Abstract

The cognitive reserve is described as the efficient connectivity between neural networks which differs from the concept of cerebral reserve, indicative of larger volume of neural cells and, therefore, an increased ability to tolerate brain insults or effects of aging itself. A more detailed explanation would include the idea that the neural compensation mechanism uses alternative ways of the brain to perform activities considered complex. This activation is not observed in normal brains and may allow the individual to maintain levels of performance close to the basal state. In the present study we describe the case of an 85-year-old female, 15 years of schooling (Social Work), whose nephew reported having noticed a change in mood three years ago. There was no complaint regarding cognitive symptoms, neither by the elderly nor by relatives and caregivers. In the global geriatric evaluation the elderly presented a performance in the cognitive screening lower than expected, but also scored positively for depressive symptomatology. In this way the patient was included in a protocol of cognitive investigation which includes: laboratory tests, structural and functional neuroimaging, neuropsychological evaluation and pragmatic functionality assessment. The results of these evaluations indicated that there were no metabolic and blood changes, besides the results of the neuropsychological evaluation that suggested preserved cognitive performance, except for discrete changes in executive function and speed of reasoning, which would even be compatible with alterations associated with depressive symptomatology. The pragmatic functional evaluation presented results that corroborated with the neuropsychological assessment. On the other hand, the results of neuroimaging (structural and functional) suggested a significant reduction in cortical volume and, in addition, nucleocapsular, subinsular and thalamic regions. There was also generalized hypometabolism, especially bilateral frontotemporal regions. This neuroimaging result would be compatible with an elderly woman diagnosed with moderate to advanced dementia. However, this patient had an extraordinary cognitive reserve and did not show impairment of cognitive and functional performance in daily life activities. In this sense it is portrayed how the cognitive reserve in an elderly person can delay the onset of cognitive decline and prolong the quality of life of both the elderly and their family.

Keywords: Cognitive Reserve; Elderly; Dementia; Functional assessment; Geriatric; Positrons emission tomography