Background
Nursing home residents frequently suffer from multimorbidity [
1]. Especially in this high-aged population, progressive decline in motor and cognitive abilities often results in decreased quality of life [
2,
3]. A large proportion of nursing home residents are physically inactive [
4,
5] and spend their time alone [
6]. Such physical inactivity has multiple negative consequences on health and well-being [
7,
8]. Cognitive decline is a risk factor for reduced activities of daily living (ADL) and instrumental activities of daily living (IADL) in older adults [
9,
10], which further contribute to a decreased quality of life. For example, declining cognitive abilities lead to functional limitations in performing fundamental physical and cognitive activities such as climbing stairs and producing intelligible speech [
11].
It has been shown that the combination of decreasing mobility and declining cognitive abilities leads to an accelerated reduction of physical activity (PA) and life space (LS) [
12‐
15]. Sedentary behavior hampers social interaction which in turn reduces cognitive stimulation [
8]. Given the interplay between PA and cognitive abilities [
16,
17], sedentary behavior aggravates cognitive impairment, leading to a vicious cycle. Beside these general impairments of cognitive abilities, age-related cognitive decline specifically affects spatial-cognitive abilities such as spatial orientation and navigation [
18]. Decrements in these specific cognitive subdomains are early biomarkers of cognitive decline [
19‐
21], with an adverse impact on mobility and, as a consequence, reduced LS mobility and PA.
LS mobility is a measure that has been positively associated with PA as well as social participation in nursing home residents [
22] and – per definition – it also incorporates the use of someone’s spatial environment [
23]. It was also shown to be positively associated with better cognitive function [
24] and a predictor of cognitive deterioration [
25,
26]. Spatial abilities underlying orientation in and navigation through the environment include remembrance of target localisation in an environment, awareness of distance and directions as well as the mental transformation of the relation between objects to own body positions and spatial orientation [
27]. Spatial abilities are determined by factors of the individual’s lifespan development in various environments [
28,
29] and decreasing spatial cognitive abilities can lead to reduced PA and a decreased LS mobility due to spatial anxiety [
30]. However, not all spatial abilities in the aging population are affected to the same degree. To distinguish between general spatial abilities and spatial abilities that decline with increasing age, it is necessary to differentiate between egocentric and allocentric reference frames [
31]. Within an egocentric reference frame, the environment is represented with regards to the current position and orientation of the person (e.g. the third door on the right leads to the dining room). Allocentric reference frames, in contrast, are centered outside the person (e.g. the dining room is located in the middle of the east wing of the building) and the spatial information is thus coded independently of the position and orientation of the person. While egocentric orientation strategies remain relatively stable in older age, allocentric strategies decrease considerably with increasing age [
3,
32‐
34]. It seems that this reduction does not depend on individual preferences in using spatial orientation strategies across the life span [
35]. During the last years, however, it has been repeatedly shown that the aging brain and body remain plastic and that older adults’ capacity can be improved through systematic motor or cognitive training [
36‐
38]. By adding physical training components, cognitive resources can be addressed more effectively and/or flexibly [
39]. Moreover, different types of dual- or multi-task training, for example combining motor exercises with unspecific orientation tasks, might positively influence the cognitive performance of older adults [
37,
40]. These studies are complemented by psychological theories, for example, the resource theory [
41], predicting that well-trained older adults have more resources available to perform cognitive tasks on a higher level. There is also evidence that specific training interventions will initiate mental stimulation and that mental compensation (e.g. through specific cognitive training like the method of loci) can enhance neural plasticity [
38,
42].
However, some studies show that dual-task training is not always more beneficial than e.g. multicomponent exercises to gain positive effects on cognitive-motor performance in older adults [
43‐
45]. To become more effective in improving dual-task performance, intervention programs should include a combination of complex balance and coordination tasks [
46]. To optimize benefits for both, cognitive and motor functions, training interventions need to be task-specific [
40,
47]. It has been shown that exercise programs including cognitive-motor elements (for example, using dual-tasking with specific muscle strengthening elements [
48] to improve ADL components [
49]) are more successful than cognitive or motor training provided separately. In addition, a recent study by Bherer and colleagues [
50] emphasized the synergistic effects of the combination of cognitive and motor training. To achieve cognitive improvements through motor training, adaptation to participants’ individual prerequisites is important [
39]. Adaptable exercise modalities are required to align exercises to individual requirements, which would thus allow for a comparable training intensity for all participants [
39]. Hence, frequency, intensity, and duration have to be controlled. A recent meta-analysis revealed that cognitive-motor training should be provided for at least twelve weeks with a minimum of 60 min per week to improve executive functions [
46]. Moreover, a progression that allows individual adaptions should be provided [
39,
46].
The aforementioned vicious cycle of decreasing mobility and general cognitive decline can be addressed by cognitive-motor training. Previous studies that investigated training of motor function [
51,
52] or spatial orientation [
53,
54] demonstrated improvements in the physical and cognitive domain. Such interventions could enhance PA and LS mobility [
55,
56], which may also stimulate overall cognitive performance. Moreover, Cassilhas and colleagues found that physical exercise (aerobic and resistance) improved spatial learning and memory [
57]. However, it remains unclear whether these programs might induce stronger effects on cognitive-motor performance if specific cognitive components had been integrated [
40]. In addition, animal studies on neurogenesis provided evidence that PA in combination with activity in cognitively enriched environments induces additive neurogenic effects in the hippocampus, an important underlying neural structure of human memory [
58] and allocentric spatial orientation [
59,
60]. Garthe and colleagues (2016) concluded that these findings underpin the physiological link between locomotion and orientation. Therefore, interacting with an enriched environment benefits cognitive functioning, including learning and memory abilities [
61]. Moving through an enriched environment might specifically foster spatial learning as a means to enable individuals to re-orientate when confronted with the same environment [
62,
63]. Moreover, in the context of long-term care Vance and colleagues [
64] addressed different methods of cognitive training interventions (e.g. method of loci) to improve cognitive abilities such as orientation abilities or compensation strategies for the loss or limitation of cognitive strategies [
64]. However, these methods have not yet become a standardized part of cognitive-motor interventions. One of the specific exercise components which have not been addressed in particular in nursing home residents is spatial orientation. It can be addressed via two different strategies within a training program. Firstly, physical training intervention can include dual-task elements addressing egocentric and allocentric aspects of spatial orientation. Secondly, integrating supportive spatial information like landmarks into care facilities is another means to compensate for decreasing spatial cognitive functions and to support the spatial orientation of nursing home residents [
65]. In addition to landmarks that are given because of their functionality within the facility (e.g. social rooms, restaurant, etc.) or that are part of the immediate environment of the facility (trees, fountains, next bus stop, etc.), these supportive landmarks can be used within a training intervention to foster spatial learning based on distinct spatial reference frames.
It has not yet been examined whether cognitive-motor training including spatial orientation tasks is suitable to increase PA, enlarge LS mobility and to improve spatial orientation and, as a consequence, elicit changes in well-being and general cognitive-motor functioning in nursing home residents. Against this background, the overall goal of this multicentric RCT (PROfit) is to investigate the efficacy of three different intervention approaches on PA, LS mobility, and spatial orientation: The PROfit basic group will perform functional strength, balance, flexibility, and walking exercises at the same location, while the PROfit plus group relocates three times during the training. The PROfit orientation group receives navigation tasks in addition to the relocation during interventions. We hypothesize that all three intervention arms will generate slower decline or even improvements in residents’ PA, LS mobility, and spatial orientation compared to a wait-list control group. We assume that PROfit plus will be more effective than PROfit basic because of residents’ improved orientation due to the different training locations. Furthermore, we expect the PROfit orientation intervention to be most beneficial due to its additional focus on spatial orientation.
Discussion
The overall goal of this multicentric RCT is to determine the effects of three different cognitive-motor training interventions on PA, LS, and spatial orientation in a sample of nursing home residents. We expect slower declines or even improvements in PA, LS mobility, and spatial orientation in participants of all three groups compared to wait-list controls. Regarding the secondary outcomes, we expect that physical functioning, cognitive functioning, and psychosocial well-being will be improved in all residents participating in one of the three intervention arms, when compared to the wait-list control group.
The interventions of the PROfit program combine components of exercise programs that have been proven to yield health benefits for nursing home residents [
51,
93,
98,
99]. Especially the physical outcomes, e.g., walking capacity, muscle strength, and balance capacity have been shown to be improved by multicomponent interventions as conducted within the PROfit approach [
91,
93,
100].
However, regarding PA and LS, effectiveness has not yet been investigated. Therefore, we extended previous intervention approaches with changes of location during training and specific spatial orientation training to follow the principles of training and task specificity to increase the training effects. By adding different locations where the training is administered, we aim to increase physical, cognitive, orientation and psychosocial parameters substantially more with
PROfit plus than with
PROfit basic. Moreover, we expect the
PROfit orientation intervention to be most effective due to its additional navigation and spatial orientation training components. We suppose that the effects of
PROfit orientation on the primary outcomes will be reached via two mechanisms: (1) increased physical and cognitive performance will enhance cognitive-motor capacities and (2), according to Vance and colleagues the spatial training will help to build up cognitive strategies to compensate for age-related losses and limitations [
64]. This, in turn, could translate into enhanced PA and LS due to better abilities to find the way, better knowledge of the nursing home building, alleys, floors, and room plans. One cognitive strategy would be the use of newly learned landmarks for an egocentric-based route strategy. Here, landmarks can be used as indicators where to turn in which direction to reach a specific goal location. Alternatively, landmarks can be integrated into an allocentric representation of the environment leading to improved knowledge of relative directions between different locations or even a survey-like representation of the environment. Introducing existing objects in and near the facility as landmarks for orientation reflects a compensatory approach [
65] which in turn allows training of different spatial strategies based on this new information, eventually leading to improved spatial orienting abilities.
Overall, potential ways to encourage nursing home residents to participate actively in social life within the care setting are provided by facilitating a program that is appropriate and adapted to residents’ capacities, needs, and desires. Moreover, introducing a specific spatial cognitive component to the program and investigating the impact of nursing home facilities’ spatial structure and landmark availability, this program will allow to develop guidelines for interventions that specifically increase spatial orientation abilities in care home facilities and their contribution to general LS mobility and well-being. Results from this trial will particularly contribute to the evidence on motor-cognitive approaches in the maintenance of mental and physical functioning.
To this end, the findings may provide suggestions and support to handle present and future challenges, occurring at health promotion initiatives in the setting of long-term care, a sector that is highly relevant in times of aging populations in Western societies. With the prevention act of 2015, German health insurances have to provide preventive services in nursing homes. The multicentric RCT will show that universal prevention through motor exercise and spatial orientation training is possible and useful to improve health status and personal resources of nursing home residents.
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