RESUMO
Alzheimer's disease (AD) is the main cause of dementia worldwide, which implies an important socioeconomic problem in developed countries. Efforts to find biomarkers to diagnose AD have been intensified, especially, to detect cognitive impairment in its early stages, also known as mild cognitive impairment (MCI). Besides, there are individuals referring memory loss that is unnoticeable in the family environment and presenting normal neuropsychological tests. The former patients are included in a clinical picture that has been recently called subjective memory complaints (SMC). To achieve an early diagnosis, optical coherence tomography (OCT) has been used to measure macular thickness in patients diagnosed with MCI (supported by neuropsychological tests) and SMC (not based on neuropsychological battery). Statistically significant differences have been found in the macular thickness of the control group (274.96 ± 17.61 µm) and for both MCI (259.48 ± 22.39 µm) and SMC (261.45 ± 24.26 µm) patients. In the near future, OCT could become a reliable biomarker and a useful tool for AD screening as well as for the monitoring of the cognitive impairment associated with AD.
RESUMO
Introducción. La enfermedad de Alzheimer (EA) es la primera causa de demencia mundial. Cada vez son más los esfuerzos para lograr una detección temprana del deterioro cognitivo y surgen en el panorama científico entidades diagnósticas como el deterioro cognitivo leve (DCL) y las quejas subjetivas de memoria (QSM). Debido a ello, aparecen numerosos biomarcadores estudiados para conseguir dicho objetivo, entre ellos la tomografía de coherencia óptica. Sujetos y métodos. Se ha realizado un estudio que utiliza la tomografía de coherencia óptica para medir el grosor macular y la capa de fibras nerviosas de la retina en pacientes diagnosticados de EA (n = 36), pacientes con DCL (n = 33), en individuos con QSM (n = 24) y en sujetos control (n = 45). Resultados. Se han encontrado diferencias estadísticamente significativas en cuanto al grosor macular entre todos los grupos estudiados (QSM: 261,8 ± 25,88 μm; DCL: 259,19 ± 22,582 μm; EA leve: 258,53 ± 14,804 μm; EA moderada: 249,32 ± 18,467 μm) y sujetos control (271,96 ± 15,57 μm). Respecto a la capa de fibras nerviosas de la retina, ocurre de igual manera, y la diferencia es estadísticamente significativa frente al grupo control (94,51 ± 9,203 μm) de todos los grupos (QSM: 90,44 ± 9,059 μm; DCL: 89,4 ± 10,421 μm; EA leve: 87,12 ± 10,279 μm; EA moderada: 82,25 ± 10,636 μm). Conclusión. La tomografía de coherencia óptica podría situarse como un futuro biomarcador y una herramienta de apoyo para facilitar el diagnóstico precoz del deterioro cognitivo y de la EA (AU)
Introduction. Alzheimers disease (AD) is the leading cause of dementia in the world today. Increasingly greater efforts are being made to be able to detect cognitive impairment in earlier stages, and diagnostic entities such as mild cognitive impairment (MCI) and subjective memory complaints (SMC) are appearing. The number of biomarkers studied with the aim of reaching this goal continues to rise, and include optical coherence tomography. Subjects and methods. The study conducted employed optical coherence tomography to measure the macular thickness and the retinal nerve fibre layer in patients diagnosed with AD (n = 36), in patients with MCI (n = 33), in individuals with SMC (n = 24) and in control subjects (n = 45). Results. Statistically significant differences have been found in terms of the macular thickness among all the groups studied (SMC: 261.8 ± 25.88 μm; MCI: 259.19 ± 22.582 μm; mild AD: 258.53 ± 14.804 μm; moderate AD: 249.32 ± 18.467 μm) and control subjects (271.96 ± 15.57 μm). The same occurs as regards the retinal nerve fibre layer and the difference is statistically significant compared with the control group (94.51 ± 9.203 μm) of all the groups (SMC: 90.44 ± 9.059 μm; MCI: 89.4 ± 10.421 μm; mild AD: 87.12 ± 10.279 μm; moderate AD: 82.25 ± 10.636 μm). Conclusion. Optical coherence tomography could be a future biomarker and support tool to facilitate the early diagnosis of cognitive impairment and AD (AU)
