The present study showed that incentives for nursing home residents with dementia to attend an enriched garden contributed to better functioning compared to residents who were invited to visit a conventional sensory garden or who were not invited to visit a garden. The concept of enrichment environments placed in gardens for Alzheimer’s disease patients is a new approach to improve the functioning of demented patients.
Previous studies highlighted the beneficial contribution of gardens to Alzheimer’s disease patients15,18. Whear et al19 published a systematic review in 2014 to assess the effects of gardens on the health of nursing home residents with dementia. They identified ten quantitative studies, all with methodological limitations and a high risk of bias. Most studies investigated dementia-related behaviour and 6 studies revealed a favourable effect on agitation. The gardens in these studies, were not specially designed for nursing home residents, except in the study by Edwards20 in which the garden that was specially designed for nursing home residents with dementia.
Our study on the effects of enriched gardens on nursing home residents with Alzheimer’s disease is original and innovative in several aspects. The design of the enriched gardens was inspired by the conceptual model of Hebb4,5 and followers6–9,21−23 based on enriched environment in which the implementation of stimulating devices in the environment had positive effects on a variety of brain functions in both animal and human studies. We applied this concept to the context of nursing homes and designed enriched gardens comprising a variety of stimulating modules, as described in Table 1. As the beneficial effect of walking outside and visiting outdoor gardens is well documented among nursing home residents19, we have conceptualized an enriched environment within a garden. To explore the specific effects of this enriched environment, we conducted this study in facilities that had both conventional sensory gardens and enriched gardens, to compare the effects of the two types of gardens in the same facilities. Both types of gardens offered similar interactions with nature, including an open-air walking path and an atmosphere of well-being, but only the enriched gardens comprised the specific modules designed to address dementia related troubles. The availability of the two types of gardens in the same facility is an infrequent occasion and also a remarkable point of our study, that led us to the conclusion that the enriched garden offered specific beneficial effects compared to conventional gardens.
In our study, the better effects observed in the enriched garden group suggest that the stimulating modules are the main active component acting in combination with favorable effects provided by the garden. We based our hypothesis on the idea that the open-air and vegetal atmosphere of the landscape garden favorize letting go by the visiting resident and create favorable conditions to interact with the existing stimulating modules. Each of twelve modules was designed to focus on specific weaknesses or disorders of residents with Alzheimer disease. In this multimodal approach, several modules were conceptualized to stimulate cognitive abilities, walking abilities and independence. Following the intervention, we observed changes in the corresponding outcomes during the trial, which were greater for residents assigned to enriched gardens than for those assigned to conventional sensory gardens. Although we did not track the effects of each individual module, we designed the intervention with 12 different modules that individually address the specific weaknesses of residents with dementia. Seven of them were designed to stimulate cognitive impairment and eight to stimulate the ability to walk and independence. It is therefore plausible that the interaction with the modules in the enriched gardens had beneficial effects on the outcomes we measured, although our study cannot ascertain this point. A better demonstration could be obtained by future studies recording in detail the interaction of residents with specific modules and examining the relationship between these interactions and the clinical effects, but this goal was far beyond the scope of this pilot study. We observed in the participants of the group Enriched garden a significant improvement in cognition that exceeded our expectations. This is consistent with a body of literature showing that cognitive stimulation can have positive effects on cognition of residents with Alzheimer's disease24. Interestingly, in another context, Then et al showed that an enriched environment at work place was protective from incident dementia (odds ratio 0.61, 95%CI: 0.47–0.79) in the Leipzig longitudinal study of the aged25,26, and the authors explained their finding by the effect of enriched environment on cognitive abilities and cognitive reserve.
Limitations
Our study has several limitations. Our study was not a randomized trial, and patients were assigned to
groups based on the location of their rooms in relation to the gardens. This pragmatic design made it
possible to compare the different groups, and it would have been technically and ethically difficult to
set up a trial with a randomization of residents. Fortunately, we did not observe large differences
between the three groups, but we cannot exclude a possible selection bias. We also did not record the attendance of the participants in the gardens nor the duration of their use, and for the enriched garden group, the number of interactions with the stimulation modules. We did not specifically measure family or professional caregiver participation in garden visits with residents, which could have had positive effects. From our clinical experience, if it was clear that staff members of the facilities felt interested by the availability of gardens, they did not spend a lot of time in gardens with residents due to their heavy workload. In addition, we did not measure staff attention for the residents which might have been different between groups and might also represent a potential bias. Finally, in our pilot study we did not assess the effects of enriched gardens on behavioural and psychological symptoms which are an important issue for certain residents with dementia.