Health

Written by:
Professor Fong Nai Kuen (Kenneth) & Dr Lau Sum Yuet (Joyce), Postdoctoral fellow

Department of Rehabilitation Sciences, The Hong Kong Polytechnic University

Holistic Care for Body, Soul and Spirit via Gerontechnology Awareness

by Hong Kong Productivity Council
 

Multisensory stimulation therapy (MST) is a non-pharmacological treatment approach that involves using multiple primary senses, including tactility, olfaction, vision, hearing, and taste, to facilitate a connection between people with cognitive impairment and the environment. Due to the directness and simplicity of sensory stimulation, it has been found to improve vigilance and attention, as well as improving the emotional and cognitive outcomes. It has been recommended in the literature as a therapeutic intervention for reducing agitation behaviours in people with cognitive impairments.

 

The behavioural and psychological symptoms of dementia (BPSD) exhibited by people with dementia, such as repetition, wandering, agitation, verbal and physical aggression, significantly impact their daily activities and the quality of life for their carers. The occurrence of BPSD may be attributed to a dysfunction in sensory equilibrium or leading to sensory deprivation. This imbalance can arise from various factors, including disturbances in the circadian rhythm of the biological clock, neurodegenerative processes, sensory deficits, as well as prolonged influences from environmental and artificial stimuli. However, through multisensory stimulation, external sensory information from the environment is transmitted to the brain via neural networks, facilitating the formation of new neural connections in key regions of the basal forebrain, hippocampus, neocortex, and brainstem. Furthermore, olfactory stimulation possesses unique characteristics. Odorants enter our nasal cavity and bind with nasal mucus, whereby olfactory information is transmitted to the brain through olfactory epithelial cells located at the upper end of our nasal cavity, allowing us to perceive smells. Notably, olfactory information is transmitted rapidly and directly to the brain to pop up a reaction or emotion without undergoing higher cortical processing.  Furthermore, human olfactory memory is generally overlooked. The hippocampus receives nearly all olfactory information via the amygdala, forming and strengthening new memories. The entorhinal cortex encodes, identifies, and contextualizes olfactory scenes, enabling us to associate them with food, plants, places, time, and relevant elements. Finally, olfactory information is integrated in the orbitofrontal cortex, enhancing emotional and reward responses to olfactory stimuli. Some of our most deeply ingrained memory associations are activated by odors. Smells linked to past occasions or moments can link us back to those times in our episodic memory. In summary, olfactory stimulation has a rapid and pronounced effect on improving emotional and cognitive functioning, with different odors possessing distinct therapeutic properties. 

 

Most of the current literature on sensory stimulation focuses on single sensory modalities, such as music therapy, light therapy, massage, or aromatherapy. Snoezelen therapy is one of the most extensively studied interventions within the field of MST for individuals with cognitive impairment. Snoezelen therapy provides specially designed rooms filled with various multisensory materials, including music, aromas, tactile elements, and fiber optics, encouraging patients to engage in their preferred sensory stimuli without any personal intervention. Aromatherapy has unique therapeutic effects on olfactory stimulation. Lavender scent, for instance, has a calming effect and helps to balance intense emotions. Green leaf scent stimulates the brain and induces relaxation of the nervous system. Lemon scent enhances focus and improves cognitive function.  

 

Horticultural therapy is another kind of MST, which can be conducted in various settings such as long-term care facilities, hospitals, and homes. Through activities such as planting, pruning, weeding, and harvesting, horticultural therapy contributes to improving physical functioning, stimulating the senses, and providing a sense of purpose and achievement. It has been demonstrated that horticultural therapy can alleviate emotional distress and reduce levels of stress and anxiety. Virtual reality (VR) technology nowadays is also extensively utilized in the medical field. Individual VR therapy, for example, can assist patients in alleviating symptoms such as pain, anxiety, and depression. Furthermore, VR training has the potential to enhance neuroplasticity in individuals with cognitive impairment, promoting cognitive function and protection, thus reducing the risk of further cognitive decline. By simulating real-life activities and cognitive tasks, VR environments can help patients maintain cognitive agility and flexibility, thereby enhancing their daily living skills and self-confidence in confronting to real-life environments. 

 

In view of this, Professor Fong Nai Kuen (Kenneth) and Dr Lau Sum Yuet (Joyce) from the Department of Rehabilitation Sciences at The Hong Kong Polytechnic University have developed a conceptually verified multisensory gardening rehabilitation serious game, namely Garden-GaTE (Garden-Game Therapy Experience) using VR technology. This application provides a gardening scenario with olfactory, visual, auditory, and tactile stimuli, allowing patients to immerse themselves in a virtual environment and navigate through it. The game employs multisensory stimulation methods, particularly olfactory stimulation, the interaction of VR, and various therapeutic elements of VR, for people with cognitive impairment. The research on the user experiences of the multisensory gardening VR serious game for people with cognitive impairment is nearing completion, and we anticipate further improvement and development of the Garden-GaTE in the near future.