Título

RETINAL NEURONAL LOSS DETECTED BY SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY AND ITS CORRELATION WITH COGNITIVE CHANGES IN PATIENTS WITH MILD COGNITIVE IMPAIRMENT

Introdução / Purpose

Mild cognitive impairment (MCI) is a clinical condition in which subjects present memory loss that greater than expected for their age but not enough to impair their daily activities. Many authors consider MCI an early stage of Alzheimer disease (AD). Peripapillary RNFL and macular thickness measurements using OCT may turn out to be a non-invasive in vivo marker in both MCI and AD patients. Our purpose was to evaluate the ability of swept-source OCT (SS-OCT) estimate retinal neural loss in eyes of patients with MCI and to assess the relationship between the cognitive impairment and SS-OCT measurements is such patients.

Material e Método / Methods

SS-OCT scans were obtained in 40 eyes of 20 patients with MCI and 40 control eyes. Peripapillary RNFL, macular full-thickness and segmented inner layers thickness parameters were calculated. The Mini-Mental State Examination (MMSE) was used to assess cognition. The two groups were compared and the relationship between MMSE scores and SS-OCT measurements in MCI
patients was verified.

Resultados / Results

All full-thickness macular measurements were smaller in MCI eyes when compared to controls, but only reached significant difference in the temporal inner and outer and the inferior inner segments. Macular RNFL and GCL++ thickness measurements, were also significantly reduced in MCI eyes. A significant correlation was found between most SS-OCT parameters and the MMSE score.

Discussão e Conclusões / Discussion

Our results suggests that macular thickness measurements reduction, mostly in the inner retinal layers, obtained by the SS-OCT reflect a neural loss in MCI patients with similar pattern of impairment that was already demonstrated in patients with AD, suggesting that neuronal loss in both conditions are pathophysiologically related. Moreover, such neuronal loss was well correlated with the cognitive impairment in MCI patients. Our results suggest that SS-OCT could be a potentially useful diagnostic tool in the management of MCI patients.

Palavras Chave

Mild cognitive impairment; Alzheimer disease; swept-source OCT; cognitive impairment; retinal layers; ganglion cell layer.