Motor Imagery Intervention for Improving Gait and Cognition in the Elderly

Change in gait speed (centimeters per second) measured during normal pace walking and walking while talking conditions using an instrumented pathway. A positive mean value is indicative of an improvement (increase) in gait speed post-intervention, whereas a negative mean value is indicative of a decrease in gait speed post-intervention.

Change in cognitive performance was assessed by the number of correct letters/time (in seconds) generated during walking while talking (WWT). This exercise consists of having the participant walk around a computerized walkway while reciting alternate letters of the alphabet (WWT), starting with the letter "B." A positive mean value reflects an improvement in cognitive performance (increase in the number of correct letters/time generated) post-intervention; whereas, a negative mean value reflects worsening in cognitive performance (decrease in the number of correct letters/time generated) post-intervention.

Change in blood-oxygen-level-dependent (BOLD) signal (neuroplasticity) during imagined walking and walking while talking (iWWT) conditions were measured using functional magnetic resonance imaging (fMRI). The mean values reported are changes in factor scores that reflect the overall change in BOLD signal pre- to post-intervention. Positive values reflect an increase in BOLD signal post-intervention, whereas, negative mean values reflect a decrease in BOLD signal post intervention. There are no minimum or maximum values or ranges or thresholds associated with the BOLD measure.

Change in Trail Making Test Form A (TMT-A), is a timed measurement of attention and processing speed. Scoring is based on the time required to complete the task (i.e., drawing a line between 24 consecutive circles randomly arranged on a page) and ranges from 0-300 seconds with shorter time indicating better performance. A negative mean difference reflects an improvement pre to post intervention. The TMT-A uses all numbers (no letters) and includes correction of errors prompted by the examiner.

Change in Trail Making Test, Form B (TMT-B), is a timed measurement of attention, processing speed, and set-shifting. Scoring is based on the time required to complete the task (i.e., drawing a line between 24 consecutive circles randomly arranged on a page) and ranges from 0-300 seconds with shorter times indicating better performance. A negative mean difference reflects an improvement pre to post intervention. The TMT-B alternates between numbers and letters requiring the participant to switch between numbers and letters in consecutive order and includes correction of errors prompted by the examiner.

Change in Trail Making Test Form B (TMT-B) minus Form A (TMT-A), a timed measure of set-shifting. Scoring is based on the change in time between completing Form B compared to Form A. A negative mean difference reflects an improvement post intervention.

Change in scoring in the letter number sequencing task, a measure of item manipulation, was derived from the letter number sequencing subtest of the working memory domain within the Wechsler Adult Intelligence Scale (WAIS) III battery, a widely used intelligence test for adults. Scoring is based on the number of correctly sequenced letters and numbers with increasing (positive) mean scores indicating an improvement in task performance post intervention. A negative mean score reflects a decrease in task performance post intervention.

Change in Stroop Interference Test: Color-Word (incongruent trials) minus Color (congruent trials) scores were determined. It is a measure of response competition and interference. Scoring is based on the time it takes to read (complete) incongruent trials relative to congruent trials. A negative mean value reflects an improvement in performance after the intervention. A positive mean value reflects an decrease in performance after the intervention.

Change in the Flanker Interference Task measures how much interference is generated by the presentation of adjacent incongruent and congruent visual information. Scoring is based on the difference in reaction time (in milliseconds) between incongruent and congruent trials responded to correctly. A negative mean is indicative of improved interference post intervention and a positive mean value is indicative of worsening interference post intervention.

Change in stride length were collected during walking while talking (WWT) conditions on an instrumented walkway. Stride length was defined as the distance between the heel points of 2 consecutive footfalls of the same foot and measured in centimeters (cm).

Change in gait variability is collected during walking while talking on an instrumented walkway. Gait variability, defined as the stride-to-stride fluctuations in walking, was measured by the coefficient of variation (CV) of the mean value of stride-to stride time. CV reflects the level of gait rhythmicity, with lower values indicating greater rhythmicity. A negative mean CV reflects improved (less) variability post intervention whereas a positive mean CV value reflects worse (increased) variability. Stride time CV is closely associated with falls

Change in gait domains (summary measures reported in standard deviation units) derived from factor analysis of quantitative gait variables collected on an instrumented walkway during normal pace walking and walking while talking. Gait domain score is calculated by summing ratings for individual items and dividing by the maximum possible score for the domain, then multiplying by 100. The domain score ranges from 0 to 100, with higher scores reflecting more gait disturbance and lower scores reflecting less gait disturbance.

Changes in free recall performance were based on the free cued serial recall test, a measure of verbal learning and memory. Scores range from 0 to 48. Mean values reflect the change in the number of items recalled pre and post intervention. A positive mean value indicates improved recall performance post intervention whereas a negative mean value reflects decreased performance post intervention.

Change in delayed figure copy recall performance from the RBANS assessment, a measure of spatial learning and memory. Figure copy recall scores range from 0 to 20. A positive mean is indicative of an increase in recall post intervention whereas a negative mean is indicative of a decrease in recall post intervention.

Change in the number of correct words generated on the controlled oral word fluency test, a measure of language processing. Scores range from 0 to 36. A positive mean reflects an improvement in language processing post intervention whereas a negative mean reflects worsening of language processing post intervention

Change in the total number of correct words generated for each category on the semantic fluency test, a measure of language processing. Scores reflect the number of correct items generated in a 60 second window. A positive mean value reflects improved semantic fluency post intervention and a negative mean value reflects worsening of semantic fluency post intervention.

Change in number of correct digit symbols generated on the digit symbol substitution test (DSST), a measure of processing speed, attention and working memory. The number of correct symbols within the allowed time in seconds is measured. A positive mean reflects an improvement in the number of correct digit symbols generated post intervention whereas a negative mean value reflects fewer correct digits generated post intervention.

SPPB is a measure of lower extremity function and includes a balance test, a chair stand test and a gait speed test. Because gait speed/velocity was our primary outcome, only administered the balance and chair stand tests were administered. Thus, possible scores range from 0-8 (rather than the typical 0-12) with 0 being worst performance and 8 being best performance.

Change in mean immediate maze performance (time in seconds), a measure of spatial navigation and memory, were determined. A negative mean value represents an improvement in immediate maze performance post intervention whereas a positive mean value represents worsening of maze performance post intervention.

Change in mean delayed maze performance (time in seconds), a measurement of spatial navigation and memory, were determined. A negative mean value represents an improvement in delayed maze performance post intervention, whereas a positive mean performance time represents worsening delayed maze performance post intervention

The number of errors during maze performance, a measure of spatial navigation and memory, will be assessed. A negative mean result is indicative of an improvement (fewer errors) post intervention whereas a positive mean result is indicative of a reduction in performance (more errors) post intervention.

The Geriatric Depression Scale (GDS) will be used to to determine mean changes in depressive symptoms from baseline. Scores range from 0 to 30. Scores of 0 - 9 are considered normal, 10 - 19 indicate mild depression and 20 30 indicate severe depression. As such, higher scores are indicative of more severe depressive symptoms. A positive mean value reflects an increase in depressive symptoms post-intervention whereas a negative value reflects a decrease in depressive symptoms post intervention.

Change in symptoms of anxiety. Scores range from 0 to 84 with higher values reflecting more anxiety symptoms. A negative mean reflects a reduction in anxiety symptoms post intervention and a positive mean value reflects an increase in anxiety symptoms post intervention

Change in mean Cortical Thickness obtained from T1-weighted structural images. A positive mean value reflects an increase in cortical thickness post intervention and a negative mean value reflects a decrease in cortical thickness post intervention

Change in White Matter Integrity obtained from diffusion-weighted imaging. Increased white matter integrity is associated with improved cognitive performance whereas decreased white matter integrity is associated with decreased cognitive performance.

Change in White Matter Hyperintensities obtained from Fluid-Attenuated Inversion Recovery imaging. Increased white matter hyperintensities may be indicative of unfavorable outcomes.