Enhancing Spatial Navigation Using Non-Invasive Brain Stimulation

Remembering how to travel from one location to another is critical in everyday life, yet this vital ability declines with normal aging and can be further affected by conditions that disproportionately affect the elderly, such as vision loss or progressive dementia. Human and animal research has shown that two distinct memory systems interact during navigation. The first, referred to as allocentric navigation, is very flexible and uses spatial knowledge of key features or landmarks to develop and use a mental map of the environment. This approach involves brain regions that are critical for new learning and memory but that decline with age. The second, referred to as egocentric navigation, is inflexible and relies on "habit" memories that link specific features with specific directions. This approach relies on brain regions that are critical for "automatic" responses and that are relatively unaffected by age.

The main problem is that allocentric navigation declines with age and is accompanied increased dependence on egocentric navigation. This change increases the risk of becoming disoriented or "lost" when traveling in unfamiliar areas or even when traveling new routes in familiar areas. Therefore, the main goal of this project is to examine whether non-invasive brain stimulation, specifically transcranial direct current stimulation, can improve allocentric navigation in healthy older adults and patients with mild cognitive impairment.

Participants will complete two functional magnetic resonance imaging sessions while learning new environments. Before one of these sessions, participants will receive active brain stimulation over the parietal cortex. Before the other session, participants will receive sham brain stimulation over the parietal cortex. The effects of this stimulation will be evaluated using both an allocentric and an egocentric memory test. Physiologic effects will be evaluated using both task-based and resting-state MRI.

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Key information

Conditions

Mild Cognitive Impairment Alzheimer Disease Alzheimer's Disease Brain Diseases Central Nervous System Diseases Cognition Disorders Cognitive Dysfunction Dementia Mental Disorders Nervous System Diseases Neurocognitive Disorders Neurodegenerative Diseases Tauopathies

Age range

50 year–88 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Atlanta VA Medical and Rehab Center, Decatur, GA, Decatur, Georgia, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

General inclusion criteria (all participants):

All medications stable for approximately 1-2 months;
No history of severe mental illness;
No current untreated alcohol or substance abuse/dependence;
English as native and preferred language;
MRI-compatible if taking part in fMRI studies
Able to give informed consent.

MCI Inclusion Criteria:

Diagnosis of amnestic MCI based on criteria set forth by Petersen (2004). Additionally, other potential causes of cognitive deficit ruled out by the referring physician;

Healthy older adults

intact cognitive functioning as measured by neuropsychological testing

Exclusion criteria

History of neurological disease or injury
History of severe mental illness
Current untreated alcohol or substance abuse
Other conditions may exclude; please discuss with contact

Treatment and study plan

Transcranial direct current stimulation (tDCS)

Device

Active and/or sham; All participants receive both stimulation condition. Groups will be counterbalanced (half receiving active tDCS in the first session and sham in the second session; the other half receiving the opposite).

Primary outcomes

Accuracy in Centimeters From Target Location for Allocentric

Time frame: Outcome assessed after each of 2 sessions (estimated within 1 week of each other)

1 active tDCS; 1 sham tDCS for each measure. Participants touched a screen (using a ELO 19" touchscreen monitor) to document the location of the landmark. The distance between the actual vs. selected location served as the dependent measure.
Hippocampal BOLD Signal During Task-based fMRI

Time frame: change between active and sham tDCS sessions (<1month)

BOLD signal change comparing active to sham tDCS during Allocentric navigation (i.e., active HD-tDCS > sham HD-tDCS). Activation maps thresholded at p<.01 with minimum cluster size of 5 voxels.
Dorsal Attention Network Connectivity During Resting-state fMRI

Time frame: change between active and sham tDCS sessions (<1month)

Change in resting state functional connectivity strength between active and sham tDCS sessions. Strength is measured by Pearson r correlations between nodes, which are z-transformed, and summated.
Egocentric

Time frame: Outcome assessed after each of the 2 sessions

Number of turns correctly recalled for each egocentric environment

Sponsors and collaborators

Lead sponsor

VA Office of Research and Development

Fed

Registry information

Important dates

Study start: 2013
Primary completion: 2017
Study completion: 2017
First posted: Oct 9, 2013
Registry last updated: Aug 31, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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