This research aims to evaluate the effect of cognitive stimulation (CS) on the functioning of the prefrontal cortex (PFC), seeking an analysis of both cerebral hemodynamics in neuroplasticity and aspects related to the initiation of neurodegenerative processes. The intervention presents an individual format and the participants are elderly without or with neurocognitive disorders (NCD). Concretely, to assess the effects of individual CS on global cognition, and mood, as well as to analyze neuronal activity with oxygenation, volume and blood flow in the brain, evaluating the impact of cognitive stimulation on brain hemodynamics. Participants in the intervention group receive two 45 min-session of CS per week for 12 weeks in addition to their treatment as usual. Participants in the control group will maintain their treatment as usual.
Faced with an unprecedented global ageing population and the current COVID-19 pandemic, the risk of social vulnerability increases in the elderly population, promoting the development and aggravation of neurodegenerative diseases, in particular NCD. The diagnostic criteria for this pathology emphasizes cognitive changes, and as such is based clinically on cognitive decline. The PFC is considered the centre of cognitive function, where it encompasses attention, memory and executive functions. Attention is the cognitive function that allows us to orient to the relevant stimuli and process them to respond accordingly. Given its functionality, it is distinguished into three types of attention: selective, divided and sustained. Attentional dysfunction can be present in several conditions where cognitive deficit is the main symptom, such as Alzheimer's disease. With regard to memory, it is subdivided according to time storage, i.e. short or long term. Short-term memory is capable of operating with certain perceived information for a limited space of time and can later be forgotten or transferred to long-term memory. Two other complementary components are distinguished in this type of memory: immediate memory and recent memory. Long-term memory is a latent memory with unlimited capacity that can remain outside the conscious circuit until circumstances require another mode of response. It involves separate, interdependent and dynamic processes of storage, consolidation and evocation. It is made up of two major subsystems: implicit or non-declarative memory, and explicit or declarative memory. Regarding executive functions, they designate the cognitive processes of control and integration aimed at the execution of behaviour directed at complex objectives, requiring sub-components such as attention, programming, time sequencing, inhibition of competing processes and information, monitoring and selection of strategies. Executive functions include various processes such as working memory, planning, response to reactions and error corrections, cognitive flexibility, inhibition, decision making. There is evidence that in the early stages of NCD, people are able to learn and improve their cognitive function through interventions such as CS. CS is recommended by the National Institute for Health and Clinical Excellence as a non-pharmacological therapy for people with mild to moderate NCD and is an intervention where the cognitive domains are not used in isolation but integrated. An individual format is associated with better results. In a systematic review on CS, studies have shown strong evidence that CS has a positive impact on cognitive function, depression, daily life activities and behaviour for people with NCD. However, no studies are known that have analyzed prefrontal cortex activity in the elderly population associated with a functional method of infrared spectroscopy (fNIRS). This method provides information on hemodynamic changes associated with cortical activation by measuring in a non-invasive way changes in the relative ratios of deoxygenated hemoglobin (HHb) and oxygenated hemoglobin (HbO2). Monitoring and recording the dynamics in the PFC of the elderly during a cognitive stimulation programme with the fNIRS method may contribute to expanding knowledge about aspects related to neurodegenerative processes and cognitive function in the elderly.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
36
The intervention group will receive 24 individual CS sessions per participant. Each session will last approximately 45 minutes and will have the following structure: session introduction (5 minutes); reality orientation (10 minutes); stimulation of cognitive domain (25 minutes); session closure (5 minutes). The sessions will be led by a previously trained therapist. The intervention program will include several activities based on the principles of CS and adjusted for participants without any neurocognitive disorder.
The acquisition by fNIRS will be performed in each CS session in four regions of interest (ROIs) in the prefrontal cortex: left dorsolateral prefrontal cortex (LDLPFC); left medial prefrontal cortex (LMPFC); right medial prefrontal cortex (RMPFC); right dorsolateral prefrontal cortex (RDLPFC).
Cediara - Social Solidarity Association of Ribeira de Fráguas
Ribeira de Fráguas, Albergaria-a-Velha, Portugal
Cognitive functioning evaluated through Mini-Mental State Examination (MMSE)
Significant statistic improvement in the participant's test scores between pre-intervention assessment and postintervention assessment. MMSE is a brief cognitive screening test. Scores range between 0-30 points. Higher scores indicate better cognitive function.
Time frame: baseline
Change in cognitive functioning evaluated through MMSE
Significant statistic improvement in the participant's test scores between pre-intervention assessment and postintervention assessment. MMSE is a brief cognitive screening test. Scores range between 0-30 points. Higher scores indicate better cognitive function.
Time frame: 12 weeks after the beginning of the intervention
Executive functions evaluated through Frontal Assessment Battery (FAB)
Significant statistic improvement in the participant's test scores between pre-intervention assessment and postintervention assessment. FAB assesses executive functions such as abstract thinking, mental flexibility, motor programming, interference sensibility, inhibitory control and environmental independence. Scores range between 0 - 18 points. Higher scores indicate better cognitive function.
Time frame: baseline
Change in executive functions evaluated through FAB
Significant statistic improvement in the participant's test scores between pre-intervention assessment and postintervention assessment. FAB assesses executive functions such as abstract thinking, mental flexibility, motor programming, interference sensibility, inhibitory control and environmental independence. Scores range between 0 - 18 points. Higher scores indicate better cognitive function.
Time frame: 12 weeks after the beginning of the intervention
Prefrontal cortex activation pattern through a fNIRS
Analysis of Oxyhemoglobin (HbO2) and Deoxyhemoglobin (HHb) variation in four regions of interest (ROIs) in the PFC: left prefrontal dorsolateral cortex (LDLPFC); left medial prefrontal cortex (LMPFC); right medial prefrontal cortex (RMPFC); right dorsolateral prefrontal cortex (RDLPFC). An increase in brain activity is generally assumed to reflect an increase in HbO2 and decrease in HHb as based on a mechanism known as neurovascular coupling.
Time frame: baseline
Change in prefrontal cortex activation pattern through a fNIRS
Analysis of Oxyhemoglobin (HbO2) and Deoxyhemoglobin (HHb) variation in four regions of interest (ROIs) in the PFC: left prefrontal dorsolateral cortex (LDLPFC); left medial prefrontal cortex (LMPFC); right medial prefrontal cortex (RMPFC); right dorsolateral prefrontal cortex (RDLPFC). An increase in brain activity is generally assumed to reflect an increase in HbO2 and decrease in HHb as based on a mechanism known as neurovascular coupling.
Time frame: during the intervention
Depressive symptomatology assessed through the Geriatric Depression Scale-15 (GDS-15)
Participants' scores in the GDS-15. This instrument evaluated depressive symptoms using yes/no answers. Scores range between 0 and 15 points. Higher scores indicate more severe depressive symptoms.
Time frame: baseline
Change in depressive symptomatology assessed through the GDS-15
Participants' scores in the GDS-15. This instrument evaluated depressive symptoms using yes/no answers. Scores range between 0 and 15 points. Higher scores indicate more severe depressive symptoms.
Time frame: 12 weeks after the beginning of the intervention
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