The Feasibility and Effect of Cognitive Training on Objective and Subjective Cognitive Functioning in Patients With Mild Cognitive Impairment: A Pilot Study

Alzheimer's disease (AD) is the most common form of dementia, a debilitating neurodegenerative disease with cognitive impairments, especially impairments in memory, at its core. AD is progressive, with cognitive symptoms gradually worsening as AD brain pathology builds over time. The clinical construct of Mild Cognitive Impairment (MCI) represents an intermediate stage between healthy ageing and early dementia with cognitive impairment that is worse than what is seen in healthy ageing, but not enough to interfere with daily living. Although, not all MCI cases lead to dementia, the majority of cases eventually progress.

The amnestic subtype of MCI, which is especially characterised by the presence of memory impairments, is the most likely to progress to AD dementia. In line with the evolution of brain neurodegeneration in AD, typically beginning in memory-related medial-temporal limbic areas, which specifically contribute to forming and accessing spatial contextual short-term memories, spatial memory deficits are especially common in amnestic MCI. AD patients and even amnestic MCI patients perform worse on visuospatial short-term memory tasks compared to healthy participants and individuals with other neurodegenerative disorders. Memory functions are essential for daily living, and memory impairments have been shown to be a major determinant of health outcomes and well-being in age-related disorders.

At the time an MCI diagnosis is made, the pathological burden is often so high that it is almost impossible to stop or reverse the cognitive impairment. Presently, there is no cure for AD or any other type of dementia, and available pharmacological treatments have only very limited effects on cognitive symptoms. A major research priority should therefore be to develop non-pharmacological approaches, which are cost-effective and potentially feasible for large-scale implementation, to preserve and promote cognitive function and improve quality of life early on in MCI.

Previous studies have shown beneficial effects of cognitive training in MCI and AD patients using a novel training procedure that has been proposed to active and relay on memory processes and brain structures that are less affected in MCI and AD - The Differential Outcome Training (DOT). DOT training is based on the principle that each stimulus-response association to be learned is followed by a unique reinforcer, relative to a condition where reinforcers are presented randomly (non-differential outcomes training, NDOT). DOT training has been shown to result in enhanced learning, including faster acquisition, better overall retention, and higher retention accuracy, in both animals and humans. Nonetheless, the effects of a prolonged DOT training on visuospatial short-term memory performance and possible transfer of any benefits to other memory tasks and cognitive domains as well as its impact on quality of life in patients with MCI requires further research.

This study aims to establish the feasibility and effectiveness of a recently developed digital, gamified type of cognitive training in individuals with MCI. The study aims to address this by using a recently developed gamified version of the DOT task. This gamified DOT task integrates the DOT procedure within a gardening task. Participants are introduced to a botanic garden that they have to keep up, which includes cleaning up, obtaining seeds, planting plants, and putting up decorations. They can obtain seeds, plants, and money by performing a visuospatial short-term memory DOT task, which they can then use for the garden.