Enhancing Frontal Lobes Plasticity in Mild Cognitive Impairment — PAS-MCI  

Mild Cognitive Impairment Clinical Trial

Official title: Enhancing Frontal Lobes Plasticity and Function in Patients With Mild Cognitive Impairment

Status Recruiting

Clinical Trial Summary

More than 5 million people live with Alzheimer's dementia (AD) in North America. No effective treatment exists yet probably because by the time AD has developed it is too late to intervene. Mild Cognitive Impairment (MCI) is a clinical state that typically precedes AD. In MCI, the prefrontal cortex supports compensatory mechanisms that depend on robust synaptic plasticity and that delay progression to AD. Using a neurostimulation approach that enhances prefrontal cortical plasticity in vivo, this project aims to enhance prefrontal cortical plasticity and function in patients with MCI. If successful, this project would discover a treatment modality that enhances compensation in MCI and ultimately, prevents progression to AD.

Clinical Trial Description

Paired Associative Stimulation (PAS) is a neurostimulation approach that induces cortical plasticity by simulating spike-timing-dependent plasticity. Combining PAS with electroencephalography (EEG) (PAS-EEG), we can assess dorsolateral prefrontal cortex (DLPFC) plasticity in vivo. Using PAS-EEG, we have demonstrated that patients with AD are impaired on DLPFC plasticity compared to healthy control (HC) individuals and that DLPFC plasticity is associated with working memory in AD and HC individuals. We have also shown that a 2-week course of daily PAS to the left DLPFC restores DLPFC plasticity in patients with AD and enhances their working memory.

Thus, we propose to study DLPFC plasticity and its relationship to executive function in MCI and then assess the efficacy of a 2-week course of PAS in enhancing DLPFC plasticity and executive function in this population.

If successful, this project will identify a novel neurostimulation intervention (PAS) to enhance prefrontal cortical function in MCI patients. This enhancement could result in modifying the trajectory of Alzheimer's disease by delaying the progression from MCI to clinical AD. This project will also identify a mechanism (neuroplasticity) that underlies enhanced prefrontal cortical function. Other interventions (e.g. behavioral, neurostimulation, pharmacological) could then be tested whether they engage neuroplasticity to enhance prefrontal cortical function.

The primary objectives and hypotheses of the study are as follows:

Objective 1: To compare baseline DLPFC plasticity and its relationship to executive function in MCI vs. HC participants. Hypothesis 1a: MCI participants will be impaired on PAS-LTP (TMS-induced cortical evoked activity) in the left DLPFC compared to HC participants. Hypothesis 1b: MCI participants will be impaired on 2-back d' compared to HC participants. Hypothesis 1c: MCI participants will be impaired on a composite executive function measure compared to HC participants. Hypothesis 1d: PAS-LTP will be associated with 2-back d' in MCI and HC participants after controlling for age, sex, and education. Hypothesis 1e: PAS-LTP will be associated with composite executive function measure in MCI and HC participants after controlling for age, sex, and education.

Objective 2: To assess the efficacy of a 10-session course of bilateral PAS in enhancing DLPFC plasticity and executive function in MCI participants. Hypothesis 2a: MCI participants randomized to 10-session course of active PAS will experience higher PAS-LTP in the left DLPFC immediately and 1 and 4 weeks after the course compared to MCI participants randomized to a 10-session course of PAS-C. Hypothesis 2b: MCI participants randomized to a 10-session course of active PAS will experience better 2-back performance immediately and 1 and 4 weeks following the 10-session course compared to MCI participants randomized to the course of PAS-C. Hypothesis 2c: MCI participants randomized to a 10-session course of active PAS will experience higher composite executive function scores immediately and 1 and 4 weeks following the 10-session course compared to MCI participants randomized to the course of PAS-C.

Objective 3: To assess whether changes in DLPFC plasticity mediate changes in executive function in MCI participants following the 10-session course. Hypothesis 3a: Changes in PAS-LTP immediately and 1 and 4 weeks following the 10-session course will mediate changes in 2-back d' at all of these three follow-up time points. Hypothesis 3b: Changes in PAS-LTP immediately and 1 and 4 weeks following the 10-session course will mediate changes in composite executive function measure at all of these three follow-up time points. Conditions/focus of study (primary disease or condition being studied).

Exploratory Objective 4: 4a: We will explore, in both HC and MCI participants, the relationships between wisdom as measured using the Jeste-Thomas Wisdom Index (JTWI) before baseline PAS-EEG and DLPFC plasticity at baseline. 4b: We will explore, in both HC and MCI participants, change in wisdom on JTWI as administered after baseline PAS-EEG in response to single PAS session. 4c: We will explore, in MCI participants only, change in wisdom after the 10-session course of PAS or PAS-C by administering JTWI before and after each follow-up PAS-EEG session. ;

Related Conditions & MeSH terms

• Cognitive Dysfunction
• Memory Impairment
• Mild Cognitive Impairment

• NCT number: NCT04583215
• Study type: Interventional
• Source: Centre for Addiction and Mental Health
• Contact: Tarek Rajji, MD
• Phone: 416-535-8501
• Email: tarek.rajji@camh.ca
• Status: Recruiting
• Phase: N/A
• Start date: October 12, 2020
• Completion date: December 1, 2026