Andrew Dimitrijevic

Research Divisions: Brain Research and Integrated Neurophysiology Research Interests: Research is directed towards neurophysiology of hearing difficulties in people who have cochlear implants using electroencephalography (EEG). Current projects include: speech and music perception, neural plasticity associated with hearing loss and restoration, working memory and measures of cognitive load, the use of mobile EEG imaging technology to monitor real-world brain function. Keywords: Speech perception, Cochlear Implant, Electroencephalography (EEG), Brain Oscillations, Mobile Brain Imaging. Detailed Description: High density EEG is used to map out brain regions underlying listening disorders. One focus is on EEG signatures of the “cocktail party” where a listener needs to focus attention on a single talker amongst many competing voices. These studies have shown that brain oscillations, in particular the alpha band, is highly correlated to attention and self-perceived “listening effort”. We also examine brain processes associated with music perception and how different instruments are encoded separately when listening an entire music piece consisting of multiple instruments. A big focus of the lab is mobile EEG imaging. This field of study goes outside the lab and into the real-world. These studies aim to characterize brain responses while a listener follows a conversation in a natural setting. Other areas of research include: cross-modal neuroplasticity associated with hearing loss and recovery with a cochlear implant and the effects of hearing loss on working memory. Collaborators: Drs. Darren Kadis and Karen Gordon METHODS USED Procedures: EEG, Electrophysiology, in-vivo electrophysiology, in-vivo recording of local field potentials, micro and macrostimulation of periphera nerves and central brain structures, stereotaxic brain surgery EQUIPMENT USED EEG systems (Neuroscan, BrainProducts, mBrainTrain Smarting Mobile), Matlab: EEGLAB, FieldTrip. Brain Electrical Source Analysis (BESA). Pupil Labs Eye Tracker.

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