Gerald T. Voelbel

CUNY Graduate Center, New York City, New York, United States

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Publications (8)14.42 Total impact

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    ABSTRACT: The present study utilized functional near infrared spectroscopy (fNIRS) to detect neural activation differences in the orbitofrontal brain region between individuals with multiple sclerosis (MS) and healthy controls (HCs) during a working memory (WM) task. Thirteen individuals with MS and 12 HCs underwent fNIRS recording while performing the n-back WM task with four levels of difficulty (0-, 1-, 2-, and 3-back). Subjects were fitted with the fNIRS cap consisting of 30 'optodes' positioned over the forehead. The results revealed different patterns of brain activation in MS and HCs. The MS group showed an increase in brain activation, as measured by the concentration of oxygenated hemoglobin (oxyHb), in the left superior frontal gyrus (LSFG) at lower task difficulty levels (i.e. 1-back), followed by a decrease at higher task difficulty (2- and 3-back) as compared with the HC group. HC group achieved higher accuracy than the MS group on the lower task loads (i.e. 0- and 1-back), however there were no performance differences between the groups at the higher task loads (i.e. 2- and 3-back). Taken together, the results suggest that individuals with MS experience a task with the lower cognitive load as more difficult than the HC group, and the brain activation patterns observed during the task confirm some of the previous findings from functional magnetic resonance imaging (fMRI) studies. This study is the first to investigate brain activation by utilizing the method of fNIRS in MS during the performance of a cognitive task.
    Brain Imaging and Behavior 06/2014; · 2.67 Impact Factor
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    ABSTRACT: Diffusion tensor imaging (DTI) has widely been used to investigate the microstructural damage of white matter tracts that occur in individuals with traumatic brain injury (TBI). In the current review, we discuss the white matter regions which are commonly affected in adults with TBI. We also describe the current literature that has utilized DTI to investigate the relationship between microstructural integrity with neuropsychological performance and clinical outcome measures. Finally, a model is presented of the potential utilization of DTI as a biomarker of efficacy in neurorehabilitation for individuals with TBI.
    Neurorehabilitation 01/2012; 31(3):281-93. · 1.42 Impact Factor
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    ABSTRACT: The current study examined the relationship between two separate but complementary methods of assessing executive functions in individuals with multiple sclerosis (MS): (1) a neurocognitive approach with the Tower of London(-DX) (TOL-DX) test and (2) a functional top-down approach with the Executive Function Performance Test (EFPT). Sixty-eight individuals with MS (79% female) and 38 healthy controls (68% female) were administered both the TOL-DX test and the EFPT. For the group with MS, significant differences were found on the TOL-DX test and the EFPT executive components and functional tasks. For the group with MS, the number of moves to complete the TOL-DX tasks was significantly positively correlated to the Organization and Sequencing executive components of the EFPT and the Simple Cooking and Bill Payment tasks of the EFPT. The results demonstrate the relationship of executive function behavior and performance of instrumental activities of daily living tasks.
    OTJR Occupation Participation Health 01/2011; 31(1):S30-7. · 0.80 Impact Factor
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    ABSTRACT: The premise of this report is that functional Near Infrared Spectroscopy (fNIRS) imaging data contain valuable physiological information that can be extracted by using analysis techniques that simultaneously consider the components of the measured hemodynamic response [i.e., levels of oxygenated, deoxygenated and total hemoglobin (oxyHb, deoxyHb and totalHb, respectively)]. We present an algorithm for examining the spatiotemporal co-variations among the Hb components, and apply it to the data obtained from a demonstrational study that employed a well-established visual stimulation paradigm: a contrast-reversing checkerboard. Our results indicate that the proposed method can identify regions of tissue that participate in the hemodynamic response to neuronal activation, but are distinct from the areas identified by conventional analyses of the oxyHb, deoxyHb and totalHb data. A discussion is provided that compares these findings to other recent studies using fNIRS techniques.
    NeuroImage 05/2009; · 6.25 Impact Factor
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    ABSTRACT: Multiple Sclerosis (MS) is a disease of the central nervous system affecting millions of people worldwide. In addition to the disabling physical symptoms of MS, roughly 65% of individuals with MS also experience significant cognitive dysfunction, especially in the domains of learning/memory, processing speed (PS) and working memory (WM). The purpose of this review is to examine major topics in research on cognitive dysfunction, as well as review recent functional magnetic resonance imaging (fMRI) studies focusing on cognitive dysfunction in MS. Additionally, directions for future research are discussed.
    Frontiers in Bioscience 02/2009; 14:1730-44. · 3.29 Impact Factor
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    ABSTRACT: An essential component for a practical noninvasive brain-computer interface (BCI) system is data recording technology that can access the information-processing activity of the brain with high fidelity and throughput. Functional near-infrared spectroscopic (fNIRS) imaging is a methodology that shows promise in meeting this need, having a demonstrated sensitivity to both the slow hemodynamic response that follows neuroactivation and to the lower amplitude fast optical response that is considered a direct correlate of neuroactivation. In this report we summarize the technology integration strategy we have developed that permits detection of both signal types with a single measuring platform, and present results that document the ability to detect these data types transcranially in response to two different visual paradigms. Also emphasized is the effectiveness of different data analysis approaches that serve to isolate signals of interest. The findings support the practical utility of NIRS-based imaging methods for development of BCI applications.
    Foundations of Augmented Cognition. Neuroergonomics and Operational Neuroscience, 5th International Conference, FAC 2009 Held as Part of HCI International 2009 San Diego, CA, USA, July 19-24, 2009, Proceedings; 01/2009
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    ABSTRACT: We have developed a method for dividing the hemoglobin signal into six discrete categories that correspond to different states of vascular autoregulation. Here we use it to reveal physiologically meaningful differences among three subject groups.
    03/2008;
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