P4‐349: Clinical efficacy of low dose levetiracetam for hippocampal hyperactivity in amnestic mild cognitive impairment

Levetiracetam for the treatment of mild cognitive impairment in Parkinson's disease: a double-blind controlled proof-of-concept trial protocol

BACKGROUND

Mild memory impairment, termed amnestic mild cognitive impairment (aMCI), is associated with rapid progression towards dementia in Parkinson's disease (PD). Studies have shown hyperactivation of hippocampal DG/CA3 subfields during an episodic memory task as a biomarker of aMCI related to Alzheimer's disease. This project investigates the feasibility of a trial to establish the efficacy of a repurposed antiepileptic drug, levetiracetam, in low doses as a putative treatment to target DG/CA3 hyperactivation and improve episodic memory deficits in aMCI in PD. Based on previous work, it is hypothesized that levetiracetam will normalize DG/CA3 overactivation in PD-aMCI participants and improve memory performance.

METHODS

Twenty-eight PD-aMCI participants, 28 PD participants without memory impairment (PD-nMI), and 28 healthy controls will be recruited. PD-aMCI participants will undertake a 12-week randomized, placebo-controlled, double-blind cross-over trial with a 14-day treatment of 125 mg levetiracetam or placebo twice daily, separated by a 4-week washout period. After each treatment period, participants will complete an episodic memory task designed to tax hippocampal subregion-specific function during high-resolution functional magnetic resonance imaging (fMRI). PD-nMI and healthy controls will undergo the fMRI protocol only, to compare baseline DG/CA3 subfield activity.

RESULTS

Episodic memory task performance and functional activation in the DG/CA3 subfield during the fMRI task will be primary outcome measures. Global cognition, PD severity, and adverse events will be measured as secondary outcomes. Recruitment, eligibility, and study completion rates will be explored as feasibility outcomes.

CONCLUSIONS

This study, the first of its kind, will establish hippocampal subregion functional impairment and proof of concept of levetiracetam as an early therapeutic option to reduce dementia risk in PD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04643327 . Registered on 25 November 2020.

Alzheimer's Disease as a Result of Stimulus Reduction in a GABA-A-Deficient Brain: A Neurocomputational Model

Several research studies point to the fact that sensory and cognitive reductions like cataracts, deafness, macular degeneration, or even lack of activity after job retirement, precede the onset of Alzheimer's disease. To simulate Alzheimer's disease earlier stages, which manifest in sensory cortices, we used a computational model of the koniocortex that is the first cortical stage processing sensory information. The architecture and physiology of the modeled koniocortex resemble those of its cerebral counterpart being capable of continuous learning. This model allows one to analyze the initial phases of Alzheimer's disease by “aging” the artificial koniocortex through synaptic pruning, by the modification of acetylcholine and GABA-A signaling, and by reducing sensory stimuli, among other processes. The computational model shows that during aging, a GABA-A deficit followed by a reduction in sensory stimuli leads to a dysregulation of neural excitability, which in the biological brain is associated with hypermetabolism, one of the earliest symptoms of Alzheimer's disease.