Accidental Falls, Aging
Conditions
Brief summary
The objective of this study is to determine if a four-week, 20-session intervention of transcranial direct current stimulation (tDCS), as compared to sham intervention, improves dual task standing and walking performance (Aim 1), as well as other physical (Aim 2) and cognitive (Aim 3) factors on the causal pathway to falls, in older adults who report two or more falls within the past year and fear of falling again in the future, yet who do not have any acute or over neurological or musculoskeletal condition. Primary endpoints will include the "dual task" costs to gait speed when walking and postural sway speed when standing, as induced by performing a serial subtraction cognitive task (i.e., \[(speeddual task - speedsingle task) / speedsingle task) X 100\] (Aim 1), the Short Physical Performance Battery (Aim 2), and the Trail Making Test (Part B minus Part A) (AIM 3). Secondary endpoints will include the dual task cost to serial subtraction performance, additional gait and balance outcomes derived from the dual task paradigm, the Timed Up-and-Go, fear of falling, habitual physical activity, and performance within a battery of neuropsychological tests focused on global cognitive function, attention, verbal fluency and memory.
Detailed description
In older adults, falls are costly, consequential and correlated with both physical and cognitive decline. Most falls occur when standing or walking. Many activities require people to stand or walk while performing tasks like talking or making decisions. Such "dual tasking" interferes with the control of standing and walking. This interference, or "cost," is exaggerated in older adults with previous falls and is predictive of future falls. Neuroimaging evidence indicates that standing and walking,especially when dual tasking, activate distributed brain networks including the left dorsolateral prefrontal cortex (dlPFC)-a brain region sub-serving executive function. Thus, strategies that facilitate activation of the left dlPFC and its connected neural networks hold promise to mitigate dual task costs, improve physical and cognitive function, and ultimately, reduce falls. Transcranial direct current stimulation (tDCS) provides a noninvasive means of selectively modulating cortical excitability. The investigators have shown in younger and older adults that a 20-minute session of tDCS designed to increase excitability of the left dlPFC reduces dual task costs and improves mobility when tested just after stimulation. The investigators have since completed a pilot, sham-controlled trial of a 2-week, 10-session tDCS intervention targeting the left dlPFC in 20 older adults with slow gait and mild-to-moderate executive dysfunction. The intervention was successfully double-blinded and well-attended. tDCS, compared to sham, reduced dual task costs and induced trends towards improved mobility and executive function over a 2-week follow-up. The investigators thus contend that tDCS targeting the left dlPFC holds promise to improve the control of standing and walking-and ultimately reduce falls-in older adults. Still, the size and duration of tDCS-induced benefits to older adult "fallers" have not been established. Moreover, to date, tDCS delivery has attempted to optimize current flow based on a "typical" brain and has thus not accounted for individual differences in skin, skull, cerebrospinal fluid and brain tissue in the aging brain. Such modeling is now possible with the current flow modeling the investigators propose. The Overall Aim is to compare, in older adults with previous falls, the effects of a tDCS intervention designed to target the left dlPFC on the dual task costs to standing and walking, and other physical and cognitive factors that are on the causal pathway to falls and important to everyday function. The investigators will conduct a randomized, sham-controlled, double-blinded trial with assessments at baseline and post-intervention (immediate, 3-, 6-month follow-up) in 120 non-demented men and women (60 per arm) aged 60 or older who are at risk of falls and report mobility and balance problems and a fear of falling, yet have no major neural or musculoskeletal disorders that explain their falls. The tDCS intervention will comprise 20, 20-minute sessions of tDCS over a 4-week period. The investigators hypothesize that, in older adults at risk of falls and over a 6-month follow-up, a tDCS intervention targeting the left dlPFC, as compared to sham, will mitigate dual task costs to the control of standing and walking and enhance other metrics of both physical and cognitive function.
Interventions
OTHERtDCS
The participant will receive 20, 20-minute sessions of tDCS on Monday-Friday, at approximately the same time of day, over four consecutive weeks.
OTHERActive-Sham
The participant will receive 20, 20-minute sessions of active-sham stimulation on Monday-Friday, at approximately the same time of day, over four consecutive weeks.
Sponsors
Hebrew SeniorLife
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Masking description
Study personnel administering tDCS and the participants will not be aware of tDCS intervention arm assignment. The investigators will ensure such double-blinding by programming the tDCS software with intervention-specific stimulation codes, as supplied by personnel uninvolved in data collection, prior to study initiation.
Intervention model description
The investigators will conduct a single site, sham-controlled, double-blinded, randomized trial of tDCS. Participants will perform baseline functional assessments, as well as a structural MRI of the brain. They will then be assigned to a four-week, 20-session intervention of either tDCS or sham (i.e., control) stimulation, via permuted block randomization stratified by sex to ensure that equal numbers of women, and equal numbers of men, are randomized to each arm.
Eligibility
Sex/Gender
ALL
Age
60 Years to 100 Years
Healthy volunteers
No
Inclusion criteria
* Men and women aged 60 or older * Self-report of mobility and balance problems * Self-report of fear of falling defined by a "yes" answer to the yes-or-no question "Is the participant worried about falling in the future?" * Trail Making Test (TMT) Part B time below 75th percentile of age-and education-based norms * A score of 10 or below on the Short Physical Performance Battery
Exclusion criteria
* Inability to stand or walk unassisted for 60 seconds * Hospitalization within the past three months due to acute illness, or as the result of a musculoskeletal injury significantly affecting gait or balance * Any unstable medical condition * a diagnosis of a gait disorder, Parkinson's disease, Alzheimer's disease or dementia, multiple sclerosis, previous stroke or other neurodegenerative disorder * Chronic vertigo * Myocardial infarction within the past 6 months * Active cancer for which chemo-/radiation therapy is being received * Psychiatric co-morbidity including major depressive disorder, schizophrenia or psychosis * Chronic use of any sedating medications (sedatives, anti-psychotics, hypnotics, anti-depressants) or change in medication within the previous month * Legal blindness * Contraindications to MRI or tDCS, including reported seizure within the past two years, use of neuro-active drugs, the risk of metal objects anywhere in the body, self-reported presence of specific implanted medical devices (e.g., deep brain stimulator, medication infusion pump, cochlear implant, pacemaker, etc.), or the presence of any active dermatological condition, such as eczema, on the scalp * A score below 22 on the Telephone Interview of Cognitive Status (TICS) * Mild or severe dementia defined by a Clinical Dementia Rating (CDR) score of one or greater
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change From Baseline in the Dual Task Cost to Gait Speed | 3-day follow-up; 3-month follow-up; 6-month follow-up | This metric will assess the change from baseline in the degree to which performing a secondary cognitive task diminishes gait speed. The dual-task cost (DTC) to gait speed is calculated by (dual-task gait speed-single-task gait speed)/single-task gait speed \*100. Greater reduction in DTC to gait speed from baseline to post intervention indicates better performance. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change From Baseline in Falls Efficacy Scale | 3-day follow-up; 3-month follow-up; 6-month follow-up | This metric will assess the change from baseline in fear of falling. Participants will rate, on a 4-point Likert scale, fear of falling when performing 16 activities. Scores are added up to calculate a total score that ranges from 16 to 64. The cut-point for high fear of falling is defined as scores \>23 for this 16-item scale. The decrease of this scale indicates lower fear of falling. |
| Change From Baseline in Montreal Cognitive Assessment (MoCA) Total Score | 3-day follow-up; 3-month follow-up; 6-month follow-up | This metric, Montreal Cognitive Assessment (MoCA), is a standardized screening measure of global cognitive function, including attention, executive function, memory, language, visuospatial abilities, abstraction, calculation, and orientation. Total scores range from 0 to 30, with higher scores indicating better cognitive performance. |
| Change From Baseline in Short Physical Performance Battery (SPPB) | 3-day follow-up; 3-month follow-up; 6-month follow-up | This metric, the Short Physical Performance Battery (SPPB), is a standardized measure of lower-extremity physical function based on standing balance, usual-pace walking speed, and repeated chair stands. Each component is scored from 0 to 4, and the component scores are summed to produce a total score ranging from 0 to 12. Higher scores indicate better lower-extremity physical function. |
| Change From Baseline in the Dual Task Cost to Stride Time Variability | 3-day follow-up; 3-month follow-up; 6-month follow-up | This metric will assess the change from baseline in the degree to which performing a secondary cognitive task diminishes the control of gait. The dual-task cost (DTC) to stride time variability (STV) is calculated by (dual-task STV - single-task STV)/single-task STV \*100. Greater reduction in DTC to STV from baseline to post intervention indicates better performance. |
| Change From Baseline in the Dual Task Cost to the Correct Rate of Serial Subtraction | 3-day follow-up; 3-month follow-up; 6-month follow-up | This metric will assess the change from baseline in the degree to which walking diminishes the ability to perform a cognitive task. The dual-task cost (DTC) to the correct rate of serial subtraction (correct rate) is calculated by (dual-task correct rate - single-task correct rate)/single-task correct rate \*100. Greater reduction in DTC to correct rate from baseline to post intervention indicates better performance. |
| Change From Baseline in Trail Making Test B - A | 3-day follow-up; 3-month follow-up; 6-month follow-up | The Trail Making Test (TMT) assesses visual attention, processing speed, cognitive flexibility, and executive function. In Part A, participants connect numbered targets in sequential order. In Part B, participants alternate between numbers and letters in sequential order. Completion time is recorded in seconds, with a maximum allowable completion time of 300 seconds. The "TMT B - A" score was calculated by subtracting the time required to complete Part A from the time required to complete Part B. This derived score reflects the additional executive-function and set-shifting demands of Part B while accounting for visual scanning and motor speed. Lower values indicate better performance. |
| Change From Baseline in Timed-Up-and-Go (TUG) Time | 3-day follow-up; 3-month follow-up; 6-month follow-up | This metric, time to complete Timed-Up-and-Go (TUG) task, is a standardized measure of functional mobility and balance. It records the time, in seconds, required for a participant to stand up from a chair, walk straightly, turn around, walk back straightly, and sit down. Faster TUG time indicates better mobility. |
| Change From Baseline in Digit Span | 3-day follow-up; 3-month follow-up; 6-month follow-up | This test will assess the change from baseline in working memory. The score of Digit Span ranges from 0 to 32. Higher total scores indicate better working memory performance. Change from baseline was calculated as the follow-up total score minus the baseline total score. Possible change scores range from -32 to 32. Positive values indicate improvement, negative values indicate worsening, and a value of 0 indicates no change. |
| Change From Baseline in Category and Phonemic Fluency Test | 3-day follow-up; 3-month follow-up; 6-month follow-up | This common test will assess the change from baseline in word retrieval. Higher scores indicate better verbal fluency performance. |
| Change From Baseline in Retention Rate in Hopkins Verbal Learning Test | 3-day follow-up; 3-month follow-up; 6-month follow-up | This common test will assess the change from baseline in s verbal learning and episodic memory. The score ranges from 0% to 100%, with higher percentages indicating better retention of previously learned verbal information. |
| Change From Baseline in Short Form (SF) - 12-physical | 3-day follow-up; 3-month follow-up; 6-month follow-up | The 12-Item Short Form Health Survey Physical Component Summary (SF-12 PCS) is a patient-reported measure of physical health and physical health-related quality of life. Scores range from 0 to 100, with higher scores indicating better physical health and functioning. |
| Change From Baseline in Short Form (SF)-12-mental | 3-day follow-up; 3-month follow-up; 6-month follow-up | This questionnaire measures the changes in mental-health-related quality of life from baseline to post-intervention follow-ups. The 12-Item Short Form Health Survey Mental Component Summary (SF-12 MCS) is a patient-reported measure of mental health and mental health-related quality of life. Scores range from 0 to 100, with higher scores indicating better mental health and functioning. |
| Change From Baseline in Dual Task Gait Speed | 3-day follow-up; 3-month follow-up; 6-month follow-up | This measure the change in gait speed when walking in dual task condition from baseline to post-intervention follow-ups. Faster speed indicates better gait performance. |
| Change From Baseline in Dual Task Gait Stride Time Variability | 3-day follow-up; 3-month follow-up; 6-month follow-up | This outcome measures the change in gait stride time variability (STV) when walking in dual task condition from baseline to post-intervention follow-ups. Lower STV indicates better gait performance. |
| Changes From Baseline in Gait Speed in Single Task Condition | 3-day follow-up; 3-month follow-up; 6-month follow-up | The outcome measures the change in gait speed when walking in single task condition from baseline to post-intervention follow-ups. faster gait speed indicates better gait performance. |
| Changes From Baseline in Gait Stride Time Variability in Single Task Condition | 3-day follow-up; 3-month follow-up; 6-month follow-up | This outcome measures the changes in gait stride time variability (STV) when walking in single task condition from baseline to post-intervention follow-ups. Lower STV indicates better gait performance. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORBrad Manor, PhD
Hebrew SeniorLife
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Continuous | 79 years STANDARD_DEVIATION 7 |
| BMI | 29 kg/m^2 STANDARD_DEVIATION 6 |
| Clinical Dementia Rating (CDR) CDR=0 | 29 Participants |
| Clinical Dementia Rating (CDR) CDR=0.5 | 14 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 6 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 82 Participants |
| Sex: Female, Male Female | 30 Participants |
| Sex: Female, Male Male | 16 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 1 / 50 | 0 / 49 |
| other Total, other adverse events | 45 / 50 | 36 / 49 |
| serious Total, serious adverse events | 12 / 50 | 7 / 49 |
Outcome results
None listed