Individual electromagnetic profiles for the prediction of episodic memory change in early stages of dementia: Developing topics. (7th December 2020)

• Record Type: Journal Article
• Authors: Colomo, Alejandra García; Sanz, David López; Nebreda, Alberto; de Frutos, Jaisalmer; Fernández, Ricardo Bruña; Losada, María Luisa Delgado; Higes, Ramón López; Maestú, Fernando
• Is Part Of: Alzheimer's & dementia. Volume 16(2020)Supplement 5
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-07
• Subjects: Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1002/alz.047457
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Background: Recent literature defines Alzheimer's disease (AD) as a continuum consisting of three differentiated stages, preclinical, prodromal and dementia, in which the progressive neurological deterioration gives rise to a growing cognitive decline. According to this idea, presenting subjective cognitive decline (SCD), on its own or in association with a diagnosable mild cognitive impairment (MCI), increases the risk of developing AD‐related dementia in the following years. AD is usually described as a disconnection syndrome. Studies performed with magnetoencephalography (MEG) and diffusion weighted imaging (DWI) have shown alterations in patterns of functional connectivity, power spectrum, fractional anisotropy, and mean diffusivity even in the initial stages of the disease. These patterns could constitute an early biomarker, and thus allow for an early diagnosis and, hopefully, treatment. The main purpose of this study is to determine which, if any, MEG and DWI variables allow for an early differentiation of subjects with SCD or MCI who will show a worse cognitive evolution. Method: We studied 64 Spanish individuals (age 71, 44 ± 4, 74), fourteen of which were diagnosed with MCI. The remaining 50 participants did not exhibit any objective neuropsychological impairment, but presented subjective cognitive complaints and were thus categorised as SCD. Participants were followed longitudinally and evaluated at two points in time approximately 3 years apart. All participants underwent a neuropsychological evaluation, a MEG scan, and a magnetic resonance imaging scan. From these scans, we calculated: functional connectivity, power spectrums, fractional anisotropy, and mean diffusivity values. The resulting values were used as predictors of the cognitive change experienced in episodic memory by means of a stepwise general linear model. Result: We found an optimal predictive model (R2 = 0, 500; p < 0, 01) consisting of variables such as the alpha power in the left inferior parietal lobe (β = 15, 387) and the mean diffusivity of the left cingulate part of the cingulum bundle (β = 149, 720). Conclusion: This region and tract have been previously reported to play a role in episodic memory, supporting the evidence that their functional or structural affectation could be an early marker of neuronal deterioration and disease progression.