INS NYC 2024 Program

Poster	Poster Session 04 Program Schedule 02/15/2024 12:00 pm - 01:15 pm Room: Shubert Complex (Posters 1-60) Poster Session 04: Neuroimaging \| Neurostimulation/Neuromodulation \| Teleneuropsychology/Technology Final Abstract #34 Assessment of functional Near-Infrared Spectroscopy Activation Patterns in Posterior Cortical Atrophy Victor Di Rita, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States Megan Schumer, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States Shoshanah Machlay, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States Alexandru Iordan, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States Benjamin Hampstead, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States Category: Neuroimaging Keyword 1: dementia - Alzheimer's disease Keyword 2: occipital lobes Objective: Posterior cortical atrophy (PCA) is a syndrome characterized by visuospatial dysfunction and occipitoparietal hypometabolism and atrophy, which are typically caused by Alzheimer’s disease. The higher-order visual integration deficits can cause profound dysfunction in everyday life, and perhaps not surprisingly, patients often report profound difficulty during spatial navigation. The current study is the first in a series of planned projects to use functional near-infrared spectroscopy (fNIRS) to evaluate patterns of brain “activation” as those with PCA navigate carefully controlled virtual environments. Such ecologically relevant tasks may ultimately enhance the early detection of PCA and provide novel outcome measures for clinical trials. We hypothesized that the characteristic occipitoparietal dysfunction would result in reduced signal relative to cognitively intact older adults (CIA). Participants and Methods: We collected fNIRS data from eight individuals with biomarker-confirmed PCA and eight age-matched cognitively intact older adults (CIA) using a spatial navigation task previously validated in fMRI. The task is comprised of 2 runs that included both allocentric and egocentric navigation, each with three 60-second blocks separated by 18-second rest blocks. Participants were instructed to either use the various landmarks within a virtual environment to form a mental map (allocentric condition) or to remember the sequence of turns taken through an environment lacking landmarks (egocentric condition). We collected data with two continuous-wave NIRSport2 devices via full-head montages developed for each group using a total of 107 channels in the CIA group and 99 channels in the PCA group. We preprocessed and analyzed the data with the Brain AnalyzIR toolbox and used EasyTopo for data visualization and restricted comparisons to channels available for both groups. Results: Activation patterns differed markedly between the two groups, with the CIA group exhibiting greater activation during the allocentric condition in channels covering the right superior parietal lobule and occipital cortices (i.e., superior, middle, and inferior gyri) as well as the angular gyri bilaterally. In contrast, the PCA group showed greater activation than the CIA during the egocentric condition in the right angular gyrus and superior parietal lobule but less in the left angular gyrus and the right superior and middle occipital gyri. Conclusions: We successfully used fNIRS to demonstrate the characteristic occipitoparietal dysfunction in those with PCA during an ecologically relevant spatial navigation task. These findings suggest fNIRS is a viable option for those unable to undergo functional magnetic resonance imaging in research settings as well as for ecologically relevant measures. Our ongoing work evaluates concurrent fNIRS and immersive virtual reality with the goal of establishing ecologically valid structure-function relationships.

Poster

02/15/2024
12:00 pm - 01:15 pm
Room: Shubert Complex (Posters 1-60)

Poster Session 04: Neuroimaging | Neurostimulation/Neuromodulation | Teleneuropsychology/Technology

Final Abstract #34

Assessment of functional Near-Infrared Spectroscopy Activation Patterns in Posterior Cortical Atrophy

Victor Di Rita, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States
Megan Schumer, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States
Shoshanah Machlay, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States
Alexandru Iordan, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States
Benjamin Hampstead, Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, United States

Category: Neuroimaging

Keyword 1: dementia - Alzheimer's disease
Keyword 2: occipital lobes

Objective:

Posterior cortical atrophy (PCA) is a syndrome characterized by visuospatial dysfunction and occipitoparietal hypometabolism and atrophy, which are typically caused by Alzheimer’s disease. The higher-order visual integration deficits can cause profound dysfunction in everyday life, and perhaps not surprisingly, patients often report profound difficulty during spatial navigation. The current study is the first in a series of planned projects to use functional near-infrared spectroscopy (fNIRS) to evaluate patterns of brain “activation” as those with PCA navigate carefully controlled virtual environments. Such ecologically relevant tasks may ultimately enhance the early detection of PCA and provide novel outcome measures for clinical trials. We hypothesized that the characteristic occipitoparietal dysfunction would result in reduced signal relative to cognitively intact older adults (CIA).

Participants and Methods:

We collected fNIRS data from eight individuals with biomarker-confirmed PCA and eight age-matched cognitively intact older adults (CIA) using a spatial navigation task previously validated in fMRI. The task is comprised of 2 runs that included both allocentric and egocentric navigation, each with three 60-second blocks separated by 18-second rest blocks. Participants were instructed to either use the various landmarks within a virtual environment to form a mental map (allocentric condition) or to remember the sequence of turns taken through an environment lacking landmarks (egocentric condition). We collected data with two continuous-wave NIRSport2 devices via full-head montages developed for each group using a total of 107 channels in the CIA group and 99 channels in the PCA group. We preprocessed and analyzed the data with the Brain AnalyzIR toolbox and used EasyTopo for data visualization and restricted comparisons to channels available for both groups.

Results:

Activation patterns differed markedly between the two groups, with the CIA group exhibiting greater activation during the allocentric condition in channels covering the right superior parietal lobule and occipital cortices (i.e., superior, middle, and inferior gyri) as well as the angular gyri bilaterally. In contrast, the PCA group showed greater activation than the CIA during the egocentric condition in the right angular gyrus and superior parietal lobule but less in the left angular gyrus and the right superior and middle occipital gyri.

Conclusions:

We successfully used fNIRS to demonstrate the characteristic occipitoparietal dysfunction in those with PCA during an ecologically relevant spatial navigation task. These findings suggest fNIRS is a viable option for those unable to undergo functional magnetic resonance imaging in research settings as well as for ecologically relevant measures. Our ongoing work evaluates concurrent fNIRS and immersive virtual reality with the goal of establishing ecologically valid structure-function relationships.