Biomedical subjects

Andréa Deslandes

Publications and source records attributed to Andréa Deslandes.

7 recordsLinked to original sources

PubMed2007

Effects of caffeine on electrophysiological and neuropsychological indices after sleep deprivation.

Caffeine is regarded as a central nervous system (CNS) stimulant. The goal of this study was to analyze electrophysiological, motor, cognitive and behavioral changes produced by caffeine ingestion after sleep deprivation. Ten subjects were evaluated after sleep deprivation, comparing the ingestion of either 400 mg of caffeine or placebo, in a double-blind randomized study. The variables analyzed were: quantitative EEG, the event-related potential (ERP-P300) and cognitive responses. The most significant quantitative EEG results, which were characterized by moment x treatment interactions, were seen in alpha and theta relative power variables. A significant decrease in relative alpha and theta was observed in the caffeine group after sleep deprivation. In relation to caffeine stimulant effects, there were no significant differences in the other parameters.

Adult↗

PubMed2006

The relation between EEG prefrontal asymmetry and subjective feelings of mood following 24 hours of sleep deprivation.

Several studies have investigated the relationship between asymmetrical EEG activity over the frontal cortex and mood. This study aimed at investigating the association between state fluctuations in frontal alpha EEG asymmetry and state changes followed by 24 h of sleep deprivation (SD). Our results show that sleep deprivation caused a significant alteration in the asymmetry values. Activation shifted from the left hemisphere, before SD, to the right hemisphere, after SD, in all frontal electrode pairs. In addition, according to the self-rating scale of SD-related mood effects, subjects became significantly less alerted and active, and sleepier. According to these results, increased right prefrontal activation might be potentially associated with the negative mood states typically seen after sleep deprivation, although the causal relationship is still uncertain. However, more studies will be necessary to establish the viability of EEG asymmetry and the cerebral lateralization hypothesis to explain the SD-related affective changes.

Adult↗

PubMed2006

Electroencephalographic changes after one night of sleep deprivation.

Total or partial sleep deprivation (SD) causes degrading effects on different cognitive and psychomotor functions that might be related to electrophysiological changes frequently observed. In the present study, we investigated the effects of one night of sleep deprivation on waking EEG. Experimental protocol consisted of recording electroencephalographic data from eleven healthy young subjects before (baseline) and after (time 2) one night of sleep deprivation. A natural log transformation was carried out and showed a significant increase in theta T6 (p=0.041), O2 (p=0.018) and OZ (p=0.028); and delta T6 (p=0.043) relative power; and a decrease in alpha Fp1 (p=0.040), F3 (p=0.013), Fp2 (p=0.033), T4 (p=0.050), T6 (p=0.018), O2 (p=0.011) and Oz (p=0.025) and beta (p=0.022) absolute power. These outcomes show that the EEG power spectra, after sleep deprivation, exhibit site-specific differences in particular frequency bands and corroborate for the premise of local aspects of brain adaptation after sleep deprivation, rather than global.

Adult↗

PubMed2005

[Neuromodulatory effects of caffeine and bromazepam on visual event-related potential (P300): a comparative study].

UNLABELLED: The P300 component of the event-related potential (ERP) is a general measurement of "cognitive efficiency". It is an index of the ability of an individual's central nervous system (CNS) to process incoming information. OBJECTIVE: To compare the neuromodulatory effects of caffeine and bromazepam on the visual ERP (P300), in relation to a P300 normative database. METHOD: 15 right-handed individuals (7 male and 8 female), between 20 and 30 years of age, healthy, free of any cognitive impairment and not making use of psychoactive substances were studied. Participants were submitted to a visual discrimination task, which employed the "oddball" paradigm, after the administration of caffeine and bromazepam, in a randomized, double-blind design. RESULTS: Statistically significant differences were observed when the caffeine and bromazepam conditions were compared to the normative database. CONCLUSION: The present results suggest that caffeine and bromazepam have distinct modulatory effects on CNS functioning.

Adult↗

PubMed2004

Visual event-related potential (P300): a normative study.

UNLABELLED: The P300 component of the Event-Related Potential (ERP) is a general measurement of "cognitive efficiency". It is an index of the ability of an individual's Central Nervous System (CNS) to process incoming information. OBJECTIVE: To develop a normative database for the visual P300. METHODOLOGY: 30 right-handed individuals (same number of each sex), between 20 and 30 years of age, healthy, free of any cognitive impairment and not making use of psychoactive substances. Participants were submitted to a visual discrimination task, which employed the "oddball" paradigm. RESULTS: The expected scalp distribution trend was seen for latency but not for amplitude values. CONCLUSION: A high variability of latency and amplitude values was observed across the age span. Mean reaction time for the entire sample of the study was 391.56 +/- 37.03 ms.

Adult↗

PubMed2004

Quantitative electroencephalography (qEEG) to discriminate primary degenerative dementia from major depressive disorder (depression).

Electroencephalography (EEG) can be a valuable technique to assess electrophysiological changes related to dementia. In patients suspected of having dementia, the EEG is often quite informative. The sensitivity of the EEG to detect correlates of psychiatric disorders has been enhanced by means of quantitative methods of analysis (quantitative EEG). Quantitative features are extracted from, at least, 2 minutes of artifact-free, eyes closed, resting EEG, log-transformed to obtain Gaussianity, age-regressed, and Z-transformed relative to population norms (Neurometrics database). Using a subset of quantitative EEG (qEEG) features, forward stepwise discriminant analyses are used to construct classifier functions. Along this vein, the main objective of this experiment is to distinguish profiles of qEEG, which differentiate depressive from demented patients (n = 125). The results showed that demented patients present deviations above the control group in variables associated to slow rhythms: Normed Monopolar Relative Power Theta for Cz and Normed Bipolar Relative Power Theta for Head. On the other hand, the deviation below the control group occurs with the variable associated to alpha rhythm: Normed Monopolar Relative Power Alpha for P3, in dementia. Using this method, the present investigation demonstrated high discriminant accuracy in separating Primary Degenerative Dementia from Major Depressive Disorder (Depression).

Aged↗

PubMed2003

Neurocortical electrical activity tomography in chronic schizophrenics.

Functional imaging of brain electrical activity was performed in 25 chronic medicated schizophrenics and 40 controls, analyzing the classical frequency bands (delta, theta, alpha, and beta) of 19-channel EEG during resting state to identify brain regions with deviant activity of different functional significances, using LORETA (Low Resolution Tomography) and SPM99 (Statistical Parametric Mapping). Patients differed from controls due to an excess of slow activity comprising delta + theta frequency bands (inhibitory pattern) located at the right middle frontal gyrus, right inferior frontal gyrus, and right insula, as well as at the bilateral anterior cingulum with a left preponderance. The high temporal resolution of EEG enables the specification of the deviations not only as an excess or a deficit of brain electrical activity, but also as inhibitory (delta, theta), normal (alpha), and excitatory (beta) activities. These deviations point out to an impaired functional brain state consisting of inhibited frontal and prefrontal areas that may result in inadequate treatment of externally or internally generated information.

Adult↗