Spectral Analysis of EEG in Familial Alzheimer's Disease with E280A Presenilin-1 Mutation Gene

Abstract

To evaluate the hypothesis that quantitative EEG (qEEG) analysis is susceptible to detect early functional changes in familial Alzheimer's disease (AD) preclinical stages. Three groups of subjects were selected from five extended families with hereditary AD: a Probable AD group (18 subjects), an asymptomatic carrier (ACr) group (21 subjects), with the mutation but without any clinical symptoms of dementia, and a normal group of 18 healthy subjects. In order to reveal significant differences in the spectral parameter, the Mahalanobis distance (D (2)) was calculated between groups. To evaluate the diagnostic efficiency of this statistic D (2), the ROC models were used. The ROC curve was summarized by accuracy index and standard deviation. The D (2) using the parameters of the energy in the fast frequency bands shows accurate discrimination between normal and ACr groups (area ROC = 0.89) and between AD probable and ACr groups (area ROC = 0.91). This is more significant in temporal regions. Theses parameters could be affected before the onset of the disease, even when cognitive disturbance is not clinically evident. Spectral EEG parameter could be firstly used to evaluate subjects with E280A Presenilin-1 mutation without impairment in cognitive function.

Figure 1

Averaged spectral power in the three groups. In y-axis are represented the values of the logarithm of the spectrum for each value of frequencies and derivation.

Figure 2

Histograms of D ² calculated for the Z log spectra of the narrow band model. The x-axis shows the values of the Mahalanobis distance for each subjects. Y-axis shows the observed frequencies (number of subjects).

Figure 3

Histograms of D ² for Z log spectral values in two regions of the three groups. In x-axis are represent the values of Mahalanobis distance for each subject. y-axis represents the observed frequencies.

Figure 4

Histograms of D ² calculated in (a) slow (delta theta) and (b) fast (alpha beta) frequencies for all regions of the three groups. The x-axis shows the values of the Mahalanobis distance for each subjects. Y-axis shows the observed frequencies (number of subjects).