Adults, Older Adults
Conditions
Keywords
remote ischemic conditioning, motor learning
Brief summary
The purpose of this research is to determine if the beneficial effects of remote limb ischemic conditioning on learning seen in young adults are found in middle-aged and older adults.
Detailed description
Ischemic conditioning is an endogenous phenomenon in which exposing a target organ or tissue to one or more brief episodes of ischemia results in protection of that organ against subsequent ischemia. The effects of ischemic conditioning are not confined within an organ but can be can be transferred from one organ to another, a technique called remote ischemic conditioning. A clinically feasible method for this is remote limb ischemic conditioning (RLIC), where episodes of ischemia and perfusion are induced with a blood pressure cuff placed on the arm. The overall goal of this line of work is to use ischemic conditioning to enhance learning and outcomes in persons with neurologic injuries. Two previous studies have shown that remote limb ischemic conditioning (RLIC) can enhance learning a motor task in healthy young adults. The next step is to determine which individuals would receive maximum benefit from RLIC before applying these findings to clinical rehabilitation populations such as stroke. Numerous factors, such as age, body mass index (BMI), sex, and cardiovascular comorbidities may influence the response. The current study determines if RLIC can enhance learning in middle-aged and older adults with their burden of co-morbidities.
Interventions
BEHAVIORALRLIC
See descriptions under arm/group descriptions. RLIC is delivered for 7 visits, occurring on consecutive weekdays.
BEHAVIORALSham conditioning
See descriptions under arm/group descriptions. Sham conditioning is delivered for 7 visits, occurring on consecutive weekdays.
BEHAVIORALBalance training
All participants undergo training on a balance board, learning to hold the board level with equal weight on each leg. This is a motor learning task. Participants perform the balance task for 15, 30-second trials per day at visits 3-7.
Sponsors
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Washington University School of Medicine
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Masking description
Participants are masked to their group assignment.
Intervention model description
Single blinded, randomized, controlled trial
Eligibility
Sex/Gender
ALL
Age
40 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
1. 40-80 years old 2. Had sufficient cognitive skills to provide informed consent and actively participate.
Exclusion criteria
(determined by self-report): 1. History of a neurological condition, balance impairment, or vestibular disorder. 2. History of attentional disorders (ADD/ADHD) that could affect learning. 3. History of sleep apnea which could confound the effects of RLIC. 4. Presence of lower extremity condition, injury, or surgery that would compromise performance on the balance task. 5. Learning disability, sensory, or communication problem that would prevent completion of the study. 6. History of epilepsy, peripheral vascular disease, or blood diathesis which could contraindicate RLIC. 7. Current intensive weight lifting or interval training exercise which could confound the effects of RLIC. 8. Current substance abuse or dependence.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Balance Score | 1 week | Balance score at the end of training - balance score at baseline, where balance score is the average amount of time in seconds that a participant maintains the stability platform within ±3° of horizontal position during 5 trials of 30 seconds each. Five trials are averaged to form the balance score at each time point. |
Countries
United States
Participant flow
Recruitment details
Participants recruited by word-of-mouth and through participant registry. Assessed for eligibility, n = 182. Excluded, n = 100 with n = 33 not meeting criteria, n = 64 declined to participate, and n = 3 pilot participants who were not randomized.
Participants by arm
| Arm | Count |
|---|---|
| Remote Limb Ischemic Conditioning (RLIC) RLIC is achieved via blood pressure cuff inflation to 20 mmHg above systolic blood pressure on the dominant arm. RLIC requires 45 minutes and involves 5 cycles of 5 minutes blood pressure cuff inflation followed by alternating 5 minutes of cuff deflation. RLIC is performed on visits 1-7.
RLIC: See descriptions under arm/group descriptions. RLIC is delivered for 7 visits, occurring on consecutive weekdays.
Balance training: All participants undergo training on a balance board, learning to hold the board level with equal weight on each leg. This is a motor learning task. Participants perform the balance task for 15, 30-second trials per day at visits 3-7. | 33 |
| Sham Conditioning Sham conditioning is achieved via blood pressure cuff inflation to 10 mmHg under diastolic blood pressure on the dominant arm. Sham conditioning requires 45 minutes and involves 5 cycles of 5 minutes blood pressure cuff inflation followed by alternating 5 minutes of cuff deflation. Sham conditioning is performed on visits 1-7.
Sham conditioning: See descriptions under arm/group descriptions. Sham conditioning is delivered for 7 visits, occurring on consecutive weekdays.
Balance training: All participants undergo training on a balance board, learning to hold the board level with equal weight on each leg. This is a motor learning task. Participants perform the balance task for 15, 30-second trials per day at visits 3-7. | 36 |
| Total | 69 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Allocated to Groups | Withdrawal by Subject | 1 | 1 |
| Analyzed | Protocol Violation | 4 | 1 |
| Intervention and Follow up | Withdrawal by Subject | 4 | 2 |
Baseline characteristics
| Characteristic | Remote Limb Ischemic Conditioning (RLIC) | Sham Conditioning | Total |
|---|---|---|---|
| Age, Continuous | 60.4 years STANDARD_DEVIATION 10.5 | 61.8 years STANDARD_DEVIATION 9 | 61.2 years STANDARD_DEVIATION 10 |
| Body mass index | 26.5 kg/m^2 STANDARD_DEVIATION 4.4 | 26.8 kg/m^2 STANDARD_DEVIATION 5.1 | 26.6 kg/m^2 STANDARD_DEVIATION 4.8 |
| Race/Ethnicity, Customized Race African-American | 8 Participants | 10 Participants | 18 Participants |
| Race/Ethnicity, Customized Race Caucasian | 25 Participants | 26 Participants | 51 Participants |
| Region of Enrollment United States | 33 Participants | 36 Participants | 69 Participants |
| Sex: Female, Male Female | 22 Participants | 25 Participants | 47 Participants |
| Sex: Female, Male Male | 11 Participants | 11 Participants | 22 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 33 | 0 / 36 |
| other Total, other adverse events | 0 / 33 | 0 / 36 |
| serious Total, serious adverse events | 0 / 33 | 0 / 36 |
Outcome results
Primary
Change in Balance Score
Balance score at the end of training - balance score at baseline, where balance score is the average amount of time in seconds that a participant maintains the stability platform within ±3° of horizontal position during 5 trials of 30 seconds each. Five trials are averaged to form the balance score at each time point.
Time frame: 1 week
Population: Only participants who completed the entire protocol and did not have a protocol deviation were analyzed.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Remote Limb Ischemic Conditioning (RLIC) | Change in Balance Score | 5.55 seconds | Standard Deviation 4.85 |
| Sham Conditioning | Change in Balance Score | 4.81 seconds | Standard Deviation 3.47 |
p-value: 0.984Mixed Models Analysis
p-value: 0.455Mixed Models Analysis
p-value: 0.803Mixed Models Analysis
p-value: 0.233Mixed Models Analysis
p-value: 0.29Mixed Models Analysis