Evaluation of a Cognitive Training Therapy Based on Synchronized Oscillatory Stimulation in Patients With Mild Cognitive Impairment Through a Randomized Clinical Trial

Background At the global level, sociodemographic change is happening, characterized by progressive aging of the population and a modification of the epidemiological profile, with an increase in the prevalence of chronic diseases and other pathologies associated with aging, such as dementia. Dementia is an acquired and chronic pathology characterized by an impairment of brain functions involving cognitive, psychological, and behavioral symptoms. These symptoms affect people's ability to carry out their usual daily activities. These disabilities imply a challenge for the people themselves, their families, the state, and public policies.

To date, the therapeutic approach to patients with dementia has focused primarily on late-stage drug treatment. However, this type of intervention has reported good results on specific dimensions, and an efficacy questioned long-term. The use of drugs with non-pharmacological therapies has proposed that it would be more effective to complement the treatment of patients, and the efforts should be directed towards prevention. In this context, in prodromal phases of dementia, such as Mild Cognitive Impairment (MCI), it is suggested early interventions.

MCI refers to the intermediate stage between the cognitive changes observed by normal aging and those that occur due to dementia. Patients with MCI are especially likely to benefit from non-pharmacological intervention. Since these patients would maintain some degree of neuroplasticity, the patients would learn and apply new strategies to improve their cognitive functioning.

One critical component of cognitive skills affected in neurodegenerative diseases and dementias is working memory (WM). WM represents a fundamental pillar of cognitive functions and is the gateway to the maintenance of long-term memory. The traditional view assumes that the capacity of WM is a specific feature of each individual and that it is not modifiable. However, recent evidence has accumulated that the capacity of WM is susceptible to be enhanced by training. This improvement is related to enhanced activity, connectivity, and selectivity between the frontal and parietal cortex.

Despite these findings, most evidence comes from healthy populations with conserved neuroplasticity. This constitutes a problem for neurodegenerative diseases because it has been corroborated that neuroplasticity is limited in these pathologies. In this context, cognitive rehabilitation in these diseases must include therapeutic tools aimed at increasing neuroplasticity. The use of non-invasive brain stimulation offers an opportunity to increase the capacity of neuroplasticity in this population. However, there has not been a rehabilitation proposal that incorporates this technique into intervention programs. Advancements have been made in neuroscience on the mechanisms underlying WM that have not been incorporated into early intervention and cognitive training in subjects with MCI.