The neuropsychologist Ana Isabel Moneo Troncoso, alluding to incomplete infarction and the capacity offered by Cognitive Stimulation (CS) to promote neuronal plasticity, explains the importance of early neurorehabilitation in cases of cerebrovascular accident (CVA) for greater recovery.

What is a cerebrovascular accident?

A CVA, stroke or apoplexy, refers to the acute neurological injury that occurs due to a pathological alteration in blood vessels, resulting in one of the most prevalent neurological diseases in recent years and a major public health problem.

In cases of a ruptured blood vessel, it is referred to as “hemorrhagic stroke,” accounting for 15% of cases. When a blood clot forms, leading to a decrease in blood flow, it is referred to as “ischemic stroke,” accounting for 85% (Zhao et al., 2022).

CVA is associated with both physical and cognitive impairments, resulting in deterioration. Once the damage occurs, cognitive sequelae affect between 25% and 80% of survivors, leading to alterations in cognitive functioning (Mane, Chouhan, & Guan, 2020).

The most frequent impairments include difficulties:

• In attention (selective and divided).
• In memory (storage and retrieval).
• In executive function (organization and planning).
• And alterations in mood, among others.

This is why it is particularly relevant to focus on comprehensive rehabilitation, considering the cognitive domain, as the sequelae limit the patient’s autonomy and quality of life (Ardila, Silva, & Acosta, 2013).

The role of Brain-Derived Neurotrophic Factor (BDNF) in neuronal survival

After the injury occurs, selective necrosis (non-physiological cell death due to irreparable or incurable damage, leading to decay) affects a group of cells within the area, preserving some neuronal cells, glia, and microvasculature. Following the partial cell death called “incomplete infarction,” surviving neurons can be detected even two days after the damage occurs. The latest advances highlight the importance of Brain-Derived Neurotrophic Factor (BDNF), the most expressed protein in the Central Nervous System, present 7 to 14 days after the injury (Jiang et al., 2017).

Brain-Derived Neurotrophic Factor (BDNF)

BDNF is a protein located in neuronal dendrites and axons, involved in neurogenesis or the formation of new neurons, cellular differentiation, programmed cell death (apoptosis), and neuronal survival. In cases of neurological disorders, it plays essential roles in damage reorganization through the activation of different pathways.

As a consequence of the damage, there is cellular proliferation and migratory movement towards the lesion site, with changes in the migratory process associated with the neurotrophic factor (Pisani et al., 2023).

The protective effects of the protein should be highlighted, as it is involved in axonal and dendritic growth, as well as synaptic establishment and maintenance, facilitating long-term potentiation (LTP) (which will be explained later). Therefore, it is worth noting the neuroprotective and brain regeneration role of BDNF in cases of damage (Simko, Kent, & Rektorova, 2022).

The protein is mainly found in cortical, amygdalar, cerebellar, and hippocampal areas, with the latter region being linked to learning and memory. Activation of intracellular processes has been observed following BDNF activation, promoting underlying processes of learning and memory.

Given the key role of the protein in countering damage, early rehabilitation is essential for improving cognitive functioning and therefore achieving greater recovery (Pisani et al., 2023).

Post-CVA rehabilitation through cognitive stimulation

Cognitive Stimulation (CS) is one of the most evidence-based rehabilitation techniques for CVA, as explained in the scientific literature. It refers to a set of techniques and strategies aimed at optimizing the effectiveness of various cognitive capacities and functions (perception, attention, reasoning, abstraction, memory, language, orientation processes, and praxis). All of this is achieved through specific situations and activities structured in what are called “cognitive training programs” (Villalba & Espert, 2014).

The neurobiological foundations that determine the intervention’s effectiveness are based on both neuroplasticity and cognitive reserve, among others. The term neuroplasticity refers to the modifiable nature of human behavior, as the brain has a great capacity to adapt to new situations and restore balance after damage. Since the nervous system is highly plastic, changes can occur both structurally and functionally, thus enhancing synaptic plasticity to promote recovery (Castillo, Fernández, & Chamorro, 2020).

Synaptic plasticity

Synaptic plasticity refers to the connection between adjacent neurons, allowing the passage of information. Neuronal circuits are routes of communication exchange that undergo modifications through learning and practice. After acquiring new knowledge, repeated practice over time improves communication via synaptic connectivity, resulting in strengthened connections (known as LTP).

Cognitive reserve

Cognitive reserve refers to the brain’s capacity to tolerate brain lesions without cognitive and behavioral symptoms. Stimulation over the years through knowledge acquisition, physical activities, and social interaction increases this reserve, leading to a delay in the clinical expression of cognitive deficits (Kwakkel, Kollen, & Lindeman, 2004).

Transcranial Direct Current Stimulation (tDCS)

The latest advances in rehabilitation indicate combined therapies involving CS and other techniques, such as Transcranial Direct Current Stimulation (tDCS), to enhance cognition since both techniques offer benefits independently.

tDCS is a non-invasive and painless cerebral neuromodulation technique aimed at modulating regional cortical excitability or inhibition instantly through two electrodes placed on the scalp (Conde-Antón et al., 2020).

Neural changes are associated with modulation of neurotransmitter activity (dopamine, serotonin, glutamate, acetylcholine, among others) and alterations in neurotrophic factors. After tDCS application, BDNF modulation promotes growth and neuronal connections, improving recovery from damage (Madeiros et al., 2012).

Conclusion

Given the notorious incidence of CVA cases in recent years, it is essential to know the benefits of early neurorehabilitation in cases of cerebrovascular accident. Not only are the sequelae of the damage minimized, but it also offers an improvement in the cognitive and functional capacity of the patient. All this will favor a positive impact on the perception of quality of life, greater autonomy and an improvement in mood, which reduces social isolation. Therefore, there will be an improvement in family dynamics, benefiting both patients and family members and/or caregivers.

Bibliography

• Ardilla, W., Silva, F. y Acosta, M.R. (2013). Perfil neuropsicológico en pacientes con ACV isquémico de la arteria cerebral media izquierda. Acta Neurología Colombia 29 (1), 36-43.
• Castillo, G., Fernández, B. y Chamorro, D. (2020). Neuroplasticidad: Ejercicios para retrasar los efectos de la Enfermedad de Alzheimer mediante Estimulación Cognitiva. Revista Investigación científica tecnológica 4 (2), 115-122.
• Conde-Antón, A., Hernando-Garijo, I., Jiménez-del-Barrio, S., Mingo-Gómez, M.T., Medrano-de-la-Fuente, R. y Ceballos-Latia, L. (2020). Efectos de la estimulación transcraneal por corriente directa y de la estimulación magnética transcraneal en pacientes con fibromialgia. Revisión sistemática. Neurología, 38 (2023), 427-439.
• Jiang, M.Q., Zhao, Y.Y., Cao, W., Wei, Z.Z., Gu, X., Wei, L. y Yu, S.P. (2017). Long-term survival and regeneration of neuronal and vasculature cells inside the core region after ischemic stroke in adult mice. Brain Pathol 27(4), 480-498.
• Kwakkel, G., Kollen, B. y Lindeman, E. (2004). Understanding the pattern of functional recovery after stroke: facts and theories. Restor Neurol Neurosci 22 (3-5), 281-99.
• Mane, R., Chouhan. T. y Guan, C. (2020). BCI for stroke rehabilitation: motor and beyond. J Neural Eng. 17 (4), 1-21.
• Medeiros, L., de Souza, I., Vidor, LP., de Souza, A., Deitos, A., Volz, MS., Fregni, F., Caumo, W. y Torres, IL. (2012). Neurobiological effects of transcranial direct current stimulation: a review. Front Psychiatry, 3 (110), 1-11.
• Pisani, A., Paciello, F., Del Vecchio, V., Malesci, R., De Corso, E., Cantone, E., y Fetoni, A. R. (2023). The Role of BDNF as a Biomarker in Cognitive and Sensory Neurodegeneration. Journal of personalized medicine, 13(4), 652.
• Skimo, P., Kent, J., Rektorova, I. (2022). In non-invasive brain stimulation effective for cognitive enhancement in Alzheimer`s disease? An updated metaanalysis. Clinical Neurophysiology 144, 23-40.
• Villalba, S. Y Espert, R. (2014). Estimulación cognitiva: Una revisión neuropsicológica. Therapeía 6 73-93.
• Zhao, Y. Zhang, X., Chen, X. y Wei, Y. (2022). Neuronal injuries in cerebral infarction and ischemic stroke: From mechanisms to treatment (Review). International Journal of Molecular Medicine 49, 1-9.

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