Perturbation Training Reduces Falls in People With AD (STAD)

Motor Learning of Fall Resistant Skills From Laboratory-induced Falling Among People With Mild Alzheimer's Disease

This study will examine the overall capacity of people with Alzheimer's disease learning fall-resistant skills from perturbation training.

Falls can cause injury and death in older adults. Those with Alzheimer's disease are at an even higher fall risk. Our goal is to test if people with mild Alzheimer's disease can learn fall prevention skills from the exposure to large-scale perturbations on a treadmill. Two groups with mild Alzheimer's disease will be enrolled. One group will attend a perturbation training session while the other group receives no training. Groups will then be exposed to perturbations on the ground immediately and three or six months after the training. Over six months after the training, daily-living falls will be tracked for both groups. The falls following the perturbations in the lab and daily-living all-cause falls will be compared between groups to test our specific aims: 1) to test if people with Alzheimer's disease can adapt to large-scale external perturbations and learn fall resistant motor skills; 2) to inspect whether people with Alzheimer's disease can retain motor skills learned in Aim 1; and 3) to determine if people with Alzheimer's disease can generalize fall resistant skills to different contexts (treadmill to overground, inside the lab to outside the lab).

This arm will receive a single-session perturbation training treatment on a treadmill under the protection of a safety harness.

This arm will not receive perturbation training but will go through harnessed walking on the same treadmill for the same time as the other group.

Participants will experience repeated perturbations mixed with non-perturbed trials on the treadmill with the protection by a harness.

The outcome of each perturbation trial will be determined as a fall if the peak load cell force exceeds 30% of the body weight. The load cell records the force applied to the human body by the safety harness system after a perturbation. The lab-induced faller rate will be calculated as the ratio of the number of fallers to the number of participants within each group.

Dynamic stability will be calculated for each perturbation trial based on the kinematics of the body's center of mass relative to the base of support.

The number of all cause falls in daily-living activities after the training session will be recorded for each participant.

Berg balance scale will be used to objectively determine a participant' ability (or inability) to safely balance during a series of preset tasks. The score of the Berg Balance Scale is between 0 and 56 with a higher value indicating a better balance ability.

Functional mobility will be assessed using the Timed-Up-and-Go test. The time used to complete the test will be recorded. The shorter the time, the better mobility.

Strength capacity will be tested on the knee joint as the maximum strength the knee joint can produce. The measurement will be taken on an isokinetic dynamometer.

The tactile sensation level at the dominant sole will be determined as the number of sites where the participant can feel the pressure produced by the monofilament.

This test will be done when the participant is standing on a pair of force plates. The center of pressure movement will be calculated from the ground reaction force measured by the force plates. The center of pressure excursion in the anteroposterior and mediolateral directions will be calculated.

Inclusion Criteria: Participants must be at least 65 years old; Participants have a clinical diagnosis of probable AD; Participants can read and understand English; Participants must be able to walk independently at least 25 feet; Participants must be able to stand independently for at least 30 seconds; Participants must have a Monteral Cognitive Assessment score of 11-21 or Mini Mental Status Examination score between 18 and 23. Exclusion Criteria: Individuals have ever experienced perturbation training; Individuals have hypotension or uncontrolled hypertension; Individuals exhibit osteoporosis; Participants suffer from coexisting psychiatric disorders, or other neurological conditions, or injuries, etc.