Extraction of auditory evoked potentials from ongoing eeg

Download

index.pdf

Date

2005

Author

Aydın, Serap

Metadata

Show full item record

Item Usage Stats

163
views

57
downloads

In estimating auditory Evoked Potentials (EPs) from ongoing EEG the number of sweeps should be reduced to decrease the experimental time and to increase the reliability of diagnosis. The rst goal of this study is to demon- strate the use of basic estimation techniques in extracting auditory EPs (AEPs) from small number of sweeps relative to ensemble averaging (EA). For this purpose, three groups of basic estimation techniques are compared to the traditional EA with respect to the signal-to-noise ratio(SNR) improve- ments in extracting the template AEP. Group A includes the combinations of the Subspace Method (SM) with the Wiener Filtering (WF) approaches (the conventional WF and coherence weighted WF (CWWF). Group B con- sists of standard adaptive algorithms (Least Mean Square (LMS), Recursive Least Square (RLS), and one-step Kalman ltering (KF). The regularization techniques (the Standard Tikhonov Regularization (STR) and the Subspace Regularization (SR) methods) forms Group C. All methods are tested in sim- ulations and pseudo-simulations which are performed with white noise and EEG measurements, respectively. The same methods are also tested with experimental AEPs. Comparisons based on the output signal-to-noise ratio (SNR) show that: 1) the KF and STR methods are the best methods among the algorithms tested in this study,2) the SM can reduce the large amount of the background EEG noise from the raw data, 3) the LMS and WF algo- rithms show poor performance compared to EA. The SM should be used as 1 a pre-lter to increase their performance. 4) the CWWF works better than the WF when it is combined with the SM, 5) the STR method is better than the SR method. It is observed that, most of the basic estimation techniques show denitely better performance compared to EA in extracting the EPs. The KF or the STR e®ectively reduce the experimental time (to one-fourth of

Subject Keywords

Research.

URI

http://etd.lib.metu.edu.tr/upload/12606641/index.pdf
https://hdl.handle.net/11511/15770

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Serum Glycan Signatures of Gastric Cancer Özcan Kabasakal, Süreyya; Ruhaak, L. Renee; Torres, Javier; Cooke, Cara L.; An, Hyun Joo; Hua, Serenus; Williams, Cynthia C.; Dimapasoc, Lauren M.; Kim, Jae Han; Camorlinga-Ponce, Margarita; Rocke, David; Lebrilla, Carlito B.; Solnick, Jay V. (American Association for Cancer Research (AACR), 2014-02-01) Glycomics, a comprehensive study of glycans expressed in biologic systems, is emerging as a simple yet highly sensitive diagnostic tool for disease onset and progression. This study aimed to use glycomics to investigate glycan markers that would differentiate patients with gastric cancer from those with nonatrophic gastritis. Patients with duodenal ulcer were also included because they are thought to represent a biologically different response to infection with Helicobacter pylori, a bacterial infection tha...
Inhibitory effects of plant originated extracts on bovine lens aldose reductase Zaimoğlu, Selin; Çoruh, Nursen; Department of Biotechnology (2004) Aldose reductase, E.C.1.1.1.21, catalyzes the reduction of different types of aldehydes to their corresponding alcohols, and especially reduces various aldo-sugars using NADPH as the coenzyme. Under hyperglycemic conditions aldose reductase is involved in the development of diabetic complications. As a result, interest has been placed over the years on the development of potent aldose reductase inhibitors for possible use in the therapy of these severe diabetic complications. In this study, aldose reductase...
Properties of light emitting diodes following cobalt-60 irridiation Özcan, Şafak; Günal, İbrahim; Department of Physics (2004) The main purpose of this study is to investigate the effects of gamma radiation on the properties of the light emitting diodes. GaP and GaAsP LEDs are used in the study. It is observed that the exposure of a light emitting diode affects its various properties. A cobalt-60 gamma-cell is used to irradiate the selected light emitting diodes. For the different total doses of gamma pre-irradiation and post-irradiation I-V characteristics and spectral responses are recorded. The capacitance characteristics are me...
Steering of redundant robotic manipulators and spacecraft integrated power and attitude control-control moment gyroscopes Altay, Alkan; Tekinalp, Ozan; Department of Aerospace Engineering (2005) In this thesis, recently developed Blended Inverse (B-inverse) steering law is applied to two different redundant actuator systems. First, repeatability of Binverse is demonstrated on a redundant robotic manipulator. Its singularity avoidance and singularity transition performance is also demonstrated on the same actuator system. It is shown that B-inverse steering law provides singularity avoidance, singularity transition and repeatability. Second, its effectiveness is demonstrated for an Integrated Power ...
Stability Augmentation of a Semi-Autonomous Wheelchair Ayık, H. Müjde; Özgören, Mustafa Kemal; Department of Mechanical Engineering (2004) In this thesis, the dynamic modeling of a wheelchair-human system is performed, and the effects of steering action and sudden slope changes along the path on the system stability are analyzed for different road and driving conditions. For the cases where the wheelchair system is unstable three methods are proposed for stability augmentation. This study is performed to improve the stability of the wheelchair system under varying road conditions so as to increase the limit of independency for wheelchair users...

Citation Formats

S. Aydın, “Extraction of auditory evoked potentials from ongoing eeg,” Ph.D. - Doctoral Program, Middle East Technical University, 2005.