[How far reaches earliness of optical coherence tomography in cognitive impairment]

Alzheimer's 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.

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).

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).

Optical coherence tomography could be a future biomarker and support tool to facilitate the early diagnosis of cognitive impairment and AD.