Is Environmental Enrichment Ready for Clinical Application in Human Post-stroke Rehabilitation?

Abstract

Environmental enrichment (EE) has been widely used as a means to enhance brain plasticity mechanisms (e.g., increased dendritic branching, synaptogenesis, etc.) and improve behavioral function in both normal and brain-damaged animals. In spite of the demonstrated efficacy of EE for enhancing brain plasticity, it has largely remained a laboratory phenomenon with little translation to the clinical setting. Impediments to the implementation of enrichment as an intervention for human stroke rehabilitation and a lack of clinical translation can be attributed to a number of factors not limited to: (i) concerns that EE is actually the “normal state” for animals, whereas standard housing is a form of impoverishment; (ii) difficulty in standardizing EE conditions across clinical sites; (iii) the exact mechanisms underlying the beneficial actions of enrichment are largely correlative in nature; (iv) a lack of knowledge concerning what aspects of enrichment (e.g., exercise, socialization, cognitive stimulation) represent the critical or active ingredients for enhancing brain plasticity; and (v) the required “dose” of enrichment is unknown, since most laboratory studies employ continuous periods of enrichment, a condition that most clinicians view as impractical. In this review article, we summarize preclinical stroke recovery studies that have successfully utilized EE to promote functional recovery and highlight the potential underlying mechanisms. Subsequently, we discuss how EE is being applied in a clinical setting and address differences in preclinical and clinical EE work to date. It is argued that the best way forward is through the careful alignment of preclinical and clinical rehabilitation research. A combination of both approaches will allow research to fully address gaps in knowledge and facilitate the implementation of EE to the clinical setting.

<p>Challenging rehabilitation environment for older patients</p>

“…Until recently, an enriched environment remained largely a laboratory phenomenon with little translation to the clinical setting. In animals, an enriched environment proved to be a robust intervention for fostering brain plasticity and recovery from various types of brain injury, including stroke 61. This latter research showed that the ideal enriched environment encourages socialization, exercise, sensory and cognitive stimulation, and task-specific exercise.…”

Effects of Enriched Physical Activity Environments on Balance and Fall Prevention in Older Adults: A Scoping Review

“…In addition, relevant studies in the systematic review and meta-analysis studies were also included after reading the full-text of the published article. Key terms were adapted from studies that aimed to increase participation in physical activity and rehabilitation exercises through changing the environment (McDonald, Hayward, Rosbergen, Jeffers, & Corbett, 2018).…”

The effects of environmental enrichment on skin barrier recovery in humans: a randomised trial

“…Despite substantial evidence demonstrating EE's beneficial effects in animals, few studies have been conducted in humans 16 . There are a number of issues to consider when adapting these interventions for humans.…”

“…In many studies, a control environment is where animals are reared in simple cages with only the necessary bedding, food and water available 19 . However, this can be seen as a state of impoverishment, with enrichment being closer to the normal state for wild animals 16 . Therefore, the provision of EE actually normalises the typical living condition and rescues the deficits caused by impoverishment.…”

“…A third issue is that animals usually have continuous access to EE over a period of weeks 16 . Such long experiments are impractical to replicate in humans because they would require isolating individuals for long periods of time.…”