A Study of Dual-task Exercise Training to Prevent Falls Among Older Adults With Mild Cognitive Impairment

This measure will reflect change in the incidence of falls as a result of intervention. Study participants will be given a falls calendar to record number of falls at home. Falls are defined as "when you land on the floor or the ground, or fall and hit objects like stairs or pieces of furniture, by accident." This information will be ascertained monthly via a phone call by study assessors

Reflects change in lower extremity function with intervention. This is measured by Short Physical Performance Battery which involves three functional tasks: static balance, gait speed, and getting in and out of a chair, with scores ranging from 0 (worst performance) to 12 (best performance).

Reflects change in lower extremity physical function with intervention. This is measured by the Timed Up and Go test (TUG; in seconds) which assesses mobility and fall risk. The test measures the time taken by an individual to stand up from a standard chair, walk a distance of 3 meters, turn, walk back to the chair, and sit down. Lower scores represent better lower extremity physical function.

Reflects change in dual-task costs in gait speed with intervention. The TUG test protocol will be repeated under a dual-task condition where the participant is asked to walk while performing an arithmetic task (i.e., starting at the number 81 and sequentially subtracting 5 from the resulting number). Lower scores on this walk indicate better performance. Dual-task walking cost is defined as the difference between single- and dual-task walking speed, expressed in percentage, with less negative values representing improvement in dual-task walking speed relative to single-task walking.

Reflects change in lower extremity strength and endurance with intervention. This is measured by the 30-second chair stand test. The test is conducted by asking the participant to stand up from a chair and sit down fully and to perform as many cycles of sit-to-stand-to-sit as possible in 30 seconds. Higher scores (number of stands) represent higher levels of strength and endurance.

Reflects change in global cognitive function. This is measured by MoCA which measures cognitive function of multiple domains (attention/concentration, executive functions, short term memory, language, visuospatial abilities, orientation to time and place). MoCA has a total score that ranges from 0 to 30, with higher scores representing better cognitive functioning.

Reflects change in executive function with intervention. This is measured by Trail Making Test (TMT) which consists of two parts (A and B). In Part A, the participant is asked to count the number (1 through 25) off the screen out loud as quickly as possible. In Part B, the participant is asked to recite numbers and letters in an alternating sequence (1-A-2-B-3-C . . . 12-L) as quickly as possible. Errors are corrected immediate with the clock running. For Parts A and B, scoring is expressed in terms of the time (in seconds) to completion. The difference in time taken to complete Part B versus Part A is calculated to form a measure of executive function, with smaller difference scores indicating better executive function.

Reflects change in memory with intervention. This is measured by a category fluency test in which the participant is asked to generate the names of as many animals as possible in 60 seconds.

Reflects change in attention with intervention. This is measured by Forward Digit Span test. During the test, the participant is asked to repeat a series of digits in the order given. The maximum raw score is 16, with higher scores indicating better attention.

Reflects change in short-term working memory with intervention. This is measured by Backward Digit Span test. During the test, the participant is asked to repeat a series of digits in reverse order. The maximum raw score is 16, with higher scores indicating better memory.

Number of fallers from participants at 6 months in each intervention group

Reflects change in the perceptions of balance with intervention. This is measured by the Activity-specific Balance Confidence Scale which assesses one's confidence in performing various activities of daily living without compromising one's balance. It includes such items as picking up an object from the floor, standing on a chair to reach, and walking on icy sidewalks. The scale contains 16 items scored on a range from 0% to 100% (0 indicating no confidence and 100 indicating full confidence).

Reflects change in quality of sleep with intervention. This is measured by the Pittsburgh Sleep Quality Index which includes seven indices: subjective quality, latency (i.e., time needed to fall asleep), duration (i.e., number of hours of actual sleep per night), efficiency (i.e., total sleep time divided by time in bed, converted to a score of 0-3), sleep disturbances (e.g., waking up in the middle of the night and the like), use of sleep medication, and daytime dysfunction (e.g., having difficulty staying awake during the day). Each of the component scores ranges from 0 to 3, with the PSQI global score ranging from 0 to 21 points, with higher scores indicating poorer sleep quality.

Reflects change in the level of depression with intervention. This is measured by the Geriatric Depression Scale (GDS). The 15-item version of the GDS will be used with the scores ranging from 0 to 15. A score of 0 to 4 is considered to be within the normal range, 5 to 9 indicates mild depression, and a score of 10 or more indicates moderate to severe depression.

Reflects change in quality of life with intervention. This is measured by EuroQol EQ-5D which assesses health status in five domains: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each domain is measured at three levels: no problems (coded as 1), some problems (2), and extreme problems (3). An EQ-5D utility score will be calculated for each participant based on the U.S. population-based (preference-weighted) health index scores on a scale ranging from less than 0 (worst health state) to 1.0 (best or perfect health state).

Reflects change in frailty with intervention. Frailty is measured by the Frailty Questionnaire which assesses 5 components: Fatigue, Resistance, Ambulation, Illness, and Loss of Weight. The scale scores range from 0 to 5 (i.e., 1 point for each component; 0=best to 5=worst) and represent frail (3-5), pre-frail (1-2), and robust (0) health status

Reflects change in physical activity with intervention. Total weekly minutes spent in vigorous physical activity (PA) and moderate PA will be measured. Two self-report PA measures will be calculated: total weekly minutes of vigorous + moderate PA in bouts of ≥10 min, excluding walking (MVPA) and total weekly minutes of walking in bouts of ≥10 min (Walk). We will report Total PA (MVPA + Walk), which is conceptually the same construct as accelerometry MVPA in ≥10 min bouts.