Hippocampal correlates of episodic memory in Parkinson's disease: A systematic review of magnetic resonance imaging studies.
Dana PourzinalJi Hyun J YangArnold BakkerKatie L McMahonGerard J ByrneGregory M PontoneZoltan MariNadeeka N W DissanayakaPublished in: Journal of neuroscience research (2021)
The present review asks whether magnetic resonance imaging (MRI) studies are able to define neural correlates of episodic memory within the hippocampus in Parkinson's disease (PD). Systematic searches were performed in PubMed, Web of Science, Medline, CINAHL, and EMBASE using search terms related to structural and functional MRI (fMRI), the hippocampus, episodic memory, and PD. Risk of bias was assessed for each study using the Newtown-Ottawa Scale. Thirty-nine studies met inclusion criteria; eight fMRI, seven diffusion MRI (dMRI), and 24 structural MRI (14 exploring whole hippocampus and 10 exploring hippocampal subfields). Critical analysis of the literature revealed mixed evidence from functional and dMRI, but stronger evidence from sMRI of the hippocampus as a biomarker for episodic memory impairment in PD. Hippocampal subfield studies most often implicated CA1, CA3/4, and subiculum volume in episodic memory and cognitive decline in PD. Despite differences in imaging methodology, study design, and sample characteristics, MRI studies have helped elucidate an important neural correlate of episodic memory impairment in PD with both clinical and theoretical implications. Natural progression of this work encourages future research on hippocampal subfield function as a potential biomarker of, or therapeutic target for, episodic memory dysfunction in PD.
Keyphrases
- magnetic resonance imaging
- contrast enhanced
- working memory
- cerebral ischemia
- cognitive decline
- diffusion weighted imaging
- case control
- computed tomography
- systematic review
- magnetic resonance
- oxidative stress
- mild cognitive impairment
- public health
- cognitive impairment
- subarachnoid hemorrhage
- resting state
- mass spectrometry
- prefrontal cortex
- brain injury
- tyrosine kinase
- photodynamic therapy
- current status
- temporal lobe epilepsy
- single cell