Ries, Julie D. PT, PhD; Drake, Jamie Michelle PT, DPT; Marino, Christopher PT, DPT
Alzheimer disease (AD) affects 5.3 million individuals in the United States, and with the aging of the US population, this number will continue to increase.1 Historically, individuals with AD were excluded from research studies and exercise programs intended to improve physical and functional performance in older adults. More recently, researchers have begun to evaluate the feasibility and the effectiveness of these exercise programs for individuals with AD and other forms of dementia. Although there are conflicting reports about the effectiveness of exercise programs for older individuals with cognitive impairment,2–5 the feasibility of individuals with dementia participating in organized exercise programs has been demonstrated by numerous studies.6–12 In their 2008 Cochrane Review on physical activity programs for persons with dementia, Forbes et al13 concluded that “There is insufficient evidence to determine the effectiveness of activity programs in managing or improving cognition, function, behavior, depression, and mortality in people with dementia.”
Individuals with AD have a higher risk of falls than their age-matched peers,14–17 and they experience greater morbidity and mortality associated with falls.18–20 Balance exercise programs have been shown to be effective in reducing falls in cognitively intact older adults21–23; however, there is limited evidence of the effectiveness of balance exercise programs for individuals with AD. An exercise program that leads to improved performance on balance and mobility tests in individuals with AD could mean a reduced incidence of falls in this population. This could have a positive impact on quality of life and delay the need to move from a day-care environment to an assisted living or skilled nursing facility. Maintaining the individual with AD in the least restrictive environment while decreasing morbidity and healthcare costs related to the sequelae of falls can save healthcare dollars and have a positive effect on a major public health issue.18,20
Individuals with AD represent a unique challenge in motor learning. Although the ability for declarative memory formation and learning is lost with AD, the ability to use procedural memory and learning systems seems to remain intact.24–26 Individuals with AD maintain some ability for learning and relearning of motor skills through the use of procedural memory and learning. These individuals learn best under constant, consistent practice conditions; they learn best with practice of a specific, relevant task and may have difficulty generalizing the skills practiced.24,25,27 For the best possible outcome, it seems essential to integrate these principles when creating an exercise program for individuals with AD. Based on the evidence in the motor learning literature,24,25,27 characteristics of an effective balance intervention for individuals with AD would include a program that is functional, relevant, familiar, and designed with appropriate constant, blocked, massed practice conditions to facilitate optimal learning. Constant (as opposed to variable) practice refers to repetition under consistent and specific task conditions, blocked (as opposed to random) practice indicates that a block of task trials is completed before moving to another task, and massed (as opposed to distributed) practice indicates more practice than rest in a practice session.28
Another consideration in working with individuals with AD is to choose appropriate outcome measures. The study of outcome measures for use with individuals with AD and other dementias is a recent addition to the rehabilitation literature.29–31 Reliability and validity of specific outcome measures for this population, and minimal detectable change (MDC) scores, which can help to determine whether individuals are making “true” changes in performance over time, are now available.
The purpose of this pilot study was to assess the feasibility and effectiveness of a small-group balance exercise program for individuals in an AD day program. It was hypothesized that this functionally based balance intervention would improve balance, as defined by performance on balance and gait outcome measures.
This was an exploratory pilot study using a pre- and post-test design. The project was approved by the Marymount University Institutional Review Board.
Seven individuals at a local adult day center were recruited to participate in this pilot study. The facility administrator identified appropriate participants based on the inclusion and exclusion criteria and approached participants and guardians on behalf of the researchers to make initial contact. Inclusion criteria consisted of diagnosis of AD or probable AD per primary care physician, medical stability, ability to walk with or without assistive device without the physical assistance of another person, and ability to follow one-step commands. Individuals were excluded from the study if they had any neurologic or musculoskeletal comorbidity that might affect their gait or balance (eg, cerebral vascular accident, Parkinson disease, recent orthopedic surgery), limiting cardiac or pulmonary condition or if they were a new participant (within past three weeks) of the adult day center. Informed consent was provided by proxy decision makers for all participants. Assent forms were offered, but all proxy decision makers opted not to have participants sign the assent forms.
Data were collected from each participant's facility health record, including birth date and age, sex, height and weight, home environment, social and family history (to allow researchers to establish rapport by discussing familiar people and activities), medications, medical history, ambulation status, and assistive device requirement.
The professional literature is rich with practical tips on optimal interaction and communication with individuals with AD, and every effort was made to integrate these concepts into the study protocol to maximize success of interactions. A personal connection between patient and caregiver is deemed necessary for optimal social interaction and engagement of participants32–34; thus, the collection of personal information allowed researchers to establish rapport with participants. Many authors cite the importance of a low-stress environment and working in a familiar place with familiar people as key factors to facilitating optimal performance in individuals with AD.35–39 The progression of cuing was another component of the protocol that was clearly outlined for the administration of pretests and posttests and for the exercise activities. The progression of cuing began with verbal instruction with concurrent visual cue, followed by gesturing or demonstration, followed by tactile guidance, and, finally, physical assistance.40,41 These general guidelines were used across all activities within the study and are represented in Table 1.
The week before beginning the exercise program, participants were administered a Mini-Mental Status Examination (MMSE)42 by the principal investigator and were rated with the Functional Assessment STaging (FAST) tool,43,44 with the assistance of a staff informant. These tools were used to classify the level of dementia. The FAST is a functionally oriented tool used by the Alzheimer's Association to educate about the progression of AD; scores range from 1 (normal adult with no cognitive or functional decrement) to 7 (severe AD), with levels 6 and 7 having subscores A through E, giving the tool 15 levels. The functional nature of the tool is evident in the descriptors of each stage. For instance, stage 4 (mild AD) is defined as “assistance required in complex tasks (handling finances, marketing, or planning dinner for guests).” Stage 5 (moderate AD) is defined as “assistance required in choosing proper clothing.” The MMSE scores range from 0 to 30, with lower scores representing more profound cognitive impairment. Use of the MMSE allowed for general comparison of level of cognitive function of participants in this study with other published studies, as this is a widely used cognitive screening tool. A score of ≤23 on the MMSE is the generally accepted indicator of cognitive impairment, with 18 to 23 indicating mild impairment and 0 to 17 indicating severe impairment.45
Participants performed pretests of three clinical measures of balance and gait on the same day. The outcome measures chosen were Timed Up and Go (TUG), Berg Balance Scale (BBS) score, and gait speed (GS) as measured by the GAITRite walkway (CIR Systems, Inc., Havertown, PA). Both self-selected GS (SSGS) and fast GS (FGS) were assessed. For the TUG,46 participants began seated in a chair with arm rests, and on the instruction “Go,” the participant stood, walked 3 m, circled around a cone, walked back to the chair, and sat down. The participants were instructed to go as fast as they comfortably could. They performed this activity twice after a practice trial, and the time for the trial began when the participant's bottom left the chair and ended when the bottom contacted the chair. This modified protocol of beginning the stop watch on movement initiation as opposed to command for movement has been previously documented.29 This approach was adopted to capture only the mobility component of the TUG and not the time required for progression of cuing strategies before movement. Participants also frequently needed prompting cues during the test (eg, “go around the cone” and “sit in that chair”). The outcome score was the mean of two performances. The TUG has been evaluated for use with individuals with AD and other dementias and found to have excellent test-retest reliability (intraclass correlation coefficient [ICC] = 0.92–0.99).29,47,48
The BBS49–52 consists of 14 different balance activities, ranging in difficulty from sitting unsupported in a chair to picking up an object from the floor or turning in a circle while standing. The activities are function oriented, and each item is scored from 0 (unable to perform) to 4 (proficient performance). The BBS has been used with older adults with cognitive deficits, and test-retest reliability has been found to be excellent (ICC = 0.97).31,47 The SSGS was assessed using the GAITRite walkway and software system. Participants walked twice (after one practice walk) across the 12-foot walkway instrumented with sensors that recorded the temporal and spatial parameters of gait; the walkway was arranged to allow the acceleration and deceleration periods of the walk to occur before the start and after the end of the mat, respectively. The GAITRite walkway has been found to have excellent validity and reliability for GS53,54 and has been used with individuals with AD with high test-retest reliability (ICC = 0.96–0.977).29,30 Mean GS of two passes on the mat at SSGS gave the SSGS score and mean GS of two passes on the mat at FGS gave the FGS score.
The balance exercise intervention was an eight-week, twice-weekly class with 45 minutes for each session. The program was performed in the therapy room of the adult day center. The class was held at consistent times and days each week. The ratio of participants to instructor was never greater than 2:1, and the same licensed physical therapist and student physical therapists supervised the classes each week. The structure of the exercise program was based on available literature concerning motor learning in individuals with AD. The program was designed to be functional and relevant and to include tasks that would be familiar to the participants. It was organized with constant, blocked, massed practice conditions to facilitate optimal learning in the participants.
Balance is defined as maintaining the center of gravity (COG) over the base of support (BOS). Thus, justification for the majority of exercises is related to changes in COG or BOS within a functional context. Although some of the exercises might also be appropriate as strengthening, coordination, or flexibility interventions, they were chosen primarily as challenges to balance. The exercise activities included in the program and their justifications are included in Table 2. The exact same activities were not performed each session, although the underlying principles of maintaining balance during changes to the COG and BOS and the functional nature of the exercises were consistent throughout all sessions. Whenever participants were trying an activity for the first time, they were provided with 1:1 supervision. The low participant-to-instructor ratio also allowed individual attention to performance and appropriate adaptation or progression of activities for each participant. Depending on the activity and the day, some tasks were performed in the larger group, and some were performed at stations, either in pairs or individually with an instructor.
An attendance log was maintained to monitor attendance and participation. Individuals got credit for participation if they engaged in 50% or more of a given exercise class. Recording in a narrative log after each session allowed class instructors to summarize their perceptions of participant engagement and performance. The week after the final exercise session, each participant again underwent the series of three balance and mobility outcome measures outlined previously. Testing occurred in the same place, at the same general time of day, and in the same order as the pretests, and the posttesting session was scored by the same examiner as the pretesting session.
Data were analyzed for each participant by comparing changes in performance between pretest and posttest (ie, individual change score) with pre-established MDC scores at the 90% confidence interval (MDC90) for the chosen outcome measures for this population. When an individual change score exceeds the MDC90 score, this represents a “true” change in performance, beyond what would be expected from individual variability and measurement error for the chosen outcome measure. The pre-established MDC90 score used for the TUG was 4.09 seconds,29 for the SSGS was 9.44 cm/sec,29 and for the BBS score was 6.4.31 There are no established MDC90 scores for FGS, and for this reason, it is not considered one of the primary outcome measures for this study.
Of the seven individuals recruited, five completed the exercise program and pretesting and posttesting. One individual was relocated to an inpatient facility after pretesting and attending one exercise class. A second participant engaged in pretesting and attended the first three weeks of exercise classes, but refused to attend subsequent classes. The characteristics of the five participants who completed the protocol are summarized in Table 3. There were no documented falls at the facility for any of the participants before or during the study; however, data related to history of falls outside of the facility were not available.
The BBS scores improved in all five participants, with three participants having scores that improved by >6.4 of the pre-established MDC90. Four participants improved in TUG performance time, with three participants improving their time by >4.09 seconds of the pre-established MDC90. Three participants improved in SSGS, with all of them improving their speed by >9.44 cm/sec of the pre-established MDC90. Three participants showed improvements in FGS, whereas two participants demonstrated a decline in FGS performance. Two participants improved their SSGS to the extent that their post-test SSGS was comparable with their pretest FGS (within 7.1 cm/sec for participant 3 and within 1.3 cm/sec for participant 5). Individual pre- and posttest scores and change scores are given in Table 4.
The five participants who completed the exercise intervention demonstrated excellent attendance and very good participation. There were no changes in medical status or medications for any of the participants during the study. Routinely, participants who came to class engaged in all class activities; however, there were a few occasions in which individuals were present but unable or unwilling to participate. Reasons for lack of participation included general fatigue, headache, foot pain, disinterest, or agitation. No individual missed more than one session for the same reason.
Except participant 2, all participants who completed the program made significant improvement in at least two of the three primary outcome measures, as determined by change scores greater than MDC90. Participant 3, who had 100% participation, showed significant improvement in all three outcome measures. Participant 2 did not seem to put forth her best effort on the day of post-testing because she verbalized general health concerns (as was a common behavior for her) and complaints of vague lower extremity discomfort throughout all testing activities. Her constant verbalizations were not conducive to capturing her best performance on post-tests. Efforts to reschedule the post-testing were unsuccessful. Participant 4, who showed significant gains in BBS score and TUG, offered a poor effort on SSGS and FGS, as evidenced by walking with hands in pockets and scuffing feet along the mat during post-testing. She was frustrated with the posttest session by the time of the third and final tests (SSGS and FGS). Participant 5, whose participation level was lowest (69%), showed significant gains in both BBS score and SSGS. Both participants 3 and 5 increased their SSGS such that their post-test SSGS were comparable with their pretest FGS.
Worthy of mention is the attrition of two of the original seven program participants. One participant had been awaiting placement in an inpatient facility, and a bed was available during the first week of the exercise intervention. This individual was an 83-year-old man with an MMSE score of 16 and FAST score of 5 (moderate AD). The other individual had been experiencing an increase in agitated behavior before the initiation of the exercise program. He participated in pretesting and the first six exercise classes without incident; however, he became agitated on invitation to join the class on subsequent days, and he was ultimately withdrawn from the study. This individual was a 90-year-old man with an MMSE score of 18 and FAST score of 6D (moderately severe AD). Of the seven participants initially recruited, the two individuals who withdrew from the study represented the most cognitively impaired (MMSE score of 16) and the most functionally impaired (FAST score of 6) participants. Although no conclusions can be drawn from this observation, consideration of dementia level may be an important component in the implementation of an exercise intervention.
Kenny et al,55 in examining predictors of transition from dementia-specific assisted living facilities to skilled nursing facilities, identified that GS and balance (as determined by a modified BBS) were significant predictors of movement to an increased level of care. They suggested that interventions geared toward improving balance and GS and minimizing fall risk in this population, could potentially affect the high transfer rate to skilled nursing facilities. This is convincing justification for designing an efficacious balance intervention.
The feasibility of group exercise interventions with some focus on balance training for individuals with AD and other dementias has been well established,8,11,12,56 and a few studies have provided some evidence of effectiveness of interventions in improving balance and gait performance or attenuating loss of function.8,11,56 Toulotte et al11 studied the effects of a general exercise program on measures of balance in older adults with cognitive impairment of various etiologies (mean MMSE, 16.3 ± 6.5). They found that the exercise group showed significant gains in balance (TUG and SSGS) after the 16-week, twice-weekly exercise program compared with a control group. However, there was an apparent difference in the two groups before the intervention in balance performance, and this is not addressed by the authors. Santana-Sosa et al57 reported findings from a controlled study of a 12-week, three times per week exercise intervention for individuals with AD (mean MMSE [training group], 20.1 ± 2.3; mean MMSE [control group], 19.9 ± 1.7), which demonstrated significant improvement in balance and gait (using Tinetti scale) in the training group, with no significant change in the control group. This was a small (eight subjects in each group) but well-designed study demonstrating the balance benefits of a generalized (resistance, flexibility, and coordination) exercise program in individuals with AD.
In examining an intervention of longer duration, Rolland et al8 demonstrated the attenuation of decline in activities of daily living and improvement in GS compared with a control group, in nursing home residents with AD (mean MMSE, 8.8 ± 6.6) who participated in a 12-month exercise program. Christofoletti et al56 compared six months of motor interventions across three randomized groups of individuals with dementia. Group 1 (mean MMSE, 18.7 ± 1.7) received interdisciplinary treatment (individualized physical therapy, group occupational therapy, and group physical education totaling two hours per day, five days per week); Group 2 (mean MMSE, 12.7 ± 2.1) received individualized physical therapy three times per week for one hour; and Group 3 (mean MMSE, 14.6 ± 1.2) received no motor intervention (control). Although the authors concluded that individuals in both Groups 1 and 2 “improved” their balance, this may be somewhat overstated because there was no evidence that performance scores on the chosen outcome measures (TUG and BBS score) are significantly different from preintervention to postintervention; a decline in performance was observed in the control group. A recent study by Kwak et al58 identified the beneficial effect on balance of a one-year group exercise program in individuals with senile dementia, but the authors did not define how balance was assessed in the study, making interpretation of results difficult.
In each of these previous studies, balance is one of the many components in the exercise programs, not the primary focus. In this study, upright balance training was the principal purpose of the exercise intervention. Basic exercise principles of specificity of training- and task-oriented activities informed the design of the exercise program used in this study. Littbrand et al12 confirmed that impaired cognitive function does not negatively affect the feasibility of participating in a high-intensity weight-bearing exercise program (primarily upright standing and walking activities), although given the design of their study, the authors could not draw conclusions about the effectiveness of their intervention. Netz et al59 demonstrated that older adults with dementia did not benefit from a seated, low-intensity exercise program; however, when the same group participated in a more rigorous exercise program performed while standing or walking, they showed improvement in TUG performance. Accordingly, the majority of activities within the exercise intervention in this study were upright static or dynamic activities.
Another unique aspect of this study was the deliberate design of the intervention to address the motor learning needs of individuals with AD. None of the authors of the reviewed studies offered extensive comment on the design of the exercise programs used in their protocols. The use of constant, blocked, massed practice and the low instructor-to-participant ratio, which allowed individualized progression of tasks to appropriately challenge participants, were considered key to the success of the intervention in this study.
Participants generally enjoyed the exercise program, as evidenced by their mood during the majority of exercise sessions. With the exception of participant 5, individuals had no explicit memory of engaging in the exercise program from session to session. They greeted researchers as if for the first time during every session, and when questioned whether they recalled participating in an exercise class, they responded that they did not. Given that individuals with AD may have intact procedural (implicit) motor learning capacity,24,25 the improvement observed in this study demonstrates motor memory of the activities practiced during the exercise program, despite the lack of declarative (explicit) memory (ie, ability to recall participation in the class). The BBS items on which the subjects showed the most improvement were items that were practiced often in the context of the exercise class (eg, turn to look behind, standing with one leg in front, standing on one foot), reinforcing the idea that specificity of training is important for this population. Toward the end of the intervention, staff at the adult day center provided unsolicited comments on the improved abilities of the participants.
Drawing definitive conclusions from this exploratory pilot study would be premature. The small sample size and lack of a control group are considerable limitations; however, the results of this study reveal the need for future research, including larger studies and randomized controlled trials, to assess the effectiveness of carefully designed small-group balance interventions to improve balance and potentially to decrease the risk of falls in individuals with AD. Considerations for further study might include the level of dementia of participants, “dosage” of exercise intervention, instructor-to-participant ratio, and identification of minimally clinically important difference scores (in relation to MDC scores) in these individuals.
This pilot study confirmed the feasibility of a small-group upright balance exercise program for individuals with AD in a day-care setting. The eight-week, twice weekly exercise intervention was designed with attention to the evidence available in the motor learning literature on individuals with AD. Constant, blocked, massed practice was used, and specific guidelines were followed for communication and cuing with the participants. This exercise program seemed to be effective in improving balance in individuals with mild to moderate AD. Further research is warranted.
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