Functional Neuroimaging Studies

Deafness &Other Communication Disorders

Investigators

Linked publications & trials

Abstract

Functional imaging techniques are being used to characterize brain activation patterns in normal subjects and individuals with neurological disorders affecting human communication. Brain activation patterns characterized using PET, fMRI, EEG, MEG and other brain mapping techniques are used to characterize phenotypic presentation, pathophysiology and treatment of communication disorders. PET scans are performed on the GE Advance and Scanditronix PC2048-15B tomographs using the H215O and C-11 Raclopride methods. Data are analyzed using Statistical Parametric Mapping software and newer covariance techniques developed in the section. fMRI studies are performed on 1.5 and 3.0 Tesla instruments. Functional images are acquired using spiral, echoplanar imaging and arterial spin-tagging methods. Data are analyzed using MEDx, AFNI, and SPM software and newer covariance techniques developed in the Section. High density EEG studies are conducted using a Neuroscan 64 channel system and analyzed using BESA, Neuroscan and Brain Voyager packages. A series of combined fMRI and EEG/ERP studies of language in normal volunteers demonstrated unique task related patterns of brain activity for reading, naming, and semantic processing that will serve as a baseline when these paradigms are used to study language recovery in post-stroke aphasia. An arterial spin taggin fMRI study demonstrated the feasibility of studying continuous speech with this method (not possible with standard fMRI techniques because of artifact production) that will be useful in studying recovery of syntactic abilities in aphasics as well. Structural MRI studies evaluating relationships between aphasic symptoms and lesion location are ongoing, with over 30 patients studied thus far. PET studies in deaf subjects using American Sign Language demonstrated modality independent features of language processing, strongly lateralized to the left hemisphere regardless of the hand used in signing. Other PET studies demonstrated unique patterns of brain activity for production of voice in humans. A number of additional studies in which fMRI and EEG methods are combined to study language processing in controls and aphasic are being prepared for publication.