Abstract
BackgroundTo investigate to what extent Alzheimer's Disease (AD) affects Resting State activity, the possible impairment of independent electrophysiological parameters was determined in Eye-open and Eye-closed Conditions. Specifically, Flash-Visual Evoked Potential (F-VEP) and quantitative EEG (q-EEG) were examined to establish whether abnormalities of the former were systematically associated with changes of the latter.MethodsConcurrently recorded F-VEP and q-EEG were comparatively analysed under Eye-open and Eye-closed Conditions in 11 Controls and 19 AD patients presenting a normal Pattern-Visual Evoked Potential (P-VEP). Between Condition differences in latencies of P2 component were matched to variations in spectral components of q-EEG.ResultsP2 latency increased in 10 AD patients with Abnormal Latency (AD-AL) under Eye-closed Condition. In these patients reduction of alpha activity joined an increased delta power so that their spectral profile equated that recorded under Eye-open Condition. On the opposite, in Controls as well as in AD patients with Normal P2 Latency (AD-NL) spectral profiles recorded under Eye-open and Eye-closed Conditions significantly differed from each other. At the baseline, under Eye-open Condition, the spectra overlapped each other in the three Groups.ConclusionUnder Eye-closed Condition AD patients may present a significant change in both F-VEP latency and EEG rhythm modulation. The presence of concurrent changes of independent parameters suggests that the neurodegenerative process can impair a control system active in Eye-closed Condition which the electrophysiological parameters depend upon. F-VEP can be viewed as a reliable marker of such impairment.
Highlights
To investigate to what extent Alzheimer's Disease (AD) affects Resting State activity, the possible impairment of independent electrophysiological parameters was determined in Eye-open and Eye-closed Conditions
Some data derived from analysis of Flash-Visual Evoked Potential (F-Visual Evoked Potentials (VEPs)) and quantitative-EEG (q-EEG) frequency spectra seem to support this assumption
As defined by DSM-IV, had to meet the following criteria: a) diagnosis of Probable AD according to the definition of NINCDSADRDA [20]; b) degree of cooperation sufficient to carry out a Pattern-Visual Evoked Potential (P-VEP) sequence
Summary
To investigate to what extent Alzheimer's Disease (AD) affects Resting State activity, the possible impairment of independent electrophysiological parameters was determined in Eye-open and Eye-closed Conditions. Flash-Visual Evoked Potential (F-VEP) and quantitative EEG (q-EEG) were examined to establish whether abnormalities of the former were systematically associated with changes of the latter. It has been reported that in Resting State [1], Eye-open and Eye-closed Conditions correspond to distinct patterns of activation [2,3,4], outlining different corticosubcortical network systems [5]. In normal Conditions the two modalities are independent from each other and present a different behaviour in Resting State. F-VEP latency, measured at its P2 component peak, does not differ when moving from Eye-open to Eye-closed Condition [8] whereas EEG activity does, as established since Berger's first observation (1929). AD is characterized by a reduction of normal dominant posterior EEG rhythm (for reviews see [13,14,15]) with a significant decrease of alpha power [16,17] in Eye-closed Rest State
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
