FDG PET/CT hypometabolism and verbal memory assessment in mesial temporal lobe epilepsy
Abstract number :
3.418
Submission category :
11. Behavior/Neuropsychology/Language / 11A. Adult
Year :
2021
Submission ID :
1886450
Source :
www.aesnet.org
Presentation date :
12/6/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:56 AM
Authors :
Racheal Smetana, PsyD - University of Virginia Health; Prem Batchala, MD - Assistant Professor, Radiology and Medical Imaging, University of Virginia Health; Tamer Albataineh, MD - Nuclear Medicine Fellow, Radiology, University of Virginia Health; Bern Lee, PhD - Neuropsychologist, Neurology, Ochsner Health; Salma Abbas, MD - Instructor, Radiology and Medical Imaging, University of Virginia Health; Nathan Fountain, MD - Director of F.E. Dreifuss Comprehensive Epilepsy Program, Neurology, University of Virginia Health; Donna Broshek, PhD, ABPP-CN - John Edward Fowler Professor, Psychiatry & Neurobehavioral Sciences, University of Virginia Health; Mark Quigg, MD - Professor of Neurology, Neurology, University of Virginia Health
Rationale: 18F-FDG PET/CT and neuropsychological assessments are often used in the preoperative evaluation of patients with intractable epilepsy. In mesial temporal lobe epilepsy (MTLE), temporal lobe hypometabolism can be identified on inter-ictal 18F-FDG PET/CT. Similarly, MTLE patients demonstrate deficits in neuropsychological tasks associated with the temporal lobe (e.g., memory). Previous studies on MTLE demonstrated correlation between hypometabolism in the dominant temporal lobe and verbal memory deficits for MTLE. Such studies used outdated tests, a single verbal memory measure without analyzing learning, or did not examine temporal lobe structures. We hypothesize that deficits in verbal learning and memory correlate with hypometabolism in the dominant temporal lobe. We further explore relationships of verbal learning/memory with hypometabolism in dominant and non-dominant temporal lobe structures, including the hippocampus and amygdala, cingulate and thalamic structures, and medial and lateral temporal lobe structures.
Methods: Data were gathered via retrospective review of adult MTLE patients who underwent pre-surgical evaluation and completed pre-operative 18F-FDG PET/CT and comprehensive neuropsychological assessment at University of Virginia (UVA) Health between 2012 and 2021 (n=30). Quantitative PET/CT analysis (region-based Z-scores of the temporal lobe structures) was calculated using MIMneuro®. Neuropsychological data for IQ and verbal memory (WMS-IV Logical Memory [LMI & LMII]; Rey Auditory Verbal Learning Test [RAVLT] Learning and Long Delay Recall) were converted to Z-scores. Initial relationships between clinical variables, regional hypometabolism, and neuropsychological data were examined with Pearson’s correlations. Stepwise linear regression was used to determine the relationship between regions of hypometabolism and verbal learning/memory at alpha of 0.05, with IQ and years of education entered as covariates.
Results: Scores on RAVLT Learning were associated with hypometabolism in the dominant inferior temporal lobe (p=.027) and non-dominant cingulate gyrus (p=.044). RAVLT Long Delay Recall was associated with hypometabolism in the non-dominant hippocampus (p=.029), and dominant (p=.046) and non-dominant (p=.034) precuneus. LMI was associated with hypometabolism in the dominant hippocampus (p=.036) and dominant middle temporal lobe (p=.044). LMII was associated with hypometabolism in the dominant amygdala (p=.045) and non-dominant hippocampus (p=.030).
Conclusions: Hypometabolic regions varied on learning and delayed recall trials across measures. We did not find consistent association between dominant left hippocampus hypometabolism and verbal memory, and many non-dominant structures were associated with verbal memory deficits. This is discrepant from the material-specific model of memory functioning and indicates that observed verbal memory deficits in MTLE likely emerge from networks within and beyond dominant lobe limbic structures.
Funding: Please list any funding that was received in support of this abstract.: None.
Behavior