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4 Compensatory Functional Activation During Motion Discrimination in Parkinson’s Disease

Published online by Cambridge University Press:  21 December 2023

Stephanie R Nitschke*
Affiliation:
The Mind Research Network, Albuquerque, NM, USA.
Nicholas Shaff
Affiliation:
The Mind Research Network, Albuquerque, NM, USA.
Chris Wertz
Affiliation:
The Mind Research Network, Albuquerque, NM, USA.
David Stone
Affiliation:
The Mind Research Network, Albuquerque, NM, USA.
Andrei Vakhtin
Affiliation:
The Mind Research Network, Albuquerque, NM, USA.
Andrew Mayer
Affiliation:
The Mind Research Network, Albuquerque, NM, USA.
Elena K. Festa
Affiliation:
Brown University, Providence, RI, USA.
William C. Heindel
Affiliation:
Brown University, Providence, RI, USA.
David P. Salmon
Affiliation:
University Of California San Diego, San Diego, CA, USA.
Gerson Suarez Cedeno
Affiliation:
University Of New Mexico, Albuquerque, NM, USA
Amanda Deligtisch
Affiliation:
University Of New Mexico, Albuquerque, NM, USA
Sarah Pirio Richardson
Affiliation:
University Of New Mexico, Albuquerque, NM, USA
Sephira G. Ryman
Affiliation:
The Mind Research Network, Albuquerque, NM, USA.
*
Correspondence: Stephanie Nitschke, The Mind Research Network, snitschke@mrn.org
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Abstract

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Objective:

PD patients commonly exhibit executive dysfunction early in the disease course which may or may not predict further cognitive decline over time. Early emergence of visuospatial and memory impairments, in contrast, are more consistent predictors of an evolving dementia syndrome. Most prior studies using fMRI have focused on mechanisms of executive dysfunction and have demonstrated that PD patients exhibit hyperactivation that is dependent on the degree of cognitive impairment, suggestive of compensatory strategies. No study has evaluated whether PD patients with normal cognition (PD-NC) and PD patients with Mild Cognitive Impairment (PD-MCI) exhibit compensatory activation patterns during visuospatial task performance.

Participants and Methods:

10 PD-NC, 12 PD-MCI, and 14 age and sex-matched healthy controls (HC) participated in the study. PD participants were diagnosed with MCI based on the Movement Disorders Society Task Force, Level II assessment (comprehensive assessment). Functional magnetic resonance imaging (fMRI) was performed during a motion discrimination task that required participants to identify the direction of horizontal global coherent motion embedded within dynamic visual noise under Low and High coherence conditions. Behavioral accuracy and functional activation were evaluated using 3 * 2 analyses of covariance (ANCOVAs) (group [HC, PD-NC, PD-MCI] * Coherence [High vs. Low]) accounting for age, sex, and education. Analyses were performed in R (v4.1.2(Team, 2013)).

Results:

PD-MCI (0.702± 0.269) patients exhibited significantly lower accuracy on the motion discrimination task than HC (0.853 ± 0.241; p = 0.033) and PD-NC (0.880 ± 0.208; p =0.039). A Group * Coherence interaction was identified in which several regions, including orbitofrontal, posterior parietal and occipital cortex, showed increased activation during High relative to Low coherence trials in the PD patient groups but not in the HC group. HC showed default mode deactivation and frontal-parietal activation during Low relative to High coherence trials that was not evident in the patient groups.

Conclusions:

PD-MCI patients exhibited worse visuospatial performance on a motion discrimination task than PD-NC and HC participants and exhibited hyperactivation of the posterior parietal and occipital regions during motion discrimination, suggesting possible compensatory activation.

Type
Poster Session 04: Aging | MCI
Copyright
Copyright © INS. Published by Cambridge University Press, 2023