Objective: To test the association between confrontation naming performance and Alzheimer’s disease (AD) co-pathology as defined by cerebrospinal fluid (CSF) biomarkers in Lewy body dementia (LBD) patients.
Background: LBD (dementia with Lewy bodies [DLB] and Parkinson’s disease dementia [PDD]) is characterized by alpha-synuclein pathology, but ~50% have sufficient AD co-pathology at autopsy for a second neuropathological diagnosis. These patients have worse overall prognosis, but little is known regarding the specific influence of co-pathology on cognition. While LBD cognitive impairment is heterogeneous with core features of executive and visuospatial dysfunction, language difficulty is not uncommon and previous postmortem work suggests difficulties in temporal lobe-mediated confrontation naming tasks may be associated with AD tau co-pathology.
Method: We selected LBD patients (n=58; DLB=39; PDD=19) with available CSF and neuropsychological data. CSF Abeta42 and total-tau concentrations were measured using the Luminex platform. We used an autopsy-validated cutpoint (Total-tau:Abeta42 ratio>0.3) to categorize patients as LBD with (LBD+AD=22) and without (LBD-AD=36) AD co-pathology. We used ANCOVA to test between-group comparisons on confrontation naming (30-item Boston Naming Test=BNT) and measures of executive (Letter Fluency=LF) and visuospatial (modified 6-item Judgment of Line Orientation=JOLO) functioning while adjusting for age, sex, and intervals from dementia onset and CSF collection to test date. Spearman correlation related BNT performance to CSF analytes.
Results: LBD+AD (mean=23.23, n=22) performed worse on BNT than LBD-AD (mean=26.03, n=36) (F=6.355, p<0.05; demographic covariates were not associated with BNT, p>0.1). In contrast, both groups were similarly impaired on LF (LBD+AD mean=8.53, n=15; LBD-AD mean=9.67, n=27) (F=0.397, p>0.1) and JOLO (LBD+AD mean=3.50, n=8; LBD-AD mean=3.86, n=21) (F=0.153, p>0.1). There were no significant differences between clinical phenotype on any tests (p>0.1). We also found a correlation between lower BNT score and increased CSF total-tau (rho=-0.28, p<0.05) but not ABeta42(rho=0.13, p>0.1).
Conclusion: These findings suggest that AD tau co-pathology has a specific influence on phenotypic expression of LBD in the language domain. BNT may be a useful clinical test to screen for likely mixed pathology, which has important prognostic implications.
References: Previously presented at American Academy of Neurology (AAN) Annual Meeting, April 2020.
To cite this abstract in AMA style:
E. Howard, D. Irwin, K. Rascovsky, N. Nevler, S. Shellikeri, D. Mechanic-Hamilton, T. Tropea, A. Chen-Plotkin, A. Siderowf, D. Weintraub, L. Shaw, J. Trojanowski, M. Grossman, K. Cousins. Confrontation Naming Deficit in Lewy Body Dementia Patients with Alzheimer’s Disease Co-Pathology [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/confrontation-naming-deficit-in-lewy-body-dementia-patients-with-alzheimers-disease-co-pathology/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2020
MDS Abstracts - https://www.mdsabstracts.org/abstract/confrontation-naming-deficit-in-lewy-body-dementia-patients-with-alzheimers-disease-co-pathology/