Clinical and Neuroimaging Correlates of Cognitive Impairment in Parkinson’s Disease
Frank Ramirez1, Thiago Macedo e Cordeiro2, Erin Furr-Stimming1, Natalia Pessoa Rocha1
1Neurology, University of Texas Health Science Center-Houston, 2Neurology, UTHealth Science Center at San Antonio
Objective:
Define clinical correlates of cognitive impairment in Parkinson’s disease (PD) patients of low education level and identify structural brain predictors of cognitive performance.
Background:
Cognitive assessments for PD have limitations in evaluating populations of lower education levels or with mild cognitive impairments. Symptom severity and diagnoses are aided by clinical scales that demand a minimum level of cognition and literacy. Interventions, i.e. DBS, and clinical trials, generally require prior cognitive evaluation to ensure patient eligibility and comprehension. These scales are subject to flooring effects that exclude groups with cognitive deficits. If specific brain region atrophy correlates to clinical assessments, this could be an alternative option to the intervention vetting process.
Design/Methods:
Retrospective analysis of MRI-imaging and clinical data from 41 PD individuals (15F/25M, median age 65 years, education level median 6.5 years, and illness duration median 10 years). Group comparisons for (control vs. PD) and (PD cognitive impairment vs. PD without cognitive impairment) were assessed by conventional statistics (Student’s t-test, Mann-Whitney test). Correlation analysis (Pearson, Spearman) was run to investigate the association between Mattis Dementia Rating Scale (MDRS) scores and neuroimaging data. Clinical variables (age, gender, Unified Parkinson’s Disease Rating Scale (UPDRS) total score, and volumetric/cortical thickness measurements analyzed in a logistic regression model as potential predictors of cognitive impairment in PD.
Results:
Cortical thickness and volume differences between 22 brain regions of interest (ROI) in both hemispheres for (PD vs healthy controls) were observed. A low (≤130) MDRS-total score, reflective of lower cognitive performance, correlated with the cortical thickness (LH/RH-insula, RH-entorhinal cortex, LH-pars orbitalis, LH-supramarginal gyrus) and RH-fusiform gyrus volume. Additionally, the UPDRS-total score was the only significant predictor of cognitive impairment in the regression analyses.
Conclusions:
The UPDRS-total score, a surrogate measure of total PD disease burden, was the most consistent clinical correlate of cognitive impairment in PD.
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