End): August 31, 2015
Field of knowledge:Health Sciences - Speech Therapy
Principal Investigator:Lucia Figueiredo Mourão
Grantee:Lucia Figueiredo Mourão
Host: Georgia A. Malandraki
Home Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
Local de pesquisa : Columbia University in the City of New York, United States  

Abstract

Resting state functional connectivity using Magnetic resonance (Rs-fMRI) is a relatively new and powerful method for evaluating regional interactions that occur when a subject is not performing an explicit task. Swallowing is a complex sensorimotor activity. Neural imaging studies of swallowing indicate that multiple cortical regions are involved in the neural control of swallowing in healthy adults. These included pericentral and perisylvian areas, the cingulate gyrus, the insula, thalamus, basal ganglia nuclei, premotor and prefrontal regions, parieto-occipital areas, and the cerebellum. Older adults seem to exhibit a more symmetrical/bilateral cortical control of swallowing, while younger adults tend to generally exhibit this control in the dominant hemisphere, which may indicate neural compensatory mechanisms of the aging brain. A cerebral lesion, as a consequence of a vascular cerebral accident, could result in swallowing dysfunction. In a study of cerebral activation of swallowing in unilateral stroke dysphagic patients, using fMRI, results revealed that recovery is related to cortical swallowing representation in the compensation or recruited areas of the intact hemisphere. Thus, the swallowing process might require a compensatory mechanism after stroke. Our primary aim in this study is to identify the functional connectivity of the swallowing network areas in healthy adults, and in patients with chronic stroke and dysphagia. We will attempt this by using resting state fcMRI. Our hypothesis is that functional connectivity will be relatively intact in the healthy groups but reduced or altered in the stroke patients. Methods: ten chronic stroke patients and ten healthy right-handed adults will be recruited. All participants will be evaluated by an oral sensorimotor examination, the mini mental status examination, a depression scale based on Hachinski Ischemia scale score, and with a Fiberoptic Endoscopic Evaluation of Swallowing (FEES). All participants will be also asked to refrain from any alcohol and caffeine use for 12 hours prior to the experiment. In the Stroke Group (SG), the participants will have been diagnosed with ischemic stroke, unilateral cerebral lesion, and dysphagia (diagnosed by FEES). More than six months must have passed after the stroke for the patient to be included in the study, and patients must have a level of aphasia that is mild enough not to compromise the execution of scan instructions. The inclusion criteria for the healthy participants will be: absence of a history of speech, language, or swallowing difficulties, or any neurological involvement. The control group will be age and sex matched with the SG. During the resting state experiment scan, the participants will be instructed to "relax, stay still, close your eyes and do not fall asleep". The experiment will take about 30 minutes. Functional connectivity will be extracted from the spontaneous activity of the resting brain. During the resting state, high temporal coherence of low-frequency (<0.08 Hz) fluctuations (LFFs) in fMRI time series will be observed between spatially distinct functionally related brain regions that are identified as swallowing network areas. Seed based connectivity analyses will be performed with 6mm to 8mm radius seed regions in known swallowing network areas, such as primary and secondary motor and sensory cortices, anterior and posterior insula, frontal operculum, and anterior cingulate gyrus. All participants will be familiarized with the experimental procedures before beginning the study. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
MOURAO, LUCIA FIGUEIREDO; FRIEL, KATHLEEN M.; SHEPPARD, JUSTINE JOAN; KUO, HSING-CHING; LUCHESI, KAREN FONTES; GORDON, ANDREW M.; MALANDRAKI, GEORGIA A. The Role of the Corpus Callosum in Pediatric Dysphagia: Preliminary Findings from a Diffusion Tensor Imaging Study in Children with Unilateral Spastic Cerebral Palsy. DYSPHAGIA, v. 32, n. 5, p. 703-713, OCT 2017. Web of Science Citations: 4.

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