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Conversion of mild cognitive impairment patients in Alzheimer's disease: prognostic value of Alpha3/Alpha2 electroencephalographic rhythms power ratio.

Moretti DV - Alzheimers Res Ther (2015)

Bottom Line: In the higher alpha3/alpha2 frequency power ratio group, greater memory impairment was correlated with greater cortical atrophy and lower perfusional rate in the temporo-parietal cortex.High EEG upper/low alpha power ratio was associated with cortical thinning and lower perfusion in the temporo-parietal lobe.Moreover, atrophy and lower perfusion rate were both significantly correlated with memory impairment in MCI subjects.

View Article: PubMed Central - PubMed

Affiliation: Alzheimer' Disease Rehabilitation Unit, IRCCS S. Giovanni di Dio Fatebenefratelli, Brescia, Italy. davide.moretti@afar.it.

ABSTRACT

Introduction: The increase in electroencephalogram (EEG) alpha3/alpha2 frequency power ratio has been demonstrated as a biomarker characteristic of subjects with mild cognitive impairment (MCI) who will develop Alzheimer's disease (AD).

Methods: Seventy-four adult subjects with MCI underwent clinical and neuropsychological evaluation, EEG recording, and high-resolution 3D magnetic resonance imaging (MRI). This group has been evaluated after a three years follow-up. Twenty-seven of these subjects underwent perfusion single-photon emission computed tomography (SPECT) evaluation also. Increasing alpha3/alpha2 power ratio, was computed for each subject. Differences in EEG markers, cortical thickness, brain perfusion among the groups were estimated.

Results: In the higher alpha3/alpha2 frequency power ratio group, greater memory impairment was correlated with greater cortical atrophy and lower perfusional rate in the temporo-parietal cortex. After a follow-up of three years, these patients converted in AD.

Conclusion: High EEG upper/low alpha power ratio was associated with cortical thinning and lower perfusion in the temporo-parietal lobe. Moreover, atrophy and lower perfusion rate were both significantly correlated with memory impairment in MCI subjects. The increase of EEG upper/low alpha frequency power ratio could be useful for identifying individuals at risk for progression to AD dementia and may be of value in the clinical context.

No MeSH data available.


Related in: MedlinePlus

Discriminant factor analysis results: root1 vs root2 (see text for details)
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Fig5: Discriminant factor analysis results: root1 vs root2 (see text for details)

Mentions: The results of discriminant factor analysis show a statistically significant result for the model (F30,185 = 11.16; p < 0.00001; Wilks Lambda 0.04). A correct classification of groups was performed in the 85 % of cases in the first group, in the 94 % in the second group, and in the 86 % in the third group. The mean correct percentage of correct classification was 88.3 %. Based on the model structure, the variables accepted, ordered for statistical significance, were: theta/gamma frequency ratio (p < 0.0003) and alpha3/alpha2 frequency ratio (p < 0.03). EEG markers, together with duration of disease, were the most powerful variables in discriminating groups. The canonical analysis shows that the variables accepted were arranged in two discriminant functions (or roots). The two roots were all statistically significant (root1, p < 0.0001, root2, p < 0.001). Figure 5 shows a scatterplot of canonical scores (root1 vs. root2). The factor loadings of the variables on each discriminant function, as addressed by the factor structure matrix, shows that in root1 the theta/gamma relative power ratio has positive (0.5), and alpha3/alpha2 relative power ratio has negative, correlations (−0.7) whereas in root2 the theta/gamma relative power ratio has negative, (−0.6) and alpha3/alpha2 relative power ratio has positive (0.8), correlations with the discriminant function. As a consequence, an increase of theta/gamma relative power ratio better identifies the third group, and the increase of alpha3/alpha2 relative power ratio better identifies especially the second group.Fig. 5


Conversion of mild cognitive impairment patients in Alzheimer's disease: prognostic value of Alpha3/Alpha2 electroencephalographic rhythms power ratio.

Moretti DV - Alzheimers Res Ther (2015)

Discriminant factor analysis results: root1 vs root2 (see text for details)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4696332&req=5

Fig5: Discriminant factor analysis results: root1 vs root2 (see text for details)
Mentions: The results of discriminant factor analysis show a statistically significant result for the model (F30,185 = 11.16; p < 0.00001; Wilks Lambda 0.04). A correct classification of groups was performed in the 85 % of cases in the first group, in the 94 % in the second group, and in the 86 % in the third group. The mean correct percentage of correct classification was 88.3 %. Based on the model structure, the variables accepted, ordered for statistical significance, were: theta/gamma frequency ratio (p < 0.0003) and alpha3/alpha2 frequency ratio (p < 0.03). EEG markers, together with duration of disease, were the most powerful variables in discriminating groups. The canonical analysis shows that the variables accepted were arranged in two discriminant functions (or roots). The two roots were all statistically significant (root1, p < 0.0001, root2, p < 0.001). Figure 5 shows a scatterplot of canonical scores (root1 vs. root2). The factor loadings of the variables on each discriminant function, as addressed by the factor structure matrix, shows that in root1 the theta/gamma relative power ratio has positive (0.5), and alpha3/alpha2 relative power ratio has negative, correlations (−0.7) whereas in root2 the theta/gamma relative power ratio has negative, (−0.6) and alpha3/alpha2 relative power ratio has positive (0.8), correlations with the discriminant function. As a consequence, an increase of theta/gamma relative power ratio better identifies the third group, and the increase of alpha3/alpha2 relative power ratio better identifies especially the second group.Fig. 5

Bottom Line: In the higher alpha3/alpha2 frequency power ratio group, greater memory impairment was correlated with greater cortical atrophy and lower perfusional rate in the temporo-parietal cortex.High EEG upper/low alpha power ratio was associated with cortical thinning and lower perfusion in the temporo-parietal lobe.Moreover, atrophy and lower perfusion rate were both significantly correlated with memory impairment in MCI subjects.

View Article: PubMed Central - PubMed

Affiliation: Alzheimer' Disease Rehabilitation Unit, IRCCS S. Giovanni di Dio Fatebenefratelli, Brescia, Italy. davide.moretti@afar.it.

ABSTRACT

Introduction: The increase in electroencephalogram (EEG) alpha3/alpha2 frequency power ratio has been demonstrated as a biomarker characteristic of subjects with mild cognitive impairment (MCI) who will develop Alzheimer's disease (AD).

Methods: Seventy-four adult subjects with MCI underwent clinical and neuropsychological evaluation, EEG recording, and high-resolution 3D magnetic resonance imaging (MRI). This group has been evaluated after a three years follow-up. Twenty-seven of these subjects underwent perfusion single-photon emission computed tomography (SPECT) evaluation also. Increasing alpha3/alpha2 power ratio, was computed for each subject. Differences in EEG markers, cortical thickness, brain perfusion among the groups were estimated.

Results: In the higher alpha3/alpha2 frequency power ratio group, greater memory impairment was correlated with greater cortical atrophy and lower perfusional rate in the temporo-parietal cortex. After a follow-up of three years, these patients converted in AD.

Conclusion: High EEG upper/low alpha power ratio was associated with cortical thinning and lower perfusion in the temporo-parietal lobe. Moreover, atrophy and lower perfusion rate were both significantly correlated with memory impairment in MCI subjects. The increase of EEG upper/low alpha frequency power ratio could be useful for identifying individuals at risk for progression to AD dementia and may be of value in the clinical context.

No MeSH data available.


Related in: MedlinePlus